Best Design for Network

[notoftheearth]

Hello,

We have two areas of the datacenter which are phyically separated (perhaps 250 meters).  Up until now these areas have been on two different subnets.  However, now we need to start moving some servers from the one area to the other without changing their IP addresses.

One layer three switch routes packets between the two subnets.  What is involved in reconfiguring the network so that these new servers can be moved without losing connectivity?  There are access layer, distribution layer and core switches on both subnets.  I'm looking to try to get a comprehensive view of the steps and implications including everything that might be involved in this that I haven't thought of including what side affects this might have.

For example,

Steps

-Reconfigure layer three switch

-Configure VLANs on switches in the new area

Implications

-Broadcast traffic increases in the new area

-What are other implications

Any other input appreciated -thanks

[Mohamed Sobair]

I think you should be looking at Cisco LAM (Local Area Mobility) feature, it enables hosts to be moved from one Subnet (Vlan) to another without changing thier IP Addresses. This Solution shouldnt involve DHCP.

The Solution is normally implemented during a Network Migration and shouldnt be a permenant solution after migration.

The router where Mobile Arp is configured on will be acting as a proxy for all arp requests sendsby the host (Still Arp requests will be sent to the original Gateway of the subnet) Via the Proxy router.

For More information about Cisco LAM, please check the bellow link:

http://www.cisco.com/en/US/products/ps9390/products_white_paper09186a00800a3ca5.shtml

Regards,

Mohamed

[notoftheearth]

OK thanks for the input. In this case I'm not sure if that would work

because this does need to be a long term solution - the both areas of the

datacenter need to be able to permanently host systems on the subnet that

is currently only accessible in one area.

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[Jon Marshall · Accepted solution]

I can't read either of you .gif files so this may not be relevant. If they are in the same DC are the servers connected to access-layer switches or to the aggregate/distro layer ?

If access-layer switches are these connected to the aggregate layer by L2 trunks ? if so you should just be able to move the servers without readdressing.

It's not clear without a topology diagram what the issue actually is.

Jon