PW Status Signaling and BFD over VCCV
Contents
1. circuits created prior to the upgrade will not use PW status signaling until after the node is restarted e PW status signaling is supported for all PWE3 types The Tellabs 8800 series MSRs report PW status change for any of the following conditions e The ULC is operationally down e The PLM is operationally down e The port is operationally down or administratively disabled e The LAG APS or multilink group is operationally down Page 36 148 76 880080 36 Rev A 7 09 11 MPLS Pseudowires TMOS MPLS Application Manual The interface is operationally down or administratively disabled e An SFP transmit or receive optic fault occurs e Local SONET faults like LOS LOF AIS and NBET for example are detected e Receive remote SONET faults like RDI AIS FBET for example are detected e AIS and RDI receive ATM OAM fault indications are detected Configuring PW Status Signaling Enabling PW Status Signaling By default PW status signaling is disabled Enable PW status signaling globally on a node as described in Table 11 2 page 36 149 Table 11 2 Enable PW Status Signaling Command Entry Purpose Step 1 8800 enable config protocol mpls ldp Enter LDP configuration mode Step 2 8800 cfg mp ldp pw status signaling enable Administratively enable PW status signaling on a node Step 3 8800 cfg mp ldp exit all Exit LDP configuration mode Step 4 8800 show protocol mpls ldp Display LD2. deleted PW status signaling is not applied and the associated label is withdrawn instead PW Signaling Functionality PW status signaling functions on a Tellabs 8800 series MSR with the following conditions e For PW status signaling to be active both PE nodes on a PWES circuit must support PW status signaling Although you can configure and enable PW status signaling on one PE node notification messages are not sent until both ends are configured and enabled e If either PE node does not include the PW status in the label mapping message then both PE routers revert to LDP Label Withdraw messages to signal status e The use of group and wildcard notification messages is supported This minimizes the number of messages sent when a status change affects multiple pseudowires The PW ID field in all LDP PW messages contains a group ID as well as a specific PW ID When a message omits a specific PW ID the message then applies to all PWs in the group The Tellabs 8800 series MSR uses the same group ID for all PWE3 circuits using the same port side Layer 2 interface e Only single segment PWs not multi segment PWs can apply PW status signaling e Ifyou upgrade an existing network that does not support PW status signaling PW status signaling remains disabled by default in the upgraded network After upgrading a node and enabling PW status signaling circuits created after the upgrade will use PW status signaling However
3. 100 In mullseconas Step3 8300 cfg ckt side ckt12 2 exit Exit the circuit configuration mode Step4 8800 show ckt name ckt12 detail Display BFD configuration parameters for a dynamic circuit to verify minimum BFD packet transmission interval Setting the Detection Time Table 11 5 page 36 155 lists configuration commands to set the BFD detection Multiplier of a PW Endpoint time multiplier on the LSP side of a dynamic circuit Note This procedure assumes that side id 1 of the circuit is already configured Refer to the Tellabs 8800 TMOS User Manual 76 880080 4 for details about configuring this side of the circuit Page 36 154 76 880080 36 Rev A 7 09 TMOS MPLS Application Manual 11 MPLS Pseudowires Table 11 5 BFD over VCCV Detection Time Multiplier Configuration Command Entry Purpose Step1 8800 enable config enable config Enter the LSP side of the dynamic circuit configuration ckt name ckt12 side id 2 mode Step2 8800 cfg ckt side ckt12 2 lsp Set the BFD detection time multiplier dynamic ckt bfd detect multiplier 5 Step3 8800 cfg ckt side ckt12 2 exit Exit the circuit configuration mode a Step4 8800 show ckt name ckt12 detail Display BFD configuration parameters for a dynamic circuit to verify detection time multiplier Setting the Minimum Receive Interval for BFD Control Packets at a PW Endpoint dynamic circuit Table 11 6 page 36
