Network planning to move out from one building to the other with a break down of class b network.

[isaacman]

Hi all.
I have a class b network 10.13.x.x/16 with intervlan\transit
10.13.4.x/24 Server vlan
10.13.5.x/24 voice
10.13.6.x/24 Dept 1
10.13.7.x/24 Dept 2
10.13.8.x/24 Dept 3
10.13.9.x/24 Dept 4
Transite Vlan
10.13.20.8/27 internet vlan
10.13.21.16/27 Wan Vlan
We are planning on moving over to a new building and plan on keeping the same ip subnet 10.13.x.x class.
We plan on moving into phases 1 2 3...
For the first phase we plan on deploying a L2 network to new building 10.13.10.0/24 with a site to site VPN.
Once all phases are done we will move over the server 7 and voice vlan. We plan on keeping the same class c network for those Vlans to the new building.

Do you know if this will be some type of issues with routing.

 

[VinceWhirlwind]

I would say it will probably be a *lot* easier to create new VLANs and subnets on the new site. Gradually migrate people over and eventually decommission the VLANs and subnets from the old site.
(While you're at it, get rid of the old-school "Dept 1" style of VLANing and replace it with geographic VLANing - each edge switch(-stack) should have just one Voice VLAN and one Data VLAN. And each VLAN should only extend to one edge switch location. You will vastly simplify your network management and reduce your risk of outages, etc...)

Otherwise you're either going to be having fun (not!) tunneling your VLANs across sites during the migrations, OR, trying to project-manage entire-subnet-big-bang migrations where the subnet has to be decommissioned and then recommissioned elsewhere, creating all sorts of planning headaches and outages, all for no good reason when you could be migrating seamlessly to up-and-running new subnets. MUCH simpler.

 

[chieftan]

Vince has hit the nail on the head. Using a new range is always easier - unless - you have lots of static addresses on the current range.

When performing a complete migration, plan correctly and effeciently. I would, personally, start at the edge and work inwards to the core. From a routing perspective, all new routes will need to be added (statically or dynamically).

The successful migrations are the ones that have been planned correctly first.