Multi-domain source routed forwarding based on collaborating network controllers

Patent metadata

Field	Value
Publication number	US-9680745-B2
Application number	US-201414159072-A
Country	US
Kind code	B2
Filing date	Jan 20, 2014
Priority date	Jan 20, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

Efficient and scalable source routed forwarding can be achieved in multi-domain networks by substituting path identifiers for intra-domain hop lists in source route hop lists. The path identifiers are then replaced with the corresponding intra-domain hop lists at the ingress edge nodes of each corresponding domain. The path identifiers do not specify individual hops along an intra-domain path segment, and are therefore typically shorter than the intra-domain hop lists. To facilitate multi-domain source routed forwarding techniques, routing tables in edge nodes of the corresponding domains are updated to associate the path identifiers with the corresponding intra-domain hop lists during (or immediately following) inter-domain path computation.

First claim

What is claimed:

1. A method for source routed forwarding in a network, the method comprising:
receiving, by an edge node in a domain, a first data packet of a traffic flow over an inter-domain path, the first data packet preceding every other data packet in the traffic flow, the inter-domain path being a source-routed path traversing a route specified by a source of the first data packet, the first data packet appended with a packet header carrying a source route hop list, wherein the source route hop list specifies a path identifier of an intra-domain path segment without specifying individual hops along the intra-domain path segment, and wherein the intra-domain path segment is a portion of the inter-domain path that extends through the domain;
identifying, by the edge node, a hop list associated with the path identifier, the hop list specifying a sequence of next-hop addresses along the intra-domain path segment;
replacing the path identifier with the hop list in the packet header such that the next-hop addresses along the intra-domain path segment can be read directly from the packet header by intermediate nodes on the intra-domain path segment; and
forwarding the first data packet to a next hop of the intra-domain path segment in accordance with the hop list.

2. The method of claim 1 , wherein identifying the hop list associated with the path identifier comprises:
locating an entry associating the path identifier with the hop list in a forwarding table stored at the edge node.

3. The method of claim 2 , wherein the edge node identifies the hop list without querying external devices during a period between receiving the first data packet and forwarding the first data packet.

4. The method of claim 3 , further comprising:
receiving, by the edge node, a first control message from a controller prior to receiving the first data packet over the inter-domain path, the first control message instructing the edge node to write the entry into the forwarding table; and
receiving, by the edge node, a second control message from the controller after forwarding the first data packet to the next hop of the intra-domain path segment, the second control message instructing the edge node to remove the entry from the forwarding table.

5. The method of claim 1 , wherein the first data packet carries data, and wherein forwarding the first data packet to the next hop comprises forwarding the first data packet over a data plane of the network.

6. The method of claim 1 , wherein a length of the path identifier is shorter than a length of the hop list.

7. The method of claim 1 , wherein the path identifier comprises a Multiprotocol Label Switching (MPLS) label.

8. The method of claim 1 , wherein the path identifier comprises an internet protocol (IP) version four (IPv4) or IP version six (IPv6) address.

9. The method of claim 1 , wherein the path identifier comprises a type length value (TLV) encoding.

10. An edge node in a domain, the edge node comprising:
a processor; and
a computer readable storage medium storing programming for execution by the processor, the programming including instructions to:
receive a first data packet of a traffic flow over an inter-domain path, the first data packet preceding every other data packet in the traffic flow, the inter-domain path being a source-routed path traversing a route specified by a source of the first data packet, the first data packet appended with a packet header carrying a source route hop list, wherein the source route hop list specifies a path identifier of an intra-domain path segment without specifying individual hops along the intra-domain path segment, and wherein the intra-domain path segment is a portion of the inter-domain path that extends through the domain;
identify a hop list associated with the path identifier, the hop list specifying a sequence of next-hop addresses along the intra-domain path segment;
replace the path identifier with the hop list in the packet header such that the next-hop addresses can be read directly from the packet header by intermediate nodes on the intra-domain path segment; and
forward the first data packet to a next hop of the intra-domain path segment in accordance with the hop list.

11. The edge node of claim 10 , wherein the instructions to identify the hop list associated with the path identifier include instructions to:
locate an entry associating the path identifier with the hop list in a forwarding table stored at the edge node.

12. The edge node of claim 10 , wherein the path identifier comprises one of a Multiprotocol Label Switching (MPLS) label, an internet protocol (IP) version four (IPv4) address, an IP version six (IPv6) address, and a type length value (TLV) encoding.

13. A method for source routed forwarding, the method comprising:
receiving, by a controller, a request to configure an inter-domain path between a source node and a destination node for a traffic flow, the inter-domain path being a source-routed path traversing a route specified by the source node;
obtaining, by the controller, a path identifier of an intra-domain path segment extending through a domain, the intra-domain path segment representing a portion of the inter-domain path;
constructing a source route hop list that specifies the path identifier without specifying individual hops along the intra-domain path segment;
sending the source route hop list to a device, wherein the source route hop list is configured to be appended to a first data packet of the traffic flow at the source node prior to the first data packet being communicated over the inter-domain path, the first data packet preceding every other data packet in the traffic flow; and
sending, or prompting another controller to send, a first control message to an edge node in the domain, the first control message instructing the edge node to replace the path identifier with a hop list in a header of the first data packet upon receiving the first data packet over the inter-domain path and prior to forwarding the first data packet over the intra-domain path segment, the hop list specifying a sequence of next-hop addresses along the intra-domain path segment, wherein replacing the path identifier with the hop list at the edge node enables intermediate nodes on the intra-domain path segment to directly read the next-hop addresses along the intra-domain path segment from the header of the first data packet.

14. The method of claim 13 , wherein the path identifier excludes information relating to individual hops along the intra-domain path segment.

15. The method of claim 13 , the first control message further instructing the edge node to write an entry into a forwarding table that associates the path identifier with a hop list specifying a sequence of hops along the intra-domain path segment.

16. The method of claim 15 , wherein the first control message is sent to the edge node prior to the first data packet being communicated over the inter-domain path.

17. The method of claim 16 , further comprising:
sending, or prompting another controller to send, a second control message to the edge node after the first data packet is transported over the inter-domain path, wherein the second control message instructs the edge node to remove the entry from the forwarding table.

18. The method of claim 13 , wherein the path identifier comprises one of a Multiprotocol Label Switching (MPLS) label, an internet protocol (IP) version four (IPv4) address, an IP version six (IPv6) address, and a type length value (TLV) encoding.

Assignees

• Huawei Tech Co Ltd

Inventors

• Roch Evelyne
• Ashwood-Smith Peter

Classifications

• H04L45/04

  Interdomain routing, e.g. hierarchical routing · CPC title

• H04L45/50

  using label swapping, e.g. multi-protocol label switch [MPLS] · CPC title

• H04L45/34 Primary

  Source routing · CPC title

• H04L12/28 Primary

  characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks] (wireless communication networks H04W {; arrangements for dividing the transmission path H04W40/00}) · CPC title

• H04L45/42

  Centralised routing · CPC title