Method and apparatus for determining the status of a transmission link
Contents
1. calculates at the pro cessor 116 the status of the transmission link 108 based 56 References hua on the first status and the second status U S PATENT DOCUMENTS 6 154 446 11 2000 Kadambi et al 370 239 30 Claims 3 Drawing Sheets MANAGEMENT DEVICE PROCESSOR 116 114 MEMORY 102 105 112 106 FIRST SECOND DEVICE DEVICE 104 U S Patent Nov 19 2002 Sheet 1 of 3 US 6 484 202 1 MANAGEMENT DEVICE PROCESSOR 116 114 U S Patent Nov 19 2002 Sheet 2 of 3 US 6 484 202 1 GREATEST LEAST WEIGHT WEIGHT OUT OF SERMICE OUT OF SERVICE OUT OF SERVICE FACILITY IN SERVICE MANUAL AUTOMATIC PROBLEM Kho ce c FIG 2 CALCULATE THE STATUS OF THE TRANSMISSION LINK BASED ON FIRST STATUS AND SECOND STATUS 300 FIG 3 U S Patent Nov 19 2002 Sheet 3 of 3 US 6 484 202 1 FIG 4 400 401 CLEAR ALL BITS 403 IS PORT OUT OF SERVICE MANUAL 413 SET OUT OF SERVICE MANUAL BIT IS PORT OUT OF SERVICE AUTOMATIC IS PORT TESTING IS THERE AN OUT OF SERVICE FACILITY PROBLEM SET OUT OF SERVICE FACILITY PROBLEM BIT i m SET IN SERVICE 499 05 6 484 202 1 1 METHOD AND APPARATUS FOR DETERMINING THE STATUS OF A TRANSMISSION LINK FIELD OF THE INVENTION The present invention relates generally to communication systems and more particularly to a method2. the first port is connected as described below with regard to FIG 4 In the preferred embodiment of the present invention the first status of the first port is sent from the first device to the management device The first status is preferably sent from the first device to the management device via a first path that connects the first device to the management device The management device receives 303 the second status of a second port The determination of the second status of the second port is preferably done at a second device to which the second port is connected as described below with regard to FIG 4 In the preferred embodiment of the present invention the second status of the second port is sent from the second device to the management device The second status is preferably sent from the second device to the management device via a second path that connects the second device to the management device In the preferred embodiment the first path and the second path are distinct from each other Alternately the first path and the second path can be on the same link status of the transmission link between the first port and the second port is then calculated 305 based at least in part upon the first status and the second status In the preferred embodiment of the present invention the calcula tion is done at the management device The management device calculates the status of the transmission link by setting the transmi
3. 03 out of service automatic bit 204 and out of service manual bit 205 In the embodiment depicted in FIG 2 out of service manual bit 205 is the most significant bit and in service bit 201 is the least significant bit In the preferred embodiment as depicted in FIG 4 each port has a state information block and each of these bytes is cleared prior to determining the status of the port As the state is checked preferably from the most significant end to the least significant end a bit is set if a condition is found and the byte is then returned In the preferred embodiment the management device performs an ORing operation on the two bytes This sets the status of the transmission link between the two ports to the higher or most significant of the two ports that define the transmission link FIG 3 depicts a flowchart 300 for calculating the status of a transmission link in accordance with the preferred embodi ment of the present invention In the preferred embodiment of the present invention the management device calculates the status of the transmission link Alternately the first device or the second device can calculate the status of the transmission link In accordance with the preferred embodiment the man agement device receives 301 the status of a first port The determination of the first status of the first port is preferably 10 15 20 30 40 45 50 55 60 65 4 done at a first device to which
4. 6 wherein the means for calculating the status of the transmission link comprises a management device 12 Amethod for determining the status of a transmission link between a first port of a first device and a second port of a second device the method comprising the steps of determining a first status of the first port determining a second status of the second port and calculating the status of the transmission link utilizing the first status and the second status 13 A method for determining the status of a transmission link in accordance with claim 12 wherein the step of calculating the status of the transmission link comprises the step of setting the status of the transmission link to the greater of the first status and the second status 05 6 484 202 1 7 14 Amethod for determining the status of transmission link in accordance with claim 12 wherein the status of the transmission link is calculated to be out of service if either the first status or the second status is out of service 15 Amethod for determining the status of a transmission link in accordance with claim 12 the method further com prising the step of sending an alarm when the status is calculated to be a predetermined value 16 Amethod for determining the status of a transmission link in accordance with claim 12 the method further com prising the step of updating a log when the status is calcu lated to be a predetermined value 17 Amethod for de
5. US006484202B1 a United States Patent ao Patent No US 6 484 202 LeDuc et al 45 Date of Patent Nov 19 2002 54 METHOD AND APPARATUS FOR 6 335 932 B2 1 2002 Kadambi et al 370 391 DETERMINING THE STATUS OF A 6 335 935 B2 1 2002 Kadambi et al 370 396 TRANSMISSION LINK FER 2 75 Inventors Douglas Edward LeDuc Yorkville IL citediby examinet US David Frank Simak Wheaton IL US Primary Examiner Moustafa 73 Assignee Lucent Technologies Inc Murray Hill 74 Attorney Agent or Firm John B MacIntyre NJ US 57 ABSTRACT Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 The present invention provides a method apparatus and U S C 154 b by 0 days communication system 100 for determining the status of a transmission link 108 between a first port 105 of a first 21 Appl No 09 441 437 device 104 and a second port 107 of a second device 22 Filed Nov 16 1999 106 The communication system 100 includes a manage 51 Int CI GO6F 13 00 ment device 102 The management device 102 includes 2 e pes c um Hee an ipit port arprocessoc 116 The management 58 Field of Search 704 200 201 device 102 receives a first status of the first port 105 and 704 212 213 224 370 242 244 248 second status of the second port 107 on the input port 251 103 The management device 102
