Forum Discussion

Sagar_Shah_9610's avatar
Sagar_Shah_9610
Icon for Nimbostratus rankNimbostratus
Jun 03, 2009

How does BigIP define a connection

Hello,

 

 

I am looking forward to upgrade my BigIP 3400 series and for sizing purposes. We all are pouncing couple of questions to each other while brainstorming.

 

 

Please help me on some of the questions that we are completely clueless -

 

 

1. On BigIP I see a performance graphs called 'Active Connection' and 'New Connection'; in this what does 'connection' actually mean. Is that the L3 or L4 or L7 connections processed by the box or something else?

 

 

2. On our network we've hardly 30K users (unique IP addresses) connected but during that time 'Active connection' graph shows 2M active connections!!! Do 30K users have capability to generate 2M active connections?? Or is there something wrong in my BigIP??

 

 

Any response on this will be appreciated.

 

 

Thank you

 

Sagar.
management
monitoring

2 Replies

  • The_Bhattman's avatar
    The_Bhattman
    Icon for Nimbostratus rankNimbostratus
    Jun 09, 2009
    I believe the term connection is somewhere between Layer 5 and 4. The Active Connections are basically connections that are passing traffic or sitting idle but open and the New Connection is simple new connections that did exist before - this is constantly being measured and compared to the last connections. Yes it's possible for 30K users to generate 2M connections, depending on what they are using on the the client side or how the application is influencing the client. For example I can generate 100 connections form my Internet Explorer to a single website - simply opening up new browser windows creates a new connection, etc. This all depends on their OS and the client they are using. Also you could have many clients that are not terminating their connections so the amount of connections can accumulate over time idling - which is inherently bad.

     

     

    My guess is that you need to sniff the communication path and see what's going on. Also check out any areas where you need to limit the amount of idle connections existing.

     

     

    Hope this helps,

     

    CB

     

     

     

     

     

  • Sagar_Shah_9610's avatar
    Sagar_Shah_9610
    Icon for Nimbostratus rankNimbostratus
    Jun 10, 2009
    Hello CB,

     

     

    Appreciate your response, I found out that a state between either two IP addresses, IP addresses and ports or IP addresses and ports and limited L7 information consists of a connection. Apparently and ICMP packet traversing BigIP from one host to another is also considered to be connection. In my deployment, i've got BigIP sitting inline between upstream and downstream router. Most of my virtual servers configured to process the traffic are Performance L4 Virtual servers. Apparently, I came across a field called 'Connection idle timeout' which is by default set to 300sec. By changing this value to 120sec. I discovered that the number of active connections dropped down by 35% and memory utilization also dropped down by 40% without creating any sorts of issues in the network. Hence, the reduction of 'connection idle timeout' value has helped in fixing my issue.

     

     

    Sagar