RFC 1570 (rfc1570) - Page 2 of 18
PPP LCP Extensions
Alternative Format: Original Text Document
RFC 1570 PPP LCP extensions January 1994
This feature is defined as a separate LCP Code, rather than a
Configuration-Option, so that the peer need not include it with
other items in configuration packet exchanges, and handle
"corrected" values or "rejection", since its generation is both
rare and in one direction. It is recommended that
Identification packets be sent whenever a Configure-Reject is
sent or received, as a final message when negotiation fails to
converge, and when LCP reaches the Opened state.
A summary of the Identification packet format is shown below. The
fields are transmitted from left to right.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Identifier | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Magic-Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message ...
+-+-+-+-+-+-+-+-+
Code
12 for Identification
Identifier
The Identifier field MUST be changed for each Identification sent.
Length
>= 8
Magic-Number
The Magic-Number field is four octets and aids in detecting links
which are in the looped-back condition. Until the Magic-Number
Configuration Option has been successfully negotiated, the Magic-
Number MUST be transmitted as zero. See the Magic-Number
Configuration Option for further explanation.
Message
The Message field is zero or more octets, and its contents are
implementation dependent. It is intended to be human readable,
and MUST NOT affect operation of the protocol. It is recommended
Simpson