Sharing L2 between two DC

[AllertGen]

Hello, everyone.
Because of solution of our system engineers I’m hitting a problem with network design. We’re planning to do a second DC and our system engineers want to aggregate blade systems at both DC to one cluster. So I need to find a solution to share network segments (for example like 172.20.1.0/24, 172.20.2.0/24, etc) between two DCs.

I need this sharing because in this blade cluster one virtual host can migrate from blade system of first DC to blade system at the second DCs. So I need something like L2 trunk between switches of each DC (switches works as L3 gateway in each vlan). My main problem in this is a L3VPN of ISP between DCs (also there is a case of 1450 MTU. Yes, because of the encryption). So if host would migrate from one blade to another it should be avaibke from both DCs.

Is there any technology for such cases? We are looking for Nexus 3K device at the DCs so if there is some technology in the NX-OS for this it would be very helpful (I know about APIC fabric of 9k series, but this devices cost too much). Or is there some SDN solutions for such problems?

Best Regards.

[Pawan Raut]

Point to Point leased line could be the solution for L2 between two DCs.

[Mark Malone]

OTV would be a good option but lower end 3ks wont support it , only 7ks and ASR 1ks do

maybe run a vpc between them as another option , your limited with 3k trying to link DCs

[AllertGen]

Hi, mark malone.

Thank you very much for info. N7K cost way too much (and I need 2 of them in each DC for reservation + licenses). But I'm planning to buy ASR 1002X (maybe 1002HX). At this case I should terminate all vlans at the ASR device (instead of switch)? Also not good because I need to use VRRP (or create a cluster).

Does vPC works over L3?

Best Regards.

[AllertGen]

By info here: http://www.cisco.com/c/en/us/support/docs/ip/ip-routing/118997-technote-nexus-00.html looks like N3K is supporting L3 vPC. So I wiil look at this direction and will come back if I would find any useful info.

Best Regards.

Update: Looks like vPC is not my solution, because you can have only 2 devices in 1 vPC domain (or am I wrong?) and I will already use it for aggregating 2 Nexus devices in the one DC.  Or is there some way to use multiple vPC domains to aggregate 4 devices with each other (for sharing MAC table)? Also, how it will forward L2 traffic from one device to another? In L2 there is a peer link ports. But what with L3?

I'm also thinking about MPLS to create my own L2VPN over L3 of ISP. But is it possible in such case? Do I need modules with L2 port at the router and it can be done by internal technologyes of the switch?

[AllertGen]

Ok, I decided to look at EoMPLS. If it will be not good then I will use L2TP. Lab tests is howing that it's works good. But the problem is fragmentation. Need to find a way to avoid this. But I'll deal with it.

My second big problem is that I'm using swithces as L3 gateway at the each vlan. So is there a way to make a stack of 4 nexus devices (as gateway should work the most close device to the source of the traffic)? As I undestood vPC can be done only between 2 devices. So is there a way to connect 4 nexus devices as 1 logical device?

Best Regards.

[AllertGen]

Hi, Pawan Raut.

Yap, I know about leased line L2 that I could ask ISP. But my problem is that I can't use such line between DCs. It is because I need to use an additional VPN between DCs and due to requirements I can use only L3 VPN.

Thanks for your help.

Best Regards.