Re: IRB (I thought I understood it until...!)

From: Dave Genton (cisco_instructor@xxxxxxxxxx)
Date: Tue Aug 01 2000 - 12:08:55 GMT-3


   
This is what I had to config to get that scenario to work..

interface BVI1
 no ip address
 no ip directed-broadcast
 ipx network 700

bridge 1 protocol ieee
 bridge 1 route appletalk
 bridge 1 route decnet
 bridge 1 route ip
 bridge 1 route ipx
 no bridge 1 bridge appletalk
 no bridge 1 bridge decnet
 no bridge 1 bridge ip
bridge 1 priority 1

Dave

----- Original Message -----
From: "Simon Baxter" <Simon.Baxter@au.logical.com>
To: "Kevin Baumgartner" <kbaumgar@cisco.com>
Cc: <ccielab@groupstudy.com>
Sent: Monday, July 31, 2000 5:24 PM
Subject: RE: IRB (I thought I understood it until...!)

> Yeah.
>
> Don't know what version you're running, but 11.3 doesn't have the command
> bridge 1 irb :
>
> RTRB(config)#brid 1 ?
> acquire Dynamically learn new, unconfigured stations
> address Block or forward a particular Ethernet address
> aging-time Set forwarding entry aging time
> bridge Specify a protocol to be bridged in this bridge
> group
> circuit-group Circuit-group
> domain Establish multiple bridging domains
> forward-time Set forwarding delay time
> hello-time Set interval between HELLOs
> lat-service-filtering Perform LAT service filtering
> max-age Maximum allowed message age of received Hello
BPDUs
> multicast-source Forward datagrams with multicast source addresses
> priority Set bridge priority
> protocol Specify spanning tree protocol
> route Specify a protocol to be routed in this bridge
> group
>
>
> You're right though, when you configure irb it automatically configures
ip,
> ipx etc for routing (not bridging)
>
> Simon
>
> -----Original Message-----
> From: Kevin Baumgartner [mailto:kbaumgar@cisco.com]
> Sent: Tuesday, August 01, 2000 10:13 AM
> To: Simon Baxter
> Cc: ccielab@groupstudy.com
> Subject: RE: IRB (I thought I understood it until...!)
>
>
> The bridge 1 route ipx, bridge 1 route ip, etc. just tells it to do irb
for
> these
> protocols. (actually I believe if you do bridge 1 irb, it may
automatically
> do
> bridge 1 route ipx and bridge 1 route ip) Still need to put the IPX or IP
> network
> address on the BVI interface so that this network is routed. Otherwise
this
> bridged network will not be routeable.
>
> Kevin
>
> At 09:32 AM 8/1/00 +1000, you wrote:
> >I guess the idea is that traffic bridged from the r1/r7 lan is bridged
over
> >the r1/r5 serial link and then selectively (with bridge 1 route ipx,
brisge
> >1 bridge ip etc) routed (or bridged) from the BVI on r5.
> >
> >I haven't built it, but it sounds straight forward enough??
> >
> >
> >Simon
> >
> >
> >-----Original Message-----
> >From: Kevin Baumgartner [mailto:kbaumgar@cisco.com]
> >Sent: Tuesday, August 01, 2000 3:54 AM
> >To: Mark Lewis
> >Cc: ccielab@groupstudy.com
> >Subject: Re: IRB (I thought I understood it until...!)
> >
> >
> >At 04:44 PM 7/31/00 +0000, you wrote:
> >
> >
> > >Hi people,
> > >
> > >This is a question about lab 8, so if you haven't done it yet, avert
your
> >eyes now !
> > >
> > >
> > >
> > >On lab 8b, you have to configure bridging between the ethernet segment
> >connected to r1 & r7 and the serial connection between r1 & r5. So far so
> >good. However, then you are required to configure IRB on r5. Why? I was
> >under the (obviously mistaken) impression that with IRB you use it with
> >multiple interfaces in a bridge-group and it provides routing (ref. Cisco
> >LAN Switching (CiscoPress)). There's only one interface in the bridge
group
> >on r5. Is this something to do with encapsulation ??!!
> >
> > IRB allows routing between and routed network and a bridged network.
> This
> >can be IP, IPX, Appletalk and I believe a few other protocols.
> >The key part about using IRB is that you need to create what is called a
> >"BVI" interface. This is similar to a physical interface and here you
> >configure either IP address, IPX, Appletalk for the bridged network. So
in
> >lab 8b the IPX network that is defined on r7 has to be define also
> >on the BVI interface on r5. The great thing now is that you can route
> >between the bridged network and the rest of the IPX networks on the
> >ethernet side of r5.
> >
> > Just defining bridge-groups on r5 doesn't give you IRB. You need to
> >define the BVI interface and apply the network address to it.
> >The easiest way to thing of why you would use IRB is to see what happens
if
> >you are just using bridge-groups. It's a competely flat network.
> >Basically one big network for everyone. This is not the really world.
There
> >are going to be a number of subnetted networks already and you
> >need to somehow put your bridged network as part of this subnetted
network.
> >This is how IRB comes into play.
> >
> > Kevin
> >



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