Voice Technology Basics
Voice over Frame Relay
Voice over Frame Relay (VoFR) technology consolidates voice
and voice-band data (including fax and analog modems) with data services over
a Frame Relay network. The VoFR standard is specified in FRF.11 by the Frame Relay
Forum.
VoFR allows PBXs to be connected using Frame Relay PVCs. The goal is to replace
leased lines and lower costs. With VoFR, customers can easily increase their link
speeds to their Frame Relay service or their CIR to support additional voice,
fax, and data traffic.
Frame Relay Services
Frame Relay is a packet-switching WAN technology that has achieved
widespread support among vendors, users, and communications carriers. Its development
has been spurred by the need to internetwork LANs at high speeds while maintaining
the lower costs associated with packet-switching networks.
Frame Relay offers very high access speeds. In North America,
initial Frame Relay access rates start at 56 Kbps and go up to 1.544 Mbps. In
Europe, the initial Frame Relay access rates start at 64 Kbps and go up to 2.048
Mbps. Companies can contract with their service provider for a committed information
rate (CIR).
The Frame Relay standard today uses permanent virtual circuits
(PVCs). All traffic for a PVC uses the same path through the Frame Relay network.
The endpoints of the PVC are defined by a data-link connection identifier (DLCI).
The CIR, DLCIs, and PVCs are defined when the user initially subscribes to a Frame
Relay service.
Frame Relay allows remote host access for applications such as the following:
- Remote host connectivity
- Credit card authorization
- Online information services
- Remote order entry
Frame Relay supports multiple virtual connections over a single physical interface.
This means that Frame Relay is often the ideal solution to provide many users
with simultaneous access to a remote location. In these cases, the Frame Relay
connection helps optimize the return on investment of the host system.
How VoFR Works
A voice-capable router connects both a PBX
and a data network to a public Frame Relay network. A voice-capable
router includes a Voice Frame Relay Adapter (VFRAD) or a voice/fax
module that supports voice traffic on the data network.
Choosing VoFR
Frame Relay provides another popular transport
for multiservice networks since Frame Relay networks are common
in many areas. Frame Relay is a cost-effective service that
supports bursty traffic well.
Frame Relay enables customers to prioritize voice frames over
data frames to guarantee quality of service (QoS).
Related Topics
|
