Path: utzoo!attcan!uunet!van-bc!skl
From: skl@van-bc.wimsey.bc.ca (Samuel Lam)
Newsgroups: comp.protocols.appletalk
Subject: Re: Ethertalk Phase II header
Message-ID: <2050@van-bc.wimsey.bc.ca>
Date: 21 Sep 90 08:38:52 GMT
References: <1410@alfred.tegra.COM>
Reply-To: Samuel Lam <skl@wimsey.bc.ca>
Distribution: na
Organization: Balliffe Intersystem, Vancouver, B.C., Canada
Lines: 17

In article <1410@alfred.tegra.COM>, cooper@tegra.UUCP (Al Cooper) wrote:
)It seems that the Phase 2 packets are in 802.2 format
)instead of normal Ethernet format used by Phase I and TCP/IP. The 802.2
)header differs in that instead of a protocol type following the
)destination and source addresses there is a byte count. If this is
)all true, does that mean that there is no way to differentiate the
)two formats, and therefore no way to run both TCP/IP and Ethertalk
)at the same time?

The way to separate the Ethernet and IEEE 802.3 packets on the wire
is to look at the 13rd and 14th octet of the packet (the Ethertype/
802.3-length field).  If this value is less than 0x0600 it's an Ethernet
packet, otherwise it's an IEEE 802.3 packet.

...Sam
-- 
Internet: <skl@wimsey.bc.ca>	UUCP: {van-bc,ubc-cs,uunet}!wimsey.bc.ca!skl