4. 155 lists configuration commands to set the required minimum receive interval in milliseconds for BFD packets on the LSP side of a Note This procedure assumes that side id 1 of the circuit is already configured Refer to the Tellabs 8800 TMOS User Manual 76 880080 4 for details about configuring this side of the circuit Table 11 6 BFD over VCCV Required Minimum Receive Packet Interval Configuration Command Entry Purpose Step1 8800 enable config enable config Enter the LSP side of the dynamic circuit configuration ckt name ckt12 side id 2 mode Step2 8800 cfg ckt side ckt12 2 lsp Set the required minimum interval in milliseconds dynamic ckt bfd i k h he PE i required min rx interval 500 between received BFD control packets that the is capable of supporting Step3 8800 cfg ckt side ckt12 2 1 exit Exit the circuit configuration mode a Step4 8800 show ckt name ckt12 detail Display BFD configuration parameters for a dynamic circuit to verify minimum BFD packet receive interval Setting the BFD Session Timeout for a PW Endpoint Table 11 7 page 36 155 lists configuration commands to set the BFD session timeout on the LSP side of a dynamic circuit Note This procedure assumes that side id 1 of the circuit is already configured Refer to the Tellabs 8800 TMOS User Manual 76 880080 4 for details about configuring this side of the circuit Table 11 7 BFD
5. 36 149 11 MPLS Pseudowires TMOS MPLS Application Manual 8800 show ckt pw status enable Circuit Name Type Ad Op out vclabel vcid vianl vlan en dn 1010 vilan42 vlan en up 1023 Total Up 1 Total Down 1 Total 2 BFD over VCCV for PWE3 Bidirectional Forwarding Detection BFD over Virtual Circuit Connectivity Verification VCCV is a pseudowire PW fault detection mechanism BFD over VCCV is an Operations and Maintenance OAM failure detection method applied in an MPLS network to validate the data plane and verify PW connectivity In an MPLS network carrying traffic over PWE8s it is important to quickly detect PW failures to minimize impact to customer traffic The Tellabs 8800 series MSR also supports an operator initiated LSP ping as a diagnostic tool to detect PWES circuit failures For details about LSP ping refer to Basic Ping and Traceroute Operations page 36 86 BFD over VCCV offers the following advantages over LSP ping when detecting PW faults e Faster detection time e Monitors a greater number of PWs The implementation of both BFD over VCCV and LSP ping in the Tellabs 8800 series MSR provides validation and consistency of data and control planes The following topics are available to help configure BFD over VCCV for PWE3 service e About BFD over VCCV for PWE3 page 36 150 e BFD over VCCV Functionality on the Tellabs 8800 Series MSR page 36 152 e BFD over VCCV Configuration Guidelines page 36 153
6. Also referred to as a node or PE node e Pseudowire PW A connection between two PEs Each PE terminates an AC The PW is a path for an emulated circuit originating from the AC to traverse the PSN e PSN Tunnel A tunnel across a PSN on which PWs are carried The following sections describe a generalized PW setup and maintenance Setting Up an LDP Session page 36 144 Setting Up the Pseudowire page 36 144 Tearing Down a PW page 36 144 Figure 11 2 page 36 145 outlines a lifetime scenario for a PWES circuit Two Tellabs 8800 Series MSRs PE nodes A and B set up an LDP session using an extended discovery mechanism Extended discovery supports LDP sessions between PE nodes that are not directly connected with targeted hello messages to specific addresses This establishes the nodes A and B as pseudowire endpoints The nodes exchange LDP Label Mapping messages to set up the pseudowire The PW exchanges labels when the following three conditions are met e An LDP session is established between peer nodes e The pseudowire circuit is administratively enabled The peer addresses are known to the LDP session The PW is considered operationally up when free of AC and local forwarding errors and when the labels have been successfully exchanged In the case where a pseudowire is no longer needed a PE node initiates a PW teardown by sending an LDP label withdraw message All labels associated with the pseudowire are re
