IPsec (IP Security)

IPsec is the IETF protocol suite (RFCs 4301-4309 and 7296) that provides authentication, integrity, and encryption at the IP layer. It supports two modes: transport mode for end-to-end protection of payloads and tunnel mode for site-to-site VPNs. In mobile networks, IPsec is mandatory for backhaul protection between eNB/gNB and the security gateway, for S1/N3 traffic, and is widely used to protect Diameter and GTP between roaming partners. IKEv2 handles key exchange, with strong cipher suites (AES-GCM, SHA-2, ECDHE) recommended.

Categories: Radio Access NetworkCore NetworkSignaling

IPsec 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.

The mobile core carries subscriber sessions, mobility and policy. 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.

To place IPsec in the wider telecom-security picture, review 5G SA, AMF, Base Station (BS), Capacity Planning, CAPEX and CSCF — each entry cross-references back to this page so you can walk the topic in either direction.

Related terms

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.