Re: Exploring EVPL / NNI redundancy options

["Eric C. Miller via NANOG" <nanog () lists nanog org>]

Every carrier calls it something different, but it boils down to a VLAN on the carrier's port that takes you PtP to 
another site. For example:

Dallas datacenter has a NNI with Provider. On that NNI, you've been given VLAN 101 that PtPs to Site.
Atlanta datacenter has a NNI with Provider. On that NNI, you've been given VLAN 201 that PtPs to Site.

Site has an "Enhanced" UNI where Provider has given you 2 VLANs. VLAN 101 is PtP to Dallas, VLAN 201 is PtP to Atlanta.

Some MEF-head will surely correct the terminology here, but having worked with just about every national carrier, they 
all use the terms in different ways.

...Or, you can buy an E-LAN type service that is any-to-any and then do your own network over top of it. Most problems 
I've had with E-LANs revolve around spanning-tree (make sure your edge devices aren't sending BPDUs into the E-LAN) or 
the provider VPLS locking up where certain endpoints can't be seen from other endpoints. Be prepared to recover your 
network using hairpin routing from a couple of sites while the provider resets everything.

Eric
________________________________
From: Mark Blackford via NANOG <nanog () lists nanog org>
Sent: Friday, January 16, 2026 8:33 AM
To: North American Network Operators Group <nanog () lists nanog org>
Cc: Mark Blackford <mblackf () gmail com>
Subject: Exploring EVPL / NNI redundancy options

Does anyone have experience implementing redundancy on their EVPL services
within the same carrier?  For instance, I have many point-to-point
scenarios using EVPL providers to connect sites to Dallas. I’m looking to
add a new pop in Atlanta this year for expansion and redundancy.

It seems possible to have a “Site A” with a current drop off NNI in Dallas
added to the new POP on Atlanta within the same carrier network for data
center redundancy, but I am not sure how practical that is in terms of cost
and implementation. Latency would vary of course, and I am assuming they
give you a different VLAN (but maybe not?).

I welcome any comments like if this is a good idea or not, what carriers I
should consider, and experience with cost.

Thanks in advance!

Mark Blackford
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