1988 was the year that CCITT released specification I.122, named Framework for Providing Additional Packet Mode Bearer Services. This release specified how LAPD protocols could be used in applications other than ISDN. Soon after, ANSI also became involved, which meant that specifications became complete.
1990 saw two other papers released:
I.293 ISDN Frame Node Bearer Services (FMBS)
I.370 Congestion Management for the Frame Relaying Bearer Service
Some of the other papers are as follows:
| ANSI | CCITT |
| Framework | | I.122 |
| Service Description | T1.606 | I.233.1 |
| Data Transfer Protocol | T1.618 | Q.922 |
| Congestion Management | T1.606 | I.370 |
| Access Signalling | T1.617 | Q.933 |
Q.922 (1992) defines an enhanced version of LAPD. It species, among other things:
- congestion controls
- transmission error checking
- frame length inspection
checking of data for bytes before and after bit insertion and extraction (ie. if data is not in byte format, it will not be encapsulated in a frame
- multiplexing using the address field
- frame delimiting, alignment and transparency
There will be more on this topic to come by the 5th of January 1998
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