7. Configuring BFD over VCCV page 36 153 About BFD over VCCV for PWE3 BFD over VCCV uses the BFD protocol as a connectivity verification type over a VCCV control channel to monitor PW connectivity and quickly detect faults The PW uses the Pseudowire Emulation Edge to Edge PWE3 mechanism to carry customer traffic across a PSN Refer to About Pseudowires page 36 143 for an explanation of the terms used in this section This section provides background information about the protocols used when implementing BFD over VCCV in the following sections e About BFD page 36 151 e About VCCV page 36 151 e BFD over VCCV page 36 151 Page 36 150 76 880080 36 Rev A 7 09 TMOS MPLS Application Manual About BFD About VCCV BFD over VCCV 76 880080 36 Rev A 7 09 11 MPLS Pseudowires BFD is a generic low overhead short duration failure detection protocol It provides failure detection on any kind of path between systems including physical links virtual circuits tunnels MPLS LSPs multihop routed paths and unidirectional links When applied to PWs BFD provides fault detection through the continuous monitoring of the PW data path For additional BFD capabilities not covered in this section refer to the Tellabs 8800 TMOS User Manual 76 880080 4 Virtual Circuit Connectivity Verification VCCV is a control plane protocol for pseudowires to aid in end to end fault detection and diagnostics VCCV provides a control channel
8. UDP fault det Remote CC TTL expiry Remote CV LSP ping BFD IP UDP fault det BFD parameters Detect mult 3 Desired min tx interval 100 msec Required min rx interval 100 msec Session establish time 0 sec Admin enabled Oper up Failure reason none Auto optimize mode disabled Lsp pref ip disable dest 1 1 1 1 preference all lsp L2 intf pos avg pkt size 1518 negotiated MTU local 1496 remote 1496 lsp cac bandwidth O Min 0 Max L2IfSlotId 1 Out Label 1024 Out Intf ge 1 3 3 4 1 DownStream i T erg ead i Use the show protocol bfd session stats command to display BFD session specific statistics 8800 show protocol bfd session stats Application Mpls Circuit Name vlan50 Discriminator 0x14000004 Last up 07 07 2009 10 18 19 Last poll not available Last down not available No diagnostic Session up count 1 Statistics last cleared not available Control Packet Statistics Sent 62528 Received 62530 Use the show protocol bfd global stats command to display BFD packet statistics 8800 show protocol bfd global stats Global Control Packet Statistics Sent 2844625 Revd 5571001 Accepted 2785426 Packet Discard Reason Statistics Bad Version 2 0 Page 36 157
9. failed and takes appropriate action Other PE node functions like alarm reporting and PW status signaling are notified about the failure detected through BFD over VCCV If PW status signaling is enabled the PE node signals the status to the PE peer BFD over VCCV Functionality on the Tellabs 8800 Series MSR The following topics describe how BFD over VCCV operates on the Tellabs 8800 series MSR BFD over VCCV Characteristics Page 36 152 BFD over VCCV Characteristics page 36 152 PW Down Status Notification page 36 153 Applying BFD over VCCV on Existing PWs page 36 153 The Tellabs 8800 series MSR implementation of BFD over VCCV is as follows The PW is declared down when BFD control packets are not received within a configured interval BFD over VCCV operates only in asynchronous mode In asynchronous mode a pair of systems periodically sends BFD control packets to each other If a number of packets in a row is not received by the other the session is declared to be down Echo function is not available for BFD over VCCV The Tellabs 8800 series MSR takes an active role as a PW endpoint BFD session comes up after the PW is operationally up and after BFD is administratively enabled on both sides of the PW Support for CC type TTL Expiry Support for CV types BFD IP UDP Fault Detection and LSP Ping The following BFD session parameters are configurable Enable Disable the BFD session Desired minimum transmit
