IRules & CPU

Depends on what you mean by segregation...

 

 

The control side (usually referred to as the host in BigIP) has access to the TMM (forwarding part), in that you can access the TMM interfaces etc from the host itself (e.g. For monitors which run on the host side).

 

 

However the TMM forwarding doesn't have access to the host... So forwarded traffic can't use the management interfaces for example.

 

 

This means that your management side (host) can monitor and access your poolmembers, perform diags etc, but your user traffic can't hop over to your (more secure... ) management side.

 

 

H

My question is ,

 

why increasing traffic can cause CPU increase ( Specially when using Irules ) if forwarding is separated from Control ?

 

(

SSHSSH, the simple fact you are using iRules most likely means that the data in each packet/connection/request needs to be inspected, hence the CPU overhead. If you use a Performance (Layer 4) or Forwarding VS and iRules that don't operate above layer 4 then these are mostly handled in hardware/on the forwarding plane.

 

 

There isn't an easy separation between the two planes I'm afraid, certainly not in the SDN sense. Although TMM (and thus LTM) and the HMS run different operating systems they 'share' RAM and (a single) CPU and one is dependent on the other. However, as I said use the right type of VSs and things get handled directly in hardware. If you can't then expect the traffic load to have an affect on CPU.

 

Is IRules Handeled @ Control Or Forwarding Plan ?

Mostly the Control plane but of course with a complex product like BIG-IP it's not really that simple.

Update: Page 31 of this provides your 'official' answer: http://www.f5.com/pdf/investor-relations/aim-2012-analysts-investors-meeting-slides.pdf