X.25 Type Numbers

(last updated 2007-08-30)

Registry Name: X.25 Type Numbers
Reference: N/A
Registration Procedures: Not assigned by IANA

Note:
ITU-T TSB defines the high order two bits of the first octet of call user
data as follows:

00 - Used for other ITU-T TSB recommendations (such as X.29)
01 - Reserved for use by "national" administrative
     authorities
10 - Reserved for use by international administrative authorities
11 - Reserved for arbitrary use between consenting DTEs

Registry:
Call User Data (hex)   Protocol                       Reference
---------------------  -----------------------------  ------------
01                     PAD                            [AXL]
C5                     Blacker front-end descr dev    [AXL]
CC                     IP                             [RFC877][AXL]*
CD                     ISO-IP                         [AXL]             
CF                     PPP                            [RFC1598]
DD                     Network Monitoring             [AXL]

*NOTE: ISO SC6/WG2 approved assignment in ISO 9577 (January 1990).


References
----------
[RFC877]  Korb, J., "A Standard for the Transmission of IP Datagrams
          Over Public Data Networks", RFC 877, Purdue University,
          September 1983.

[RFC1598] Simpson, W., "PPPin X.25", RFC 1598, Daydreamer, March 1994.


People
------
[AXL]     Alain Lanssiers <alanssie&cisco.com>

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