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IBM BC-201 Network Router User Manual

1. r 37x5 z Local site Without yw STUN T1 serial link aaa Remote 7 zi site P g g g aw ee 4z _ zzz IBM 3x78 terminals Workstation IBM mainframe yD 37x5 Workstation xy Local r Va Ethernet site Cp ZE With STUN T1 serial link E xa CoA Ethernet e T orkstation 3x74 go D IBM 3x78 terminals 2075 mi Cisco 10S Bridging and IBM Netw orking Configuration Guide 78 11737 02 Overview of IBM Networking LLC2 and SDLC Parameters Wi BSTUN Netw orks The Bisync feature enables your Cisco 2500 3600 4000 4500 4700 and 7200 series router to support devices that use the Bisync data link protocol This protocol enables enterprises to transport Bisync traffic over the same network that supports their SNA and multiprotocol traffic eliminating the need for separate Bisync facilities At the access router traffic from the attached Bisync device is encapsulated in IP The Bisync traffic can then be routed across arbitrary media to the host site where another router supporting Bisync will remove the IP encapsulation headers and present the Bisync traffic to the Bisync host or controller over a serial connection HDLC can be used as an alternative encapsulation method for point to point links BSTUN Features S The Cisco implementation of BSTUN provides the following features Encapsulates Bisync Adplex ADT Security Systems Inc Diebold as
2. X 25 S3028 As shown in Figure 93 any devices in the SNA communication path that use X 25 whether end systems or intermediate systems require a QLLC implementation Figure 93 SNA Devices Running QLLC Running QLLC Running QLLC 3029 As shown in Figure 94 the QLLC conversion feature eliminates the need to install the X 25 software on local IBM equipment A device attached locally to a Token Ring network can communicate through a router running the QLLC Conversion feature with a remote device attached to an X 25 network using QLLC Typically the locally attached device is an FEP an AS 400 or a PS 2 and the remote device is a terminal controller or a PS 2 In this case only the remote device needs an X 25 interface and the FEP can communicate with the terminal controller as if it were directly attached via a Token Ring network Figure 94 Router Running QLLC Conversion Feature Running QLLC 9 _ eee Token 2 s Z 7 l y Ring 8 D 2 z More elaborate configurations are possible The router that implements QLLC conversion need not be on the same Token Ring network as the FEP As shown in Figure 95 QLLC LLC2 conversion is possible even when an intermediate IP WAN exists between the router connected to the X 25 network and the router connected to the Token Ring Cisco IOS Bridging and IBM Netw orking Configuration Guide PBC 220 E 78 11737 02 Overview of IBM Networking IBM Network Media Translation W
3. s X 25 interface as a virtual Token Ring so that the X 25 virtual circuit appears to the Token Ring device and to the router itself as if it were a Token Ring to which the remote X 25 device is attached Also in this figure the LLC2 connection extends from the 37x5 FEP across the Token Ring network to the router The QLLC X 25 session extends from the router across the X 25 network to the 3x74 cluster controller Only the SNA session extends across the Token Ring and X 25 networks to provide an end to end connection from the 37x5 FEP to the 3x74 cluster controller As Figure 97 shows a router need not directly connect the two IBM end nodes instead some type of backbone WAN can connect them Here RSRB transports packets between Router A and Router B while Router B performs all conversion between the LLC2 and X 25 protocols Only the router attached to the serial line Router B needs to be configured for QLLC conversion Both Router A and Router B are configured for normal RSRB Cisco 10S Bridging and IBM Networking Configuration Guide ere J BC 221 Overview of IBM Networking HZ IBM Network Media Translation Figure 97 QLLC Conversion Between a Single 37x5 and Multiple 3x74s across an Arbitrary WAN Without local 3270 acknowledgment lt _ LLC2 session gt lt QLLC X 25 session gt With local ee LLC2 session gt lt TCP session lt x QLLC X 25 session acknowledgment i i NRI
4. Dynamic CP name generation offers the ability to use the Cisco IOS hostname as the SNA CP name or to generate a CP name from an IP address These facilities reuse one SNASw configuration across many routers and eliminate the specific configuration coordination previously required to configure a unique CP name for each SNA node in the network Administrators can still explicitly configure the CP name within the SNASw configuration Dynamic SNA BTU Size Most SNA node implementations require specific tuning of the SNA basic transmit unit BTU in the configuration SNASw analyzes the interface maximum transfer units MTUs of the interfaces it uses and dynamically assigns the best MTU values for that specific port For served dependent PU 2 0 devices SNASw uses the downstream MAXDATA value from the host and dynamically sets the SNA BTU for that device to the MAXDATA value DLUR Connect Out amp SNASw can receive connect out instructions from the IBM Communications Server for S 390 This function allows the system to dynamically connect out to devices that are configured on the host with the appropriate connect out definitions This feature allows connectivity to SNA devices in the network that were traditionally configured for connect out from the host Note DLUR connect out can be performed over any supported data link type Responsive M ode Adaptive Rate Based Flow Control Early HPR implementations failed to perform well in envir
5. Figure95 QLLC Conversion Running on a Router with an Intermediate IP Network a X 25 QLLC session _ gt S TCP session gt lt LLC2 session gt jpa i u RSRB E 3 P Router A Router B The Cisco Implementation of QLLC Conversion SNA uses QLLC and X 25 as link layer protocols to provide a reliable connection QLLC itself processes QLLC control packets In a Token Ring environment SNA uses LLC to provide a reliable connection The LAN to X 25 LNX software provides a QLLC conversion function to translate between LLC and QLLC Figure 96 shows the simplest QLLC conversion topology a single Token Ring device for example a 37x5 FEP communicates with a single remote X 25 device in this case a 3x74 cluster controller In this example a router connects the Token Ring network to the X 25 network Figure 96 QLLC Conversion Between a Single 37x5 and a Single 3x74 lt LLC2 session gt lt QLLC X 25 session _ gt Cae oy Ring Scns 37x5 y Router phe 3x74 3270 Oo lt SNA session gt z In Figure 96 each IBM end node has no indication that its counterpart is connected to a different medium running a different protocol The 37x5 FEP responds as if the 3x74 cluster controller were communicating over a Token Ring whereas the 3x74 responds as though the 37x5 FEP were communicating over an X 25 network This is accomplished by configuring the router
6. and Token Ring X 25 SMDS and T1 T3 using TCP IP encapsulation Because TCP IP encapsulation is used you can use any of the Cisco routing protocols to route the packets Copies frames to destinations based on address STUN in passthrough mode does not modify the frames in any way or participate in SDLC windowing or resending these functions are left to the communicating hosts However STUN in local acknowledgment mode does participate in SDLC windowing and resending through local termination of the SDLC session Ensures reliable sending of data across serial media having minimal or predictable time delays With the advent of STUN and WAN backbones serial links now can be separated by wide geographic distances spanning countries and continents As a result these serial links have time delays that are longer than SDLC allows for bidirectional communication between hosts The STUN local acknowledgment feature addresses the problems of unpredictable time delays multiple resending or loss of sessions Allows for configuration of redundant links to provide transport paths if part of the network goes down Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 g Bc 213 Overview of IBM Networking ME STUN and BSTUN Figure 90 shows the difference between an IBM network with STUN and one without STUN Figure 90 IBM Network Configuration without STUN and with STUN Workstation Ethernet IBM mainframe
7. gt lt LLC2 session gt lt LLC session gt 1107a lt SNA session gt With local acknowledgment for LLC2 enabled in both routers Router A acknowledges frames received from the 37x5 The 37x5 still operates as if the acknowledgments it receives are from the 3x74 Router A looks like the 3x74 to the 37x5 Similarly Router B acknowledges frames received from the 3x74 The Cisco 10S Bridging and IBM Networking Configuration Guide BC 208 78 11737 02 Overview of IBM Networking DLSw W 3x74 operates as if the acknowledgments it receives are from the 37x5 Router B looks like the 3x74 to 37x5 Because the frames do not have to travel the WAN backbone networks to be acknowledged but are locally acknowledged by routers the end machines do not time out resulting in no loss of sessions Enabling local acknowledgment for LLC2 has the following advantages Local acknowledgment for LLC2 solves the T1 timer problem without having to change any configuration on the end nodes The end nodes are unaware that the sessions are locally acknowledged In networks consisting of hundreds or even thousands of machines this is a definite advantage All the frames acknowledged by the Cisco IOS software appear to the end hosts to be coming from the remote IBM machine In fact by looking at a trace from a protocol analyzer one cannot say whether a frame was acknowledged by the local router o
8. CMPC chapter in this publication Cisco 10S Bridging and IBM Networking Configuration Guide BC 246 78 11737 02 Overview of IBM Networking CMCC Adapter Features for SNA Environments W CMCC Adapter Features for SNA Environments Cisco SNA The Cisco IOS software supports the following features for CMCC adapters in SNA environments Cisco SNA page 247 Cisco Multipath Channel page 248 TN3270 Server page 248 The CSNA feature provides support for SNA protocols to the IBM mainframe from Cisco 7500 Cisco 7200 and Cisco 7000 with RSP7000 series routers using CMCC adapters over both ESCON and parallel interfaces As an IBM 3172 replacement a CMCC adapter in a Cisco router supports the External Communications Adapter XCA feature of the Virtual Telecommunications Access Method VTAM Support for the XCA feature allows VTAM to define the CMCC s Token Ring devices as switched devices XCA support also allows the CMCC adapter to provide an alternative to FEPs at sites where the NCP is not required for SNA routing functions The CSNA feature supports communication between a channel attached mainframe and the following types of devices attached to a LAN or WAN PU 2 0 SNA node PU 2 1 SNA node PU 5 4 SNA node CSNA also supports communication between two mainframes running VTAM that are either channel attached to the same CMCC adapter card or channel attached to different CMCC adapter cards The CSNA fe
9. Differences Between the CIP and CPA Table 4 illustrates the differences between the CMCC adapters Table 4 Differences Between the CIP and the CPA Product Differences CIP ECPA PCPA Router platform Cisco 7500 Cisco 7200 Cisco 7200 Cisco 7000 with RSP7000 Channel interfaces ESCON Parallel ESCON Parallel Maximum number of interfaces 2 1 1 Maximum memory 128 MB 32 MB 32 MB Cisco IOS release support Cisco IOS Release 10 2 Cisco IOS Cisco IOS and later Release 11 3 3 T and later Release 11 3 3 T and later Virtual port number 0 0 Channel interface state tracking HSRP SNMP alerts Yes Disabled Use the state tracks signal command to enable Disabled Use the state tracks signal command to enable Cisco IOS Bridging and IBM Networking Configuration Guide BC 244 78 11737 02 Overview of IBM Networking CMCC Adapter Features for TCP IP Environments W Supported Environments The Cisco IOS software supports the following environments and features on the CMCC adapters TCP IP Environments CLAW TCP IP offload IP host backup CMPC and TN3270 server features SNA and APPN Environments CSNA CMPC and TN3270 server features CMCC Adapter Features for TCP IP Environments The Cisco IOS software supports the following features for CMCC adapters in TCP IP environments Common Link Access to Workstation page 245 TCP IP Offload page 245 IP Host Ba
10. NCP to distinguish among SNA devices on the same Cisco 10S Bridging and IBM Networking Configuration Guide 5 224 iE wie Overview of IBM Networking SNAFRAS W permanent virtual circuit Cisco supports SAP multiplexing which allows you to configure unique LLC2 SAPs for each downstream SNA device so that they can share a single permanent virtual circuit to an FEP The Cisco IOS software is responsible for terminating the local data link control frames such as SDLC and Token Ring frames and for modifying the data link control frames to 802 2 compliant LLC frames The LLC provides a reliable connection oriented link layer transport required by SNA For example 802 2 LLC is used to provide link layer acknowledgment sequencing and flow control The Cisco IOS software encapsulates these 802 2 LLC frames according to the RFC 1490 format for SNA traffic The frames are then forwarded to the SNA host on a Frame Relay PVC In the reverse direction the software is responsible for de encapsulating the data from the Frame Relay PVC and for generating and sending the appropriate local data link control frames to the downstream devices RFC 1490 Bridged Format for LLC2 BAN BAN provides functionality similar to BNN except that it uses a bridged frame format as illustrated in Figure 100 Figure 100 RFC 1490 Bridged Frame Format Q 922 address Control 0x03 pad 0x00 NLPID SNAP 0x80 OUI 00x0 OUI 0x80 C2 bridged