10. pseudowire with PW status signaling Two Tellabs 8800 series MSRs PE nodes A and B set up an LDP session using an extended discovery mechanism Extended discovery supports LDP sessions between PE nodes that are not directly connected with targeted hello messages to specific addresses This establishes the nodes A and B as pseudowire endpoints The nodes exchange LDP Label Mapping messages to set up the pseudowire With PW status signaling enabled the nodes exchange Label Mapping messages regardless of the AC state or LSP availability The LDP Label Mapping message includes the PW status code which is used during the lifetime of the pseudowire The PW exchanges labels when the following three conditions are met e An LDP session is established between peer nodes e The pseudowire circuit is administratively enabled e The peer addresses are known to the LDP session With PW status signaling enabled the PE nodes attempt to establish the PW even if the AC is operationally down or if there is a local forwarding error Refer to Setting Up the Pseudowire page 36 144 for a PW setup with PW status signaling disabled During the lifetime of a PW PW status signaling uses the PW status code to signal AC errors and local forwarding errors Refer to PW Status Signaling Error Faults Conditions page 36 147 for details on the PW status code In the case where a pseudowire is no longer needed a PE node initiates a PW teardown by sending an L
11. DP label withdraw message All labels associated with the pseudowire are removed With PW status signaling enabled the PW label is withdrawn only when one or more of the following conditions occur e The pseudowire configuration is deleted e The operator disables the pseudowire 76 880080 36 Rev A 7 09 Page 36 146 TMOS MPLS Application Manual PW Status Signaling Error Faults Conditions 11 MPLS Pseudowires e LDP session down or LDP address down errors occur Figure 11 3 PW Lifetime Scenario with PW Status Signaling Enabled PWES3 configured Setup A to B LSP PW Establish Delete PWE3 configuration Delete A to B LSP PW Tear Down PWE3 AC or PSN PW error i g AC or PSN PW recovers wi PWE3 torn down Send LDP Label Mapping Message PWE3 established P Label Mapping Message Setup B to A LSP PW Send LD Send LDP Notification PWE3 circuit is down Send trap Send LDP Notification PWES3 circuit is up Send trap LDP Label Withdraw Message A to B LSP PW deleted LDP Label Withdraw Message Delete B to A LSP PW PE Node A PE Node B Table 11 1 page 36 147 lists PW fault descriptions based on pseudowire type error conditions and the network side where the fault is detected Table 11 1 Error Conditions Carried in the PW Status TLV PW Type Error Condition Side PW Fault Description Ss E Any PW BFD session down LSP PW not forwa
12. Mapping messages An exchange of Label Mapping messages occurs with one of the following actions e Ifthe system restarts or if MPLS undergoes a graceful restart e Change of PW operational status disable PW status signaling BFD over VCCV Configuration Guidelines Apply the following guidelines when configuring BFD over VCCV on a pseudowire e Configure BFD over VCCV only on ATM Ethernet VLAN including Q in Q or SAToP PWES circuits e The PE peer must also support CC type TTL Expiry and CV type BFD IP UDP Fault Detection e Adhere to scaling of up to 100 BFD sessions with a one 1 second transmit receive interval and a detect multiplier of five 5 Configuring BFD over VCCV Enabling or Disabling BFD on a PW Endpoint 76 880080 36 Rev A 7 09 Use the following TMOS commands to configure a BFD session on a PW Configure both ends of the PW to enable the BFD session Refer to the Tellabs 8800 TMOS Command Reference Manual 76 880080 5 and the Tellabs 8800 TMOS Operations Reference Manual 76 880080 6 for details including default values and available ranges Table 11 3 page 36 154 lists configuration commands to enable BFD on the LSP side of a dynamic circuit Page 36 153 11 MPLS Pseudowires TMOS MPLS Application Manual Note This procedure assumes that side id 1 of the circuit is already configured Refer to the Tellabs 8800 TMOS User Manual 76 880080 4 for details about configuring this side of the
