Bridge two or more VLAN's on Cisco7600

Unanswered Question
Jun 10th, 2010

Hi All,

I have question regarding connecting two VLAN's on 7600.

The schemat is like below:

[7600] <-- TRUNK --> [SWITCH] |--PORT IN VLAN 1501--[PC1 IP]


                              |--PORT IN VLAN 1502--[PC1 IP]

I have checked another routers for example 7200 and 3800 - there I can use bridge-groups with protocol ieee and bridge those two VLAN's.

On 7600 there seems to be no such option - only protocol vlan-bridge is supported, so this is fallback bridging.

I have also tried vlan translation on 7600 but it is also not working.

I know that I can use ES+ cards, but for know I cannot have them and have to use the hardware which is mainly SUP720, SUP32 and WS-X cards.

Any suggestions how can I do the functionality I need?

Best regards,


I have this problem too.
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Giuseppe Larosa Thu, 06/10/2010 - 10:27

Hello Greg,

you should be able to use fallback bridging also for IPv4 traffic by adding appropriate commands

I was able to do so with C6500 and native IOS years ago

so unless they removed or restricted the feature

the key commands are those of IRB

bridge 1 bridge ip

or you can use a cable between two access ports one in vlan X and one in vlany to do the trick (single point of failure)

Hope to help


grzegorz.cegielski Thu, 06/10/2010 - 11:25

Hi p.bevilacqua,

the problem is that in real this [Switch] I've mentioned is not a real switch. It is some GPON device which I have translated to the architecture of the Switch and PC's.

So I cannot have different IP address in different VLAN, because the idea is to allow communication like in described schema.



Giuseppe Larosa Fri, 06/11/2010 - 09:24

Hello Greg,

but for testing a bridging architecture you just need one vlan not two, I don't understand why you want to use two vlans for this

I cannot test now I have many C6500 but all in production, because as Paolo has noted it is not wise to perform inter-vlan bridging

It worked for me in 2004 while I was preparing to test EoMPLS on a production network.

I would use only one vlan for this test if the GPON is a passive optical network it can be emulated with a single vlan

Hope to help


grzegorz.cegielski Wed, 06/23/2010 - 11:18

Hi Giuslar,

the problem is that the GPON system has different VLAN for each PON endpoint device and each service on that endpoint device, so all what is going out of this GPON system is tagged traffic.

I dit checked the VLAN translation, but it also does not work.

I did also checked the transparent biridging between two dot1q subinterfaces but the system is saying that the feature is configured on non supported interface types, when receiving the ARP packets from the endpoints.

Best regards,



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