11. NetBIOS It complies with the DLSw standard documented in RFC 1795 and the DLSw Version 2 standard DLSw is an alternative to RSRB that addresses several inherent problems that exist in RSRB such as SRB hop count limits SRB s limit is seven e Broadcast traffic including SRB explorer frames or NetBIOS name queries Unnecessary traffic acknowledgments and keepalives Data link control timeouts Cisco IOS Bridging and IBM Networking Configuration Guide BC 204 78 11737 02 Overview of IBM Networking DLSw W This section contains a brief overview of DLSw DLSw Standard page 205 DLSw Version 2 Standard page 205 DLSw Features page 206 DLSw Standard The DLSw standard documented in RFC 1795 defines the switch to switch protocol between DLSw routers The standard also defines a mechanism to terminate data link control connections locally and multiplex the traffic from the data link control connections to a TCP connection The standard always calls for the transport protocol to be TCP and always requires that data link control connections be locally terminated the equivalent of the Cisco local acknowledgment option The standard also requires that the SRB RIF be terminated at the DLSw router The standard describes a means for prioritization and flow control and defines error recovery procedures that ensure data link control connections are appropriately disabled if any part of their associated circuits bre
12. PID 0x00 09 pad 0x00 Frame control Destination source MAC 12 bytes DSAP SSAP Control SNA data N PCS 5 wo Because it includes the MAC header information in every frame BAN supports multiple SNA devices sharing a single permanent virtual circuit without requiring SAP multiplexing BAN also supports load balancing across duplicate data link connection identifiers to the same or different front end processors at the data center to enhance overall availability BAN works for devices attached by either Token Ring or Ethernet Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 B 8C 225 Overview of IBM Networking E NCIA NCIA NCIA I NCIA Server Native Client Interface Architecture NCIA is a new software architecture introduced by Cisco to make accessing IBM SNA applications over routed internetworks more scalable and flexible NCIA is a component of the Cisco IOS software The architecture is intended to combine the benefits of the native SNA interface at end stations and mainframes with those of TCP IP across the network backbone NCIA extends the use of the TCP IP protocol all the way to the SNA end station Because of the wide range of media supported by TCP IP including dialup telephone lines for remotely located users NCIA makes multiprotocol access to corporate backbone networks much more flexible for SNA users NCIA allows SNA end stations such as PCs or wo
13. SDLC frames in either the Transmission Control Protocol Internet Protocol TCP IP or the HDLC protocol Allows two devices using SDLC or HDLC compliant protocols that are normally connected by a direct serial link to be connected through one or more Cisco routers reducing leased line costs When you replace direct serial links with routers serial frames can be propagated over arbitrary media and topologies to another router with a STUN link to an appropriate endpoint The intervening network is not restricted to STUN traffic but rather is multiprotocol For example instead of running parallel backbones for DECnet and SNA SDLC traffic this traffic now can be integrated into an enterprise backbone network Supports local acknowledgment for direct Frame Relay connectivity between routers without requiring TCP IP Cisco 10S Bridging and IBM Networking Configuration Guide PBC 212 E 78 11737 02 Overview of IBM Networking STUN andBSTUN W Allows networks with IBM mainframes and communications controllers to share data using Cisco routers and existing network links As an SDLC function STUN fully supports the IBM SNA and allows IBM SDLC frames to be sent across the network media and shared serial links illustrates a typical network configuration without STUN and the same network configured with STUN Encapsulates SDLC frame traffic packets and routes them over any of the supported network media serial FDDI Ethernet
14. TCP connection between two routers with local acknowledgment enabled LLC2 is an ISO standard data link level protocol used in Token Ring networks LLC2 was designed to provide reliable sending of data across LAN media and to cause minimal or at least predictable time delays However RSRB and WAN backbones created LANs that are separated by wide geographic distances spanning countries and continents As a result LANs have time delays that are longer than LLC2 allows for bidirectional communication between hosts Local acknowledgment addresses the problem of unpredictable time delays multiple resending and loss of user sessions In a typical LLC2 session when one host sends a frame to another host the sending host expects the receiving host to respond positively or negatively in a predefined period of time commonly called the T time If the sending host does not receive an acknowledgment of the frame it sent within the T1 time it retries a few times normally 8 to 10 If there is still no response the sending host drops the session 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking E DLSw Figure 86 illustrates an LLC2 session in which a 37x5 on a LAN segment communicates with a 3x74 on a different LAN segment separated via a wide area backbone network Frames are transported between Router A and Router B by means of DLSw However the LLC2 session between the 37x5 and the
15. between passthrough mode and local acknowledgment mode The upper half of Figure 89 shows STUN configured in passthrough mode In passthrough mode the routers act as a wire and the SDLC session remains between the end stations In this mode STUN provides a straight passthrough of all SDLC traffic including control frames The lower half of Figure 89 shows STUN configured in local acknowledgment mode In local acknowledgment mode the routers terminate the SDLC sessions and send only data across the WAN Control frames no longer travel the WAN backbone networks 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking ME STUN and BSTUN Figure 89 Comparison of STUN in Passthrough Mode and Local Acknowledgment Mode oe Ss 8 lt SNA session gt SDLC session Se _ lt TCP session _ gt ii i i 37x5 EA lt e IBM 1 l y SDLC session gt SDLC session _ lt SNA session gt 2 Note To enable STUN local acknowledgment you first enable the routers for STUN and configure them to appear on the network as primary or secondary SDLC nodes TCP IP encapsulation must be enabled The Cisco STUN local acknowledgment feature also provides priority queueing for TCP encapsulated frames STUN Features The Cisco STUN implementation provides the following features Encapsulates
16. function on the 3172 Interconnect Controller Model 3 but with increased performance For details about configuring a CMCC adapter for TCP IP offload see the Configuring CLAW and TCP IP Offload Support chapter in this publication 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking HI CMCC Adapter Features for TCP IP Environments IP Host Backup You can connect multiple mainframes to a single CMCC adapter using an ESCON director Often these mainframes run using the ESCON Multiple Image Facility EMIF which permits the physical machine to be divided into multiple logical partitions LPARs By defining an unused partition on another mainframe a user can move the operating system from a failed mainframe or mainframe partition to the unused partition By having multiple paths to each device the move is accomplished without changing the mainframe software This function also permits moving an IP stack between multiple operating system images On the CMCC adapter each IP connection is treated as a physical device The CMCC adapter does not support multiple active paths to a single IP connection or device Prior to IP Host Backup the router configuration had to be changed whenever the mainframe operating system was moved from one mainframe or LPAR to another The IP Host Backup feature permits the mainframe operating system to be moved from one mainframe to another withou
17. is connected is configured with SDLLC The routers communicate via RSRB using direct encapsulation RSRB over an FST connection or RSRB over a TCP connection SDLLC with RSRB and local acknowledgment A 37x5 FEP on a Token Ring and a 3x74 cluster controller connected to a serial line are connected to different routers Only the device to which the 3x74 is connected is configured with SDLLC The routers communicate via RSRB over a TCP connection that has local acknowledgment enabled In all these topologies each IBM end node the FEP and cluster controller has no indication that its counterpart is connected to a different medium running a different protocol The 37x5 FEP responds as if the 3x74 cluster controller were communicating over a Token Ring whereas the 3x74 responds as though the 37x5 FEP were communicating over a serial line That is the SDLLC software makes translation between the two media transparent to the end nodes Virtual Token Ring Concept Central to the Cisco SDLLC feature is the concept of a virtual Token Ring device residing on a virtual Token Ring Because the Token Ring device expects the node with which it is communicating also to be on a Token Ring each SDLLC device on a serial line must be assigned an SDLLC virtual Token Ring address SDLLC VTRA Like real Token Ring addresses SDLLC VTRAs must be unique across the network In addition to the SDLLC VTRA an SDLLC virtual ring number must be assigned to each SD
18. link services interface CLSI to communicate with other software modules in the router such as SNASw DLSw and DSPU and acts as the data intermediary between them and NCIA clients The NCIA server s role as an intermediary is transparent to the client Figure 101 NCIA Server Client Server Model SNASw DLSw DLSw local switch DSPU SNA SSeS SS LLC2 NCIA server RSRB NCIA client Ethernet Token Ring TCP IP TCP IP A D io NDLC NCIA Data Link Control NDLC is the protocol used between clients and servers NDLC serves two purposes Establishes the peer connection Establishes the circuit between the client and the server The peer session must be established before an end to end circuit can be set up During the set up period for the peer session the MAC address representing a client is defined The MAC address can be defined by the client or by the server when the client does not have a MAC address The NCIA Server feature supports connect in and connect out from the server s perspective but connect out is not supported if the client station does not listen for the incoming connection For a server to connect out clients must connect to the server first After registering itself by providing its own MAC address the client can then optionally disconnect from the server When a server receives an explorer and its destinati
19. lt SNA LU6 2 Cisco IOS Bridging and IBM Networking Configuration Guide ere E BC 241 Overview of IBM Networking ME CMCC Adapter Hardware For a TCP IP host connection the router with CTRC routes the DRDA packets over TCP IP without protocol changes To use this TCP IP passthrough feature of CTRC the host database version must support direct TCP IP access Figure 111 illustrates such a configuration Figure 111 Cisco Router Configured with the CTRC Feature for DB2 Communications TCP IP Host Network ODBC client a RDBMS J 5 g TCP IP CTRC TCP IP 27133 DRDA server DBS database When configured for DB2 communications on a router the CTRC feature enables desktop applications to access data in remote databases located on IBM hosts CTRC receives database access messages from the client over a TCP IP link CTRC either converts the messages to SNA and sends them to the host using APPC services provided by the Cisco SNA Switching Services or routes the client messages to the TCP IP enabled host without protocol changes Benefits of CTRC CTRC provides TCP IP end users and servers with fast reliable and secure access to IBM DB2 databases using the SNA protocol CTRC replaces expensive and hard to manage UNIX and NT gateways for database access CTRC lets Windows or UNIX client applications call CICS transactions without requiring changes to the client or host software In addition CTRC provides Cisc
20. meaningless so the virtual MAC address represents just one session and is defined as part of the X 25 configuration Because one physical X 25 interface can support many simultaneous connections for many different remote devices you only need one physical link to the X 25 network The different connections on different virtual circuits all use the same physical link The most significant difference between QLLC conversion and SDLLC is the fact that a typical SDLC SDLLC operation uses a leased line In SDLC dial up connections are possible but the maximum data rate is limited In QLLC both switched virtual circuits SVCs and permanent virtual circuits PVCs are available but the favored use is SVC While the router maintains a permanent connection to the X 25 network a remote device can use each SVC for some bounded period of time and then relinquish it for use by another device Using a PVC is very much like using a leased line Cisco IOS Bridging and IBM Networking Configuration Guide ca 78 11737 02 Overview of IBM Networking SNAFRAS W Table 3 shows how the QLLC commands correspond to the SDLLC commands Table 3 QLLC and SDLLC Command Comparison QLLC Command Analogous SDLLC Command qllc largest packet sdllc ring largest frame sdllc sdlc largest frame qllc partner sdllc partner qllc sap sdllc sap qlic srb x25 map qlic x25 pve qllic sdllc traddr qlic xid sdllc xid source bridge qllic local ack
21. other APPN nodes in the network CMPC can be used in conjunction with DLSw RSRB SR TLB SRB SDLLC QLLC ATM LAN emulation and FRAS host to provide connectivity to VTAM CMPC supports connections to PU 2 1 nodes APPN NN APPN EN and LEN Subarea connections are not supported The CMPC feature can coexist with the CLAW TCP IP Offload CSNA CMPC and TN3270 server features on the same CMCC adapter For details about configuring a CMCC adapter for CMPC see the Configuring CSNA and CMPC chapter of this guide TN 3270 Server TN3270 communications in a TCP IP network consist of the following basic elements TN3270 client Emulates a 3270 display device for communication with a mainframe application through a TN3270 server over an IP network The client can support the standard TN3270 functions as defined by RFC 1576 or the enhanced functionality provided by TN3270E defined in RFC 2355 TN3270 clients are available on a variety of operating system platforms TN3270 server Converts the client TN3270 data stream to SNA 3270 and transfers the data to and from the mainframe e Mainframe Provides the application for the TN3270 client and communicates with the TN3270 server using VTAM Cisco IOS Bridging and IBM Networking Configuration Guide BC 248 78 11737 02 Overview of IBM Networking SNA Functions CMCC Adapter Features for SNA Environments W The TN3270 server feature offers an attractive soluti
