METHODS AND DEVICES FOR CONSTRUCTING LABEL AND FORWARDING LABEL PACKET

• US 20180019944A1
• Filed: 06/24/2015
• Published: 01/18/2018
• Est. Priority Date: 01/19/2015
• Status: Active Grant

• Current Assignee: Xi'An Zhongxing New Software Co., Ltd. (ZTE Corporation)
• Original Assignee: ZTE Corporation
• Inventors: PENG, Shaofu, CHEN, Ran, LIAO, Ting
• Granted Patent: US 10,581,733 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 45/34 Source routing
• 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 45/64 using an overlay routing layer
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]

Abstract

Methods and devices for constructing a label and forwarding a label packet are provided. A node receives a message which carries a segment list and a segment list Identifier (ID) for identifying the segment list. The node constructs a label forwarding table according to the segment list and the segment list ID, and performs forwarding according to the label forwarding table; and/or the node maintains a mapping relationship between the segment list and the segment list ID.

Claims

1. A method for constructing a label and forwarding a label packet, comprising:

receiving, by a node, a message which carries a segment list and a segment list Identifier (ID) for identifying the segment list;

constructing, by the node, a label forwarding table according to the segment list and the segment list ID, and performing forwarding according to the label forwarding table; and

/or, maintaining, by the node, a mapping relationship between the segment list and the segment list ID.

2. The method as claimed in claim 1, wherein the message is sent by an ingress node after the ingress node receives the segment list and the segment list ID sent by a controller;

and/or, the message is sent by the controller.

3. The method as claimed in claim 2, wherein,

the node receives the message that the controller sends through a southbound interface protocol, wherein the southbound interface protocol comprises:

Broader Gateway Protocol-Link State (BGP-LS), Path Computation Element Communication Protocol (PCEP), open flow protocol (OPENFLOW) or network configuration protocol (Netconf); and

/or,

the node receives the message that the ingress node sends through an extended Interior Gateway Protocol (IGP).

5. The method as claimed in claim 1, further comprising:

receiving, by the node, a revocation message sent by a controller or an ingress node, wherein the revocation message is used for indicating the node to delete the mapping relationship between the segment list and the segment list ID, and/or is used for indicating the node to delete the label forwarding table.

6. The method as claimed in claim 1, wherein,

when the node is a last node in the segment list and a previous node of the node does not carry an inner label in a forwarding packet, the node does not construct a label table item in the label forwarding table, wherein the inner label is constructed according to a Segment Routing Global Block (SRGB) of a next node of the node and the segment list ID.

7. The method as claimed in claim 1, the segment list ID is a global label or an index, wherein the global label is an index offset when Segment Routing Global Blocks (SRGBs) of all nodes in a Segment Routing (SR) domain are the same.

8. The method as claimed in claim 7, wherein when the segment list ID is an index and the node is not a last node,

the node constructs an ingress label according to an SRGB of the node and the segment list ID, and constructs an egress label stack which comprises at least one of the followings:

an inner label, or one or more outer labels;

wherein the inner label is constructed according to an SRGB of a next node of the node and the segment list ID; and

the one or more outer labels comprise at least one of the followings;

a label corresponding to a node ID to which each remaining node corresponds, or a label corresponding to a node ID to which a next node of the node corresponds.

9. The method as claimed in claim 8, wherein when an indicator bit indicates that an egress label is needed to be encapsulated according to a specific Readable Label Depth (RLD), the node constructs the egress label stack, which comprise the one or more outer labels, according to the specific RLD.

10. The method as claimed in claim 7, wherein when the segment list ID is an index and the node is the ingress node,

if an indicator bit indicates that an egress label is needed to be encapsulated according to a specific Readable Label Depth (RLD), an ingress node constructs an egress label stack which comprises at least one of the followings:

an inner label, or one or more outer labels;

wherein the inner label is constructed according to the segment list ID and an SRGB of a farthest node in the segment list which is able to be encapsulated in a scope limited by the specific RLD;

the one or more outer labels are as follows from outside to inside;

a label corresponding to a first node in the segment list, which is determined according to a direct connect nexthop indicated by a shortest path from the ingress node to a first node in the segment list;

labels corresponding to nodes from a second node to an mth node in the segment list, each of which is determined according to a previous node of this node in the segment list, wherein the mth node is determined according to the farthest node in the segment list which is able to be encapsulated in the scope limited by the specific RLD;

or

if an indicator bit indicates that an egress label is not needed to be encapsulated according to a specific Readable Label Depth (RLD), an ingress node constructs an egress label stack which comprises at least one of the followings;

an inner label or an outer label;

wherein the inner label is constructed according to an SRGB of a first node except the ingress node in the segment list and the segment list ID, and the outer label is determined according to a direct connect nexthop indicated by a shortest path from the ingress node to a first node except the ingress node in the segment list.

