In a segment routing environment, how are segments distributed within the control plane?

Pseudowires are used for emulating point-to-point services over a packet-switched network, not for distributing segment routing information in the control plane.

While BGP (specifically BGP-LS or other MP-BGP extensions) can be used to distribute Segment Routing information in certain scenarios, the primary intra-domain distribution is via IGPs.

Distance-vector routing protocols like RIP do not inherently support the extensions required for segment routing SID distribution or maintain a full topology database.

Segment Routing leverages extensions to Interior Gateway Protocols (IGPs) like OSPF or IS-IS, which are link-state routing protocols, to distribute segment identifiers (SIDs). These IGPs flood topology and SID information throughout their area, allowing all routers to build a complete view of the network and compute segment-based forwarding paths.