22. protocol data across a TCP IP network to a mainframe ALPS provides connectivity between agent set control units ASCUs and a mainframe host that runs the airline reservation system Figure 104 shows the basic ALPS topology and the protocols implemented in the feature Three major components provide the end to end transportation of airline protocol traffic across the network the P1024B Airline Control ALC or P1024C UTS protocol the TCP IP based MATIP protocol conversion and the TCP IP access to the mainframe Cisco IOS Bridging and IBM Networking Configuration Guide ere E BC 229 Overview of IBM Networking HE DSPU and SNA Service Point Figure 104 ALPS Architecture router LEE t y ASCUs running ALC or UTS Mainframe with airline reservation system XP amp F 25065 ASCUs running ALC or UTS Network Remote management system router The Cisco ALPS feature provides an end to end solution for airlines and central reservation systems The ALPS feature is integrated in the Cisco IOS software and allows airlines to replace their existing hardware and software with Cisco routers For customers who already use Cisco routers this feature allows them to consolidate networking overhead and functionality DSPU and SNA Service Point Downstream physical unit DSPU is a software feature that enables the router to function as a PU concentrator for SNA PU type 2 nodes PU concentration at the device simplifies the
23. protocols to a Frame Relay format understood by the Network Control Program NCP that runs in an FEP The Cisco IOS software and the NCP support two frame formats RFC 1490 routed format for LLC2 specified in the FRF 3 Agreement from the Frame Relay Forum and known in NCP literature as Frame Relay Boundary Network Node BNN support Support for this feature requires NCP 7 1 or higher e RFC 1490 802 5 source route bridged format known in NCP literature as Frame Relay Boundary Access Node BAN support Support for this feature requires NCP 7 3 or higher 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking E SNA FRAS Management service point support in FRAS allows the SNA network management application NetView to manage Cisco routers over the Frame Relay network as if it were an SNA downstream PU FRAS provides dial backup over RSRB in case the Frame Relay network is down While the backup Public Switched Telephone Network PSTN is being used the Frame Relay connection is tried periodically As soon as the Frame Relay network is up it will be used This section contains a brief overview of SNA FRAS which is described in the following topics RFC 1490 Routed Format for LLC2 BNN page 224 RFC 1490 Bridged Format for LLC2 BAN page 225 RFC 1490 Routed Format for LLC2 BNN 2 RFC 1490 specifies a standard method of encapsulating multiprotocol traffic with dat
24. task of PU definition at the upstream host while providing additional flexibility and mobility for downstream PU devices The DSPU feature allows you to define downstream PU type 2 devices in the Cisco IOS software DSPU reduces the complexity of host configuration by letting you replace multiple PU definitions that represent each downstream device with one PU definition that represents the router Because you define the downstream PUs at the router rather than the host you isolate the host from changes in the downstream network topology Therefore you can insert and remove downstream PUs from the network without making any changes on the host The concentration of downstream PUs at the router also reduces network traffic on the WAN by limiting the number of sessions that must be established and maintained with the host The termination of downstream sessions at the router ensures that idle session traffic does not appear on the WAN SNA service point support in the Cisco IOS software assumes that NetView or an equivalent product is available at the SNA host The user interacts with the network management feature in the router and at the SNA host In the Cisco IOS software you can configure the host connection and show the status of this connection At the SNA host you can use the NetView operator s console to view alerts and to send and receive Cisco syntax commands to the Cisco device Cisco 10S Bridging and IBM Networking Configuration G
25. the need for a separate front end processor FEP The only differences between CMCC software applications running on the CIP and a CPA are performance and capacity The performance difference is based upon differences in the internal bus architecture of a CIP and a CPA and the capacity difference is based on the difference in maximum memory configurations 128 MB for CIP and 32 MB for CPA For more information about differences between the CIP and CPA see the Differences Between the CIP and CPA section on page 244 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking ME CMCC Adapter Hardware The Cisco 7200 series router supports online insertion and removal OIR which allows you to install or remove port adapters while the system is operating Note In this chapter references to Channel Port Adapter CPA correspond to both the ECPA and the PCPA Refer to the Cisco 7200 Series Port Adapter Hardware Configuration Guidelines publication for more details ESCON Channel Port Adapter An ECPA is classified as a high speed port adapter providing a single ESCON physical channel interface Current Cisco 7200 configuration guidelines recommend using no more than three high speed port adapters in a single Cisco 7200 router Parallel Channel Port Adapter A PCPA provides a single parallel channel physical interface supporting 3 0 or 4 5 Mbps data transfer rates
26. 2 parameters for the local Token Ring interfaces can affect overall performance Refer to the chapter Configuring LLC2 and SDLC Parameters in this manual for more details about fine tuning your network through the LLC2 parameters The routers at each end of the LLC2 session execute the full LLC2 protocol which could result in some overhead The decision to use local acknowledgment for LLC2 should be based on the speed of the backbone network in relation to the Token Ring speed For LAN segments separated by slow speed serial links for example 56 kbps the T1 timer problem could occur more frequently In such cases it might be wise to turn on local acknowledgment for LLC2 For LAN segments separated by a T1 backbone delays will be minimal in such cases FST or direct should be considered Speed mismatch between the LAN segments and the backbone network is one criterion to help you decide to use local acknowledgment for LLC2 There are some situations such as the receiving host failing between the time the sending host sends data and the time the receiving host receives it in which the sending host would determine at the LLC2 layer that data was received when it actually was not This error occurs because the router acknowledges that it received data from the sending host before it determines that the receiving host can actually receive the data But because both NetBIOS and SNA have error recovery in situations where an end device goes dow
27. 3x74 is still end to end that is every frame generated by the 37x5 traverses the backbone network to the 3x74 and the 3x74 on receipt of the frame acknowledges it Figure 86 LLC2 Session Without Local Acknowledgment jokey Be B lt LLC2 session gt 1106a lt SNA session gt On backbone networks consisting of slow serial links the T1 timer on end hosts could expire before the frames reach the remote hosts causing the end host to resend Resending results in duplicate frames reaching the remote host at the same time as the first frame reaches the remote host Such frame duplication breaks the LLC2 protocol resulting in the loss of sessions between the two IBM machines One way to solve this time delay is to increase the timeout value on the end nodes to account for the maximum transit time between the two end machines However in networks consisting of hundreds or even thousands of nodes every machine would need to be reconfigured with new values With local acknowledgment for LLC2 enabled the LLC2 session between the two end nodes would not be not end to end but instead would terminate at two local routers Figure 87 shows the LLC2 session with the 37x5 ending at Router A and the LLC2 session with the 3x74 ending at Router B Both Router A and Router B execute the full LLC2 protocol as part of local acknowledgment for LLC2 Figure 87 LLC2 Session with Local Acknowledgment lt TCP session
28. A Routing Services HPR Capable SNA Routing Services SNASw provides the following SNA routing functions Routes SNA sessions between clients and target SNA data hosts Controls SNA traffic in a multiprotocol environment in conjunction with other Cisco IOS quality of service QoS features Supports networks with a high proportion of SNA traffic and multiple enterprise servers especially those that continue to support the traditional SNA endstation platform and new client types Supports all types of SNA application traffic including traditional 3270 and peer LU 6 2 Supports an OS 390 Parallel Sysplex configuration working in conjunction with the IBM Communications Server for S 390 formerly VTAM and the MVS Workload Manager to provide higher availability in the data center using the High Performance Routing HPR feature Supports System Services Control Point SSCP services to downstream SNA devices using the Dependent LU Requester DLUR feature Provides dynamic link connectivity using connection networks CNs which eliminates much of the configuration required in networks with numerous data hosts Branch Extender The BEX function enhances scalability and reliability of SNA routing nodes by eliminating topology updates and broadcast directory storms that can cause network instability BEX appears as an NN to downstream EN LEN node and PU devices while also appearing as an EN to upstream devices The BEX fu
29. A Switching Services functionality supersedes all functionality previously available in the APPN feature in the Cisco IOS software SNASw configuration will not accept the previous APPN configuration commands Previous APPN users should use this chapter to configure APPN functionality using the new SNASw commands SNASw provides an easier way to design and implement networks with SNA routing requirements Previously this network design was accomplished using APPN with full network node NN support in the Cisco router This type of support provided the SNA routing functionality needed but was inconsistent with the trends in Enterprise networks today The corporate intranet is replacing the SNA WAN Enterprises are replacing their traditional SNA network with an IP infrastructure that supports traffic from a variety of clients using a variety of protocols requiring access to applications on a variety of platforms including SNA applications on Enterprise servers While SNA routing is still required when multiple servers must be accessed the number of nodes required to perform this function is decreasing as the IP infrastructure grows and as the amount of native SNA traffic in the network decreases SNASw enables an enterprise to develop their IP infrastructure while meeting SNA routing requirements The number of NNs in the network and the amount of broadcast traffic are reduced Configuration is simplified and SNA data traffic can be transpo
30. C2 Local Acknowledgment page 209 DLSw Support for Other SNA Features page 210 DLSw is fully compatible with any vendor s RFC 1795 implementation and the following features are available when both peers are using DLSw Peer groups and border peers Backup peers Promiscuous and on demand peers Explorer firewalls and location learning NetBIOS dial on demand routing feature support UDP unicast support Load balancing Support for LLC1 circuits Support for multiple bridge groups Support for RIF Passthru SNA type of service feature support Local acknowledgment for Ethernet attached devices and media conversion for SNA PU 2 1 and PU 2 0 devices Conversion between LLC2 to SDLC between PU 4 devices Local or remote media conversion between LANs and either the SDLC Protocol or QLLC SNA View Blue Maps and Internetwork Status Monitor ISM support MIB enhancements that allow DLSw features to be managed by the CiscoWorks Blue products SNA Maps and SNA View Also new traps alert network management stations of peer or circuit failures For more information refer to the current Cisco IOS release note for the location of the Cisco MIB website Local Acknowledgment When you have LANs separated by wide geographic distances and you want to avoid multiple resending or loss of user sessions that can occur with time delays encapsulate the source route bridged traffic inside IP datagrams passed over a
31. CP IP N J SNA Cisco 7200 ESCON or parallel series with CPA m D Channel 1 0 Z Channel Interface Processor The CIP for the Cisco 7000 with RSP7000 and Cisco 7500 series routers is designed for high end network environments that demand high performance high port density and high capacity solutions The CIP provides support for IBM ESCON and bus and tag parallel channel attachment using the following types of interfaces ESCON Channel Adapter ECA Parallel Channel Adapter PCA A single CIP can support up to two physical channel interfaces in any combination of either PCA or ECA Each CIP is pre configured with the appropriate channel adapters at manufacturing time The Cisco 7000 with RSP7000 and Cisco 7500 series routers support online insertion and removal OIR which allows you to install or remove CIPs while the system is operating Channel Port Adapter The CPA is available for the Cisco 7200 series routers The CPA expands the value of the Cisco IBM channel solution by providing channel connectivity to mid range mainframe configurations The CPA is a standard single width port adapter that provides support for IBM ESCON and bus and tag parallel channel attachment using the following types of interfaces ESCON Channel Port Adapter ECPA Parallel Channel Port Adapter PCPA Each CPA provides a single channel interface with a single I O connector for Cisco 7200 series routers In some situations this eliminates
