How does Router PPS is measured?

Unanswered Question

I am talking with respect to Cisco Portable Sheet-Router Pefromance

-----------------------Cisco Portable Sheet-Router Perfomace---------------------------------

Router Switching Performance in Packets Per Second (PPS)

Numbers are given with 64 byte packet size, IP only, and are only an indication of raw switching performance.

These are testing numbers, usually with FE to FE or POS to POS, no services enabled. As you add ACL's,

encryption, compression, etc - performance will decline significantly from the given numbers, unless it is a

hardware-assisted platform, such as the 7600 or 12000, which process QoS, ACL's, and other features in

hardware (or when a hardware assist is installed, for instance an AIM-VPN in a 3745 will offload the encryption

from the CPU). Every situation is different - please simulate the true environment to get applicable performance

values.

Knowing the performance for a specific router platform is not a good indication of how well a specific feature will

perform. If a feature is supported in the CEF path, for instance, and we know the feature-free CEF throughput in a

specific configuration, then we only know the platform's "never-to-exceed" performance but we do not know the

actual performance of any given feature, which will always be less.

All numbers are for IP packets only - no IPX/AT/DEC, etc. - Mbps calculated by pps * 64bytes * 8bits/byte;

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1)In portable sheet they are talking about various router model and their throuput in Mbps and PPS but i don't understand this speed is with respect to per interface or central processor (doesn't matter how many interface is connected to that router)?

2)What is use of using 100MBps Interface if router throughput is itself low?

I have this problem too.
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Jon Marshall Wed, 08/05/2009 - 02:32

Bonito

1) The Mbps/PPS figures are for the router as a whole and not per interface

2) Well you can either have 10Mbps or 100Mbps or 1Gbps interface. If the router has 20Mbps throughput you have to use 100Mbps interfaces because if you used 10Mbps interfaces then the actual interface speed becomes the bottleneck.

Jon

Joseph W. Doherty Wed, 08/05/2009 - 03:36

#1 As Jon also notes, is for all packets being processed by the router. BTW, you also need to consider duplex traffic.

#2 As packet size increases, required PPS rate decreases to support provide the same bandwidth. Many software routers can effectively push more traffic as the packet sized increases, although their maximum PPS rate doesn't often scale directly with the reduced PPS requirements.

I.e., the perforamance sheets, more or less, provides worst case, not best case.

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