Router pps and users

hclisschennai · ‎04-08-2009

HI,

I am using Cisco 1841 Router. From Cisco datasheet i found that it forwards at the rate 75000 PPS (Packet per Second).

If i have 1000 Users in the LAN, how to calculate whether this router is capable of handling the Load without overwhelming the CPU. Here the user traffic will be only browsing. I think opening a web page may require 5 to 10 KB on an average.

What is the best method to size the router based on the Number of Users and traffic pattern.

Please guide me

R.B.Kumar

dsweeny · ‎04-14-2009

Take a look here. It might help you out:

Router Switching Performance in Packets Per Second (PPS)

http://www.cisco.com/web/partners/downloads/765/tools/quickreference/rout

Joseph W. Doherty · ‎04-14-2009

It's quite easy to size a router for a certain traffic load. What's often not easy to predict is what the load will be based on just number of users. This because, so much depends on what user activity is with regard to network utilization and application design.

Perhaps the "best" and/or easiest method, would be to capture the network offered load from a "typical" user, and assuming other users will be the same, multiple by X number of users.

PS:

At 75 Kpps, the router, in theory, can push about 38 MB. Allowing for both duplex and no more than 50% CPU utilization, you might be "safe" with supporting no more than 10 Mbps.

Edison Ortiz · ‎04-14-2009

R.B.Kumar,

If i have 1000 Users in the LAN, how to calculate whether this router is capable of handling the Load without overwhelming the CPU.

What type of WAN connection?

If you have a T1, it does not matter how fast or powerful the router is. If you have a lot of traffic demand, the CPU will increase on any router due to packet drops.

__

Edison.