Ethereal-dev: Re: [Ethereal-dev] implementing a dissector for PPP sent over a CDMA1x data netw

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From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Fri, 5 Dec 2003 19:32:04 -0800
On Fri, Dec 05, 2003 at 08:21:23AM -0800, Michael Lum wrote:
> With respect to the standards you can probably get those free
> 
> at www.3gpp2.org
> 
> (NOTE the "2").

Well, that was fun.  I looked at some obvious standards, and didn't find
8881 in any of them.

Then I Googled for

	gre 0x8881 type

and found:

	http://www.hitachi-system.co.jp/sniffer/product/mobile/mobile_info.html

which seems to imply that 0x8881 is an alternative type code for
PPP-over-GRE (it's in Japanese, except for the occasional bit of
English, and I can't read any words in Japanese other than "Nihon") -
*AND* found

	http://www.3gpp2.org/Public_html/specs/C.S0047-0_v1.0_110403.pdf

"Link-Layer Assisted Service Options for Voice-over-IP: Header Removal
(SO60) and Robust Header Compression (SO61)" which says

	If GRE encapsulation is used to transport the PDUs to and from
	the PCF (see also [12]), the PDU shall be placed in the payload
	field of the GRE packet.  The GRE payload will then consist of
	one of the PDUs defined in Section 2.5.3.  In addition, the
	protocol type field in the GRE shall be set to hex value 0x8881;
	endpoints will know the format of the payload based on the
	connected service option number.  Also note that there are no
	specific requirements on the use of the GRE Sequence Number if
	GRE encapsulation is used.

but which doesn't mention PPP anywhere.