55
SSxDSL-5M
InfoElm
08:21:36
> +POWER<
> <
2006-05-23 00:07:16.372 #00026
U TE->NT C/R:0 P/F:0
SAPI : 016 TEI : 088
L2 MSGTYPE : I
NS : 003 NR : 002
L3 MSGTYPE : CALLREQ
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Figure 38 X.25 Current Trace-Decode View
The following is reported:
2006-05-23: Year/Month/Date
00:07:16.372: Hour/Minute/Second. Fraction of a second.
#00026: Five digit message number.
U or ST: Interface that captured the message.
TE->NT: Direction of transmission.
C/R: Command/Response field bit that identifies a frame as either
a command or a response.
P/F: This is the Poll/Final bit. In command frames, it is the P-bit;
in response frames, it is the F-bit. When the P-bit is set to 1, it
demands a response (F-bit set to 1). The F-bit is then set to 1
to indicate that this frame is a response from a poll command.
Messages with P-bit do not require a response and may be sent
consecutively without responses.
SAPI: Service Access Point Identifier identifies the point where
layer 2 services are provided to a layer 3 entity. There are four
assigned SAPI values:
• 0: Call control procedures (normal voice/data call setups).
• 1: Packet mode using Q.931 call procedures (B-ch packet
calls).
• 16: Packet communication conforming to X.25 level 3 proce-
dures (D-ch packet calls).
• 63: Layer 2 management procedures.
TEI: Terminal Endpoint Identifier identifies the terminal at the end
of the connection. The values may be in the range of 0 to 127.
These values are grouped as follows:
