[c-nsp] GRE tunnel to do span vlan across two datacenters?

[Jason Gurtz]

> If I get the pictures right, you could get away with a VLAN on C1 with
> two ports in dot1q tunnel mode + l2protocol tunnel stp, and a similar
> situation in C2, so V1 and V2 will have their own spanning tree and C1
> and C2 will not partecipate in it (if you need also L3 in V1/V2, you
will
> have to use a different physical interface).

Hadn't thought of this little gem but it could be a pretty great solution.
There are L3 needs which could get a little messy, but hey it's messy any
way it goes I think.

> But I'd rather use dark fiber if at all possible, as Gert said.

Unfortunately, there is only two pairs available so it seems to me like
stp is needed in the core to maintain redundancy. Stp is not the end of
the world though it's been a Cadillac ride without :)

> Or elaborate on the fact that Layer 3 is by definition the layer where
> things like forwarding, routing around failures, etc. take place, and
> servers should learn to live with it: this is hard to swallow after
years
> of VMware and Microsoft NLB, but that's the hard truth.

Thankfully, no consultant has uttered NLB yet but I'm not holding my
breath!

~JasonG