Term of the Moment
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Definition: frame relay
A high-speed packet switching protocol used in wide area networks (WANs). Providing a granular service of up to DS3 speed (45 Mbps), it has become popular for LAN to LAN connections across remote distances, and services are offered by most major carriers.
The FRAD (Frame Relay Access Device)
Attachment to a frame relay network is made via a FRAD on the customer's premises, which may be a separate device or software in the router. The FRAD connects to a switch port on the service provider's network via the User-to-Network Interface (UNI). All traffic for one customer generally travels over the same line, which is typically a multiple of 64 Kbps. Frame relay switches interconnect via point-to-point lines or an ATM backbone.
Permanent and Switched Circuits
Frame relay provides Permanent Virtual Circuits (PVCs) and Switched Virtual Circuits (SVCs). They are logical connections provisioned ahead of time (PVCs) or on demand (SVCs).
Voice Over FR
Voice can be packetized to travel over a frame relay network, often providing significant cost savings with some sacrifice in voice quality, depending on network configuration. In 1998, the Frame Relay Forum finalized the Voice Over FR specification. FRF.11 defines the formats, and FRF.12 subdivides large frames in order to interleave real-time voice with data on slow connections.
A Superb Resource
"Frame Relay for High-Speed Networks" by Walter Goralski is must reading not only to learn about frame relay, but about wide area networking in general. Goralski factors in history, trends and related networking technologies. Published by John Wiley & Sons, Inc., 1999)
A Frame Relay Network
The FRAD (Frame Relay Access Device)
Attachment to a frame relay network is made via a FRAD on the customer's premises, which may be a separate device or software in the router. The FRAD connects to a switch port on the service provider's network via the User-to-Network Interface (UNI). All traffic for one customer generally travels over the same line, which is typically a multiple of 64 Kbps. Frame relay switches interconnect via point-to-point lines or an ATM backbone.
Permanent and Switched Circuits
Frame relay provides Permanent Virtual Circuits (PVCs) and Switched Virtual Circuits (SVCs). They are logical connections provisioned ahead of time (PVCs) or on demand (SVCs).
Voice Over FR
Voice can be packetized to travel over a frame relay network, often providing significant cost savings with some sacrifice in voice quality, depending on network configuration. In 1998, the Frame Relay Forum finalized the Voice Over FR specification. FRF.11 defines the formats, and FRF.12 subdivides large frames in order to interleave real-time voice with data on slow connections.
A Superb Resource
"Frame Relay for High-Speed Networks" by Walter Goralski is must reading not only to learn about frame relay, but about wide area networking in general. Goralski factors in history, trends and related networking technologies. Published by John Wiley & Sons, Inc., 1999)
This illustration depicts the customer and service provider sides of a frame relay network. An ATM backbone is shown, because it is a common method of interconnecting FR switches. The FRAD may be a separate device (left side of illustration) or software built into the router (right).