Configuring Vofr - HP FlexNetwork MSR Series Configuration Manual

Configuring VoFR

Overview
Voice over frame relay (VoFR) enables a router to transmit voice and voice-band data (for example,
fax data and analog data from a modem) over a frame relay network. When voice traffic is sent over
frame relay, it is segmented and encapsulated for transmission across a frame relay network.
VoFR supports permanent virtual circuit (PVC) statistical multiplexing to carry multiple channels of
voice, data, and fax over one PVC. In the case of concurrent transmission of voice and data, voice
takes precedence over data. Moreover, VoFR limits the concurrent session channels according to
the voice bandwidth and/or reserves a bandwidth exclusively for voice to ensure the voice quality.
VoFR satisfies various demands of different user groups. It enables terminal users to concurrently
use different services, like data, voice and faxes, on a leased line. This improves the bandwidth use
and lowers the communication cost.
Fundamental VoFR architecture
Figure 99 Fundamental VoFR architecture
Originating
voice gateway
Telephone A
Figure 99, the FR-supported voice gateway provides an interface between the frame relay network
In
and the public switched telephone network (PSTN). Telephone A and Telephone B are connected to
the voice gateway through the PSTN. When Telephone A originates a call to Telephone B, the
originating voice gateway converts analog signals into digital signals and encapsulates them into
voice packets that can be transmitted over the frame relay network. These voice packets are then
transmitted to the terminating voice gateway, which converts them back to recognizable analog
signals and transmits them to Telephone B across PSTN. This completes a phone-to-phone
communication process.
Protocols and standards
VoFR not only complies with audio codecs such as G.711A-law, G.711μ-law, G.723R53, G.723R63,
G.729R8, and G.729A, but also supports the Q.931-like protocol for call control. In addition, VoFR
encapsulates signaling by using T1.617 and voice by using FRF.11.
and standards that VoFR complies with.
Frame Relay
PSTN
Terminating
voice gateway
PSTN
310
Telephone B
Figure 100
shows the protocols