Session Border Control in IMS and VoLTE / V2oLTE

Wireline and wireless network operators have united around a system architecture evolution known as the unified packet core (UPC). Driven by CableLabs, ETSI and 3GPP standards bodies, the UPC features the IP multimedia subsystem (IMS): a core set of functions, protocols and reference interfaces that can deliver the broad range of multi-screen offerings critical to the success of emerging 4G / LTE Advanced and other next generation infrastructures.

IMS is the foundation on which carriers can support a complete portfolio of immersive telephony services, such as voice and video over LTE(VoLTE / V2oLTE) and the rich communication suite RCS/RCS-e (Joyn) defined by the GSMA.

Session border control in next generation networks

With the fundamental role of providing scalable, centralized service delivery, specifications related to IMS have defined an innovative approach to session border control based on a distributed signaling / media architecture. Meanwhile implementation models have extended SBC function to incorporate other IMS core functions such as the Proxy Call Session Control Function (P-CSCF). 

When operating in access network environments an IMS SBC must support application layer gateway (ALG) access gateway (AGW) specifications, while at interconnect peering points, an IMS SBC must conform to Interconnect Border Control Function (IBCF) and Transition Gateway (TrGW) standards. 

V2oLTE and RCS present some unique deployment challenges – specifically when scaling session control functions. NGN SBCs cannot simply be architected around classic voice calling profiles and metrics. SIP methods for instant messaging, presence and availability fundamentally break this classic modeling. With RCS services, the explosive growth of SIP Message, Options, Subscribe and Notify packets bear no relationship to the amount of media being transported. 

Perimeta: an SBC architected for next generation networks and services

Perimeta session border controllers, from Metaswitch, are purpose-built to meet the demands of applications and services within these next generation network architectures.  

Perimeta can scale signaling and media completely independently of each other. The Perimeta signaling session controller (SSC) is tuned specifically for message processing performance, while the media session controller (MSC) handles the voice and video flows that are critical to VoLTE / V2oLTE.

This approach results in the only complete SBC solution targeted at emerging IMS and LTE infrastructure and capable of handling the innovative new services these networks must support to enable operators to remain relevant in the OTT app revolution.

Functions of IMS SBCs in access and interconnect infrastructures