Seamless segment routing

• US 10,164,838 B2
• Filed: 06/30/2017
• Issued: 12/25/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Filsfils, Clarence, Ward, David D., Bryant, Stewart F., Frost, Daniel C., Nainar, Nagendra Kumar, Pignataro, Carlos M.
• Primary Examiner(s): Renner, Brandon M
• Application Number:
  US15/639,398
• Publication Number:
  US 20170302561A1
• Time in Patent Office: 543 Days
• Field of Search: None
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/12 Shortest path evaluation
• CPC Class Codes: H04L 45/46 Cluster building
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/507 Label distribution
• CPC Class Codes: H04L 45/54 Organization of routing tables
• CPC Class Codes: H04L 45/74 Address processing for routing
• CPC Class Codes: H04L 45/745 Address table lookup; Address filtering
• CPC Class Codes: H04L 45/7452 Multiple parallel or consecutive lookup operations lookup operation involving Bloom filters H04L45/7459
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 49/608 ATM switches adapted to switch variable length packets, e.g. IP packets

Abstract

A method, network device, and computer readable medium are disclosed. In one embodiment of the method, a data packet is received at a node within a first segment routing enabled access network. The first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network, and a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided network. The method embodiment further includes receiving from a centralized controller a remote segment identifier stack, where the remote segment identifier stack encodes a path extending from the first area edge node to the second access network. The embodiment of the method continues with encapsulating the data packet with a full segment identifier stack comprising the remote segment identifier stack, and forwarding the encapsulated data packet toward the first area edge node.

Claims

1. A method comprising:

receiving, at a node within a first segment routing enabled access network, a data packet, wherein

the first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network,

the first area comprises two or more nodes within the subdivided segment routing enabled network, and

a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided segment routing enabled network;

receiving, from a centralized controller for the subdivided segment routing enabled network, a remote segment identifier stack, wherein

the remote segment identifier stack encodes a path extending from the first area edge node to the second segment routing enabled access network;

encapsulating the data packet with a full segment identifier stack comprising the remote segment identifier stack; and

forwarding the encapsulated data packet toward the first area edge node.

2. The method of claim 1, further comprising:

sending, to the centralized controller, a request for the remote segment identifier stack.

3. The method of claim 2, wherein the request comprises destination information for the data packet.

4. The method of claim 3, wherein the destination information comprises a destination address carried by the data packet.

5. The method of claim 3, wherein the destination information comprises a unique identifier for a segment routing enabled node within the second segment routing enabled access network.

6. The method of claim 3, wherein the request further comprises an identification of the first area edge node.

7. The method of claim 1, wherein the full segment identifier stack further comprises an area-segment identifier identifying the first area.

8. The method of claim 7, wherein the full segment identifier stack further comprises a nodal segment identifier identifying the first area edge node.

9. A network device comprising:

one or more network interfaces adapted for connection of the network device within a first segment routing enabled access network, wherein

the first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network, and

the first area comprises two or more nodes within the subdivided segment routing enabled network; and

a processor adapted to

receive a data packet, wherein

a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided segment routing enabled network,

receive, from a centralized controller for the subdivided segment routing enabled network, a remote segment identifier stack, wherein

the remote segment identifier stack encodes a path extending from the first area edge node to the second segment routing enabled access network,

encapsulate the data packet with a full segment identifier stack comprising the remote segment identifier stack, and

forward the encapsulated data packet toward the first area edge node.

10. The network device of claim 9, wherein the processor is further adapted to send, to the centralized controller, a request for the remote segment identifier stack.

11. The network device of claim 10, wherein the request comprises destination information for the data packet.

12. The network device of claim 11, wherein the request further comprises an identification of the first area edge node.

13. The network device of claim 9, wherein the full segment identifier stack further comprises an area-segment identifier identifying the first area.

14. The network device of claim 13, wherein the full segment identifier stack further comprises a nodal segment identifier identifying the first area edge node.

15. A non-transitory computer readable medium comprising executable instructions, wherein a method is implemented in response to executing the instructions, the method comprising:

receiving, at a node within a first segment routing enabled access network, a data packet, wherein

the first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network,

the first area comprises two or more nodes within the subdivided segment routing enabled network, and

a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided segment routing enabled network;

receiving, from a centralized controller for the subdivided segment routing enabled network, a remote segment identifier stack, wherein

the remote segment identifier stack encodes a path extending from the first area edge node to the second segment routing enabled access network;

encapsulating the data packet with a full segment identifier stack comprising the remote segment identifier stack; and

forwarding the encapsulated data packet toward the first area edge node.

16. The non-transitory computer readable medium of claim 15, wherein the method further comprises:

sending, to the centralized controller, a request for the remote segment identifier stack.

17. The non-transitory computer readable medium of claim 16, wherein the request comprises destination information for the data packet.

18. The non-transitory computer readable medium of claim 17, wherein the request further comprises an identification of the first area edge node.

19. The non-transitory computer readable medium of claim 15, wherein the full segment identifier stack further comprises an area-segment identifier identifying the first area.

20. The non-transitory computer readable medium of claim 19, wherein the full segment identifier stack further comprises a nodal segment identifier identifying the first area edge node.