32. LLC device on a serial line The SDLLC virtual ring number differs from the virtual ring group numbers that are used to configure RSRB and multiport bridging Cisco 10S Bridging and IBM Networking Configuration Guide BC 218 78 11737 02 Overview of IBM Networking IBM Network Media Translation W As part of its virtual telecommunications access method VTAM configuration the IBM node on the Token Ring has knowledge of the SDLLC VTRA of the serial device with which it communicates The SDLC VTRA and the SDLLC virtual ring number are a part of the SDLLC configuration for the router s serial interface When the Token Ring host sends out explorer packets with the SDLLC VTRA as the destination address in the MAC headers the router configured with that SDLLC VTRA intercepts the frame fills in the SDLLC virtual ring number address and the bridge number in the RIF then sends the response back to the Token Ring host A route is then established between the Token Ring host and the router After the Cisco IOS software performs the appropriate frame conversion the system uses this route to forward frames to the serial device Resolving Differences in LLC2 and SDLC Frame Size IBM nodes on Token Ring media normally use frame sizes greater than 1 KB whereas the IBM nodes on serial lines normally limit frame sizes to 265 or 521 bytes To reduce traffic on backbone networks and provide better performance Token Ring nodes should send frames tha
33. OS Bridging and IBM Networking Configuration Guide PBC 250 E 78 11737 02
34. Overview of IBM Networking The IBM networking technologies described in this publication can be categorized as network related or host related technologies The IBM Networking section of the Cisco IOS Bridging and IBM Networking Configuration Guide discusses the following network related software components RSRB page 202 DLSwe page 204 STUN and BSTUN page 211 LLC2 and SDLC Parameters page 215 IBM Network Media Translation page 217 SNA FRAS page 223 NCIA page 226 ALPS page 229 The IBM Networking section of the Cisco IOS Bridging and IBM Networking Configuration Guide discusses the following host related software and hardware components DSPU and SNA Service Point page 230 SNA Switching Services page 232 Cisco Transaction Connection page 239 CMCC Adapter Hardware page 242 The following Cisco IOS software features are supported on the CMCC adapters Common Link Access to Workstation page 245 TCP IP Offload page 245 IP Host Backup page 246 Cisco Multipath Channel page 246 Cisco SNA page 247 Cisco Multipath Channel page 248 TN3270 Server page 248 This overview chapter gives a high level description of each technology For configuration information refer to the corresponding chapters in this publication 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking HE RSRB RSRB Note All commands supported on the Cisco 7500 series rou
35. Simplicity By placing all SNA routers in the data center few SNA routers are required and they can be easily configured using virtually identical configurations Improved Availability By adding Cisco unique capabilities to connect out and distribute traffic across multiple ports access to resources is improved and traffic can be distributed across multiple ports Additionally by supporting the newest HPR Adaptive Rate Based ARB flow control algorithm bandwidth management for SNA traffic is improved Increased Management Capabilities Two new traces interprocess and data link provide an easier way to view SNASw activity The APPN Trap MIB allows the user to notify the operator in event of a debilitating problem Console message archiving provides better tracking of network activity The ability to format traces in a format so that they are readable by other management products simplify network management because results are more readily available Architectural Compliance Even though SNASw is easier to use and SNASw networks are easier to design SNASw interfaces with SNA implementations on the market upstream NNs end nodes ENs low entry networking LEN nodes and PU 2 0 It also provides full DLUR support to allow dependent PU and LU traffic to flow over the APPN network to SNA data hosts Cisco IOS Bridging and IBM Networking Configuration Guide 78 11737 02 E EC 233 Overview of IBM Networking E HPR Capable SN
36. TCP IP The Cisco router with CTRC exists in the TCP IP network and clients use a CTRC IP address and port on the router to connect to the IBM host system that exists in either an SNA network or a TCP IP network When CTRC is appropriately configured on a router client based ODBC applications can connect to the following IBM D2 relational databases DB2 for OS 390 MVS DB2 for Virtual Machine VM SQL DS DB2 for Virtual Storage Extended VSE SQL DS DB2 for OS 400 DB2 Universal Database UNIX Windows OS 2 For an SNA host connection the router with CTRC converts DRDA packets over TCP IP to DRDA packets over APPC LU 6 2 and then routes them to DB2 databases CTRC runs as a TCP IP daemon on the router accepting DRDA client connections over TCP IP When a client connects to the database on an IBM mainframe host CTRC allocates an APPC conversation over SNA to an IBM server and acts as a gateway between DRDA over TCP IP and DRDA over APPC Figure 110 illustrates how the Cisco router configured with the CTRC feature enables the exchange of database information between ODBC client applications running DRDA in a TCP IP network and a DRDA based IBM system that accesses DB2 relational data Figure 110 Cisco Router Configured with the CTRC Feature for DB2 Communications SNA Host Network ODBC client DRDA server RDBMS rr J G E g OTRE i DB2 database TCP IP gt SNA SNA TCP IP APPC 26076 i TCP IP
37. Token TO e eeu x n 5 Virtual Router A E Router B ring How communication sessions are established over the communication link varies depending on whether or not LLC2 local acknowledgment has been configured on Router A s Token Ring interface In both cases the SNA session extends end to end and the QLLC X 25 session extends from Router B to the 3x74 cluster controller If LLC2 local acknowledgment has not been configured the LLC2 session extends from the 37x5 FEP across the Token Ring network and the arbitrary WAN to Router B In contrast when LLC2 local acknowledgment has been configured the LLC2 session extends from the 37x5 FEP Router A where it is locally terminated A TCP session is then used across the arbitrary WAN to Router B Comparing QLLC Conversion to SDLLC Although the procedures you use to configure QLLC are similar to those used to configure SDLLC there are structural and philosophical differences between the point to point links that SDLC uses and the multiplexed virtual circuits that X 25 uses The most significant structural difference between QLLC conversion and SDLLC is the addressing To allow a device to use LLC2 to transfer data both SDLLC and QLLC provide virtual MAC addresses In SDLLC the actual MAC address is built by combining the defined virtual MAC whose last byte is 0x00 with the secondary address used on the SDLC link in this way SDLLC supports multidrop In QLLC conversion multidrop is
38. a link Level 2 of the OSI model framing The encapsulation for SNA data is specified in the FRF 3 Agreement The Frame Relay encapsulation method is based on the RFC 1490 frame format for user defined protocols using Q 933 NLPID as illustrated in Figure 98 Figure 98 Frame Relay Encapsulation Based on RFC 1490 DLCI Control NLPID L2 L3 DSAP Control F Q 922 0x30 Q 933 Protocol ID Protocol ID SSAP C jz address 0x08 0x4c 802 2 0x08 S z The protocol ID for SNA subarea FID4 is 0x81 The protocol ID for SNA subarea FID2 is 0x82 The protocol ID for APPN FID2 is 0x83 FRAS allows the router acting as a FRAD to take advantage of the SNA BNN support for Frame Relay provided by ACF NCP 7 1 and OS 400 V2R3 Downstream PU 2 0 and PU 2 1 devices can be attached to the router through SDLC Token Ring or Ethernet links The router acting as a FRAD is connected to the Network Control Program NCP or AS 400 through a public or private Frame Relay network as illustrated in Figure 99 Figure99 SNA BNN Support for Frame Relay a Frame Relay The frame format that communicates across the Frame Relay BNN link is defined in RFC 1490 for routed SNA traffic From the perspective of the SNA host for example an NCP or AS 400 the Frame Relay connection is defined as a switched resource similar to a Token Ring BNN link Because the frame format does not include link addresses to allow the
39. aks The DLSw standard does not specify when to establish TCP connections The capabilities exchange allows compliance to the standard but at different levels of support The standard does not specify how to cache learned information about MAC addresses RIFs or NetBIOS names It also does not describe how to track either capable or preferred DLSw partners for either backup or load balancing purposes The standard does not provide the specifics of media conversion but leaves the details up to the implementation It does not define how to map switch congestion to the flow control for data link control Finally the MIB is documented under a separate RFC DLSw Version 2 Standard In the Version 1 standard a network design requires fully meshed connectivity so that all peers were connect to every other peer This design creates unnecessary broadcast traffic because an explorer propagates to every peer for every broadcast The Version 2 standard is documented in RFC 2166 It includes RFC 1795 and adds the following enhancements IP Multicast page 206 UDP Unicast page 206 Enhanced Peer on Demand Routing Feature page 206 Expedited TCP Connection page 206 Users implement DLSw Version 2 for scalability if they are using multivendor DLSw devices with an IP multicast network DLSw Version 2 requires complex planning because it involves configuration changes across an IP network 78 11737 02 Cisco IOS Bridging and IBM Network
40. ams call CICS transactions and the Extended Presentation Interface EPI which lets distributed applications call CICS transactions that were originally accessed via 3270 terminals e CTRC supports the ability to configure routes for CICS transaction Each transaction can be routed to a specific CICS region In addition to its CICS related functionality CTRC includes the feature previously known as Cisco Database Connection CDBC which allows Cisco routers to use IBM s distributed relational database architecture DRDA protocol to provide a gateway between client workstations running Open DataBase Connectivity ODBC compliant applications on TCP IP networks and IBM DB2 databases on SNA networks ODBC is a call level interface developed by Microsoft Corporation that allows a single application to access database management systems from different vendors using a single interface SNA is a large complex feature rich network architecture developed by IBM CTRC adds support for TCP IP passthrough allowing the use of a TCP IP network rather than a SNA network between a Cisco router and a DB2 database if the database version supports direct TCP IP access To match functionality provided in DRDA over TCP IP CTRC adds support for Password Expiration Management PEM in SNA networks where PEM is supported e CTRC supports the following MIBs CISCO DATABASE CONNECTION MIB my 93 CISCO TRANSACTION CONNECTION MIB my 144 For descri
41. ature provides SNA connectivity through a MAC address that is defined on an internal adapter in a CMCC The internal adapter is a virtual adapter that emulates the LAN adapter in an IBM 3172 Interconnect Controller Each internal adapter is defined in a corresponding XCA major node in VTAM which provides an access point LAN gateway to VTAM for SNA network nodes The internal adapter is configured on an internal virtual Token Ring LAN located in the CMCC Each CMCC can be configured with multiple internal Token Ring LANs and internal adapters Each internal Token Ring LAN must be configured to participate in source route bridging to communicate with the LAN devices attached to the router By providing Cisco Link Services CLS and the LLC2 protocol stack on the CMCC adapter card all frames destined to or from the CMCC adapter card are switched by the router The presentation of LAN media types allows the CSNA feature to take advantage of current SRB RSRB DLSw SR TLB internal SDLLC QLLC services and APPN functionality through SNASw The CSNA feature can coexist with the CLAW TCP IP Offload CMPC CMPC and TN3270 server features on the same CMCC adapter For details about configuring a CMCC adapter for CSNA see the Configuring CSNA and CMPC chapter in this publication 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking HI CMCC Adapter Features for SNA Environment
42. ching Services SNASw through a Cisco IOS feature called virtual data link control VDLC LNM over DLSw allows DLSw to be used in Token Ring networks that are managed by IBM s LNM software Using this feature LNM can be used to manage Token Ring LANs control access units and Token Ring attached devices over a DLSw network All management functions continue to operate as they would in a source route bridged network or an RSRB network DSPU over DLSw allows the Cisco DSPU feature to operate in conjunction with DLSw in the same router DLSw can be used either upstream toward the mainframe or downstream away from the mainframe of DSPU DSPU concentration consolidates the appearance of multiple physical units PUs into a single PU appearance to VTAM minimizing memory and cycles in central site resources VTAM NCP and routers and speeding network startup SNA service point over DLSw allows the Cisco SNA service point feature to be used in conjunction with DLSw in the same router Using this feature SNA service point can be configured in remote routers and DLSw can provide the path for the remote service point PU to communicate with NetView This allows full management visibility of resources from a NetView 390 console while concurrently offering the value added features of DLSw in an SNA network SNASw over DLSw allows the Cisco APPN Branch Extender functionality to be used in conjunction with DLSw in the same router With thi
