Seamless path monitoring and rapid fault isolation using bidirectional forwarding detection in a network environment

• US 9,497,107 B1
• Filed: 03/14/2014
• Issued: 11/15/2016
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Nainar, Nagendra Kumar, Akiya, Nobushige, Ward, David D., Pignataro, Carlos M., Saad, Tarek, Sivabalan, Muthurajah
• Primary Examiner(s): Sam, Phirin
• Assistant Examiner(s): Ghafoerkhan, Faiyazkhan
• Application Number:
  US14/211,710
• Time in Patent Office: 977 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 41/0677 Localisation of faults
• CPC Class Codes: H04L 43/0811 by checking connectivity
• CPC Class Codes: H04L 43/10 Active monitoring, e.g. heartbeat, ping or trace-route
• CPC Class Codes: H04L 45/22 Alternate routing
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]

Abstract

An example method for seamless path monitoring and rapid fault isolation using bidirectional forwarding detection (BFD) in a network environment is provided and includes determining a BFD target identifier type for communicating in a BFD session in a network environment, determining a non-zero globally assigned BFD discriminator value associated with the BFD target identifier type, populating a Your Discriminator field in a BFD Control Packet with the non-zero globally assigned BFD discriminator value, with a My Discriminator field in the BFD Control Packet being populated with a locally assigned BFD Discriminator value, and initiating the BFD session by transmitting the BFD Control Packet to a target node in the network. In a specific embodiment, the BFD target identifier type is type 3, and the non-zero globally assigned BFD discriminator is an Alert Discriminator reserved by substantially all nodes in the network exclusively for BFD traceroute operations.

Claims

1. A method, comprising:

determining a bidirectional forwarding detection (BFD) target identifier type for communicating in a BFD session in a network environment;

determining a non-zero globally assigned BFD discriminator value associated with the BFD target identifier type, wherein, if the BFD target identifier type is indicative of executing traceroute operations in the network, the non-zero globally assigned BFD discriminator is an Alert Discriminator reserved by nodes in the network exclusively for BFD traceroute operations;

populating a Your Discriminator field in a BFD Control Packet with the non-zero globally assigned BFD discriminator value, wherein a My Discriminator field in the BFD Control Packet is populated with a locally assigned BFD Discriminator value; and

initiating the BFD session by transmitting the BFD Control Packet to a target node in the network, wherein the target node is configured to listen for BFD Control Packets having the non-zero globally assigned BFD discriminator value in respective Your Discriminator fields.

2. The method of claim 1, wherein the non-zero globally assigned BFD discriminator comprises any 32 bit value that can uniquely identify the target node in the network.

3. The method of claim 1, wherein if the BFD target identifier type is type 1 on an Internet Protocol (IP) network, the non-zero globally assigned BFD discriminator is an IP address of the target node when the network uses IPv4 addresses, and the non-zero globally assigned BFD discriminator is a router identifier (router ID) associated with the target node when the network uses IPv6 addresses.

4. The method of claim 1, wherein if the BFD target identifier type is type 2 on a segment routing (SR) enabled network, the non-zero globally assigned BFD discriminator is a node segment ID associated with the target node.

5. The method of claim 1, wherein the BFD target identifier type is type 3 for executing traceroute operations in the network.

6. The method of claim 5, further comprising specifying a BFD diagnostic code associated with the Alert Discriminator in the BFD Control Packet, wherein the BFD diagnostic code indicates a reason for using the type 3 BFD target identifier.

7. The method of claim 1, wherein the network is enabled for Multiprotocol Label Switching (MPLS), wherein the method further comprises setting a destination address in the BFD Control Packet to a localhost address, wherein the BFD Control Packet is transmitted using MPLS.

8. The method of claim 7, wherein a last 23 bits of the localhost address includes an MPLS label for MPLS label verification, wherein the last 23 bits of the localhost address is set to zero for reachability validation.

9. The method of claim 8, wherein the MPLS label includes an adjacency segment ID on a SR enabled network.

10. The method of claim 1, wherein the target node receives the BFD Control Packet, examines the Your Discriminator and My Discriminator fields, swaps values in the My Discriminator and Your Discriminator fields in a response BFD Control Packet, and transmits the response BFD Control Packet to a source address provided in the BFD Control Packet.

11. Non-transitory tangible media that includes instructions for execution, which when executed by a processor of a network node, is operable to perform operations comprising:

determining a BFD target identifier type for communicating in a BFD session in a network environment;

determining a non-zero globally assigned BFD discriminator value associated with the BFD target identifier type, wherein, if the BFD target identifier type is indicative of executing traceroute operations in the network, the non-zero globally assigned BFD discriminator is an Alert Discriminator reserved by nodes in the network exclusively for BFD traceroute operations;

populating a Your Discriminator field in a BFD Control Packet with the non-zero globally assigned BFD discriminator value, wherein a My Discriminator field in the BFD Control Packet is populated with a locally assigned BFD Discriminator value; and

initiating the BFD session by transmitting the BFD Control Packet to a target node in the network, wherein the target node is configured to listen for BFD Control Packets having the non-zero globally assigned BFD discriminator value in respective Your Discriminator fields.

12. The media of claim 11, wherein the non-zero globally assigned BFD discriminator comprises any 32 bit value that can uniquely identify the target node in the network.

13. The media of claim 11, wherein if the BFD target identifier type is type 1 on an IP network, the non-zero globally assigned BFD discriminator is an IP address of the target node when the network uses IPv4 addresses, and the non-zero globally assigned BFD discriminator is a router ID associated with the target node when the network uses IPv6 addresses.

14. The media of claim 11, wherein if the BFD target identifier type is type 2 on a SR enabled network, the non-zero globally assigned BFD discriminator is a node segment ID associated with the target node.

15. The media of claim 11, wherein the BFD target identifier type is type 3 for executing traceroute operations in the network.

16. An apparatus, comprising:

a memory element for storing data; and

a processor, wherein the processor executes instructions associated with the data, wherein the processor and the memory element cooperate, such that the apparatus is configured for;

determining a BFD target identifier type for communicating in a BFD session in a network environment;

determining a non-zero globally assigned BFD discriminator value associated with the BFD target identifier type, wherein, if the BFD target identifier type is indicative of executing traceroute operations in the network, the non-zero globally assigned BFD discriminator is an Alert Discriminator reserved by nodes in the network exclusively for BFD traceroute operations;

populating a Your Discriminator field in a BFD Control Packet with the non-zero globally assigned BFD discriminator value, wherein a My Discriminator field in the BFD Control Packet is populated with a locally assigned BFD Discriminator value; and

initiating the BFD session by transmitting the BFD Control Packet to a target node in the network, wherein the target node is configured to listen for BFD Control Packets having the non-zero globally assigned BFD discriminator value in respective Your Discriminator fields.

17. The apparatus of claim 16, wherein the non-zero globally assigned BFD discriminator comprises any 32 bit value that can uniquely identify the target node in the network.

18. The apparatus of claim 16, wherein if the BFD target identifier type is type 1 on an IP network, the non-zero globally assigned BFD discriminator is an IP address of the target node when the network uses IPv4 addresses, and the non-zero globally assigned BFD discriminator is a router ID associated with the target node when the network uses IPv6 addresses.

19. The apparatus of claim 16, wherein if the BFD target identifier type is type 2 on a SR enabled network, the non-zero globally assigned BFD discriminator is a node segment ID associated with the target node.

20. The apparatus of claim 16, wherein the BFD target identifier type is type 3 for executing traceroute operations in the network.