Cisco NCS5501 as a P Router

Ben Cornish benc at
Mon May 29 00:44:53 UTC 2017

We are currently looking at the 5501 as a BGP'less super Core / P router
configuration - as a replacement for the troubled 6840 platform.
Curious who is running these with Brocade LSP's running through them ?
I'm not overly convinced these are the right platform yet and happy to take
direct feedback.

We followed Cisco Recommendation on installing 6840's into our Core as P
routers / BGP'less Super Core and had nothing but issues with them.
Wrong forwarding labels / stuck LSP's. / heaps of Optics problems.
Only to be told later that MPLS-TE Auto-Tunnel won't be coming to the
platform either.  We’ve been pretty unhappy with that platform.

Seems the Cisco code can't handle new LSP mid-point creations with the same
We currently have an issue around Brocade wanting to recalc and LSP
path(midpoint failure), but wanting to use the same LSP id to create it-
Cisco's want it to expire out first.
Cisco sees this particular issue as Brocade not understanding the RFC  - yet
Brocade say the same thing ...

Curious of anyone out there today using NCS5501's with Brocade LSP's
transiting them ?

-----Original Message-----
From: NANOG [mailto:nanog-bounces at] On Behalf Of Gustav Ulander
Sent: Sunday, 28 May 2017 12:43 AM
To: Radu-Adrian Feurdean <nanog at>; nanog at
Subject: SV: Cisco NCS5501 as a P Router

We are running 5001 also and we have the same issue with it programming the
wrong entry into the hardware.
Interesting to hear that the issue is still in 6.1.2 since we were thinking
about upgrading to that one to see if it fixes the issue but I think we will
give it a pass.
Seems the BU cant find why its happening only that it indeed is happening.
They don’t seem to be able to duplicate it in the lab either last we heard.


-----Ursprungligt meddelande-----
Från: NANOG [mailto:nanog-bounces at] För Radu-Adrian Feurdean
Skickat: den 27 maj 2017 11:31
Till: nanog at
Ämne: Re: Cisco NCS5501 as a P Router

On Thu, May 18, 2017, at 15:21, Erik Sundberg wrote:
> We're at the growing point where we need a dedicated P router for a
> core device. We are taking a serious look at the NCS5501. Is there
> anyone else using a NCS5501 as P Router or just general feedback on
> the NCS5501 if you are using it?


While we're not using the NCS5501, we do use the "previous version",
NCS5001. We're not yet at a point to care about the minuscule buffers.
Set-up : initially P-router in a very small BGP-free core (ISIS + LDP), then
added route-reflector functionality too.

As a P-router they usually behave correctly, except for the some cases where
they start routing incorrectly (according to Cisco, the wrong label is
programmed into hardware). That should have been fixed with 6.1.2, which we
have deployed, until we recently had the same issue on 6.1.2, on the exact
same box. We expect having some fun with the TAC about that.

> The big downside is it's only has a single processor

Yes, but:
 - it's powerful enough (we ended-up using them as RR too, and ~1.2M  routes
in RIB pose no problem)
 - ours being about half the price of a 5501, we have 2 of them on every
site. If you can afford the same (2 / site) do it; If you don't -  review
the copy so that you can (Brocade SLX 9540 looks like a good  alternative).

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