Solutions to overcome IP conflicts between sites

[Jonathan Schultz]

The company I work for recently bought out another company.  Currently we haven't found the need to integrate them into our network but that some will come about in the near future.  The problem we have is that both our internal networks are utilizing 10.x.x.x space and are too large to re-IP our networks.  We have a VPN tunnel set up with them and are NATing them to selected resources at the moment but this is not a scalable solution moving forward.  I'm looking for ideas/solutions to overcome this problem.

[AMediaFilm]

Slowly migrate to IPv6. Add IPv6 support to optional resource, unfold parallel IPv6 backbone, start from "courier's" department, find bottle necks and possible problems, run IPv6 and v4 in parallel. Slowly remove IPv4 when everything are ok in v6 kingdom.

[Jon Marshall]

Sorry to say but if you can't readdress one company then NAT is your only solution.

It isn't scalable as you say but if the IP subnets in use conflict then those are your only options.

With DHCP readdressing end clients shouldn't be too hard but I appreciate there may be servers, routers, switches, firewalls etc.

You really don't have any other options.

Jon

[Jonathan Schultz]

I appreciate everyone's response so far.  Has anyone tried configuring VxLAN? I am not familiar with it yet as I have acquired some documentation but yet to have had the time to read it.  Supposedly it helps address such scenarios as the one we are facing.  Was hoping to get some responses related to ACI and VxLAN.

[Jon Marshall]

VxLAN allows you to extend a L2 vlan across a L3 network but I'm not sure how this would help you unless you want to merge the same IP subnet in each site into a single vlan ?

It's is primarily a server technology and is used in the DC.

Perhaps you could clarify how you see it helping in your scenario ?

Jon

[Jonathan Schultz]

This option was actually suggested by our Cisco Sales Engineer as a viable option.  I'm not quite sure how he wants to suggest integrating it as a solution.  I understand what you mean by having to extend the vlans across L3 boundaries.  Basically we want their users to be able to access our resources and vice versa.

[Jon Marshall]

I think we would need more detail to understand how the engineer sees it working.

As I say VxLAN would allow you to merge the same IP subnet in both sites into the same vlan so that vlan now extends between sites.

Whether you want to do that is another matter.

Again, as far as I understand it, VxLAN is generally used in virtualised environments in DCs and I haven't see any cases of using it to extend client vlans in the way I think your engineer is proposing.

Doesn't mean it couldn't be done and I haven't used it so I wouldn't like to say one way or the other but I would have thought there would be new kit you would need eg. VxLAN gateways etc.

But like I say, as far as I can see, even if it was possible what he is proposing is to extend your L2 vlans between the companies and I would think carefully about that.

In addition I can't see how it would solve the problem of two devices using the same IP address as they couldn't exist in the same vlan.

Sorry I can't be more specific but I have no direct experience with it. I would certainly want to see some sort of proposed design etc. from the engineer though and all the implications spelt out before you go down that road.

Jon