BGF VoIP Solution Overview
This topic describes the Juniper Networks border gateway function (BGF) voice over IP (VoIP) solution.
The BGF VoIP Solution in a Next-Generation Network Overview
The BGF VoIP solution provides a way for the router to integrate into a Telecommunications and Internet Converged Services and Protocols for Advanced Networks (TISPAN)/IP multimedia subsystems (IMS) environment to provide VoIP functionality. IMS is a flexible network architecture that allows providers to introduce multimedia services across both next-generation packet-switched and traditional circuit-switched networks. It uses open interfaces and functional components that can be assembled flexibly to support real-time interactive services and applications.
IMS provides a standards-based architecture that allows mobile carriers to migrate to next-generation networks that support applications that combine voice, video, and data functionality. The European Telecommunications Standards Institute (ETSI) created TISPAN to extend IMS support to fixed-line carriers. This extension is commonly called fixed mobile convergence (FMC). IMS/FMC allows subscribers to access any network (wireless or fixed) from any device (computer, PDA, or cell phone) and to move seamlessly from one network to another.
The router provides the BGF role, as shown in the ETSI-TISPAN architecture in Figure 1:
Figure 1: Routers Running Junos OS in the ETSI-TISPAN Architecture
BGF VoIP Solution Terms and Abbreviations
Table 1 defines the terms and abbreviations used in this topic.
Table 1: Terms and Abbreviations
| Term | Description |
|---|---|
BGF | Border gateway function. Resides in the transport layer and polices and enforces traffic flows based on instructions from the SPDF. The router provides the BGF functionality. |
Context | An association between terminations. |
Gate | Unidirectional flow of IP packets as directed by the gateway controller. Sometimes called a pinhole. |
Gateway controller | In the BGF VoIP solution, an external device that provides signal processing and directs the behavior of the BGF. The gateway controller provides the service policy decision function (SPDF) shown in Figure 1. |
Ia | A profile of the interface between an SPDF (the gateway controller) and the BGF. |
I-BGF | Interconnect-BGF. The BGF between two peering partners. |
IMS | IP multimedia subsystem. |
IPC | The virtual BGFs and the MultiServices PIC or MultiServices Dense Port Concentrator (MS-DPC) communicate by exchanging Inter-Process Communication (IPC) messages over a TCP connection; this is internal (intra-chassis) communication. |
PGCP | Packet Gateway Control Protocol (PGCP). An H.248 v3 protocol with Juniper Networks extensions. It provides management and signaling between the BGF and an external gateway controller. |
pgcpd | A process that decodes H.248 messages that BGFs receive from external gateway controllers and translates the H.248 messages to IPC messages. You can configure the pgcpd process to run in the Routing Engine or on a MultiServices PIC. |
SPDF | Service policy decision function. Controls the BGF. In the Juniper Networks BGF VoIP solution, an external gateway controller acts as the SPDF. |
Stream | A bidirectional flow within a context. |
Termination | A local source and sink of packets. |
Virtual BGF | A virtual device on the router that provides media processing and control as directed by the gateway controller. |
