sticky sessions

'sticky sessions' aka Destination address affinity

 

 

http://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm_configuration_guide_10_1/ltm_persist_profiles.html1184508

 

 

It's based on your need. I've typically used destination address affinity for outgoing traffic using a wildcard Virtual Server and a gateway pool to ensure the same gateway is used..

 

 

Source address persistence is a good choice when the traffic is client based, in other words, the requests are coming from different IPs.. It may not be a good choice if the traffic is sourced from... oh lets say a proxy using one IP..

 

 

I have a very basic doubt related to this post. In Destination address affinity persistence , what is the destination IP for a client. Because as per my understanding i am not able to understand the use of this persistence profile when destiantion IP for a client is always load balancer.

 

 

My understanding for Source address affinity persistence says that when load balancer receives request from same client IP again then it forwards the request to the same pool member.

 

 

I am trying to understand Destination address affinity persistence on similar lines.

@Diptech, I understand your confusion... You're thinking, but a Virtual server has one address, how can I persist when my destination address is one IP?

 

 

First of all Destination Address Affinity persistence is only support with Wildcard Virtual Servers... Going back to my example.. I'm referencing outgoing traffic... In other words Traffic sourced BEHIND the LTM, where the LTM is the gateway for the hosts sourcing traffic..

 

 

Be default, the LTM will not pass this type of traffic.. One way to pass this traffic is to set up a Wildcard Virtual server, in this case you would Configure a Fast L4 VS with an address of 0.0.0.0, a mask of 0.0.0.0, and * (any) for port... You would then create a pool of gateways associated with that VS and apply the Destination Address Affinity persistence profile to the VS.. This will ensure the host is persisted to the same gateway.. Remember, in this example the destination address is ANY so the 0.0.0.0 VS is catching any and all traffic sourced behind the LTM destined for any address..

 

 

There are also some uses for this type of persistence when load balancing proxy or caching servers… I don’t have any experience with it those scenarios so maybe someone else can chime in here..