Segment Routing (SR) is a flexible and scalable way of performing source routing. The source chooses a path and encodes it in the packet header as an ordered list of segments.
Each segment is identified by the segment ID (SID) consisting of a flat 32-bit integer as illustrated in figure-1 below:
- Use case#1: single SID – 16050 – on R1 head-end to reach out to R5 as a loose path
- Use case#2 illustrates mix of loose and strict path to reach out to R5. The label stack on R1 can be interpreted to take shortest loose path to R4 (16040) and take strict path to R5