UDP (User Datagram Protocol)

The User Datagram Protocol, defined in RFC 768, is a minimal, connectionless transport on top of IP that adds only a checksum and source/destination ports. UDP is used by latency-sensitive and broadcast/multicast applications such as DNS, RTP for voice and video, GTP-U in mobile cores, and QUIC/HTTP/3. Its statelessness makes it both efficient and a frequent vector for amplification DDoS (DNS, NTP, memcached), so source-address validation and rate limiting are essential.

Categories: Radio Access NetworkCore NetworkSignaling

UDP in context

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

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.

To place UDP in the wider telecom-security picture, review Diameter, Capacity Planning, IPsec, Service-Based Architecture (SBA) Security, TLS and User Plane Security.

Related terms

Related topic hubs

  • GTP Firewall GSMA FS.20 GTP-C/GTP-U screening on GRX/IPX borders.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • GTP Security GTP-C/GTP-U threats across S5/S8, N3/N9 and GRX/IPX borders under GSMA FS.20.

More from the TelcoSec Glossary

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