Config two directly-connected ProCurve swtiches as routers

[JonathanKing]

Hello,

I will be connecting two remote sites via a 50mb Metro Ethernet connection soon. I have a 5308XL in one location and a 2848 in the other (along with lots of other switches). The 5308XL is already configured for routing while the 2848 is currently not. Each location has a VLAN 1 already setup and configured and they are not 'compatible', i.e. they have different subnets assigned: 5308XL VLAN 1 = 172.16.1.1/24 and 2848 VLAN 1 = 172.16.12.24/24

I was planning on creating a new VLAN common only to those two devices, setting up a new subnet range with appropriate routes and then connecting the two together via the 50mb Ethernet connection.

But then I wondered, why can't I use an existing IP range and VLAN? So, I would like to be able to connect them via VLAN 1 and 10, and just assign a new IP address to the 2848. So it would look like this:
5308XL (172.16.1.1, VLAN 1) <---> 2848 (172.16.1.2, VLAN 10)
I believe that VLANs do not survive beyond the router, so the fact that the ports on each switch have different VLAN IDs should not matter, right? I have to use some VLAN ID for an untagged port, so adding a 'fake' one to the 2848 should be OK.

I was planning on setting up IRDP on both so that their routes will be auto-configured.

So, the question: What is the best way to connect the two switches and configure routing? Should I make a new, shared VLAN, or use the existing ones? I'd like to not introduce a new subnet if possible.

Thanks so much for any insight you have!

-jonathan king

[Matt79]

Hi Jonathan,

Unless I've misunderstood something and completely missed the point (which is perfectly possible!!) it doesn't sound like you'll need to do any configuration changes on the switches at all.

Surely the 50Mb Metro Ethernet connection requires routers at each end, and so they will handle the routing between the two subnets. Just like a VPN - you NEED the two sites to have different subnets in order to route between them.

And so you're only required config, assuming the 50Mb link is not also a gateway to the internet, will be to add a Static Route onto the Firewall in each site to bounce traffic destined for the remote LAN to the 50Mb router on the local LAN.

If the 50Mb link is literally presented as just an ethernet cable with no routers at each end, then that's obviously a different matter and I guess would explain your quandry in the first place.

Please let me know as I'm sure we can work something out, if that's the case!

Kind regards,
Matt