- Introduction
- Segment Routing (SR) is a new view to source routing with flexible and scalable data forwarding
- Network paths are divided into segments with unique 32-bit Segment IDs (SIDs)
- SR routers behave based on packet forwarding information, not per-application behavior
- Types
- SR MPLS uses MPLS as forwarding plane, supporting both IPv4 and IPv6
- SRv6 uses IPv6 forwarding plane with IPv6 extensions
- SRGB (Segment Routing Global Block) ranges from 16000 to 23999
- Segment Types
- Prefix SID carries destination IP address prefixes calculated by IGP
- Adjacency SID identifies advertising router adjacencies between devices
- Node SID represents nodes, including loopback addresses
- Forwarding Modes
- Prefix Segment Based Mode uses IGP-calculated destination SIDs
- Adjacency Segment Based Mode uses central mechanism for SDN
- Adjacency and Node Segment Combination Mode enables flexible path calculation
- Advantages
- Enables easy SDN adaptation and simple control plane
- Provides fast reroute support and better scalability
- Supports centralized traffic engineering and interoperability with MPLS infrastructure