With the broad proliferation of LTE, the spectral efficiencies of voice over LTE and the coverage benefits of voice over Wi-Fi can finally be realized. In order to make the adoption of packet voice in the access network a reality and reap the benefits of an IMS-based rich communications infrastructure, however, network operators must complete a critical component of this end-to-end architecture: VoLTE Peering and VoLTE Roaming.
Even with the steady migration towards VoIP, mobile operator interconnect points of presence (PoPs) are often still languishing in the time division multiplex (TDM) domain. Circuit-switched interconnect trunks not only dramatically increase the cost of handing-off calls between carriers, they also complicate capacity planning, limiting the flexibility to meet changes in demand. More importantly, TDM interconnects block the ability to provide many of the enhanced calling and rich communications features enabled by new networking technologies.
Deploying a GSMA IR.92 / IR.94 VoLTE and IR.51 VoWiFi infrastructure is incomplete without extending fully-featured roaming capabilities to subscribers. To deliver on the promise of the IP Multimedia Subsystem (IMS), all communications services must be delivered from the home network, requiring each call and message to be appropriately routed from the visited network, while still locally handling emergency calls and regional numbering plans. In dynamic and continuously-evolving mobile infrastructures, however, there is no one simple solution to the issue of VoLTE Roaming, requiring capabilities beyond those outlined in GSMA IR.95.
Metaswitch’s VoLTE interconnect and VoLTE roaming solutions are designed to deliver the flexibility required to support every architectural eventuality.
The fully virtualized and cloud native Perimeta session border controller (SBC) can replace legacy circuit-switched interconnects, providing a highly flexible security demarcation between operators. Moreover, its powerful SIP/SDP message manipulation engine enables otherwise disparate VoLTE IMS implementations to interwork seamlessly by correcting the disparities in private message headers and fields which have emerged in the time these protocols have been evolving.
While S8 Home Routed (S8HR) architectures have been initially deployed to support VoLTE roaming, local regulations and service demands, along with the complexities of circuit-switched fallback (CSFB/SRVCC) where pockets of 3G coverage are still rampant, have mandated the introduction of Local Breakout (LBO) Techniques. The Perimeta SBC supports both Home Routing and Visited Routing LBO or RAVEL (Roaming Architecture for Voice over LTE with Local Breakout), guaranteeing interoperability, regardless or your preferred roaming model.