43. ckup page 246 Cisco Multipath Channel page 246 TN3270 Server page 248 Common Link Access to Workstation To transport data between the mainframe and a CMCC adapter in TCP IP environments Cisco IOS software implements the CLAW channel protocol Each CLAW connection requires two devices out of a maximum of 256 Although this allows for a maximum of 128 CLAW connections per interface a maximum of 32 CLAW connections per interface is recommended The CLAW packing feature enables the transport of multiple IP packets in a single channel operation and significantly increases throughput performance between a mainframe and a CMCC adapter Currently IBM s TCP IP stack does not support the CLAW packing feature The CLAW packing feature requires changes to the mainframe CLAW driver support In partnership with Cisco Interlink Computer Science now Sterling Software has made the corresponding CLAW driver change to Cisco IOS for S 390 Release 2 and Interlink TCPaccess 5 2 Customers must make the necessary changes to their host configurations to enable the CLAW packing feature For details about configuring a CMCC adapter for CLAW see the Configuring CLAW and TCP IP Offload Support chapter in this publication TCP IP Offload The Cisco TCP IP offload feature supports IBM s MVS VM and Transaction Processing Facility TPF operating systems The TCP IP offload feature for CMCC adapters delivers the same function as the TCP IP offload
44. e client must also have an LLC2 so that it can handle the LLC2 sessions The NCIA Server feature extends the scalability of NCIA I enhances its functionality and provides support for both the installed base of RSRB routers and the growing number of DLSw routers The NCIA Server feature includes the following enhancements You do not need to configure a ring number on the client You do not need to configure each client on the router The MAC address can be dynamically assigned by the NCIA server running on the router SNA is directly on top of TCP IP LLC2 is no longer required at end station A client is a true end station not a router peer Cisco 10S Bridging and IBM Networking Configuration Guide 5 226 iE wie Overview of IBM Networking NCIA W The NCIA Server communicates with other components in router such as RSRB SNASw DLSw and DSPU Supports both connect in and connect out The NCIA client server model is independent of the upstream implementation It is an efficient protocol between client and server NCIA Client Server M odel The NCIA Server feature uses a client server model see Figure 101 where the NCIA server is a software module on a Cisco router and the NCIA client is a PC or workstation The NCIA server performs two major functions Establishes TCP to NCIA Data Link Control NDLC sessions with clients for the purpose of sending and receiving data Uses the Cisco
45. eparate UDP port numbers allowing the IP network to be configured based on these elements The Cisco IP prioritization technologies such as weighted fair queueing WFQ prioritize the traffic through the IP network EE support on the IBM Communications Server for S 390 allows users to build highly reliable SNA routed networks that run natively over an IP infrastructure directly to the Enterprise servers These network designs reduce points of failure in the network and provide reliable SNA networks Figure 108 illustrates the EE functionality Figure 108 EE Functionality Downstream devices CS 390 PU 2 0 HPR EN HPR SNA switch a z ee A HPR PS LEN lt gt SNA HPR 4 R directly over IP UDP 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide pg Overview of IBM Networking W Usability Features Usability Features SNASw contains the following usability features designed to make SNA networks easier to design and maintain Dynamic CP Name Generation Support page 236 Dynamic SNA BTU Size page 236 DLUR Connect Out page 236 Responsive Mode Adaptive Rate Based Flow Control page 236 User Settable Port Limits page 237 Dynamic CP Name Generation Support When scaling the SNASw function to hundreds or thousands of nodes many network administrators find that defining a unique control point CP name on each node provides unnecessary configuration overhead
46. etworking Configuration Guide gy Overview of IBM Networking E ODLSw Note DLSw As previously stated local acknowledgment for LLC2 is meant only for extreme cases in which communication is not possible otherwise Because the router must maintain a full LLC2 session the number of simultaneous sessions it can support before performance degrades depends on the mix of other protocols and their loads The routers at each end of the LLC2 session execute the full LLC2 protocol which can result in some overhead The decision to turn on local acknowledgment for LLC2 should be based on the speed of the backbone network in relation to the Token Ring speed For LAN segments separated by slow speed serial links for example 56 kbps the T1 timer problem could occur more frequently In such cases it might be wise to turn on local acknowledgment for LLC2 For LAN segments separated by a FDDI backbone backbone delays will be minimal in such cases local acknowledgment for LLC2 should not be turned on Speed mismatch between the LAN segments and the backbone network is one criterion to be used in the decision to use local acknowledgment for LLC2 There are some situations such as host B failing between the time host A sends data and the time host B receives it in which host A would behave as if at the LLC2 layer data was received when it actually was not because the device acknowledges that it received data from host A before it confir
47. guration of multiple MAC addresses which respond to SNA requests over the Cisco 10S Bridging and IBM Networking Configuration Guide BC 238 78 11737 02 Overview of IBM Networking Cisco Transaction Connection W same LAN When using native LAN support SNASw responds only to requests that target the MAC address configured on the local interface Virtual Token Ring and SRB allow SNASw to respond to multiple MAC addresses over the same physical interface Connection to Frame Relay Transport Technologies Virtual Token Ring and SRB connect SNASw toa SNA Frame Relay infrastructure FRAS host and SRB Frame Relay are configured to connect virtual Token Ring interfaces that offer SNASw support for Frame Relay boundary access node BAN or boundary network node BNN technology Connection to Channel Interface Processor and Channel Port Adapter Virtual Token Ring and SRB can be used to connect SNASw to the Channel Interface Processor CIP or Channel Port Adapter CPA in routers that support those interfaces Virtual Data Link Control SNASw uses Virtual Data Link Control VDLC to connect to DLSw transport and local switching technologies VDLC is used for a number of connectivity options including the following two Transport over DLSw Supported Media page 239 DLC Switching Support for Access to SDLC and QLLC page 239 Transport over DLSw Supported M edia Using VDLC SNASw gains full access to the DLSw transport facilit
48. gures the router to communicate with specific modules For data link users such as SNASw DLSw and DSPU the NCIA server can interface to them directly For other data link providers the NCIA server must go through a DLSw local peer to communicate with them The DLSw local peer passes packets back and forth among different data link providers Advantages of the Client Server M odel The client server model used in the NCIA Server feature extends the scalability of NCIA In addition it provides support for both the installed base of RSRB routers and the growing number of DLSw routers Extended Scalability The client server model minimizes the number of central site RSRB or DLSw peer connections required to support a large network of NCIA clients see Figure 102 Rather than each client having a peer connection to a central site router the clients attach to an IP backbone through an NCIA server that in turn has a single peer connection to a central site router This scheme can greatly reduce the number of central site peer connections required For example in a network with 1000 clients and 10 NCIA servers there would be only 10 central site peer connections Note that there would still be 1000 LLC2 connections that must be locally acknowledged at the central site router but this can easily be handled in a single central site router When the number of LLC2 connections or the number of clients is in the tens of thousands NCIA servers ca
49. ies including DLSw transport over IP networks DLSw transport over direct interfaces and DLSw support of direct Frame Relay encapsulation without using IP DLC Switching Support for Access to SDLC and QLLC Through VDLC SNASw gains access to devices connecting through SDLC and QLLC This access allows devices connecting through SDLC and QLLC access to SNASw Native IP Data Link Control HPR IP SNASw support for the EE function provides direct HPR over UDP connectivity This support is configured for any interface that has a configured IP address HPR IP uses the interface IP address as the source address for IP traffic originating from this node Cisco Transaction Connection This section contains the following topics CTRC and CICS page 240 CTRC and DB2 page 241 Benefits of CTRC page 242 Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 B 8C 239 Overview of IBM Networking WE Cisco Transaction Connection The CTRC software feature provides the following functionality CTRC allows Cisco routers to use the intersystem communication ISC protocol to provide a gateway between Customer Information Control System CICS clients also known as common clients running under Windows or UNIX on TCP IP networks and CICS online transaction monitoring systems on IBM hosts e CTRC supports two interfaces to common clients the Extended Call Interface ECI which lets non CICS client progr
50. ing Configuration Guide gy Overview of IBM Networking E ODLSw IP Multicast UDP Unicast Multicast service avoids duplication and excessive bandwidth of broadcast traffic because it replicates and propagates messages to its multicast members only as necessary It reduces the amount of network overhead in the following ways Avoids the need to maintain TCP Switch to Switch Protocol SSP connections between two DLSw peers when no circuits are available Ensures that each broadcast results in only a single explorer over every link DLSw Version 2 is for customers who run a multicast IP network and do not need the advantages of border peering DLSw Version 2 uses UDP unicast in response to a IP multicast When address resolution packets CANUREACH_EX NETBIOS_NQ_ex NETBIOS_ANQ and DATAFRAME are sent to multiple destinations IP multicast service DLSw Version 2 sends the response frames ICANREACH_ex and NAME_RECOGNIZED_ex via UDP unicast Enhanced Peer on Demand Routing Feature DLSw Version 2 establishes TCP connections only when necessary and the TCP connections are brought down when there are no circuits to a DLSw peer for a specified amount of time This method known as peer on demand routing was recently introduced in DLSw Version 2 but has been implemented in Cisco DLSw border peer technology since Cisco IOS Release 10 3 Expedited TCP Connection DLSw Version 2 efficiently establishes TCP connections Previous
51. ly DLSw created two unidirectional TCP connections and then disconnected one after the capabilities exchange took place With DLSw Version 2 a single bidirectional TCP connection establishes if the peer is brought up as a result of an IP multicast UDP unicast information exchange DLSw Features DLSw is the Cisco version of DLSw and it supports several additional features and enhancements DLSw is a means of transporting SNA and NetBIOS traffic over a campus or WAN The end systems can attach to the network over Token Ring Ethernet Synchronous Data Link Control SDLC Protocol Qualified Logical Link Control QLLC or FDDI See the DLSw Design and Implementation Guide Appendix B DLSw Support Matrix for details DLSw switches between diverse media and locally terminates the data links keeping acknowledgments keepalives and polling off the WAN Local termination of data links also eliminates data link control timeouts that can occur during transient network congestion or when rerouting around failed links Finally DLSw provides a mechanism for dynamically searching a network for SNA or NetBIOS resources and includes caching algorithms that minimize broadcast traffic Cisco IOS Bridging and IBM Networking Configuration Guide BC 206 78 11737 02 Overview of IBM Networking DLSw W This section contains information on the following topics related to DLSw features Local Acknowledgment page 207 Notes on Using LL
52. mmunication Parameters such as the maximum number of information frames I frames outstanding before acknowledgment frequency of polls and response time to poll frames can be modified per interface If local acknowledgment is not enabled these parameters are modified on the SDLC interface If local acknowledgment is enabled these parameters are modified on the Token Ring interface Local acknowledgment only applies when the remote peer is defined for RSRB using IP encapsulation over a TCP connection If no local acknowledgment is used the remote peer can be defined for RSRB using direct encapsulation RSRB using IP encapsulation over an FST connection or RSRB using IP encapsulation over a TCP connection 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking IBM Network Media Translation QLLC Conversion Qualified Logical Link Control QLLC is a data link protocol defined by IBM that allows SNA data to be transported across X 25 networks Although IBM has defined other protocols for transporting SNA traffic over an X 25 network QLLC is the most widely used Figure 92 illustrates how QLLC conversion provides data link layer support for SNA communication Figure 92 SNA Data Link Layer Support Upper layers SNA A A y y Data link layer SDLC gt SDLLC lt LLC gt LNX gt QLLC
