From: George Spahl (g.spahl@xxxxxxxxxxxxx)
Date: Sun Jun 02 2002 - 12:23:12 GMT-3
Jeff,
I suppose you could have a scenario where you had a
transparently-bridged token ring network (maybe a gaggle of cisco
routers), but you also had a couple of legacy source-route bridges at
each far end which needed to pass traffic to each other over the
transparently bridged network. The default behavior for the transparent
bridges in-between would be to examine the first(Individual/Group) bit
of the source address in the token ring/802.5 frame and if the first bit
is 0 (an individual address) go ahead and forward it as it's just a
regular frame. However, if the first bit of the source address is set
to 1 (a group or multicast address) it indicates that this is a
source-routed frame and that there is routing information (a RIF field)
embedded in the frame. (If you think about it, what normal frame would
have a multicast address as a source address? That's why source-routing
can manipulate that first bit without anyone getting confused about the
source addresses.) Since a transparent bridge doesn't really know what
to do with a source-routed frame it would normally just discard it. The
command you mentioned, however, would allow the transparent bridge to
break all the normal rules and forward the source-routed frame anyway.
Hope this helps! George
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Jeff Szeto
Sent: Saturday, June 01, 2002 3:34 AM
To: ccielab@groupstudy.com
Subject: TB commnad: bridge bridge-group multicast-source
Hi Group,
I do not understand the command "bridge bridge-group multicast-source"
seeing
from the guide
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/
fibm_
c/bcfpart1/bcftb.htm
Could you please explain when I should use it?
Thank you.
Jeff
This archive was generated by hypermail 2.1.4 : Tue Jul 02 2002 - 08:12:21 GMT-3