6. a computer a modem pool or any other piece of electronic equipment that is able to be coupled to another device 10 15 20 25 30 35 40 45 50 55 60 65 2 The preferred embodiment of the present invention com prises receiving at the management device a first status of the first port and a second status of the second port The first status is preferably determined at the first device and sent to the management device while the second status of the second device is preferably determined at the second device and sent to the management device The management device which is preferably located remotely from the first device and the second device receives the first status via a first path and the second status via a second path that is distinct from the first path The first path and the second path can be distinct from the transmission link The management device then calculates the status of the transmission link based on the first status and the second status In the preferred embodiment the step of calculating the status of the transmission link comprises the step of setting the status of the transmission link to the greater or most critical of the first status and the second status Accordingly the status of the transmission link is calculated to be out of service if either the first status or the second status indicates that either link is out of service An alarm can be sent when the status is calculate
7. and apparatus for determining the status of a transmission link in a commu nication system BACKGROUND OF THE INVENTION Communication systems typically include multiple devices that communicate with each other over links con necting the devices These links commonly referred to as transmission links are typically wirelines that run between ports on the devices Each device in a typical network knows the status of its ports However the device is typically not aware of the status of ports on other devices Consequently each device does not know the status of the link since the status of the link is determined by the status of the two ports that the link is connected to Therefore each device is only aware of the status of its link and through that status whether the link attached to the port is operational Ports can have different statuses For example a port can be in service out of service or testing If a port is in an out of service state for example a transmission link utiliz ing that port typically cannot be used However the port at the other end of the transmission link is unaware of the status of the port on the other end and in the view from that port the transmission link is operational One approach used to test a transmission link between two devices is referred to as a loop back test In a loop back process a signal is sent over a transmission link from a first device to the second device The message is imme
8. and includes a first port 105 First device 104 is preferably switch but can alternately be a phone a computer a modem pool or any communication equipment that is linked to another piece of communication equipment and also linked to a management device Second device 106 is coupled to management device 102 and includes a second port 107 Second device 106 is preferably a switch but can alternately be a phone a computer a modem pool or any communication equipment that is linked to another piece of communication equipment and also linked to a management device Transmission link 108 couples first device 104 and second device 106 and is disposed between first port 105 and second port 107 In the preferred embodiment first device 104 is coupled to management device 102 by first path 110 and second device 106 is coupled to management device 102 by second path 112 First path 110 and second path 112 are preferably distinct from each other and paths 110 and 112 are also preferably distinct from transmission link 108 By isolating first path 110 second path 112 and transmission link 108 the status of the links can still be communicated when any of the paths are down or non operational FIG 2 depicts state information 200 relating to the state of a port in accordance with the preferred embodiment of the present invention State information 200 preferably includes in service bit 201 out of service facility problem bit 202 testing bit 2
9. computer and a modem pool 30 Acommunication system in accordance with claim 27 wherein the processor is located in the management device
10. d to be a predetermined value such as an out of service alarm In addition a log can be updated when the status is calculated to be a predeter mined value BRIEF DESCRIPTION OF THE DRAWINGS FIG 1 depicts a communication system including a management device coupled to a first device and a second device in accordance with the preferred embodiment of the present invention FIG 2 depicts a state information block relating to the state of a port in accordance with the preferred embodiment of the present invention FIG 3 depicts a flowchart for calculating the status of a transmission link in accordance with the preferred embodi ment of the present invention FIG 4 depicts a flowchart for determining the status of a port of a device in accordance with the preferred embodi ment of the present invention DESCRIPTION OF THE PREFERRED EMBODIMENT S FIG 1 depicts a communication system 100 including a management device 102 coupled to a first device 104 and a second device 106 in accordance with the preferred embodi ment of the present invention Management device 102 preferably includes an input port 103 a processor 116 and memory 114 Input port 103 is effective in receiving a first status of first port 105 and a second status of second port 107 Input port 103 is prefer ably an Ethernet connection running TCP IP Transmission Control Protocol Internet Protocol It should be understood that management device 102 can include a pl
11. diately looped back to the first device In this manner the trans mission link can be tested to determine whether the trans mission link is operational One problem with loop back testing is that the transmis sion link is out of service while the loop back testing is occurring In addition loop back testing is typically a test condition meaning that it is operator driven Typically a loop back test is performed after determining that there is a problem with the transmission link The loop back test is just one test used to determine the state of the link Consequently since the loop back test is run only after an error has occurred the loop back test is not a real time way of determining the status of the transmission link Therefore a need exists for a method and apparatus that is able to determine in real time the status of a transmission link between two devices SUMMARY OF THE INVENTION It is an object of the present invention to provide a real time solution to the aforementioned problem by utiliz ing the states of a first port and a second port to determine the status of a transmission link disposed between the first and second ports The present invention provides a method apparatus management device and communication system for deter mining the status of a transmission link between a first port of a first device and a second port of a second device The first device and the second device can be a switch a phone
