Nortel Networks Circuit Card - Manual (Page 905)

Appendix A: LAPB Data Link Control protocol Page 905 of 906
Circuit Card Description and Installation
Description of procedure
The basic LAPB procedures must be implemented to satisfy the following:
• standard use of the poll/final bit (for more information, see
ISO-4375-1979-[E])
• exception condition reporting and recovery implemented in accordance
with BX.25 and ADCCP specifications
• link set-up and disconnect implemented according to BX.25
specifications
Table 281
Commands and responses
Command Response Option
I 8
RR RR
RNR RNR
REJ REJ or FRMR 2
SABM UA
DISC DM
Legend:
I: Information
RR: Receive ready
RNR: Receive not ready
REJ: Reject
SABM: Set asynchronous balanced mode
DISC: Disconnect
RSET: Reset
FRMR: Frame reject
UA: Unnumbered acknowledge
DM: Disconnect mode
Option 2: Provides ability for more timely reporting of I frame sequence errors
Option 8: Limits the procedure to allow I frames to be commands only