Segment Routing IPv6 (SRv6) forwards IPv6 packets using the source routing model. It implements hop-by-hop forwarding by adding a Segment Routing header (SRH) into IPv6 packets, encapsulating an explicit IPv6 address stack into the SRH, and continuously updating IPv6 destination addresses while offsetting the address stack on transit nodes.
Future networks will be 5G oriented. Transport networks need to be adjusted to meet 5G requirements for network simplification, low latency, and SDN and network functions virtualization (NFV) implementation.
To develop 5G networks, users hope to implement VPN functionality more easily using IPv6 addresses. SRv6 uses existing IPv6 forwarding techniques and extends IPv6 headers to implement label forwarding-like processing. Some IPv6 addresses are instantiated as SIDs, each of which has its own explicit functions. SIDs are operated to implement simplified VPNs and flexible path planning.
Simplified network configuration and easier VPN implementation
SRv6 is based on IPv6 forwarding. It does not involve MPLS techniques and is fully compatible with existing IPv6 networks. Transit nodes can forward SRH-encapsulated IPv6 packets through routes, without the need to support SRv6.
Improved fast reroute (FRR) capability
SRv6 works with the remote loop-free alternate (RLFA) FRR algorithm, providing topology-independent loop-free alternate (TI-LFA) protection that theoretically supports all topologies and compensates for conventional tunnel protection techniques.
Flexible traffic optimization on IPv6 forwarding paths
Various types of SIDs are used, enabling the ingress to flexibly plan explicit paths and adjust service traffic.