13. P configuration mode to verify PW status signaling state Viewing PW Signaling and PW AC Fault Status The CLI show commands in this section display the status of the PW configuration and the status of the PW Use the show protocol mpls Idp command to display the global PW status signaling configuration information 8800 show protocol mpls ldp LDP Default Parameters Advertisement Mode unsolicited Label Retention Mode liberal Hello Timer 15 sec Targeted Hello Timer 45 sec Label filter Host only True Loopback only True Target Response Mode enable QoS Mode Disabled Pw status signaling Enable Use the show ckt lt ckt name gt detail or extensive commands to display the PW status related information related to the circuit 8800 show ckt name v1 detail circuit vl type vlan sidel port in status up out status up int ge 1 1 4 1 type vlan id 22 pri ignore Signal XC Alarm disabled side2 lsp in status Peer not forwarding out status Peer not forwarding dynamic out lsp test Learnt out ve label 1031 in vc label 1036 service type ethernet group id 3053453313 vc id 1031 Pw Status Signaling In Use Enabled Sent Enabled Remote Enabled PW Status Failure Local notForwarding acTxFailure PW Status Failure Remote acTxFailure psnRxFailure Use the show ckt pw status enable command to display the circuits with PW status signaling in use 76 880080 36 Rev A 7 09 Page
14. TMOS MPLS Application Manual 11 MPLS Pseudowires 11 MPLS Pseudowires Return to Main Page About Pseudowires Pseudowires 76 880080 36 Rev A 7 09 The Tellabs 8800 TMOS software supports the configuration and monitoring of pseudowires PW in a MPLS enabled Packet Switched Network PSN The following sections provide background and describe procedures for configuring PWs e About Pseudowires page 36 143 e PW Status Signaling page 36 145 e BFD over VCCV for PWE3 page 36 150 e Configuring Static Multi Segment Pseudowire page 36 158 Pseudowire Emulation Edge to Edge PWE3 is a mechanism that emulates a telecommunications service for example ATM or Frame Relay over a variety of PSN types A PWES circuit allows traffic originating from customer edge CE to traverse the PSN while maintaining characteristics of a native service From the perspective of the customer edge CE device the PW is characterized as an unshared link or circuit of the chosen service A PW is set up between two provider edge PE nodes in an MPLS network The PE then connects to the CE through an attachment circuit AC Figure 11 1 page 36 143 shows the PWE3 Reference Model with two Tellabs 8800 series MSRs acting PE nodes Figure 11 1 PWE3 Reference Model i PSN A CE PE PE CE Node A Node B Emulated Service q O OI I The Tellabs 8800 Series MSR architecture applies MPLS Label Distribution Protocol LDP and Resource Reserv
15. ation Protocol RSVP to set up and maintain pseudowires across a network A PWES circuit consists of two unidirectional flows shown as PW1 and PW2 in Figure 11 1 page 36 143 Both sides of the PW must be configured for the PWE3 circuit to be operational For example both PE Nodes A and B in Figure 11 1 page 36 143 must be configured for two PWs A to B and B to A for the PWE3 circuit to be operational Page 36 143 11 MPLS Pseudowires Key PW Terms The Life of a PSeudowire Setting Up an LDP Session Setting Up the Pseudowire Tearing Down a PW Page 36 144 TMOS MPLS Application Manual Other sections of the Tellabs 8800 TMOS and Tellabs 8890 user manuals refer to PWE8 based circuits as martini circuits or remote circuits This section uses the terms PW and PWES3 to refer to this type of virtual circuit path Refer to Key PW Terms page 36 144 for terminology used in this section The following are PWE3 terms and definitions e Attachment Circuit AC The physical or virtual circuit attaching a CE to a PE An AC can be an ATM VPI VCI an Ethernet port a VLAN or other native service e Customer Edge CE A device where a service originates and terminates In the case of PWE3 the CE is not aware that it is using an emulated service rather than a native service e Packet Switched Network PSN A network that uses IP or MPLS for packet forwarding e Provider Edge PE A device that provides PWE3 to a CE
