IP and Optical domains?

Thu Jun 23 03:40:43 UTC 2016

We have a single IP and optical group, but that’s not common at most larger carriers.  We have a fairly complex national dark fiber backbone as well as complicated metro networks.  You see a lot of vendors tout IP/optical integration around optimization of resources, but the starting point is usually a carrier who provisions both L3 protection and L1 circuit protection at the same time.  It’s obvious to most that isn’t efficient, but there are carriers out there who do that because the groups are so disjoint.  I would say that does not represent the majority of carriers today however.  Optical vendors will tout optical restoration as a means to reduce excess L3 capacity and they are right, with modern CDC ROADMs and coherent optics you can plan a network around optical restoration and gain a lot of cost reduction by reducing L3 capacity.  The tradeoff is in restoration times, as the photonic layer can’t restore very fast right now, so there is a middle ground for most networks of carrying either fully protected capacity at L3 or L1, and restoring other capacity dynamically.  Typically for a subset of traffic like high priority traffic.  

I read the bulk of this thread and IPoDWDM is interesting from a collapsing of boxes perspective if the network is simple enough it’s easy to operate and it makes financial sense.  All the major router vendors are being forced by content providers to integrate them into their boxes.   At OFC MS announced they had been working with InPhi to develop a shorter reach (80km) tunable QSFP28.  If it does not need to integrate into an optical control plane (like one doing optical restoration) then it’s a very valid solution and I think you’ll continue to see growth with it.   

I call SDN the get out of jail free card for optical vendors because they no longer have to even pretend they will interoperate via standard protocols like GMPLS.  They expose REST APIs and people are willing to take it because it’s fairly easy to deal with.  

Phil  

-----Original Message-----
From: NANOG <nanog-bounces at nanog.org> on behalf of Glen Kent <glen.kent at gmail.com>
Date: Saturday, June 18, 2016 at 17:27
To: "nanog at nanog.org" <nanog at nanog.org>
Subject: IP and Optical domains?

HI,

I was reading the following article:
http://www.lightreading.com/optical/sedona-boasts-multilayer-network-orchestrator/d/d-id/714616

It says that "The IP layer and optical layer are run like two separate
kingdoms," Wellingstein says. "Two separate kings manage the IP and optical
networks. There is barely any resource alignment between them. The result
of this is that the networks are heavily underutilized," or, from an
alternative perspective, "they are heavily over-provisioned."

Can somebody shed more light on what it means to say that the IP and
optical layers are run as independent kingdoms and why do ISPs need to
over-provision?

Thanks, Glen