[c-nsp] LDPv6 Census Check

[David Sinn]

> On Jun 11, 2020, at 12:39 PM, Saku Ytti <saku at ytti.fi> wrote:
> 
> On Thu, 11 Jun 2020 at 21:04, David Sinn <dsinn at dsinn.com> wrote:
> 
>> You've made my point for me. If you are building the core of your network out of MX's, to turn a phrase, in a past life "I fully support my competitors to do so". Large numbers of small boxes, as they have already shown in the data-center, have major cost, control and operational advantages over a small number of large ones. They also expose the inherent problems of label-switching and where IP has it's merits.
> 
> Except this implementation does not exist, but we can argue that is
> missing feature. We can argue we should be able to tell the lookup
> engine this CIDR is on-chip and it's host routes only. This is
> certainly doable, and would make IP tunnels like MPLS tunnels for
> lookup cost, just larger lookup key, which is not significant cost.

I'm not sure what implementation you are saying doesn't exist. The Broadcom XGS line is all on-die. The two largest cloud providers are using them in their transport network (to the best of my understanding). So I'm not sure if your saying that no one is using small boxes like I'm describing or what. And it doesn't have to be MPLS over IP. That is one option, but IPIP is another. 

> But even if we had this (we don't, we have for MPLS) IP would be still
> inferior, it is more tunneling overhead, i.e. I need more overspeed.
> Technically MPLS is just better tunneling header. I can understand
> sentimental arguments for IPv4 and market seems to appreciate those
> arguments particularly well.

Again, feel free to look at only one small aspect and say that it is completely better in all cases. MPLS is not better in wide ECMP cases, full stop. SR doesn't help that when you actually look at the problems at massive scale as I have done. You continually are on the trade-off spectrum of irrationally deep label stacks or enumeration of all of the possible paths through the network and burn all of your next-hop re-writes. At least if you want high-radiux, single chip systems. So this is not sentimentally around a protocol, it's the practical reality when you look at the problems at scale using commodity components. So if you want to optimize for costs and power (which is operational costs), MPLS is not where it is at.

David

> -- 
>  ++ytti