[comp.sys.mac.comm] Macs and Token Rings

rpcfod@uarthur.UUCP (Robert Patt-Corner) (01/10/91)

In article <1991Jan08.235741.10757@ux1.cts.eiu.edu>, cfejm@ux1.cts.eiu.edu (John Miller) writes:
> 
> Thanks for any replies (and, for that matter, any advice about
> how to get Macs a full range of services on a TR?)
> 
> John Miller
> Music Theory
> Eastern Illinois University
> CFEJM@UX1.CTS.EIU.EDU

We're bridging the Ethernet and TokenRing with an IBM 8209 - is it a bridge?  is it a router? only IBM knows for sure!)

Works very well, with one caveat.  Its algorithm looks for the first packet froma hardware address, notes if it's 802.3 or V2 ethernet, and locks onto that
decision for the time-to-live of a table entry.

With the Mac, which runs multiprotocol stacks, this is disastrous.  On a random
basis the 8209 will decide you're 802.3 (for instance if it sees a LAT packet
first, or a V2 AppleTalk packet first).  When that happens an ARP will be 
answered in 802.3 format.  And since TCP on the Mac (and nearly everywhere
else I think) is still EthernetV2 that ARP response will not be seen.

Our temporary work-around is to lock the 8209 to V2 ethernet.