Segment Routing Network Processing of Packets including Packets having a Multiple Segment Routing Header Packet Structure that Provides Processing and/or Memory Efficiencies

Abstract

One embodiment performs segment routing network processing of packets including segment routing packets having a multiple segment routing header packet structure that provides processing and/or memory efficiencies. In one embodiment, a particular packet is received by a particular router in a network. In response to the particular router data plane ascertaining based on the particular packet a particular segment routing (SR) policy identifying one or more ordered SR identifiers, the particular router adding one or more SR headers to the particular packet resulting in the particular packet including multiple ordered SR headers instead of the particular packet having a packet structure with a single SR header, with each of the one or more SR headers including at least one segment identifier of said one or more ordered SR identifiers. The packet with the multiple ordered SR headers is sent from the particular router.

What is claimed is: 
     
         1 . A method, comprising:
 receiving a particular packet by a particular router in a network;   in response to the particular router data plane ascertaining based on the particular packet a particular segment routing (SR) policy identifying one or more ordered SR identifiers, the particular router adding one or more SR headers to the particular packet resulting in the particular packet including a plurality of ordered SR headers instead of the particular packet having a packet structure with a single SR header, with each of said one or more SR headers including at least one segment identifier of said one or more ordered SR identifiers; and   sending the packet with the plurality of ordered SR headers from the particular router.   
     
     
         2 . The method of  claim 1 , wherein said one or more ordered SR identifiers of the particular SR policy includes two or more ordered segment identifiers in a particular order; and said adding one or more SR headers includes adding two or more ordered SR headers with said two or more ordered segment identifiers distributed among said two or more ordered SR headers such that each of said two or more ordered SR headers includes at least one of said two or more ordered segment identifiers while maintaining the particular order for processing of said two or more ordered segment identifiers among and within said two or more ordered SR headers. 
     
     
         3 . The method of  claim 2 , wherein the particular packet is said received by the particular router without any SR header, including without any of the plurality of ordered SR headers. 
     
     
         4 . The method of  claim 2 , wherein said two or more ordered segment identifiers includes at least three segment identifiers. 
     
     
         5 . The method of  claim 2 , wherein each of said two or more SR headers comprises either one or more Internet Protocol Version 6 (IPv6) Segment Identifiers (SRv6 SIDs) of said one or more ordered SR identifiers or one or more Internet Protocol Version 4 (IPv4) segment identifiers of said one or more ordered SR identifiers but does not comprise both IPv4 and IPv6 segment identifiers; and wherein said two or more ordered SR identifiers includes an IPv4 segment identifier and an IPv6 SID. 
     
     
         6 . The method of  claim 5 , wherein all of said one or more ordered SR identifiers are an IPv6 Segment Identifiers (SIDs). 
     
     
         7 . The method of  claim 2 , comprising the particular router limiting each of said two or more SR headers to less than or equal to two SR identifiers. 
     
     
         8 . The method of  claim 1 , wherein the particular packet when said received by the particular router already includes one of the plurality of ordered SR headers. 
     
     
         9 . The method of  claim 1 , comprising the particular router limiting each of said one or more SR headers to less than or equal to two SR identifiers. 
     
     
         10 . The method of  claim 1 , wherein said one or more ordered SR identifiers of the particular SR policy includes an Internet Protocol Version 4 (IPv4) segment identifier. 
     
     
         11 . The method of  claim 10 , wherein said one or more ordered SR identifiers of the particular SR policy includes an Internet Protocol Version 6 (IPv6) segment identifier. 
     
     
         12 . The method of  claim 1 , wherein the particular SR policy defines a SR path through the network that is associated with preferentially using multiple smaller SR headers representing an ordered list of SR identifiers rather than a larger SR header representing the ordered list of SR identifiers; and wherein each said one or more SR headers is limited to a maximum of a predetermined quantity of SR identifiers. 
     
     
         13 . The method of  claim 1 , comprising the particular router exchanging routing information via a routing protocol with another router in the network, which includes receiving a value representing the predetermined quantity of SR identifiers supported by the specific router, that is SR-capable, along a path through the network according to the particular SR policy, and limiting a SR header to be processed by the specific router to having a maximum of the predetermined quantity of SR identifiers. 
     
     
         14 . The method of  claim 1 , wherein the particular segment routing (SR) policy designates a specific SR identifier corresponding to a specific router, that is SR-capable, in the network;
 wherein the method includes the particular router exchanging routing information via a routing protocol with another router in the network, which includes receiving an advertisement associated with the specific router and including a value representing a predetermined quantity of SR identifiers; and   wherein a specific SR header of said one or more SR headers that includes the specific SR identifier is limited to a maximum of the predetermined quantity of SR identifiers in response to said advertisement.   
     
     
         15 . The method of  claim 14 , comprising:
 receiving the particular packet by the specific router in the network subsequent to said sending by the particular router; and   data plane processing of the particular packet based on the specific SR identifier.   
     
     
         16 . A method, comprising:
 receiving a particular packet by a specific router in a network, with the particular packet including a plurality of ordered segment routing (SR) headers instead of the particular packet having a packet structure with a single SR header, with each of the plurality of ordered SR headers including at least one segment identifier of a plurality of ordered SR identifiers, and with a specific SR identifier associated with the specific router in the destination address in the Internet Protocol Version 4 or 6 header of the particular packet; and   data plane processing, by the specific router, of the particular packet based on the specific SR identifier.   
     
     
         17 . The method of  claim 16 , including the specific router advertising, via a routing protocol with another router in the network, the specific SR identifier associated with a value representing a predetermined quantity of SR identifiers; wherein a current SR header of the plurality of ordered SR headers includes a maximum of the predetermined quantity of SR identifiers as said advertised. 
     
     
         18 . The method of  claim 16 , wherein each of the plurality of ordered SR headers comprises either one or more Internet Protocol Version 6 (IPv6) Segment Identifiers (SRv6 SIDs) of said one or more ordered SR identifiers or one or more Internet Protocol Version 4 (IPv4) segment identifiers of said one or more ordered SR identifiers but does not comprise both IPv4 and IPv6 segment identifiers; and wherein the plurality of ordered SR identifiers includes an IPv4 segment identifier and an IPv6 SID. 
     
     
         19 . An apparatus, comprising:
 one or more hardware interfaces sending and receiving packets; and   one or more network processors with memory associated therewith;   wherein the apparatus, communicatively coupled in a network, performs packet processing operations including segment routing-capable (SR-capable) packet processing operations, with said packet processing operations including:   receiving on an interface of said one or more hardware interfaces a particular packet;   in response to data plane ascertaining based on the particular packet a particular segment routing (SR) policy identifying one or more ordered SR identifiers, adding one or more SR headers to the particular packet resulting in the particular packet including a plurality of ordered SR headers instead of the particular packet having a packet structure with a single SR header, with each of said one or more SR headers including at least one segment identifier of said one or more ordered SR identifiers; and   sending the packet with the plurality of ordered SR headers from the apparatus on an interface of said one or more hardware interfaces.   
     
     
         20 . The apparatus of  claim 19 , wherein said one or more ordered SR identifiers of the particular SR policy includes two or more ordered segment identifiers in a particular order; and said adding one or more SR headers includes adding two or more ordered SR headers with said two or more ordered segment identifiers distributed among said two or more ordered SR headers such that each of said two or more ordered SR headers includes at least one of said two or more ordered segment identifiers while maintaining the particular order for processing of said two or more ordered segment identifiers among and within said two or more ordered SR headers.