53. ms that host B can actually receive the data But because both NetBIOS and SNA have error recovery in situations where an end device goes down these higher level protocols will resend any missing or lost data These transaction request confirmation protocols exist above LLC2 so they are not affected by tight timers as is LLC2 They also are transparent to local acknowledgment If you are using NetBIOS applications note that there are two NetBIOS timers one at the link level and one at the next higher level Local acknowledgment for LLC2 is designed to solve session timeouts at the link level only If you are experiencing NetBIOS session timeouts you have two options Experiment with increasing your NetBIOS timers Avoid using NetBIOS applications on slow serial lines In a configuration scenario where RSRB is configured between Router A and Router B and both routers are not routing IP a Host connected to router A through Token Ring or other LAN media has no IP connectivity to router B This restriction exists because IP datagrams received from the Host by Router A are encapsulated and sent to router B where they can only be de encapsulated and source bridged to a Token Ring In this scenario IP routing is recommended To enable the Host to reach Router B in this scenario IP routing should be enabled on Router A s Token Ring interface to which the Host is attached Data Link Switching Plus DLSw is a method of transporting SNA and
54. n these higher level protocols will resend any missing or lost data Because these transaction request confirmation protocols exist above LLC2 they are not affected by tight timers as is LLC2 They also are transparent to local acknowledgment 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide BC 209 Overview of IBM Networking E DLSw L Note If you are using NetBIOS applications note that there are two NetBIOS timers one at the link level and one at the next higher level Local acknowledgment for LLC2 is designed to solve link timeouts only If you are experiencing NetBIOS session timeouts you have two options Experiment with increasing your NetBIOS timers and decreasing your maximum NetBIOS frame size Avoid using NetBIOS applications on slow serial lines By default the Cisco IOS software translates Token Ring LLC2 to Ethernet 802 3 LLC2 To configure the router to translate Token Ring LLC2 frames into Ethernet 0x80d5 format frames refer to the section Enable Token Ring LLC2 to Ethernet Conversion in the Configuring Source Route Bridging chapter of the Cisco IOS Bridging and IBM Networking Command Reference Volume 1 of 2 DLSw Support for Other SNA Features Cisco 10S Bridging and IBM Networking Configuration Guide PBC 210 E 78 11737 02 DLSw can be used as a transport for SNA features such as LAN Network Manager LNM DSPU SNA service point and SNA Swit
55. n take advantage of downstream PU concentration to minimize the number of LLC2 connections that must be supported by the central site routers Figure 102 NCIA Server Provides Extended Scalability to Support Large Networks cy RSRB RSRB ee Eg eee IP Se Token s y backbone y Ring Mainframe with FEP cy 7 NCIA NCIA server client a cy 51914 Cisco 10S Bridging and IBM Networking Configuration Guide BC 228 78 11737 02 Overview of IBM Networking ALPS W Migration Support Using a client server model allows the NCIA Server feature to be independent of the upstream implementation allowing it to be implemented in a network that is still using RSRB and in a DLSw network It also greatly simplifies migration from RSRB to DLSw because it requires no changes at the client A single NCIA server can support either approach but not both As Figure 103 illustrates a central site router can support RSRB and DLSw concurrently allowing a portion of the NCIA servers to communicate using RSRB and another portion to communicate using DLSw Figure 103 NCIA Server Provides Independence from the Upstream Network Implementation Client AL Token ning Disws be serve RSRB DLSw r Toke me IP an i y backbone pali Cisco with FEP RSRB r CD NCIA serve Computing center wd i o Router peers ALPS The Airline Product Set ALPS is a tunneling mechanism that transports airline
56. nction eliminates APPN topology and APPN broadcast search flows between SNASw nodes and the SNA data hosts in the network This feature is key to providing a reliable turn key installation because the network administrator no longer needs to develop in depth knowledge of the level and characteristics of broadcast directory search and topology update traffic in the network Such knowledge and analysis was commonly required to build successful networks utilizing NN technology without BEX SNA Switching Services enables BEX functionality by default SNASw treats all defined links as BEX uplinks and all dynamic links created by stations connecting into SNASw as BEX downlinks No specific configuration is necessary to enable BEX functionality Cisco IOS Bridging and IBM Networking Configuration Guide PBC 234 E 78 11737 02 Overview of IBM Networking Enterprise Extender HPR IP W Figure 107 illustrates the BEX functionality Figure 107 BEX Functionality Downstream devices ua CS 390 A Pa emulate PU 2 0 W EN 7 Ea phy EN n jj an CIP E cs 390 H gt NN o Z LEN CR Enterprise Extender HPR IP SNASw also supports the EE function EE offers SNA HPR support directly over IP networks EE also uses connectionless User Datagram Protocol UDP transport SNA COS and transmission priority are maintained by mapping the transmission priority to the IP precedence and by mapping transmission priority to s
57. nd SDLC package data in frames LLC2 and SDLC stations require acknowledgments from receiving stations after a set amount of frames have been sent before sending further data The tasks described in this chapter modify default settings regarding the control field of the data frames By 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking ME LLC2and SDLC Parameters modifying the control field parameters you can determine the number of acknowledgments sent for frames received and the level of polling used to determine available stations In this manner you can set the amount of resources used for frame checking and optimize the network load SDLC is used as the primary SNA link layer protocol for WAN links SDLC defines two types of network nodes primary and secondary Primary nodes poll secondary nodes in a predetermined order Secondary nodes then send any outgoing data When configured as primary and secondary nodes our routers are established as SDLC stations The Cisco Implementation of LLC2 The Cisco LLC2 implementation supports the following features Local acknowledgment for RSRB This feature is used in our implementation of RSRB as described in the chapter Configuring Source Route Bridging Because LANs are now connected through RSRB and WAN backbones the delays that occur are longer than LLC2 allows for bidirectional communication between hosts Our local ack
58. ne path is used at a given time between the two FST peers A single path greatly decreases the likelihood that frames arrive out of sequence In the rare cases where frames do arrive out of sequence the FST code on the receiving peer discards the out of order frame Thus the Token Ring end hosts rarely lose a frame over the FST router cloud and performance levels remain adequate The same conditions are true for any slow switched topology that provides only a single path for example a single X 25 network cloud between the peers Similarly if two slow switched paths are of very different costs such that one always will be chosen over the other the chances of having frames received out of sequence are also rare However if two or more slow switched paths of equal cost exist between the two routers such as two parallel X 25 networks the routers alternate in sending packets between the two or more equal cost paths This results in a high probability of frames arriving out of sequence at the receiver In such cases the FST code disposes of every out of sequence packet leading to a large number of drops This requires that the end hosts resend frames greatly reducing overall throughput When parallel paths exist we strongly recommend choosing one as the preferred path Choose a preferred path by specifying a higher bandwidth for the path that contains the direct connections to the two or more parallel paths on the router Do not use FST when
59. ng media it is recommended that you do not use RSRB Use SRB instead Refer to the chapter Configuring Source Route Bridging for more information Cisco 10S Bridging and IBM Networking Configuration Guide T BC 202 i A Overview of IBM Networking RSRB W Configuration Considerations Use IP encapsulation only over a TCP connection within complex meshed networks to support connections between peers that are separated by multiple hops and can potentially use multiple paths and where performance is not an issue Use direct encapsulation in point to point connections In a point to point configuration using TCP adds unnecessary processing overhead Multiple peer types however can be combined to in a single router by following the directions for each peer type For example for a peer to support both TCP and FST remote peers you would need to define both a source bridge fst peername and a source bridge remote peer command for the local router using the same local IP address FST is fast switched when it receives or sends frames from Ethernet Token Ring or FDDI interfaces It is also fast switched when it sends and receives from serial interfaces configured with the High Level Data Link Control HDLC encapsulation In all other cases FST is slow switched In cases where FST is fast switched in either the Cisco routers configured for FST or in the routers contained within the IP cloud between a pair of FST peers only o
60. nk layer protocols to provide a reliable connection The translation function between these industry standard protocols takes place in the proprietary Cisco software This section contains a brief overview of IBM Network Media Translation SDLLC Media Translation Features page 218 QLLC Conversion page 220 The Cisco Implementation of QLLC Conversion page 221 Comparing QLLC Conversion to SDLLC page 222 Other Implementation Considerations page 223 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking IBM Network Media Translation Figure 91 illustrates how SDLLC provides data link layer support for SNA communication Figure 91 SNA Data Link Layer Support Upper layers SNA A A y y Data link layer SDLC lt SDLLC lt LLC j gt LNX lt gt QLLC X 25 3028 SDLLC Media Translation Features The SDLLC feature allows a PU 4 PU 2 1 or PU 2 to communicate with a PU 2 SDLC device as follows SDLLC with direct connection A 37x5 front end processor FEP on a Token Ring and the 3x74 cluster controller connected to a serial line are each connected to an interface on the same router configured with SDLLC SDLLC with RSRB A 37x5 FEP on a Token Ring and a 3x74 cluster controller connected to a serial line are connected to different routers Only the device to which the 3x74
61. nowledgment feature addresses the problem of delays resending and loss of user sessions IBM LNM support Routers using 4 or 16 Mbps Token Ring interfaces configured for SRB support Lan Network Manager LNM and provide all IBM bridge program functions With LNM a router appears as an IBM source route bridge and can manage or monitor any connected Token Ring interface LNM support is described in the chapter Configuring Source Route Bridging SDLLC media translation The SDLLC feature provides media translation between the serial lines running SDLC and Token Rings running LLC2 SDLLC consolidates the IBM SNA networks running SDLC into a LAN based multiprotocol multimedia backbone network SDLLC is described in the chapter Configuring IBM Network Media Translation ISO Connection Mode Network Service CMNS The Cisco CMNS implementation runs X 25 packets over LLC2 so that X 25 can be extended to Ethernet FDDI and Token Ring media Cisco IOS Bridging and IBM Networking Configuration Guide PBC 216 E 78 11737 02 Overview of IBM Networking IBM Network Media Translation W The Cisco Implementation of SDLC The Cisco SDLC implementation supports the following features Frame Relay Access Support FRAS With FRAS a router functions as a Frame Relay Access Device FRAD for SDLC Token Ring and Ethernet attached devices over a Frame Relay Boundary Network Node BNN link Frame Relay access support is desc
62. o 7200 and 7500 series routers with the functionality previously available in CDBC which gives ODBC client applications access to data in DB2 databases CM CC Adapter Hardw are A CMCC adapter is installed in a Cisco router to provide IBM channel attachment from the router to a mainframe host The Cisco family of CMCC adapters consists of two basic types of adapters Channel Interface Processor CIP Installed on Cisco 7000 with RSP7000 and Cisco 7500 series routers Channel Port Adapter CPA Installed on Cisco 7200 series routers Each type of adapter CIP or CPA supports both ESCON and parallel channel attachment to the host and can eliminate the need for a separate FEP All CMCC adapters support the full range of channel software applications available in the Cisco IOS software including support for the Common Link Access to Workstation CLAW protocol TCP IP offload IP host backup Cisco SNA CSNA Cisco Multipath Channel CMPC Cisco Multipath Channel CMPC and the TN3270 server Figure 112 shows the type of channel connections and environments supported by the CMCC adapters Cisco IOS Bridging and IBM Networking Configuration Guide T BC 242 UE A Overview of IBM Networking CMCC Adapter Hardware W Figure 112 Cisco Mainframe Channel Connection Adapters 7 oie Channel 1 0 ESCON LPAR1 with CIP rea A p_a Sie channel APPN SNA A sanke 1 1 Bus and Tag APPI APPN HPR TN3270 Y Be
63. on MAC address is registered an NCIA server will connect to that client if it is not connected For NetBIOS explorers addressed to functional address 0xC00000000080 the TCP session must remain up so that the server can broadcast the explorers to the client If the TCP session is down the server will not send the NetBIOS explorers to a client even when the client is registered 78 11737 02 Cisco IOS Bridging and IBM Networking Configuration Guide gy Overview of IBM Networking E NCIA After the peer session has been established the NDLC protocol establishes the circuit between the client and server This circuit is used to transfer end user data between the client and the server Because the client and its target station are not on the same transport they cannot form a direct end to end circuit Each client must form a circuit between the client and server and the server must form another circuit between the server and the target station The server links those two circuits to form an end to end circuit The server acts as a mediator between the client and the target station so that packets can be transferred between them In the NCIA server only peer keepalive is maintained There is no keepalive at circuit level The NCIA server acts as a data link provider like Token Ring or Ethernet in the router It uses CLSI to communicate with other software modules just as other data link providers do The network administrator confi
