40
Primary to Basic Rate ISDN Multiplexer
SALES: 0118 965 5100
A typical display of a long ASCII layer 2 message is shown below.
23: TA Ch BRI 2 L2
00:01:75:30.271
SAPI= 0, TEI= 40, C/R= 0, P/F=1, TYPE= INFO
N(R)= 1, N(s)= 1
The following information has been added:
(k) Send Sequence Number N(s)*
(l) Receive Sequence Number N(r)*
Layer 2 management transactions may be also decoded in long form messages. A typical
decode follows.
23: TA Ch BRI 2 L2
00:01:75:30.271
SAPI= 0, TEI= 40, C/R= 0, P/F=1, TYPE= UI
MEI= 15, Ri= 7FCD, MSG TYPE= ID Request, Ai= 0
The following information has been added:
(m) Management Entity Identifier*
(n) Reference Number (Ri)*
(o) Management Message Type*
One of ID Request, ID Assigned, ID Denied, ID Check Request, ID Check Response, ID
Remove, ID Verify.
(p) Action Indicator*
Only Information and certain Unnumbered Information messages at layer 2 include layer 3
messages.
Fields marked with * are explained further in CCITT Q.921 Digital Subscriber Signalling
System No 1, Data Link Layer.
A typical display of a hex layer 2 message is shown below.
23: TA Ch BRI 2 L2
00:01:75:30.271
02 81 00 02 41 01 81 0D 18 01 89
The information contained in the message is not decoded but simply displayed as hex octets.
