Datacenter L2 Extension: problem of L3 gateway optimization

[parisdooz12]

Hi,

I guess my problem is a very classical problem.

We have number of vlans extended between our 2 DCs (interconnexion are 2 DWDM links, using STP).

On each vlan, HSRP is deployed with active interface on DC#1 or DC#2.

this indroduces traffic optimization problem. Here is an example:

- there an application server (let's say "A") on DC#1, on a vlan with active gateway on DC#2

- there is a database (let's say "D") on DC#1, on a vlan with active gateway on DC#2

Transaction between A to D will take the following path:

- request: DC1 -> DC2 -> DC1

- answer: DC1 -> DC2 -> DC1

Of course, we have not the problem with non extended vlans.

My question is: are there new protocols/tecnics which would permit to have a active/active redundant IP gateway on both side, with client of one DC able to use the closest gateway?

Thanks by advance for your lights!

P.

[parisdooz12]

I am not sure to well understand.

What I imagined is an application working like that between server A & server B each placed in a the same DC but with gateway in the other DC.

I suppose a latency of 2 ms between the 2 DC.

A packet which go to A to B then return will take 4 x 2 = 8ms.

Imagine now if the application consist into a lot of little transacton (using TCP), and each transaction need to launch the next transaction: the pb of gateway can introduce a lot of delay for such an application (TCP synchro + data exchange - imagine 1 packet - + TCP end => each trnsation can take more or less 25ms). If there is 10000 transactions => 250s.

With local gateway, this time should be well reduced.