VLAN spanning two router interfaces???

Hey all, I've got a setup where there's a vlan that spans two geographically disperse areas. Previously, we had a foundry L3 switch taking care of all our routing. The connection between the two areas was on physical port one in the foundry. We've replaced that setup with a Juniper router and a new juniper switch. Problem is, since the router needs to ous two physical interfaces, how can we have the vlan span both interfaces? If something comes in on the LAN interface in VLAN 11, it needs to be sent out on the WAN interface as well. Is that a possibility since they're on the same subnet? Hope that makes sense.

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Comments

Aldur

From what I'm understanding you have traffic from a vlan coming in a port on the router this traffic needs to go out another port of the router which would be on the same subnet and carry the same vlan tag. This traffic must also be routable out the WAN interface as well. Is this correct?

Sounds like we need to turn those two ports into switchports, but I'm not sure if you want to do this, it all depends on what other traffic you have coming into those two ports, plus I'm not sure on the reachability to the WAN with doing this, something I would want to test out in the lab for sure.

Anyhow let me know if the understanding if your problem is correct and I'll pursue an answer.

shednik

Wow did that explanation confuse me and Aldur kinda cleared it up and made it worse

...anyway I'm not a juniper expert but would be interested to see how this would be done. Maybe draw out a diagram for us to explain how the traffic needs to traverse...

Aldur

shednik wrote:

Wow did that explanation confuse me and Aldur kinda cleared it up and made it worse ...anyway I'm not a juniper expert but would be interested to see how this would be done. Maybe draw out a diagram for us to explain how the traffic needs to traverse...

haha, I agree, I had to read the post a few times to get an idea of it, and probably made it a bit more confusing in the process, but I agree, a network topology with traffic flow would be very helpful.

JayrodEF

I think you've pretty much got it adur, I'll try to get a diagram or something maybe that'll help out a bit.

Aldur

JayrodEF wrote:

I think you've pretty much got it adur, I'll try to get a diagram or something maybe that'll help out a bit.

From what I understand this is the topology. I had to use a code box here to get the formatting to work out correctly. Hopefully it appears correctly in your browser.

                 WAN
                  |
     VLAN 11      |       VLAN 11
----------------J6350------------

where both links that connect in from VLAN 11 are on the same subnet. I know that you can, through a switchport config put both the needed ports into VLAN 11 and have them on the same subnet. I think you should have WAN reachability but I am not sure on this matter. I should have time today at work to try to lab it up. If I don't get a chance to do the lab today, I'll definitely get to it before the week is through.