16. between the ingress and egress points of a pseudowire in this case the PE nodes over which verification messages are sent This functionality permits verification of PW connectivity and the data plane used to transport the data path for the PW For details about VCCV refer to About VCCV page 36 88 With the BFD over VCCV protocol the VCCV CC and CV types refer to VCCV CC Type page 36 88 and VCCV CV Types page 36 89 for details are negotiated when the PW is established The PE can then initiate a BFD session when the following conditions are met e The BFD protocol is administratively enabled on a PW e Both CC and CV capabilities between local and peer PEs are matched e The PW is operationally up The BFD session will be operationally up only when both sides have BFD administratively enabled on a PW Figure 11 4 page 36 151 shows a VCCV control channel carrying BFD control messages that monitor a PW Figure 11 4 BFD over VCCV Monitoring a PW on an MPLS Network ATM FR Ethernet VLAN incl QinQ or SAToP BFD Messages Pseudowire Service User Traffic Page 36 151 11 MPLS Pseudowires TMOS MPLS Application Manual The PE node maintains the BFD session by periodically transmitting control packets after successful establishment of a session If packets are not received by a PE within the negotiated time interval the session to that PE is declared to be operationally down The PE assumes the pseudowire has
17. circuit Table 11 3 BFD Minimum Configuration Command Entry Purpose EEEEEEaEa aanB gt aaESeaEaEaEaEaEaE E EaES Ean R7REa 9A9hA9DAananananananananaaaS X X Y Y Y YSWOmnB Step1 8800 enable config Enter the configuration mode Step2 8800 config ckt name ckt12 side id i i p Bigs aya d ie eed cate masks Enable BFD over VCCV for the LSP side of a dynamic circuit Step3 8800 cfg ckt side bfd ckt12 2 Exit the circuit configuration mode exit all Step4 8800 show ckt name ckti2 detail Display BFD configuration parameters for a dynamic circuit to verify administrative state Setting the Minimum Table 11 4 page 36 154 lists configuration commands to set the desired minimum Transmit Interval of a PW BFD packet transmitting interval in milliseconds on the LSP side of a dynamic Endpoint circuit Note This procedure assumes that side id 1 of the circuit is already configured Refer to the Tellabs 8800 TMOS User Manual 76 880080 4 for details about configuring this side of the circuit Table 11 4 BFD over VCCV Packet Desired Minimum Transmission Interval Configuration Command Entry Purpose Step1 eK erga config ckt name ckt12 Enter the LSP side of the dynamic circuit configuration mode Step2 8800 cfg ckt side ckt12 2 side Set the desired minimum BFD packet transmitting interval id 2 lsp dynamic ckt bfd illi d desired min tx interval
18. est Addr 10 10 1 2 Oper Status Up VcId 1100 Out Lsp Name LDP_10 10 1 2 320 Last incoming Intf none Page 36 156 76 880080 36 Rev A 7 09 TMOS MPLS Application Manual 76 880080 36 Rev A 7 09 11 MPLS Pseudowires Role active Local Remote Version 1 1 Remote heard yes yes Discriminator 0x14000020 0x10000098 Min tx interval msec 1000 1000 Detect multiplier 3 3 Min rx interval msec 1000 1000 Negotiated tx interval 1000 1000 Detection time 3000 3000 Last packet 06 10 2009 18 30 12 v 1 diag No diagnostic sta Up P 0 F 0 C 0 A 0 D 0 R 0 Mult 3 len 24 My 0x10000098 Your 0x14000020 Tx 1000000 Rx 1000000 echoRx 0 Use the show ckt lt ckt name gt detail or extensive commands to display all BFD configured parameters against the circuit including the CC and CV values negotiated between the local and peer PEs 8800 show ckt name vlan detail circuit vlanl type vlan Indv Trap enable MTU check disable admin enable oper up failure reason none forwarding status forwarding sidel port in status up out status up int ge 1 1 3 1 type vlan id 1 pri ignore Signal XC Alarm disabled side2 lsp in status up out status up dynamic out lsp LDP_1 1 1 1 32 Learnt out vce label 1031 in vc label 1044 group id 268500992 vc id 1 Pw Status Signaling In Use disabled Sending disabled Remote disabled Remote in use CC TTL expiry Local CC TTL expiry Local CV LSP ping BFD IP
