Re: [nsp] bridging questions

From: Paolo Bevilacqua (pab@cisco.com)
Date: Mon Jun 05 2000 - 03:09:11 EDT


At 07:44 AM 6/5/00 +0200, Dmitri Kalintsev wrote:
>On Sat, Jun 03, 2000 at 11:12:45PM -0400, jlewis@lewis.org
>wrote:
> >
> > Now for the tricky question. All the examples I've seen of
> briding over
> > WAN interfaces have a 1:1 mapping of bridge groups to WAN
> interfaces...or
> > in one case, multiple WAN interfaces for load sharing
> associated with a
> > single bridge group. Is there any way to bridge multiple
> ethernets over a
> > single WAN link (or even better, over 1 or more load sharing
> WAN links)?
> >
> > i.e.
> >
> >
> 10.0.0.0/24--e0--|------| |------|--e0--10.0.0.0/24
> > | | one or more | |
> > 10.0.1.0/24--e1--| 3640 |==============| 3640
> |--e1--10.0.1.0/24
> > | | T1's | |
> >
> 10.0.2.0/24--e3--|------| |------|--e3--10.0.2.0/24
>
>int s0/0.1
>bridge-group 1
>int s0/0.2
>bridge-group 2
>...
>etc.
>
>If you want to do load sharing, you'll have to run some sort of
>IGP that does
>it. I'm not sure about bridging, though - you *may* need to
>have this bridged
>traffic encapsulated into IP to take advantage of load sharing
>(bridging
>would think of multiple paths as redundant and block all but
>one to ensure
>loop-free topology).

there is a feature in cisco bridging that allows load sharing
without blocking, it's called circuit-group. regarding the
mapping of the various ethernets to the wan links there is no
concern, just use as single bridge-group and the self learning
mechanism will map macs to the correct port. if you really want
keep the 1:1 mapping between LAns and WAN set the wan encap to
fr, with three PVC subinterfaces, anmd circuit groups.

         /pab

>SY,
>--
> CCNP,CCDP (R&S) Dmitri E.
> Kalintsev
> CDPlayer@irc Senior network engineer at
> NetActive Internet
> dek @ hades.uz phone: +27 (0)11 719-0333
> fax: 444-8900
> http://hades.uz UIN:7150410 cell +27
> (0)82-336-1033
>



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