IP Anycast

Anycast is a routing technique where the same IP prefix is advertised from multiple locations via BGP, and traffic is delivered to the topologically nearest instance. Used by operators for resilient DNS, SEPP and NEF frontends, and CDN edges. Anycast improves DDoS resilience by spreading attack traffic across POPs and reduces latency but complicates stateful signaling that assumes a single terminating node.

Categories: Core NetworkSignalingRoaming and Interconnect

Anycast in context

The mobile core is where subscriber sessions, mobility and policy live. In 4G it is the EPC (MME, HSS, S/PGW); in 5G it is the Service-Based Architecture with AMF, SMF, UPF, AUSF, UDM and the NRF. Core exposure is the difference between a single-subscriber leak and a fleet-wide breach.

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

To place Anycast in the wider telecom-security picture, review GTP Firewall, SMS Home Routing, GTP-U Smuggling, SMSC Hijacking, N9 and MAP Security.

Related terms

Related topic hubs

  • Roaming Security IPX/GRX interconnect risk, home-routed vs local-breakout, SEPP.
  • 5G Security 5G SBA, SEPP, SUCI, 5G-AKA, N32 and service-based interface security.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • 5G NEF Security Network Exposure Function security in the 5G core.

More from the TelcoSec Glossary

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