Method and apparatus for fault detection and isolation in data

• US 6,173,324 B1
• Filed: 07/15/1998
• Issued: 01/09/2001
• Est. Priority Date: 07/15/1998
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: DʼSouza, Kevin L.
• Primary Examiner(s): Coleman, Eric
• Application Number:
  US09/116,129
• Time in Patent Office: 909 Days
• Field of Search: 712/1, 709/238, 709/242, 709/249, 709/250, 709/224, 714/42, 714/53, 710/105
• US Class Current: 709/224
• CPC Class Codes: H04L 41/0659 by isolating or reconfiguring faulty entities
• CPC Class Codes: H04L 41/147 for predicting network behaviour
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors

Abstract

A processor (21) monitors a data network (10) to proactively detect customer connectivity troubles by actively monitoring each router (18₁ and 18₂) to determine new and missing route destinations, Border Gateway Protocol (BGP) sessions and Open Shortest Path First (OSPF) adjacencies, by execution of three sub-routines rtchk(22), bgpchk (24) and ospfchk (26), respectively. Upon detecting a new or missing route destination, BGP session or OSPF adjacency, the processor alerts those responsible for maintaining the network of such an error.

Claims

1. A method for detecting and isolating connectivity troubles in a data network that includes links extending between routers that route traffic between at least one data source and at least one data destination in accordance with route destinations stored in the routing tables in the routers as a consequence of one of a Border Gateway Protocol Session and a Open Shortest Path First Adjacency stored in each router, the method comprising the steps of:

(a) examining the routing table in each router to detect an erroneous route destination; and

if so, then generating an alarm indicative of such an error;

(b) examining each router to detect an erroneous Border Gateway Protocol (BGP) session, and if so, then generating an alarm indicative of such error; and

(c) examining each router to detect an erroneous Open Shortest Path First (OSPF) adjacency, and if so, then generating an alarm indicative of a such error.

2. The method according to claim 1 wherein steps (a), (b) and (c) are repeated.

3. The method according to claim 1 wherein an erroneous route destination is detected when a predetermined route destination is not found within a routing table in a router.

4. The method according to claim 2 wherein an erroneous route destination is detected when a new route destination is found in a routing table that was not previously detected.

5. The method according to claim 1 wherein an erroneous BGP session is detected if a prescribed BGP session is not found in a router.

6. The method according to claim 2 wherein an erroneous BGP session is detected when a new BGP session is found in a routing router that was not previously detected.

7. The method according to claim 1 wherein an erroneous OSPF adjacency is detected if a prescribed OSPF adjacency is not found in a router.

8. The method according to claim 2 wherein an erroneous OSPF adjacency is detected when a new OSPF adjacency is found in a router that was not previously detected.

9. The method according to claim 2 including the steps of:

storing route destination information, BGP session information, and OSPF adjacency information in both a Reference file and a Current file upon initial execution of steps (a), (b) and (c) and

storing route destination information, BGP session information, and OSPF adjacency information in a Current file upon each subsequent execution of steps (a), (b) and (c).

10. The method according to claim 9 wherein an erroneous route destination is detected when a predetermined route destination is found within one but not both of the Current and Reference files.

11. The method according to claim 9 wherein an erroneous BGP session is detected when a BGP session is found within one but not both of the Current and Reference files.

12. The method according to claim 9 wherein an erroneous OSPF adjacency is detected when an OSPF adjacency is found within one but not both of the Current and Reference files.

13. Apparatus for detecting and isolating connectivity troubles in a data network that includes links extending between routers that route traffic between at least one data source and at least one data destination in accordance with route destinations stored in the routing tables in the routers as a consequence of one of a Border Gateway Protocol Session and an Open Shortest Path First Adjacency stored in each router, the apparatus comprising a processor for

(a) examining the routing table in each router to detect an erroneous route destination;

and if so, then generating an alarm indicative of such an error;

(b) examining each router to detect an erroneous Border Gateway Protocol (BGP) session, and if so, then generating an alarm indicative of such error; and

(c) examining each router to detect an erroneous Open Shortest Path First (OSPF) adjacency, and if so, then generating an alarm indicative of a such an error.

14. The apparatus according to claim 13 wherein the processor includes:

a Current file for storing route destination information, BGP session information, and OSPF adjacency information upon initial examination of each router and its routing table; and

a Reference file for storing route destination information, BGP session information, and OSPF adjacency information upon each subsequent examination of each router and its routing table.

15. The apparatus according to claim 14 wherein the processor detects an erroneous route destination by checking whether a predetermined route destination is found within one but not both of the Current and Reference files.

16. The apparatus according to claim 14 wherein the processor detects an erroneous BGP session by checking whether a BGP session is found within one but not both of the Current and Reference files.

17. The apparatus according to claim 14 wherein the processor detects an erroneous OSPF adjacency by checking whether an OSPF adjacency is found within one but not both of the Current and Reference files.