19. ge contains the PW Status TLV type length value tuple PW status signaling uses the PW Status TLV to convey PW status if any AC side or local forwarding errors are detected Alternatively label withdraw can be used for to signal a change in status With label withdraw the PE node withdraws the label for the PW to signal a status change When the errors are cleared the PE then rebuilds the PW and re advertises the labels This generates LDP FEC messages and increases the processing load on a network Page 36 145 11 MPLS Pseudowires TMOS MPLS Application Manual Because PW status signaling generates fewer LDP FEC messages than label withdraw PW status signaling reduces the processing load in initiating terminating and transit nodes In addition PW status signaling enables quicker PW setup because the initiating PE node does not wait for the ACs to become active before establishing the PW PW Status Signaling and the Life of a Pseudowire Setting up an LDP Session Negotiating PW Status Signaling and Setting Up the Pseudowire Detecting PW Status Tearing Down a PW The following sections describe a generalized a PW setup and maintenance with PW status signaling enabled e Setting up an LDP Session page 36 146 e Negotiating PW Status Signaling and Setting Up the Pseudowire page 36 146 Detecting PW Status page 36 146 e Tearing Down a PW page 36 146 Figure 11 3 page 36 147 outlines a lifetime scenario for a
20. interval Detection multiplier Required minimum receive interval BFD session established wait time Refer to Configuring BFD over VCCV page 36 153 for configuration procedures Changes to BFD session parameters at any time during the BFD session are permitted without the need to first disable the BFD session on the PW Support for single segment PWs only as the BFD over VCCV protocol does not support multi segment PWs Support for dynamic PW circuits 76 880080 36 Rev A 7 09 TMOS MPLS Application Manual PW Down Status Notification Applying BFD over VCCV on Existing PWs 11 MPLS Pseudowires e BFD over VCCV support for the following PW types ATM Ethernet VLAN including Q in Q SAToP When the BFD session detects that the PW is down the Tellabs 8800 series MSR signals fault status and takes the following actions e If the PW is part of a redundant bundle the PE switches to another member of the bundle If PW status signaling is enabled the PE sends the status to the peer PE e If PW status signaling is not enabled the PE withdraws the labels e The PE uses an SNMP trap to report the change in status of the PW The Tellabs 8800 series MSR permits the application of BFD over VCCV to existing PWs To add BFD over VCCV to a set of endpoints where PW was established in FP7 3 or earlier and now upgraded FP8 0 the PW must be torn down and re established through the exchange of LDP Label
21. moved 76 880080 36 Rev A 7 09 TMOS MPLS Application Manual PW Status Signaling 11 MPLS Pseudowires Figure 11 2 PW Lifetime Scenario PWE3 configured to S i Setup A to B LSP PW end LDP Label Mapping Message am PWE3 established uw ce Setup B to A LSP PW wo send LDP Label Map etup to PWE3 established Delete PWE3 or R AC error or z PW error Q i Delete A to B LSP PW LDP Label Withdraw Message 3 A to B LSP PW deleted Delete B to A LSP PW Q LDP Label With J 2 PWE3 torn down PE Node A PE Node B The Tellabs 8800 Series MSR supports PW status signaling a capability of PWE3s and the LDP control plane PW status signaling generates fewer LDP FEC messages than label withdraw lessening the impact of CPE faults on the network The following sections describe the implementation of pseudowire PW status signaling as part of an MPLS enabled network e About Pseudowire Status Signaling page 36 145 e PW Signaling Functionality page 36 148 e PW Status Signaling and the Life of a Pseudowire page 36 146 e PW Signaling Functionality page 36 148 Configuring PW Status Signaling page 36 149 About Pseudowire Status Signaling 76 880080 36 Rev A 7 09 PW status signaling allows a PE node to notify its remote PE peer when AC errors or local forwarding errors occur When PW status signaling is enabled the PE node uses the LDP notification messages to signal error conditions The LDP notification messa
