[c-nsp] Typhoon support on XRe

Mikael Abrahamsson swmike at swm.pp.se
Thu May 4 08:23:28 EDT 2017

On Thu, 4 May 2017, adamv0025 at netconsultings.com wrote:

> Well people don't care about a lot of things, like how routers actually work
> or whether they can still protect your EF traffic when overloaded, and
> that's not necessarily a good thing even though everyone does it.
> But I guess you're right, it's just I've got a feeling we're slowly getting
> ripped off here, I mean it's alright if the LC is marketed as
> oversubscribed, but it's certainly not alright if a LC can deliver what it's
> marketed for only under certain specific circumstances and it seems like
> this "nominal performance window" is getting narrower and narrower as the BW
> the LCs are marketed for is increasing.
> And you get told - use less ports then, or buy more LCs, or don't use these
> two features together.

I have been told this before purchase. "worst case performance with all 
features turned on, is X bytes wirespeed. Less features, higher pps. if 
you want wirespeed, don't use all ports, use 2 ports instad of 4 connected 
to that NPU, then it's wirespeed on those two ports". if this wasn't true, 
I would get upset.

> Let's consider NCS5K -it's one of the "100GE for everyone at the bar" type
> of boxes, has an abundance of these dirty cheap 100GE ports, it might not
> have the most feature rich NPU but it would only ever do MPLS switching so
> no problem there. (Btw talking about raw performance, NCS 5001 is 35Mpps per
> 10GE)
> But does the NPU's architecture allow it to protect your EF traffic even
> when it's overloaded (under DDoS), I don't know I haven't checked/tested, I
> know ASR9K LCs would.

>From people who like to look at theoretical edge cases, I've been told the 
last major platform that did this was the CRS-1 with 40G per slot.

> What I'm trying to illustrate here is that raw performance of the NPU is one
> thing, but there's also other dimensions that dictate the price and
> suitability of the HW for a certain project.


> For example if it's a network that can't get DDoS traffic in it and you 
> know you're only going to have 60% utilization before upgrade, or all 
> traffic is BE, then sure nothing to worry about.

I'd also say this isn't just about PPS. It's about other features. 
Designing a network with lots of feature-rich edge/core features mean you 
need platform that supports this. If you keep down the features required, 
you typically have more platforms to choose from.

But yes, I agree, the type of traffic you're expecting worst-case dictates 
what platforms you can choose and how to use them.

Mikael Abrahamsson    email: swmike at swm.pp.se

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