Segment Routing (Segment Routing (SR))

Also known as: SR

Segment Routing (RFC 8402) is a source-routing paradigm where the ingress node encodes an ordered list of segments — topological (nodes/links) or service instructions — into the packet header, and transit nodes forward based on that list. Two data planes exist: SR-MPLS (labels) and SRv6 (IPv6 addresses as segments). Enables scalable network programming for 5G transport, slicing anchors, and service-chaining without per-flow state on core routers.

Categories: Radio Access NetworkProtocols and StandardsInternet and Routing

Segment Routing in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Telecom security is written into standards from 3GPP, GSMA, ETSI, IETF and ITU-T. Understanding which body owns which specification, and how they interlock, is essential for both design and audit work.

To place Segment Routing in the wider telecom-security picture, review Handoff (Handover), LTE-Advanced (LTE-A), PoE, TCP/IP, Telecom and DetNet — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.