Voice Solution Terms and Abbreviations

BGF

Border gateway function. Resides in the transport layer and polices and enforces traffic flows based on instructions from the SPDF. The packet gateway provides the BGF functionality.

Context

An association between terminations.

Gate

Unidirectional flow of IP packets as directed by the PGC. Sometimes called a pinhole.

Ia

A profile of the interface between an SPDF (the PGC) and the BGF (packet gateway).

I-BGF

Interconnect-BGF. The BGF between two peering partners. The packet gateway in the router provides much of the I-BGF function.

IMS

IP multimedia subsystem.

IPC

The VPGs and the MultiServices PIC communicate by exchanging Inter-Process Communication (IPC) messages over a TCP connection; this is internal (intra-chassis) communication.

PG

Packet gateway. A virtual device on the router that provides media processing and control as directed by the PGC.

PGC

Packet gateway controller. An external device that provides signal processing and directs the behavior of the PG. The PGC provides the service policy decision function (SPDF) shown in Figure 10.

PGCP

Packet Gateway Control Protocol (PGCP). An H.248 v3 protocol with Juniper Networks extensions. It provides management and signaling between the PG and the PGC.

pgcpd

The packet gateway pgcpd process running in the Router Engine decodes H.248 messages that VPGs receive from the PGC and translates the H.248 messages to IPC messages.

SPDF

Service policy decision function. Controls the BGF. In the Juniper Networks voice solution, the PGC acts as the SPDF.

Stream

A bidirectional flow within a context.

Termination

A local source and sink of packets.

Virtual packet gateways (VPGs)

A VPG consists of a packet gateway configuration on the Routing Engine. VPGs are controlled by a PGC. A VPG receives instructions from the PGC and instructs the MultiServices PIC how to treat voice traffic.