12. ld be understood that other factors can be consid ered when calculating the status of the first and second ports Further the factors can be placed in alternate orders to change the priority of the conditions that each port is currently in In addition although the preferred embodiment utilizes an ORing operation to choose the highest priority selected to determine the state of the transmission link other operation could alternately be used to calculate the state of the transmission link The present invention thereby provides a method apparatus and communication system for determining the status of a transmission link By sending the status of each port to a management device the management device is able to calculate the status of the transmission link between the two ports based upon the status of each of the ports In this manner a reliable calculation of the status of the transmis sion link is obtained thereby increasing system reliability and effectiveness Further because the ports can send their status upon the occurrence of a predetermined condition the status of the transmission link can be monitored in a much more timely fashion than the prior art Since the status of the transmission link is determined by using the status of the ports the transmission link does not need to be taken out of service in order to test its status By using the status of each of the ports of the transmission link a real time or near real time dete
13. r mination of the status of the transmission link can be obtained without the need to take the link out of service to run a loop back or similar test 10 15 20 25 35 40 45 50 55 60 65 6 While this invention has been described in terms of certain examples thereof it is not intended that it be limited to the above description but rather only to the extent set forth in the claims that follow The embodiment of this invention in which an exclusive property or privilege is claimed are defined as follows We claim 1 A method for determining the status of a transmission link between a first port of a first device and a second port of a second device the method comprising the steps of receiving at a management device a first status of the first port and a second status of the second port and calculating at the management device the status of the transmission link based on the first status and the second status 2 A method for determining the status of a transmission link in accordance with claim 1 wherein the step of receiv ing the first status and the second status comprises the step of receiving the first status and the second status at a management device located remotely from the first device and the second device 3 A method for determining the status of a transmission link in accordance with claim 1 wherein the step of receiv ing the first status and the second status comprises the step of recei
14. ssion link status to the most significant bit of the first status and the second status As one example if the first status or the second status is out of service the status of the transmission link is calcu lated to be out of service After calculating the status of the link the management device can send an alarm when the status is calculated to be a predetermined value For example if the status is deter mined to be out of service an alarm can be sent to an operator to alert the operator of the out of service state Further the management device can update a log such as an error log when the status is calculated to be a predetermined value This can assist in determining any conditions that lead to error conditions Still further the status can be stored at the management device or in memory coupled to the man agement device This stored status can then be used for comparisons calculations or display at a later time FIG 4 depicts a flowchart 400 for determining the status of a port of a device in accordance with the preferred embodiment of the present invention In the preferred embodiment of the present invention the process of flow chart 400 is accomplished in the first device and the second device The first device utilizes flowchart 400 to determine the status of the first port The second device utilizes flowchart 400 to determine the status of the second port In the preferred embodiment the first device will send the s
15. t of service automatic if the failure cannot be repaired automatically through initializa tion or other automatic action If the first port is in this mode the first device sets 415 the out of service automatic bit The process then ends 499 If the first port is not in out of service automatic mode the first device determines 407 if the first port is in a testing mode determines 407 if the first port is in a testing mode Testing mode refers to a situation where the port is currently involved in running a loop back or other facility test If the first port is in a testing mode the first device sets 417 the testing bit and then ends 499 If the first port is not in testing mode the first device determines 409 if the first port is in an out of service facility problem mode Out of service facility problem mode refers to a situation where a condition exists indicating a problem in the signal received over the link from the other port This may be due to a physical severing of a cable or fiber If the first port is in such a mode the first device sets 419 the out of service facility problem bit and then ends 499 If the first port is not in an out of service facility problem mode the first device determines 411 if the first port is in service In service indicates that the port is operating properly If the first port is in service the first device sets 421 the in service bit and the process then ends 499 It shou
