[192218] in North American Network Operators' Group
Re: MPLS in the campus Network?
daemon@ATHENA.MIT.EDU (Mark Tinka)
Sat Oct 22 18:41:56 2016
X-Original-To: nanog@nanog.org
To: =?UTF-8?B?TWFyaWFuIMSOdXJrb3ZpxI0=?= <md@bts.sk>,
Javier Solis <jhazesnooty@gmail.com>
From: Mark Tinka <mark.tinka@seacom.mu>
Date: Sun, 23 Oct 2016 00:38:47 +0200
In-Reply-To: <20161022205543.M58704@bts.sk>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On 22/Oct/16 23:59, Marian =C4=8Eurkovi=C4=8D wrote:
>
> The question here is, whether MPLS is the *optimal* solution for campus=
needs.
>
> The same functionality could be obviously achived by multiple technolog=
ies,
> and while MPLS is well supported on high-end SP routers, various limita=
tions
> appear when people try to use it on commodity ASICs which typically emp=
ower
> today's ethernet switches - one of them being e.g. limited ability to
> effectively load-balance traffic over multiple parallel links.
>
> Yes, in theory we could build all campus LANs using high-end SP routers=
, but
> when 100GE backbone is desired (which is often the case in EDU/NREN sec=
tor),=20
> the costs of such solution jump to unacceptable heights.
>
> Thus we looked for another technology, which doesn't have the usual L2 =
problems
> and is able to provide services we need (including L2 extensions to rem=
ote
> campuses) at reasonable costs and with enough simplicity.=20
>
> To avoid typical L2 problems, you clearly need a solution based on L3 r=
outing.
> And TRILL is exactly that - although it maintains L2 interface to the o=
utside
> world, internally it performs dynamic L3 routing by IS-IS protocol with=
all
> safety belts like TTL check, RPF check etc.=20
>
> IMHO, TRILL is much better fit for campus needs, since it was specifica=
lly
> designed for this networking space - and our 6-months production fully =
confirms
> that view (of course, YMMV).
I don't consider the ASR920 or CES2000 to be particularly high-end
routers, but YMMV.
True, merchant silicon presents a number of data plane challenges that
may, at first, seem non-trivial or completely go unnoticed. That is why
we stay away from the ACX5000, for example. I expect improvements to
come with newer-generation ASIC's/NP's, but that tests one's patience.
But, like I said, I have not run TRILL myself, so I'm not going to tell
you that it's not an ideal technology for this use-case. All I'll say is
that MPLS is not limited to high-end platforms, even when custom silicon
is involved.
Mark.
