[c-nsp] Cisco Nexus as MetroE switch?

[James Jun]

On Sun, Oct 18, 2015 at 07:42:27PM +1300, Nathan Ward wrote:
> Sorry, I should look better.

I would say Juniper ACX is more comparable to ASR 901 Series meant for cell sites with simple l3vpn instance or small-scale l2circuit'ing.  From my past experience, it wasn't really suited for MetroE use cases.

For the similar price footprint, ASR 920 is a clear winning choice over ACX for 1GE MetroE access.  I agree with Mark, Juniper has been lagging in MetroE space.


> 
> I???ve heard this about the label depth limitation. It???s not clear to me what this means in practice - the max depth is 3 labels, but, does that mean it can???t forward packets with more than 3 labels, or does this mean that only certain features (perhaps hashing for load balancing across multiple physicals in a bundle) can happen with 3 or less labels? The latter makes sense, the former seems kind of odd.
> I know that there is a limitation where flow labels cannot be used, and where it won???t load-balance across multiple paths. We do TE, and if we need to we???ll load balance across multiple tunnels at the head end, so I can???t see that being relevant either - it???s just another TE path from the ACX point of view.

FWIW, the 3 label stack limitation on QFX 5100 has to do with label imposition & disposition operations -- in other words, if you have a QFX5100/ACX5k (same thing) acting as  PE.  If you are using it as P LSR (core router just forwarding outer transport labels), then label stack doesn't matter as it just swaps outer label.  ECMP/Lagg hashing isn't too shabby on QFX either, it works fairly well.

That's really what ACX/QFX5k is awesome for -- it gives you a cheap 48x10GE P router at teh core, perfect for small networks needing LSRs.  It also has nice control plane so you can use it as route-reflector too if you want.  But for edge duties (i.e MetroE access, l2/l3vpn terminations, hQOS, etc), I really would not recommend it.

That being said, we've been extremely pleased with ASR 920 and 902/903 Series for MetroE access duties at very reasonable price points.  With RSP3 and ASR 907, it's an exciting time for this product; now... if they could just bring IOS XR into 9xx series, oh I could only dream.. :>


james