I know this sounds crazy but are there any tricks that can make this situation work:
We are getting ready to packup and move our existing infrastructure to a new site. Both sites are within a structured "corporate" WAN. We want to move certain server farms and end users at a time. My equipment: 2 cat6K's both with redundant MSFC's. Here is my dilemma all machines/servers are on the same subnet therefore the default gateway's are the same. We do not want to re-ip. We want to temporarily take one switch/msfc and establish our uplink to the Corporate backbone and continue to function as if we were in the same building.
My initial thoughts were tricks with HSRP(?) or changing the default gateways on the boxes to the address of the temp gateway at the new site.
Please note that this setup will require that you bridge between the two parts of the subnet. Your WAN should be big enough to support the corresponding broadcast-traffic and a fair amount of unicast.
With routing you cannot do this while you have the same subnet on both ends.
No even if the same subnet has different gateway. ie:
Lan A Lan B
220.127.116.11/23 <----(WAN)---> 18.104.22.168/23
defualt gate 22.214.171.124 126.96.36.199
Have you considered changing the IP scope for the servers moving, but natting their addresses at the original site. This will allow you to migrate to a more 'viable' solution. Bridging over the WAN sounds like a real big can 'o' worms.
WAN bridge is straight forward, but could impact hub router performance. The tunnel mentioned above, would be very good if your remote sites are not connected to the same hub router.
Point to point WAN bridge just for the migration? No impact to hub performance but could take up to 60 days for services to be delivered
If both sites are Frame Relay, provision temp PVC between two sites and again, WAN bridge traffic across temp PVC. PVC can usually be ordered and delivered within a week or two. Depends on how much of the WAN circuit you consume today, to make this a viable option.
Are the hosts IP address such that you could segment your address space, move one group of hosts to new site, advertise that portion of the address from the new site only. If the routing protocol supports, best match will work for those hosts that you move, while portion of address still advertised from old site continues normal operation.
Will this solve my goal of seperating the same subnet across the WAN.
My goal is to actually split our LAN over to sites without changing anything on the servers or workstations. For instance, lets say ServerA in Chicago needs to send a "packet of some sort" to Server B which use to be at site A. How do I move that server to Site B behind a new router and make that transition transperant.
If the goal is to split the LAN across your WAN, enable NAT on one side of your LAN. Have private IP schema & overload the addresses.
Enabling NAT is not a panacea, as there can be issues with NAT. Can be implemented as an interim solution....