CPU use and slow down with DPI

Hi Andrew,

I notice in this thread that you mention DPI and searching for P2P can use a lot of CPU resources.

I have about 40 rules and want to limit / stop as much P2P as possible. I was going to enable P2P filtering on each rule (one per user, each user with up to 5 devices), but after reading that thread I am concerned that the whole system will slow down.

I have 30mbps downstream and 3 Mbps up to the Internet (3 aggregated ADSL lines) that are pretty busy at times and usually up to about 100 clients through the BWM server. The host is win XP with a core 2 3G processor. Is this likely to significantly slow down the traffic when I enable DPI for P2P?

If this will slow things down, is there a way to nest the rules somehow so I have one master rule that does the P2P filtering then the other rules to limit speed / monthly quota etc for each user.

Oops, I should have added, if there is a significant CPU issue would a faster processor fix it?

I guess you'd have to try to find out. Try enabling P2P filtering on say, 10 rules, and observe the CPU usage in the Windows Task Manager.

It doesn't really matter if you filter at one master rule or individual rules because the number of packets to process would be the same. Theoretically a 3 GHz CPU for 30 Mbps should suffice. I recommend to give it a go on a smaller sample of rules and if it works well, expand it to all the rules.