Re: Exploring EVPL / NNI redundancy options

[Ryan Hamel via NANOG <nanog () lists nanog org>]

Mark,

Any connection between two points is a circuit. In your case, a VLAN from point A to point B being a virtual circuit.

Some carriers may charge a port fee, on top of the circuits themselves; some will waive it if you provide enough 
business. Most will allow you to "oversubscribe" the NNI with multiple (virtual) Ethernet/L2 circuits that exceed the 
physical port handoff speed, and it's on you to ensure you do not exceed the NNIs capacity, much like it is on you to 
not constantly hit the policer of the virtual circuit. You can have multiple circuits at different speeds on any port 
for varying reasons, with higher or normal SLA's, fast paths or priority traffic in the carrier network, all at 
additional expenses.

Your account managers can guide you through this and explain all of your available options.

Ryan Hamel

________________________________
From: Mark Blackford via NANOG <nanog () lists nanog org>
Sent: Friday, January 16, 2026 6:42 AM
To: North American Network Operators Group <nanog () lists nanog org>
Cc: Mark Blackford <mblackf () gmail com>
Subject: Re: Exploring EVPL / NNI redundancy options

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Thanks for the response Eric.  I'm glad you touched on the E-LAN type
services because I thought that a multi-point option over L2VPN could be an
offer.  It seems the VLAN PtP options give me more control on traffic
engineering.

For the PtP, "two VLAN" scenario that you spelled out, is that treated as
two distinct circuits at twice the cost of one circuit or do you ever have
carriers discount that a bit?  I expect to pay "something" for the
redundancy, but I don't need twice the bandwidth on the "Enhanced" NNI to
the site.

I also wonder if the site bandwidth would count towards the utilization
commitment required on the tail NNIs.Do you know how that is treated?

Thanks again!
Mark



On Fri, Jan 16, 2026 at 7:43 AM Eric C. Miller <eric () ericheather com> wrote:

> 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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