22. over VCCV Session Timeout Configuration Step1 Command Entry 8800 enable config enable config ckt name ckt12 side id 2 Purpose Enter the LSP side of the dynamic circuit configuration mode 76 880080 36 Rev A 7 09 Page 36 155 11 MPLS Pseudowires TMOS MPLS Application Manual Table 11 7 BFD over VCCV Session Timeout Configuration Continued Command Entry Purpose eee Step2 8800 cfg ckt side ckt12 2 lsp Sets the amount of wait time in seconds that an attempt dynamic ckt bfd session est wait timeout 10 to establish a BFD session to the peer node is made Once the timer expires the session is declared down and the clients associated with the session will be notified The session established wait time can be configured as 0 When set to 0 attempts to establish the session with the peer does not cease and the BFD session status of Down is never sent to client until such time after successfully establishing the session for the first time The default value for this parameter is 0 Step3 ee yresnen eer as ckt12 2 exit Exit the circuit configuration mode Step4 8800 show ckt name ckti2 detail Display BFD configuration parameters for a dynamic circuit to verify BFD session timeout interval Viewing PW Signaling and The CLI show commands in this section display the status of the BFD PW AC Fault Status session related information Use the show pro
23. rding PWES circuit Interface down Circuit AcRxFailure Attachment circuit AC receive failure AcTxFailure AC transmit failure PWE3 Circuit bundle disabled Circuit AcRxFailure AC receive failure redundant AcTxFailure AC transmit failure bundle member PWE3 Circuit bundle down Circuit AcRxFailure AC receive failure redundant AcTxFailure AC transmit failure bundle member VPLS PW Bridging instance down Circuit AcRxFailure AC receive failure AcTxFailure AC transmit failure Mirroring target Target or mirroring instance Circuit AcRxFailure AC receive failure PW not enabled AcTxFailure AC transmit failure Any LSP not found LSP PsnRxFailure Packet switched network PSN receive failure PsnTxFailure PSN transmit failure Any LDP address down LSP No PW status code label is withdrawn 76 880080 36 Rev A 7 09 Page 36 147 11 MPLS Pseudowires TMOS MPLS Application Manual Table 11 1 Error Conditions Carried in the PW Status TLV Continued PW Type Error Condition Side PW Fault Description S aaaEaEeap ppEamaamamnaceEaqaquyamq Equyyeeeeeeeeeeeeeeeeeeeee Any Circuit is administratively N A No PW status code label is withdrawn disabled Any Circuit configuration delete N A No PW status code label is withdrawn If the pseudowire circuit is administratively disabled or the circuit configuration is
24. tocol bfd session command to view all applications and interfaces including those with BFD over VCCV sessions 8800 show protocol bfd session Application Ip ipv4 Legend O OSPF I ISIS B BGP S Static Route Detect Time lel rmt Op Interface Ip Address Client s msec st ge 1 8 1 1 1 pe ee ee o 300 300 up so 1 8 3 1 1 1 4A A o 300 300 up Application Mpls Legend Pri RSVP Primary Path Bkup RSVP Backup Path Byp RSVP Bypass Tunnel vccv BFD sessions over vccv Detect time Lsp Name lel rmt Op Ckt Name Fec to msec Sig St Role 24atm1 24 24 24 24 5000 5000 VCCV up actv 24eth1 24 24 24 24 5000 5000 VCCV up actv 24vlan1 24 24 24 24 5000 5000 VCCV up actv satop 24 24 24 24 5000 5000 VCCV up actv 37atm1 37 37 37 37 5000 5000 VCCV up actv 24eth2 vbrrt 24 24 24 24 5000 5000 VCCV up actv 37vlan1 37 37 37 37 5000 5000 VCCV up actv 37qinq 37 37 37 37 5000 5000 VCCV up actv elspto37 37 37 37 37 32 5000 300 Pri up actv LDP_24 24 24 24 321 24 24 24 24 32 5000 300 LDP up actv LDP _24 24 24 24 320 24 24 24 24 32 5000 300 LDP up actv LDP_24 24 24 24 32p 24 24 24 24 32 5000 300 LDP up actv Total Up 14 Total Down 0 Total 14 Use the show protocol bfd session vccv detail or extensive command to display the BFD over VCCV session information for both local and remote PW endpoints 8800 show protocol bfd session vccv extensive Application Mpls Circuit Name 24atm1 Type VCCV Circuit Type atm Circuit D
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