Date: Thu, 11 Apr 96 17:45:09 +0100 From: "Trevor Warwick INF-SP" Organization: Madge Networks To: peter_wang@3mail.3com.com (Peter Wang/HQ/3Com), seifert@netcom.netcom.com (Rich Seifert) Cc: p8021@nic.hep.net (P8021), nfinn@cisco.com ("Norman W. Finn") Subject: Re: ["Robin Tasker": Priority in 802.1p] I'd like to get my retaliation in early on the subject of using the I/G bit for priority in 802.3. I don't know of any 802.3/Ethernet application that uses this bit at the moment, so it may initially seem like a good idea to use it. However, you need to consider the issues of translational bridging between a "prioritised 802.3" and other media. For example, some vendors do source routing on FDDI LANs. If an 802.3 frame with the I/G bit set is forwarded from an 802.3 LAN to an FDDI LAN by an old 802.3-to-FDDI bridge that doesn't understand the new meaning of the I/G bit on 802.3, stations on the FDDI LAN may interpret the frame as being source routed. This is one possible problem - I'm sure there are others. -- Trevor Warwick email : twarwick@madge.com Madge Networks, voice : +44 (0)1753 661401 Sefton Park, Bells Hill, fax : +44 (0)1753 661011 Slough, England.