[j-nsp] VPLS design - dual homed

[Ben Dale]

> My topology is a bit different though... There is no 'service provider' cloud between my MX routers.
> They are directly connected via dark fibre. Does the split horizon rule come into play here?

It does - although the physical topology looks like a ring, remember that it will be all L3 P2P links, with the VPLS overlay sitting over the top on fully-meshed LSPs making it look more like:

MX1-------MX2
 | \      /|
 |  \    / |
 |   \  /  |
 |    \/   |
 |    /\   |
 |   /  \  |
 |  /    \ |
 | /      \|
MX3-------MX4

(switch to fixed-width fonts ; )

Split-horizon will take care of the rest.

Ben