From: Derek Small (Fuse) (dwsmall@xxxxxxxxxx)
Date: Mon Apr 17 2000 - 22:17:00 GMT-3
Well now I'm really confused....
Questions about this example:
1. Why do they have a source-bridge ring-group 31 statement on RouterA?
RouterA is only doing transparent bridging with bridge groups!?!?!
2. The translational bridging statement on RouterB looks wrong from what I
know. The last value in the list of numbers at the end of the command (500
1000 1 1) is supposed to be the bridge-group.
(snippet from a router command line)
term_serv(config)#source-bridge transparent 500 1000 1 ?
<1-255> Transparent bridge group attached to the virtual ring
But the bridge-group defined on RouterB is clearly 5 ?!?!? What's up with
that?
3. I have seen this type of config before to solve this type of topology,
but it brings up my two questions again.
A) If you do not enable translational bridging on RouterB, what segment
would RouterA be able to exchange traffic with? Only the Ethernet, only the
Token Ring, or both the Token Ring and the Ethernet, but the Token Ring and
Ethernet on RouterB would not be able to exchange traffic. The later is
rather obvious, but is that the only result of not doing translational
bridging?
B) If you have the example in my second post with three routers,
R1-Ethernet only, R2-TokenRing & Ethernet, and R3 TokenRing only. What
effect would not enabling translational bridging on R2 have? Would traffic
move between the two TokenRings & between the two Ethernets only, or would
you simply not be able to move traffic between the Token Ring and Ethernet
ports on R2?
Any help on this would be GREATLY appreciated.
Thank You
Derek Small
dwsmall@fatkid.com
----- Original Message -----
From: Stan Buskus <stan.buskus@worldnet.att.net>
To: John Conzone <jkconzone@home.com>
Cc: Derek Small (Fuse) <dwsmall@fatkid.com>; ccielab
<ccielab@groupstudy.com>
Sent: Monday, April 17, 2000 6:45 PM
Subject: Re: 2 DLSW questions.
> I once thought DLSW took care of the translation. However, this is a
> quote from the Cisco documentation:
>
> "Because DLSw+ does not do local translation between different LAN
> types, Router B must be configured for SR/TLB by issuing the
> source-bridge transparent command. Also, note that the bridge groups are
> configured on the ethernet interfaces."
>
> See the example and explanation at:
>
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/ibm_c
/bcprt2/bcdlsw.htm#xtocid752139
>
> John Conzone wrote:
> >
> > Derek, translational bridging is not neccessary at all for DLSW, in
> > either scenario if I understand you correctly. The beauty of DLSW is
that
> > all that is neccessary is IP connectivity (at least that is most common,
> > although other encaps are possible),between the end peers.
> > So in your first scenario, R1 needs IP connectivity to R2. In your
> > second scenario, R1 needs IP connectivity to R3. Thats it. You don't
need
> > translational bridging in the middle for DLSW between R1 and R3.
> > What you do need is source routing enabled on the Token Ring
interface
> > side(R1) into a virtual ring, and a bridge group, typically IEEE,
applied to
> > the ethernet interface (R2, or R3 in the 2nd scenario) on that side and
that
> > is piped to DLSW with the DLSW bridge group command.
> >
> > ----- Original Message -----
> > From: Derek Small (Fuse) <dwsmall@fatkid.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Monday, April 17, 2000 2:10 PM
> > Subject: 2 DLSW questions.
> >
> > > I just need a double check on these from one of the more knowledgeable
> > DLSW
> > > people.
> > >
> > > First scenario:
> > >
> > > Token ______ R1 _______Serial______ R2 _____ Ethernet segment
> > > Ring
> > >
> > > I do not believe translational bridging is necessary for connectivity
> > > between systems on the Ethernet and Token Ring segments. Is this
correct.
> > >
> > > Second scenario:
> > >
> > > Ethernet
> > > |
> > > |
> > > Token _____R1______Serial______R2______Serial______R3______ Ethernet
> > > Ring |
> > > |
> > > Token
> > > Ring
> > >
> > > DLSW peers between R1 and R2, and between R2 and R3 are sufficient to
> > > provide full connectivity between the Token Ring on R1 and the
Ethernet on
> > > R3, only if translational bridging is configured on R2. Without
> > > translational bridging on R2 only Ethernet to Ethernet, and Token Ring
to
> > > Token Ring communications is possible. Is this correct?
> > >
> > > Thank You
> > >
> > > Derek Small
> > > dwsmall@fatkid.com
> > >
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