interface specification based on LAPD
(Q.921), the Integrated Services Digital Network
version of LAPB
(X.25 data link layer
). A common specification was produced by a consortium of StrataCom, Cisco
, and Northern Telecom.
Frame Relay is the result of wide area network
ing requirements for speed; LAN
and LAN-LAN internetworking
; "bursty" data communications; multiplicity of protocols
and protocol transparency. These requirements can be met with technology such as optical fibre
lines, allowing higher speeds and fewer transmission errors; intelligent network end devices (personal computers
, and servers
); standardisation and adoption of ISDN protocols. Frame Relay could connect dedicated lines and X.25
and other "fast packet
Frame Relay uses the same basic data link layer framing
and Frame Check Sequence
so current X.25
hardware still works. It adds addressing (a 10-bit Data Link Connection Identifier
(DLCI)) and a few control bits but does not include retransmissions, link establishment, windows or error recovery. It has none of X.25's session layer
but adds some simple interface management. Any network layer
protocol can be used over the data link layer Frames.
Frame Relay Resource Center (http://alliancedatacom.com/framerelay.asp).