Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!ig!agate!ucbvax!CLASH.CISCO.COM!satz
From: satz@CLASH.CISCO.COM (Greg Satz)
Newsgroups: comp.protocols.tcp-ip
Subject: X.25 Call User Data for higher level protocols
Message-ID: <8802032340.AA27094@ucbvax.Berkeley.EDU>
Date: 3 Feb 88 20:56:48 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 21

I am in need of the protocol identifiers used in the CALL USER DATA
field of the X.25 CALL REQUEST packet for various higher level
protocols.  I believe I know the following information but need to be
able to fill in the blanks.  Can anyone help or provide a reference as
to where I might find this data?

Who supplies these numbers?  ISO?  I would like to define an ID for a
virtual circuit that includes an extra 16 bit data field that could be
used like the ethernet type field.  Has something like this already
been defined?  Should I be using 802.2?  Comments?

		Protocol		Call User Data (byte in hex)
		--------		--------------

		    PAD			     0x01
		     IP			     0xCC
		 ISO IP			     0xCD
		    XNS			      ??
		    PUP			      ??
		 DECNET			      ??
		  Chaos			      ??