11. The method as claimed in claim 10, wherein

when the farthest node in the segment list which is able to be encapsulated in the scope limited by the specific RLD is a last node in the segment list, the egress label stack does not comprise the inner label.

13. The method as claimed in claim 10, wherein,

when the first node except the ingress node in the segment list is also a last node in the segment list, the egress label stack does not comprise the inner label.

14. The method as claimed in claim 7, wherein when the segment list ID is an index and the node is a node except the ingress node in the segment list,

if an indicator bit indicates that an egress label is not needed to be encapsulated according to a specific Readable Label Depth (RLD), an egress label stack constructed by the node comprises at least one of the followings:

an inner label or one outer label;

wherein the inner label is constructed according to an SRGB of a next node of the node and the segment list ID, and the outer label is constructed according to an SRGB of a direct connect nexthop indicated by a shortest path from the node to a next node of the node and an ID of the next node;

or

if an indicator bit indicates that an egress label is needed to be encapsulated according to a specific Readable Label Depth (RLD), a node i constructs an egress label stack which comprises at least one of the followings;

an inner label, or one or more outer labels;

wherein the inner label is constructed according to the segment list ID and an SRGB of a farthest node m in the segment list which is able to be encapsulated in a scope limited by the specific RLD;

the one or more outer labels are as follows from outside to inside;

a label corresponding to a next node i+1 of the node i, which is determined according to a direct connect nexthop indicated by a shortest path from the node i to the next node i+1 of the node i; and

labels corresponding to nodes from a node i+2 to a node m in the segment list, each of which is determined according to a previous node of this node in the segment list;

wherein the node i is a node except the ingress node in the segment list, and the node m is determined according to the farthest node in the segment list which is able to be encapsulated in the scope limited by the specific RLD.

16. The method as claimed in claim 14, wherein,

when the farthest node in the segment list which is able to be encapsulated in the scope limited by the specific RLD is a last node in the segment list, the egress label stack does not comprise the inner label.

17. The method as claimed in claim 8, wherein the specific RLD is greater than or equal to 2;

when the node encapsulates a label stack of a packet, a depth of the label stack is not greater than the specific RLD.

18. The method as claimed in claim 17, wherein the specific RLD is configured explicitly, or is a network-wide minimum value obtained by learning.

19. The method as claimed in claim 18, wherein,

nodes between the node and a next node of the node comprise at least one of the followings:

an SR node and/or a non-SR node; and

/or,

tunnels between the node and a next node of the node comprise at least one of the followings;

a Label Distribution Protocol Label Switching Path (LDP LSP), a Resource Reservation Protocol-Traffic Engineering LSP (RSVP-TE LSP), a BGP LSP, or an SR LSP.

20. The method as claimed in claim 1, wherein when the segment list comprises only one node, the segment list ID is a node ID of the node.

4. (canceled)

12. (canceled)

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24. (canceled)

25. (canceled)

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29. (canceled)

30. A device for constructing a label and forwarding a label packet, which is applied to a node and comprises a hardware processor arranged to execute program modules comprising:

a first receiving module, configured to receive a message which carries a segment list and a segment list Identifier (ID) for identifying the segment list; and

a constructing module, configured to construct a label forwarding table according to the segment list and the segment list ID, and perform forwarding according to the label forwarding table; and

/or, the constructing module is configured to maintain a mapping relationship between the segment list and the segment list ID.

31. (canceled)

32. A device for constructing a label and forwarding a label packet, which is applied to a controller and comprises a hardware processor arranged to execute program modules comprising:

a first sending module, configured to send a message to a node, wherein the message carries a segment list and a segment list Identifier (ID) for identifying the segment list, and the segment list and the segment list ID are used for indicating the node to construct a label forwarding table and perform forwarding according to the label forwarding table; and

/or, the segment list and the segment list ID are used for indicating the node to maintain a mapping relationship between the segment list and the segment list ID.

33. (canceled)

34. (canceled)

35. A device for constructing a label and forwarding a label packet, which is applied to an ingress node and comprises a hardware processor arranged to execute program modules comprising:

a third receiving module, configured to receive a message sent by a controller, wherein the message carries a segment list and a segment list Identifier (ID) for identifying the segment list; and

a third sending module, configured to send the message to a node, wherein the message is used for indicating the node to construct a label forwarding table and perform forwarding according to the label forwarding table; and

/or, the message is used for indicating the node to maintain a mapping relationship between the segment list and the segment list ID.

36. (canceled)

37. (canceled)