Frame Relay
<communications> A
DTE-
DCE 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,
Digital, and Northern Telecom.
Frame Relay is the result of
wide area networking requirements for speed;
LAN-
WAN 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, workstations, and
servers); standardisation and adoption of ISDN protocols.
Frame Relay could connect dedicated lines and
X.25 to
ATM,
SMDS,
BISDN and other "
fast packet" technologies.
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://www.alliancedatacom.com/framerelay.asp).
