[j-nsp] Segment Routing Real World Deployment (was: VPC mc-lag)

[Aaron Gould]

My entire Ethernet cellular backhaul architecture is based an a pair of pseudowires per cell tower.  We are making money off of pw's.  

Aaron

> On Jul 9, 2018, at 5:46 PM, Pavel Lunin <plunin at gmail.com> wrote:
> 
> We run MPLS all the way into the access, on ASR920's. So pw's are
>> end-to-end, and the Provisioning/NOC teams only need to look at the end
>> boxes. I found the whole idea of centralized "gateways" in the core to be a
>> bit clunky.
> 
> 
> I have no doubt that you know how to run MPLS in the access smoothly.
> However, choosing the right gear for this role has always been a hard job.
> Those folks who chose Brocade CES some 5-7 years ago, where are they now?
> 
> The problem is that most real-world networkers have not enough
> understanding of MPLS internals, or time, or both to check all those
> hardware and software limits and rather look at the vendor's specs in terms
> of "supported/not supported". This approach works _relatively_ well in many
> cases like choosing a classic switch or a firewall or even an MX/ASR-like
> full-feature PE. But for the MPLS in the access you need to tear the guts
> out of your vendor, test everything yourself in all possible scenarios and
> still be extremely suspicious about every single thing. Moreover a lot of
> people have some commercial/political limits in choosing hardware.
> 
> So, while MPLS in the access looks like a good idea, and there are people
> who manage to run it well, I know more failure than success stories.
> 
> However p2p pseudo-wire service is a kind of rare thing these days. There
>> are [quite a lot of] those poor folks who were never asked whether bridged
>> L2 VPN (aka VPLS) is needed in the network, they operate. They have no much
>> choice.
>> 
>> 
>> This is a number I'd like to, someday, actually qualify. When VPLS was the
>> buzzword in 2009, everyone was jumping on to it. I'd like to know how many
>> of those have continued with it, moved over to EVPN, moved to l3vpn, moved
>> to plain-old Internet or moved to LDP-based p2p and p2mp solutions.
> 
> Good question, indeed. In my opinion there are still a lot of folks out
> there who build DC networks with vPC, FEX, VirtualChassis, Fusion etc,
> which is finally the old good VLANs in a vendor packaged black magic box.
> Sooner or later those VLANs need to go across multiple sites. It's nearly
> improbable that having such a design, you'll mange to build a
> EVPN-VXLAN-hipster-buzz-based DCI. So VPLS is still their best friend. I've
> seen some of them who understand that it's evil, and some who believe that
> it's OK, both had no choice.
> 
> However my original point was rather about pseudo-wires than VPLS. I mean,
> I don't see a lot of pseudo-wires in the wild. Mostly because PW is a kind
> of hard to sell. Customers can be of two types: those who love Metro
> Ethernet and those who don't. It's true for real customers, whose
> requirements are amplified by the sales people, and internal infrastructure
> folks.
> 
> Those who love L2 because "it's better and easier" usually don't know what
> a pseudowire is. And they just don't care. "Like a switch" is what they are
> looking for.
> 
> Those who avoid metro-ethernet just don't need pseudowires, certainly
> automesh Kompella-style. L3VPN works well for them, or they buy L1 between
> their routers, or go EVPN.
> 
> A pseudo-wire is a kind of side application in my experience, even though
> technically it's simple and powerful. Not that it doesn't exist as a
> commercial service, but mostly used for internal infrastructure needs on an
> occasional basis.
> 
> So I tend to think, that if your business can make money out of
> pseudo-wires, it's not about your network design, you are just lucky ;)
> 
> 
> --
> Pavel
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