[c-nsp] Catalyst 6500 series switches and Cisco 7600 series routers do not support Integrated routing and bridging (IRB)

Sukumar Subburayan sukumars at cisco.com
Tue May 17 17:32:20 EDT 2005


Unfortunately, this is not possible without IRB (which is not supported on 
the Cat6k, as you have noted).

Each L2-vlan on the switch will have to terminate  to it's corresponding 
L3-SVI (Switch Virtual Interface) seen in the config as 'interface 
Vlan<vlan-no>'.

'vlan-bridge' can bridge between the bridge-group vlans for legacy 
protocols and cannot be used to terminate your bridged IP L2-VLANs to a 
single L3 interface.

I am not sure about your exact requirement, but if the you are currently 
having 4 subnets, and want to route/bridge between them. You could put 
them all in 1 SVI vlan and configure 'secondaries' to route between them.

Not sure if this is different from what you want to.

sukumar






On Mon, 16 May 2005, Manu Chao wrote:

> Hi there,
>
> I need to use IRB with bridge protocol IEEE on a 6500 running IOS
> Version 12.2(18)SXD2 but this feature doesn't exist anymore. I
> understand why but I need it ;-)
>
> I need to bridge n L2 VLANs ending on the 6500 to one L3 VLAN local to
> this same 6500.
>
> CISCO-6500(config)#bridge 1 protocol ?
>
>  dec          DEC protocol
>  ibm          IBM protocol
>  vlan-bridge  vlan-bridge protocol
>
> ---- vlan 201---->
>
> ---- vlan 202---->
>
>                              I R B  ----> vlan 200 (IP 10.0.0.1/24)
>
> ---- vlan 203---->
>
> ---- vlan 204---->
>
> Bridge protocol ieee are not support anymore.
>
> It is possible to bridge two L3 VLANs with "bridge protocol 1
> vlan-bridging " but it seems we cannot bridge and route on the same
> VLAN.
>
> Cisco release notes are clear on this issue:
>
> "Catalyst 6500 series switches and Cisco 7600 series routers do not
> support Integrated routing and bridging (IRB)"
>
>
> Can someone find a solution (other than downgrading to release 11) or
> a workaround?
>
> Thanks & Best Regards,
> Linux
>
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