From: Connary, Julie Ann (jconnary@xxxxxxxxx)
Date: Fri Jan 05 2001 - 12:05:33 GMT-3
Curtis,
Remember that DLSW in it's reachability tables uses Token-ring form -
non-canonical. A MAC coming in from the Ethernet is
translated to non-canonical before being sent across the DSLW link. So -
Ethernet - to -Ethernet the MAC starts out canonical, DLSW translates it
at first router, translates it back at second router and sends it back out
on Ethernet. Token-Ring to Token-Ring - works, DLSW does no translation.
Ethernet to Token Ring - problem if you want to either configure the
ethernet end station with say a token ring attached FEP MAC address or
populate the reachability cache in DLSW.
Here is from a previous email:
only ethernet address need to be bit swapped, you don't need do bit swaping
for TR station.
Station1-------Ethernet----------R1----------------R2------Token
ring---------Station2
if i canreach mac-address put on R2 to let Station1 access station2, you
don't need bit swapping.
if i canreach mac-address put on R1 to let Station2 access station1, you do
need bit swapping.
This is saying, that when you want to populate the reachability cache of R1
- which will send this to R2 during capabilities exchange - you must bit
swap Station 1's mac address. Then when Station 2 trys to send an explorer
to find Station 1 - it will find it because it is token ring and uses
non-canonical format, and then R1 will properly bit swap it back the
packets before sending them onto the Ethernet.
A great way to play with this is to use a 2500 router as the end stations
using SNA services. You can configure the 2500's with SNA Services to make
a connection to each other across your DLSW network. And if your routers
have both Token Ring and Ethernet you
can try out all the combinations.
Try this:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ibm_c/b
cprt2/bcdsnasw.htm#xtocid2334129
Simply define a cpname on your router, setup the appropriate source-route
or transparent bridging and
define a port and a link and watch it connect across your DLSW network-
really cool. Unfortunately my resource with an actual working config is at
home - I'll try to remember to send it.
Julie Ann
At 09:07 AM 1/5/2001 -0500, Curtis Phillips wrote:
>When dealing with DLSW between routers having ethernet and token-ring segments
>attached while filtering mac addresses is it appropriate to
>consider mac canonical -to - non-canonical conversions as part of your
>configuration?
>
>As the translational bridging is integrated into the protocol itself. Can
>someone provide a brief explanation and perhaps and example?
>
>In appreciation,
>
>Curtis
>
>
>
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