Nortel Networks 311 Appendix A LAPB Data Link Control protocol

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Appendix A
LAPB Data Link Control protocol
Contents This section contains information on the following topics:
"Introduction" (page 1129)
"Operation" (page 1129)
"Frame structure" (page 1130)
"LAPB balanced class of procedure" (page 1131)
"Commands and responses" (page 1131)
"Description of procedure" (page 1132)
IntroductionThis chapter describes the LAPB Data Link Control protocol used with the
QPC513 ESDI card. The protocol is a subset of the HDLC procedures
which are described in International Organization for Standardization
procedures ISO 3309-1979 (E), ISO 4335-1979 (E) and appendices 1 and
2, and ISO 6256-1981 (E). Refer to theseprocedures for complete LAPB
details. Applications which use an ESDI port in synchronous mode must
conform to the following requirements.
Operation Circuit Switch Equipment transfers data to the QPC513 in blocks consisting
of 1 to 128 eight-bit octets. Each block is processed in accordance with the
LAPB subset of the HDLC protocol and transmitted serially to the line at a
rate determined by the downloaded parameters.
The QPC513 card receives data serially from the line, packaged in LAPB
information frames. After determining that a block is error free, the data is
supplied to the Circuit Switch Equipment as a block.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Copyright© 2003-2008, Nor tel Networks
.