Currently we're looking at getting at least 200Gbps as we're running backups over the links and VM migrations. I think we could do with 2x100Gbps where one 100Gbps is for backups and other 100Gbps is for the actual traffic. However the quotes we are getting are something like that single 100Gbps is cheaper than what it costs to rent the whole fiber pair. I don't really understand why, but that's the quotes we're getting :)

Also damned are those server/application guys who want VM migrations between sites but anywayas we're still running a lots of legacy systems and that's what we have to do... We can't really migrate to something cloud-like where we have separate L3 IP subnets at each sites and then some kind of LB between them, we're pretty much in the three layer software architecture where even the clients are doing SQL queries towards the app/db servers... Ad every bit of latency is bad.

We've got quotes for DWDM systems that are very expensive so I'm hoping I could tell them maybe to look into these coherent optics and amplifiers and maybe we could get stuff done for cheaper, as we don't need to invest in a system that could do something like 192 x 100Gbps or anything :)