jmj@cernvax.cern.ch (Joop Joosten) (08/06/90)
The title of this article should be: "Why is it already known for 5 months that AppleTalk II is not working over translating Ethernet/FDDI bridges and that nothing has been done about it" In short: translating Ethernet/FDDI bridges SNAP encapsulate Ethernet 2 packets on FDDI and translate these packets back to Ethernet 2 packets when bridging from FDDI back to Ethernet. For this purpose the OUI=0 has been taken with the understanding that RFC1042 packets generated on an Ethernet come out of an FDDI/Ethernet bridge as Ethernet 2 packets. TCP/IP can live with that, since both packet formats should be accepted by an implementation. However, Apple decided to be different and although they took a very good decision to use multicasts in AppleTalk II, the AARP is SNAP encapsulated with an OUI=0 and is therefore coming out of an FDDI/Ethernet bridge as an Ethernet 2 packet. This packet is not accepted by the current AppleTalk II implementations, hence the problem. I know that at least one vendor of translating bridges is talking to Apple about this, but they do not seem to make much progress, since 5 months have elapsed and there are no results. It seems that the users have to start putting pressure on Apple. May be that will help to turn them around. Unfortunately, apart from an odd article in comp.protocols.tcp-ip, I have not seen anything on the other newsgroups read by people who certainly would like to know about this problem and who are or will be concerned.