VXLAN for WAN Pseudowires?

Simon Lockhart simon at slimey.org
Thu Jul 20 09:12:19 CST 2017


All,

I'm currently going through a network design for an upgrade for one of the
networks I run. Much of the wide-area traffic on the network is used purely
to transport Ethernet tail circuits back from an edge PoP to a core PoP. 
Currently we're using Extreme X460 and X670 switches to achieve this, carrying
the tail circuits within VPLS.

Two things are making me look at a change of solution for this - firstly 
Extreme have stated that they're not interested in the service provider
market any more (and reflected this in significant reductions in discounts),
and secondly we need to look at higher bandwidth port options (40G + 100G,
particularly for backhaul circuits).

As we're primarily a Cisco house, I've been looking at suitable replacements,
and the Nexus 9k range looks good - 92160YC and 9236C in particular. However,
this would mean a shift from VPLS to VXLAN. We're also looking at Cisco-like
products, such as the Arista range.

We've been doing some testing in the lab, and so far, things look good - it's
easy to configure, and appears to do the job of getting packets from A to B.

We do have two concerns, though:

1) Cisco are strongly advising against using the Nexus switches in a WAN
   scenario - as they're designed for "datacentre" use. They've so far said 
   they can't find anyone who can help validate designs using Nexus, and 
   instead are pushing us towards the NCS-5000 series switches. Same chipset,
   but 2-3 times the price! NCS does, however, support VPLS, so would be an
   easier drop-in to our existing network.

2) Traffic engineering - we don't have a lot of requirement for this, but do
   have a small number of customers who buy A and B circuits, and require them
   to be routed across different paths on our network. This is easy with MPLS
   using explicit LSPs, but we've not yet worked out how to achieve the same
   thing in VXLAN.

So, my question to the community is - have any of you used VXLAN as a wide-area
layer 2 transport technology? Any pros or cons? Gotchas? Scare stories?
Recommendations? Am I trying to shoot myself in the foot?

Many thanks,

Simon


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