As shown in Figure 11, the two main components of the voice solution are the BGF and the gateway controller. The BGF and the gateway controller communicate over the Packet Gateway Control Protocol (PGCP).
Figure 11: Voice Solution Architecture
In the BGF VoIP solution, the gateway controller is an external device that controls the BGF on the router. The gateway controller requests media services and resource allocation from the BGF, and it uses those services and resources for VoIP call signaling setup. The gateway controller maintains awareness and control over the network’s transport resource using PGCP connections with all of the BGFs in the network.
The BGF feature on the router provides Interconnect-BGF transport services for VoIP sessions. The BGF feature consists of:
The BGF and the gateway controller communicate over a Packet Gateway Control Protocol (PGCP) connection. PGCP is an H.248 v3 protocol with Juniper Networks extensions. PGCP complies with Gateway control protocol v3, ITU-T Recommendation H.248.1, September 2005 and with H.248 Profile for controlling Border Gateway Functions, ETSI Standard ES 283 018 V1.1.4, October 2007.