64. on when the following conditions need to be supported in an SNA environment Maintaining an IP backbone while providing support for SNA 3270 type clients Offloading mainframe CPU cycles when using a TN3270 host TCP IP stack with a TN3270 server Providing support for high session density or high transactions per second The TN3270 server feature on a CMCC adapter card provides mapping between an SNA 3270 host and a TN3270 client connected to a TCP IP network as shown in Figure 113 Functionally itis useful to view the TN3270 server from two different perspectives SNA Functions page 249 Telnet Server Functions page 249 Figure 113 TN3270 Implementation TN3270 server P ts Sg m x TN3270 client lt gt lt gt SNA TCP IP From the perspective of an SNA 3270 host connected to the CMCC adapter the TN3270 server is an SNA device that supports multiple PUs with each PU supporting up to 255 LUs The LU can be Type 1 2 or 3 The SNA host is unaware of the existence of the TCP IP extension on the implementation of these LUs The LUs implemented by the TN3270 server are dependent LUs To route these dependent LU sessions to multiple VTAM hosts connected to the TN3270 server in the CMCC adapter card rather than routing in the VTAM hosts the TN3270 server implements a SNA session switch with EN DLUR function SNA session switching allows you to eliminate SNA subarea routing between hosts of TN3270 traffic by es
65. onments subject to packet loss for example Frame Relay IP transport and performed poorly when combined with other protocols in multiprotocol networks SNASw implements the second generation HPR flow control architecture called Responsive Cisco IOS Bridging and IBM Netw orking Configuration Guide 5 236 i A Overview of IBM Networking ManagementEnhancements W Mode ARB architecture Responsive Mode ARB addresses all the drawbacks of the earlier ARB implementation providing faster ramp up better tolerance of lost frames and better tolerance of multiprotocol traffic User Settable Port Limits SNASw offers full control over the number of devices supported by a specific port The max links configuration on the SNASw port controls the number of devices that are served by this port When the max links limit is reached SNASw no longer responds to test frames attempting to establish new connections SNASw allows load sharing among different SNASw nodes that offer service to the same SNA MAC addresses Management Enhancements SNASw contains the following enhanced tools for managing SNA networks Console Message Archiving page 237 Data Link Tracing page 237 Interprocess Signal Tracing page 237 MIB Support for Advanced Network Management Awareness page 238 Console Message Archiving Messages issued by SNASw are archived in a buffer log that is queried and searched on the console or transferred to a file server for anal
66. ptions of supported MIBs and how to use MIBs see the Cisco MIB website on Cisco com CTRC and CICS CTRC is a Cisco IOS software feature that is available in two environments CICS DB2 When a router is configured to use CTRC for communications with CICS systems the router converts ISC packets over TCP IP to ISC packets over Advanced Program to Program Communications APPC LU 6 2 and then routes them to the appropriate CICS region CTRC converts CICS client messages received via TCP IP to SNA messages and uses Cisco SNA Switching Services to send them to the host CTRC runs as a TCP IP daemon on the router accepting ISC client connections over TCP IP When a client connects to a CICS region on an IBM mainframe host CTRC allocates an APPC conversation over SNA to an IBM server and acts as a gateway between ISC over TCP IP and ISC over APPC Figure 109 illustrates how CTRC lets CICS client applications on TCP IP networks interact with CICS transaction monitoring systems on IBM hosts Cisco IOS Bridging and IBM Networking Configuration Guide BC 240 78 11737 02 Overview of IBM Networking Cisco Transaction Connection W Figure 109 Cisco Router Configured with the CTRC Feature for CICS Communications CICS transaction CICS client monitor I eS lt cTRe 5 TCP IP gt SNA SNA 7 TCP IP APPC S TCP IP lt SNA LU 6 2 N CTRC and DB2 CTRC enables Cisco routers to implement IBM s DRDA over
67. r by a remote IBM machine The MAC addresses and the RIFs generated by the Cisco IOS software are identical to those generated by the remote IBM machine The only way to find out whether a session is locally acknowledged is to use either a show local ack command or a show source bridge command on the router All the supervisory RR RNR REJ frames that are locally acknowledged go no farther than the router Without local acknowledgment for LLC2 every frame traverses the backbone With local acknowledgment only data I frames traverse the backbone resulting in less traffic on the backbone network For installations in which customers pay for the amount of traffic passing through the backbone this could be a definite cost saving measure A simple protocol exists between the two peers to bring up or down a TCP session Notes on Using LLC2 Local Acknowledgment LLC2 local acknowledgment is enabled with TCP and DLSw Lite remote peers If the LLC2 session between the local host and the router terminates in either router the other will be informed to terminate its connection to its local host If the TCP queue length of the connection between the two routers reaches the high water mark the routers sends Receiver Not Ready RNR messages to the local hosts until the queue limit is reduced to below this limit It is possible however to prevent the RNR messages from being sent by using the dlsw llc2 nornr command The configuration of the LLC
68. ribed in the chapter Configuring SNA Frame Relay Access Support SDLLC media translation The SDLLC feature provides media translation between the serial lines running SDLC and Token Rings running LLC2 SDLLC consolidates the IBM SNA networks running SDLC into a LAN based multiprotocol multimedia backbone network SDLLC is described in the chapter Configuring IBM Network Media Translation SDLC local acknowledgment SDLC local acknowledgment is used with SDLC STUN TCP IP must be enabled With local acknowledgment STUN SDLC connections can be terminated locally at the router eliminating the need for acknowledgments to be sent across a WAN SDLC local acknowledgment is described in the section Establish the Frame Encapsulation Method in the chapter Configuring STUN and BSTUN IBM Network Media Translation The Cisco IOS software includes the following media translation features that enable network communications across heterogeneous media SDLLC media translation enables a device on a Token Ring to communicate with a device on a serial link QLLC conversion enables an IBM device to communicate with an X 25 network without having to install the X 25 software on local IBM equipment SDLLC is a Cisco Systems proprietary software feature that enables a device on a Token Ring to communicate with a device on a serial link by translating between LLC2 and SDLC at the link layer SNA uses SDLC and LLC as li
69. rkstations to encapsulate SNA traffic in TCP IP rather than requiring the traffic to travel through routers The first phase of NCIA NCIA I used Cisco RSRB encapsulation The current phase NCIA Server uses a new client server model NCIA Server is not backward compatible to NCIA I This section contains a brief overview of NCIA NCIA I page 226 NCIA Server page 226 Advantages of the Client Server Model page 228 The Cisco NCIA server feature implements RFC 2114 Data Link Switch Client Access Protocol Using the Cisco RSRB technology NCIA I encapsulates the Token Ring traffic inside IP datagrams passed over a TCP connection between a router and a client A virtual ring is created to allow the router to interconnect any client The virtual ring acts as a logical Token Ring in the router so that all the Token Rings connected to the router are treated as if they are all on the same Token Ring The virtual ring is called a ring group The ring group number is used just like a physical ring number and shows up in any route descriptors contained in packets being bridged A ring group must be assigned a ring number that is unique throughout the network An NCIA I client acts as both an RSRB router and an end station It must have a fake ring number and a fake bridge number so that it looks like an end station sitting on a real Token Ring The fake ring and bridge numbers are visible to both the RSRB router and the NCIA client Th
70. rted within the IP infrastructure The following features provide this functionality HPR Capable SNA Routing Services page 234 Branch Extender page 234 Enterprise Extender HPR IP page 235 Usability Features page 236 Management Enhancements page 237 LAN and IP Focused Connection Types page 238 Benefits of SNASw SNASw provides the following benefits Scalable APPN Networks page 233 IP Infrastructure Support page 233 e Reduced Configuration Requirements page 233 Network Design Simplicity page 233 Improved Availability page 233 Increased Management Capabilities page 233 Architectural Compliance page 233 Cisco 10S Bridging and IBM Networking Configuration Guide T BC 232 U A Overview of IBM Networking Benefits of SNASw W Scalable APPN Networks With the Branch Extender BEX function the number of network nodes and the amount of broadcast traffic are reduced IP Infrastructure Support Limiting SNASw routers to the data center and using the BEX function eliminates SNA broadcasts from the IP network With Enterprise Extender EE SNA traffic is routed using the IP routing infrastructure while maintaining end to end SNA services Reduced Configuration Requirements By eliminating NNs and using the BEX function configuration tasks are minimized Additionally Cisco has enhanced its auto configuration capability to eliminate previously required commands Netw ork Design
71. s Cisco Multipath Channel CMPC is Cisco System s implementation of IBM s MultiPath Channel MPC feature on Cisco 7500 Cisco 7200 and Cisco 7000 with RSP7000 series routers CMPC allows VTAM to establish Advanced Peer to Peer Networking APPN connections using both High Performance Routing HPR and Intermediate Session Routing ISR through channel attached router platforms Routers configured for CMPC can be deployed in Parallel MVS Systems Complex sysplex configurations CMPC can be used to establish an APPN connection between VTAM and the following types of APPN nodes e VTAM on another host that is channel attached to the same CMCC adapter e VTAM on another host that is channel attached to a different CMCC adapter in the same router e TN3270 server using Dependent LU Requester DLUR in the same CMCC adapter e SNASw in the router with the CMCC adapter Other APPN nodes external to the CMCC adapter and router such as Communications Server 2 AS 400 other LAN or WAN attached VTAM hosts or remote routers One read subchannel and one write subchannel are supported for each MPC TG The read subchannel and write subchannel may be split over two physical channel connections on the same CMCC adapter CMPC insulates VTAM from the actual network topology The MPC protocols are terminated on the CMCC adapter and converted to LLC protocols After they are converted to LLC protocols other Cisco features can be used to connect VTAM to
72. s This MIB proactively send traps with information about changes in SNA resource status This implementation reduces the frequency of SNMP polling necessary to manage SNA devices in the network The CiscoWorks Blue Maps application retrieves relevant SNASw data from these MIBs and displays it in a manner that simplifies and speeds up problem isolation and resolution LAN and IP Focused Connection Types SNASw supports several connection types to serve all SNA connectivity options including the following types Token Ring Ethernet and FDDI page 238 Virtual Token Ring page 238 e Virtual Data Link Control page 239 Native IP Data Link Control HPR IP page 239 Token Ring Ethernet and FDDI SNASw natively supports connectivity to Token Ring Ethernet and FDDI networks In this configuration mode the MAC address used by SNASw is the local configured or default MAC address of the interface Virtual Token Ring Using virtual Token Ring allows SNASw access to SRB which allows the following configuration Attachment to Local LANs page 238 Connection to Frame Relay Transport Technologies page 239 e Connection to Channel Interface Processor and Channel Port Adapter page 239 Attachment to Local LANs Virtual Token Ring allows you to connect to local LAN media through SRB technology Because there is no limit to the number of virtual Token Ring interfaces that can connect to a specific LAN this technology allows confi
73. s feature DLSw can be used to access SNASw in the data center DLSw can also be used as a transport SNASw upstream connectivity providing nondisruptive recovery from failures The DLSw network can appear as a connection network to the SNASw nodes Using DLSw as a transport for other Cisco IOS SNA features requires a feature called VDLC Cisco IOS data link users such as LNM DSPU SNA service point and SNASw write to a virtual data link control interface DLSw then reads from this interface and sends out the traffic Similarly DLSw can receive traffic destined for one of these Data Link Users and write it to the virtual data link control interface from which the appropriate Data Link User will read it In Figure 88 SNASw and DLSw use Token Ring and Ethernet respectively as real data link controls and use virtual data link control to communicate between themselves When one of the high layer protocols passes data to the virtual data link control the virtual data link control must pass it to a higher layer protocol nothing leaves the virtual data link control without going through a data link user Overview of IBM Networking STUN andBSTUN W Figure 88 VDLC Interaction with Higher Layer Protocols SNASw DLSw Data link users CLSI Token i eee i l VDLC I Ethernet Data link controls Ring 1 l Nis 63S 0 See E 51909 The higher layer protocols make no dis
