nanog mailing list archives

RE: [c-nsp] LDPv6 Census Check


From: <adamv0025 () netconsultings com>
Date: Mon, 15 Jun 2020 11:13:25 +0100

From: Saku Ytti <saku () ytti fi>
Sent: Monday, June 15, 2020 11:02 AM

On Mon, 15 Jun 2020 at 12:46, <adamv0025 () netconsultings com> wrote:

Yes it can indeed, and that's moving towards the centre between the
extreme cases that David laid out.
It's about how granular one wants to be in identifying an end-to-end path
between a pair of edge nodes.
I agree with you that MPLS is still better than IP, and I tried to
illustrate that even enumerating every possible paths using deep label
stack is not a problem (and even that can be alleviated using hierarchy of
LSPs).

The entirety of my point is, if we were rational, we'd move towards
increasingly efficient solutions. And technically everything we do in MPLS
tunnels, we can do in IP tunnels and converse. Should we imagine a future
where all features and functions are supported in both, it's clear we should
want to do MPLS tunnels. Just the [IGP][BGP-LU] 8B overhead, compared to
IP 40B overhead should drive the point home, and ultimately, that's the only
difference, rest is implementation.

And I'm saddened we've been marketed snake-oil like SRv6 with fake
promises of inherent advantages or simplicity 'just IP'.

We can do better than MPLS, absolutely. But IP is worse.

Yes I absolutely agree,

Not to mention this whole thread is focused solely on next-hop identification -which is just the lowest of the layers 
of abstraction in the vertical stack. 
We haven’t talked about other "entities" that need identification like: VPNs, applications, policies (yes I'm looking 
at you VXLAN!) etc... - all of which are way better identified by a simple label rather than IPinIPinIP....

adam  


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