[j-nsp] New 16port 10G Card and new MPC with 4x10G MIC Cards - coexistance of old DPCs and new Cards in same chassis -- looking for experience feedback

[Pavel Lunin]

Hi Richard,



> * Supposedly there is some capability to do local switching on the Trio
> PFE, but I've been told that support is extremely limited, and even
> doing something like configuring egress filters defeats the local
> switching and forces everything through the fabric.
>

Sounds as interesting as strange. If this was correct, MX80 would had as
limited capabilities as what you described. Moreover I have no idea (do
you?) where these limitations can arise. Most stuff like filtering, etc is
done by LU, SCB does not do anything with the packet.


* Supposedly the reason the MX80 is able to get 60G of performance out
> of a single Trio PFE is that the normal 30G limitation comes from the MQ
> ASIC which interconnects Trio components having to split its capacity
> between MIC-facing and fabric-facing. Because MX80 has no fabric and a
> single pfe, the MQ can be reconfigured to handle 60G of MIC facing
> capacity. This would seem to imply that local switching on a MPC could
> support > 30G.
>

This is what I managed to get from local SE. They say a single MQ has 60G
overall performance and this is the actual limit. MX80 built-in ports are
connected to what is used for fabric-faced interface on MPCs. BTW, this
leads to some limitations like impossibility to connect LQ to those 4x10G
(per-port queues only).

Moreover they also said quite with no doubts (I explicitly asked about this)
that it does not matter which direction the traffic goes, you anyway have 60
Gigs per MQ. Say if you only use MX80 biult-in ports, you can have them
fully loaded (40 Gbps). Looks like we can assumme the same for 16x10G MPC.

More strange thing is why it's written in the datasheet that MX80 (no, I'm
not asking anymore why it's MX80 but neither MX120 nor MX60) can do 65 Mpps.
65 Mpps is about 30 Gigs, isn't it? Well, if so, it seems either what I've
been told by the SE is a complete nonsense, or someone was drunk preparing
the numbers for datasheet.

My hypotheses is MQ can actually do twice as much: 65 Mpps from the
interfaces to back-plane and 65 backwards. Otherwise you'll never get 30
Gbps FD with MPC1. But this knowledge is too burdensome for sales people,
because if you don't know it, you can just multiply 65 by the number of
chips in a box and get the right pps number. One could hardly understand
that each MQ actually does twice as much work but each packet passes two MQ
and you need multiply and than divide by 2 accordingly.

--
Pavel