74. source bridge sdllc local ack Other Implementation Considerations SNA FRAS Consider the following when implementing QLLC conversion To use the QLLC conversion feature a router must have a physical link to an X 25 public data network PDN It must also have an SRB RSRB path to an IBM FEP This link could be a Token Ring or Ethernet interface or even FDDI if RSRB is being used QLLC conversion can run on any router with at least one serial interface configured for X 25 communication and at least one other interface configured for SRB or RSRB QLLC conversion security depends upon access control in SRB RSRB and X 25 and upon XID validation You can configure DLSw for QLLC connectivity which enables the following scenarios Remote LAN attached devices physical units or SDLC attached devices can access an FEP or an AS 400 over an X 25 network Remote X 25 attached SNA devices can access an FEP or an AS 400 over a Token Ring or over SDLC For information on configuring DLSw for QLLC conversion refer to the Configuring DLSw chapter You can configure DSPUs for QLLC For more information on this configuration refer to the Configuring DSPU and SNA Service Point chapter Using Frame Relay Access Support FRAS the Cisco IOS software allows branch SNA devices to connect directly to a central site front end processor over a Frame Relay network FRAS converts LAN or Synchronous Data Link Control SDLC
75. t are as large as possible As part of the SDLLC configuration on the serial interface the largest frame size the two media can support should be selected The Cisco IOS software can fragment the frames it receives from the Token Ring device before forwarding them to the SDLC device but it does not assemble the frames it receives from the serial device before forwarding them to the Token Ring device Maintaining a Dynamic RIF Cache SDLLC maintains a dynamic RIF cache and caches the entire RIF that is the RIF from the source station to destination station The cached entry is based on the best path at the time the session begins SDLLC uses the RIF cache to maintain the LLC2 session between the router and the host FEP SDLLC does not age these RIF entries Instead SDLLC places an entry in the RIF cache for a session when the session begins and flushes the cache when the session terminates You cannot flush these RIFs because if you flush the RIF entries randomly the Cisco IOS software cannot maintain the LLC2 session to the host FEP Other Considerations The following are additional facts regarding SDLC and SDLLC As part of the Cisco SDLC implementation only modulus 8 Normal Response Mode NRM sessions are maintained for the SDLC session SDLC sessions are always locally acknowledged LLC2 sessions can be optionally configured for local acknowledgment e SDLLC does not apply to SNA subarea networks such as 37x5 FEP to 37x5 FEP co
76. t requiring a change to the router configuration at the time of the move Note IP Host Backup does not provide single system image or automatic failover to a waiting backup application Host operator action on the mainframe is required in these instances For more information about configuring a CMCC adapter for IP host backup see the Configuring CLAW and TCP IP Offload Support chapter in this publication Cisco Multipath Channel CMPC is the Cisco implementation of IBM s MPC feature The CMPC feature supports the MPC features and protocols necessary to support IP CMPC enables High Performance Data Transfer HPDT It allows TCP IP connections to the host through CMCC adapters using either the TCP IP stack or the High Speed Access Services HSAS IP stack CMPC offers the following support Support for TCP IP and HSAS Transmission Group TG Support for one IP stack per MPC group Support for one read subchannel and one write subchannel per CMPC group The read subchannel and write subchannel in an MPC group can be on different physical channels Support for up to 64 KB per I O block Runs on the CIP and the CPA Up to 64 MPC groups can be configured on a CMCC depending on memory configuration The CMPC feature can coexist with the CLAW TCP IP Offload CSNA CMPC and TN3270 server features on the same CMCC adapter For details about configuring a CMCC adapter for CMPC see the Configuring
77. tablishing APPN links with the primary LU hosts directly Using the DLUR function is optional so that the TN3270 server can be used with VTAM versions prior to version 4 2 which provide no APPN support In these non APPN environments access to multiple hosts is accomplished using direct PU configuration in the TN3270 server Telnet Server Functions From the perspective of a TN3270 client the TN3270 server is a high performance Telnet server that supports Telnet connections negotiation and data format The server on the CMCC adapter card supports Telnet connection negotiation and data format as specified in RFC 1576 referred to as Traditional TN3270 and RFC 2355 referred to as TN3270 Enhancements Unless the TN3270 server uses a Token Ring connection to a FEP or other LLC connectivity to the mainframe host it requires CSNA or CMPC support For more information about configuring CSNA or CMPC support see the Configuring CSNA and CMPC chapter in this publication 78 11737 02 Cisco 10S Bridging and IBM Networking Configuration Guide BC 249 Overview of IBM Networking HI CMCC Adapter Features for SNA Environments To enable the TN3270 server feature you must have a CMCC adapter installed in a Cisco 7000 with RSP7000 Cisco 7500 series router or a Cisco 7200 router For details about configuring the TN3270 server on a CMCC adapter see the Configuring the TN3270 Server chapter in this publication Cisco I
78. ters are also supported on the Cisco 7000 series routers In contrast to Source Route Bridging SRB which involves bridging between Token Ring media only RSRB is a Cisco technique for connecting Token Ring networks over non Token Ring network segments DLSw is the Cisco strategic method for providing this function The Cisco RSRB software implementation includes the following features Provides for multiple routers separated by non Token Ring segments Three options are available Encapsulate the Token Ring traffic inside IP datagrams passed over a Transmission Control Protocol TCP connection between two routers Use Fast Sequenced Transport FST to transport RSRB packets to their peers without TCP or User Datagram Protocol UDP header or processor overhead Use data link layer encapsulations over a single serial line Ethernet Token Ring or Fiber Distributed Data Interface FDDI ring connected between two routers attached to Token Ring networks Provides for configurable limits to the size of the TCP backup queue Figure 85 shows an RSRB topology The virtual ring can extend across any non Token Ring media supported by RSRB such as serial Ethernet FDDI and WANs The type of media you select determines the way you set up RSRB Figure 85 RSRB Topology Token A Non Token Ring Goce Token Ring t J Media y Ring Token Token Ring Ring Virtual rin 2327 Note If you bridge across Token Ri
79. the probability exists for frames to lose their order in your network If you have a network where frames are routinely reordered it is better to use the TCP protocol for RSRB TCP provides the overhead necessary to bring frames back in order on the receiving router FST to remain fast does not provide for such a mechanism and will discard out of order frames Logical Link Control type 2 LLC2 local acknowledgment can be enabled only with TCP remote peers as opposed to LAN or direct serial interface remote peers because the Cisco IOS software needs the reliability of TCP to provide the same reliability that an LLC2 LAN end to end connection provides Therefore the direct media encapsulation options for the source bridge remote peer command cannot be used If the LLC2 session between the local host and the router terminates on either side of the connection the other device will be informed to terminate its connection to its local host If the TCP queue length of the connection between the two routers reaches 90 percent of its limit they send Receiver not Ready RNR messages to the local hosts until the queue limit is reduced to below this limit The configuration of the LLC2 parameters for the local Token Ring interfaces can affect overall performance Refer to the Configuring LLC2 and SDLC Parameters chapter for more details about fine tuning your network through the LLC2 parameters 78 11737 02 Cisco IOS Bridging and IBM N
80. tinction between the VDLC and any other data link control but they do identify the VDLC as a destination In the example shown in SNASw has two ports a physical port for Token Ring and a logical virtual port for the VDLC In the case of the SNASw VDLC port when you define the SNASw VDLC port you can also specify the MAC address assigned to it That means data going from DLSw to SNASw by way of the VDLC is directed to the VDLC MAC address The type of higher layer protocol you use determines how the VDLC MAC address is assigned STUN and BSTUN The Cisco IOS software supports serial tunnel STUN and block serial tunnel BSTUN Our BSTUN implementation enhances Cisco 2500 4000 4500 4700 7200 series routers to support devices that use the Binary Synchronous Communication Bisync data link protocol and asynchronous security protocols that include Adplex ADT Security Systems Inc Diebold and asynchronous generic traffic BSTUN implementation is also supported on the 4T network interface module NIM on the Cisco 4000 and 4500 series routers Our support of the bisync protocol enables enterprises to transport Bisync traffic and SNA multiprotocol traffic over the same network This section contains the following topics STUN Networks page 211 STUN Features page 212 BSTUN Networks page 215 BSTUN Features page 215 STUN Networks STUN operates in two modes passthrough and local acknowledgment Figure 89 shows the difference
81. uide PBC 230 E 78 11737 02 Overview of IBM Networking DSPU and SNA Service Point W Figure 105 shows a router functioning as a DSPU concentrator Figure 105 Router Acting as a DSPU Concentrator Mainframe DSPU ee with 1 PU and Sti s a 8 LUs defined an s PU 2 2 LUs Typically a router establishes one or more upstream connections with one or more hosts and many downstream connections with PU type 2 devices From an SNA perspective the router appears as a PU type 2 device to the upstream host and assumes the role of a system services control point SSCP appearing as a PU type 5 device to its downstream PUs eee LF AF E Tok gt m Ring W yp RSRB y i IE lt PU2 PU5 5 PU2 1LU 83223 The SSCP sessions established between the router and its upstream host are completely independent of the SSCP sessions established between the router and its downstream PUs SNA traffic is routed at a logical unit LU level using a routing algorithm that maps downstream LUs onto upstream LUs Figure 106 illustrates the SNA perspective of DSPU Figure 106 SNA Perspective of DSPU Y Upstream PU PU type 2 LU routing algorithm Downstream PU A Downstream PU B PU type 5 PU type 5 3224 Cisco 10S Bridging and IBM Networking Configuration Guide ere E BC 231 Overview of IBM Networking E SNA Switching Services SNA Switching Services amp Note SN
82. ynchronous generic and Monitor Dynamics Inc traffic for transfer over router links The tunneling of asynchronous security protocols ASP feature enables your Cisco 2500 3600 4000 4500 or 7200 series router to support devices that use the following asynchronous security protocols adplex adt poll select adt vari poll diebold async generic mdi Provides a tunnel mechanism for BSTUN over Frame Relay without using TCP IP encapsulation Supports Bisync devices and host applications without modification Uses standard synchronous serial interfaces on Cisco 2500 series and the 4T network interface module NIM on the Cisco 4000 series and Cisco 4500 series e Supports point to point multidrop and virtual multidrop configurations Note The async generic item is not a protocol name It is a command keyword used to indicate generic support of other asynchronous security protocols that are not explicitly supported LLC2 and SDLC Parameters The LLC2 and SDLC protocols provide data link layer support for higher layer network protocols and features such as SDLC Logical Link Control SDLLC and RSRB with local acknowledgment The features that are affected by LLC2 parameter settings are listed in the The Cisco Implementation of LLC2 section on page 216 The features that require SDLC configuration and use SDLC parameters are listed in the The Cisco Implementation of SDLC section on page 217 LLC2 a
83. ysis Each message has a single line that identifies the nature of the event that occurred The buffer log also maintains more detailed information about the message issued Data Link Tracing SNA frames entering or leaving SNASw are traced to the console or to a cyclic buffer These frames are analyzed at the router or transferred to a file server for analysis The trace is sent to a file server in a SNA formatted text file or in binary format readable by existing traffic analysis applications Interprocess Signal Tracing The SNASw internal information is traced in binary form offering valuable detailed internal information to Cisco support personnel This information helps diagnose suspected defects in SNASw Cisco 10S Bridging and IBM Networking Configuration Guide 78 11737 02 Ee Overview of IBM Networking HZ LAN and IP Focused Connection Types MIB Support for Advanced Netw ork Management Awareness SNASw supports the following Management Information Bases MIBs IETF draft standard DLUR MIB RFC 2232 which defines objects for monitoring and controlling network devices with DLUR Dependent LU Requester capabilities IETF draft standard APPN MIB RFC 2455 which defines objects for monitoring and controlling network devices with Advanced Peer to Peer Networking APPN capabilities APPN Traps MIB RFC 2456 which defines objects for receiving notifications from network devices with APPN and DLUR capabilitie

IBM BC-201 Network Router User Manual

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