[j-nsp] MX960 with 3 RE's?

[Adam Vitkovsky]

> From: Saku Ytti [mailto:saku at ytti.fi]
> Sent: Friday, January 15, 2016 10:18 AM
> On 15 January 2016 at 03:13, Christopher E. Brown
> <chris.brown at acsalaska.net> wrote:
> > When the same folks were asked about the 16XGE card and the 120G (and
> > later 160G) performance it was indicated that there was an additional
> > layer of logic/asics used to tie all 4 trios in the 16XGE to the bus
> > and that these ASICs offloaded some of the bus related overhead
> > handling from the TRIOs, freeing up enough capacity to allow each TRIO in
> the 16XGE to provide a full 40G duplex after jcell/etc overhead.
>
>
> Sorry Christopher for being suspicious, but I think you must have done some
> mistake in your testing.
>
> Only difference that I can think of, on top of the multicast replication, is that
> 16XGE does not have TCAM. But that does not matter, as the TCAM isn't
> used for anything in MPC1/MPC2, it's just sitting there.
> MPC1/MPC2 can be bought without QX. You specifically metnion '3D-Q'.
> If you were testing with QX enabled, then it's wholly different thing.
> QX was never dimensioned to push all traffic in every port via QX, it's very
> very much underdimensioned for this. If MQ can do maybe ~70Gbps
> memory BW, QX can't do anywhere near 40Gbps. So if you enable QX or
> ingress+egress, you're gonna have very very limited performance.
>
Saku is right, if you do the math then 40.960Gbps is a theoretical maximum for QX as a whole.

adam



        Adam Vitkovsky
        IP Engineer

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