Micro SIDs: a solution for Efficient Representation of Segment IDs in SRv6 Networks

The Segment Routing (SR) architecture is based on loose source routing. A list of instructions, called segments can be added to the packet headers, to influence the forwarding and the processing of the packets in an SR enabled network. In SRv6 (Segment Routing over IPv6 data plane) the segments are represented with IPv6 addresses, which are 16 bytes long. There are some SRv6 service scenarios that may require to carry a large number of segments in the IPv6 packet headers. Reducing the size of these overheads is useful to minimize the impact on MTU (Maximum Transfer Unit) and to enable SRv6 on legacy hardware devices with limited processing capabilities that could suffer the long headers. In this paper we present the Micro SID solution for the efficient representation of segment identifiers. With this solution, the length of the segment list can be drastically reduced.