16. tatus of the first port to the management device and the second device sends the status of the second port to the management device The management device uses these status values to calculate the status of the transmission link between the first port and the second port process of flowchart 400 is described below with regard to the first device determining the status of the first port It should be understood that the same process is preferably utilized by the second device to determine the status of the second port For clarity only a description of the first device determining the status of the first port is given below In accordance with the preferred embodiment the first device clears 401 all bits The first device then determines 05 6 484 202 1 5 403 if the first port is an out of service manual mode Out of service manual mode refers to a situation where a technician instructs the system to take the port out of service This is typically done for system maintenance purposes If the first port is out of service the first device sets 413 the out of service manual bit The process then ends 499 If the first port is not in out of service manual mode the first device determines 405 if the first port is in an out of service automatic mode Out of service automatic refers to a situation where a device or port fails and the system recovers from the failure The recovery typically leaves the device or port ou
17. termining the status of a transmission link in accordance with claim 12 wherein the step of determining the first status of the first port is performed at the first device 18 method for determining the status of a transmission link in accordance with claim 17 the method further com prising the step of sending the first status from the first device to a management device 19 Amethod for determining the status of a transmission link in accordance with claim 12 wherein the step of determining the second status of the second port is per formed at the second device 20 A method for determining the state of a transmission link in a communication system in accordance with claim 19 further comprising the step of sending the second status from the second device to a management device 21 Amethod for determining the status of a transmission link in accordance with claim 12 the method further com prising the step of storing the status 22 A management device for determining the status of a transmission link between a first port of a first device and a second port of a second device the management device comprising an input port effective in receiving a first status of the first port and a second status of the second port and a processor for calculating the status of the transmission link based on the first status and the second status 10 15 20 25 30 35 8 23 A management device in accordance with claim 22
18. the management device further comprising memory effec tive to store the status of the transmission link 24 A management device in accordance with claim 22 the management device further comprising an output port effective to output the status of the transmission link 25 A management device in accordance with claim 22 wherein the first status and the second status are associated with the first device and the second device respectively and the input port and the processor are located remote from the first device and the second device 26 A management device in accordance with claim 25 wherein the input port receives the first status and the second status via a path other than the transmission link 27 A communication system comprising a management device a first device coupled to the management device and including a first port a second device coupled to the management device and including a second port a transmission link coupling the first port to the second port and a processor for calculating the status of the transmission link based at least in part upon the state of the first port and the second port 28 Acommunication system in accordance with claim 27 wherein the first device is selected from a group consisting of a switch a phone a computer and a modem pool 29 Acommunication system in accordance with claim 27 wherein the second device is selected from a group consist ing of a switch a phone a
19. urality of input ports but only one is depicted for clarity In the preferred embodiment management device 102 is located remotely from first device 104 and second device 106 Processor 116 is effective for calculating the status of transmission link 108 In the preferred embodiment proces sor 116 calculates the status of transmission link 108 based on the first status of first port 105 and the second status of second port 107 Memory 114 is effective in storing the status of transmis sion link 108 Memory 114 can be Random Access Memory RAM electromagnetic optical flash or any other media effective in storing the status of transmission link 108 05 6 484 202 1 3 Management device 102 preferable includes an output port 118 that is effective in outputting the status of trans mission link 108 This port is preferably a Graphical User Interface GUI but can alternately be a command line interface a printer a browser or a terminal The port is preferably connected to a monitoring device such as a terminal personal computer or workstation for operation and use of the system Management device 102 is effective for determining the status of a transmission link 108 Transmission link 108 is a link such as T1 El 053 STS1 or OC12 disposed between a first port 105 of a first device and a second port of a second device the management device comprising First device 104 is coupled to management device 102
20. ving the first status via a first path and receiving the second status via a second path 4 A method for determining the status of a transmission link in accordance with claim 3 wherein the first path and the second path are distinct from each other 5 A method for determining the status of a transmission link in accordance with claim 3 wherein the first path and the second path are distinct from the transmission link 6 An apparatus for determining the status of a transmis sion link between a first port of a first device and a second port of a second device the apparatus comprising means for receiving a first status of the first port and a second status of the second port and means for calculating the status of the transmission link based on the first status and the second status 7 An apparatus in accordance with claim 6 wherein the means for receiving the first status and the second status comprises a management device 8 An apparatus in accordance with claim 6 wherein the means for receiving is located remotely from the first device and the second device 9 An apparatus in accordance with claim 6 wherein the means for receiving receives the first status via a first path and receives the second status via a second path distinct from the first path 10 An apparatus in accordance with claim 6 wherein the first path and the second path are distinct from the trans mission link 11 An apparatus in accordance with claim
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