source_address persistance

It is the Client ip address

"Source address affinity persistenceAlso known as simple persistence, source address affinity persistence supports TCP and UDP protocols, and directs session requests to the same server based solely on the source IP address of a packet."

https://techdocs.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm-concepts-11-5-1/11.html

Hi Hien_Truong , 

> F5 Persistence ( Source Address Affinity ) is based on users Source ips , F5 by default stores these IPs in which called " Persistence Record Table " this table and its records make F5 to take a load balance decision and choose which pool member should handle subsequant Requests per each user source address " Record ". 
 

> user source address is classified into " users real ips or a Forward proxies ips " , F5 does not know if this a real user ips or requests are proxied by a proxy in external path , so you may find hundreds of Requests come from single ip address with short time due to a proxy on its external way. 
So that F5 source address persistence is now a proper way for Persistence in case of existing a proxy in Requests way. 

> Could you please clarify your set up or Scenario to get a clear vision. 

Hi Hien_Truong ,

Many computing environments want to use a BIG-IP® system to intelligently manage their HTTP traffic. You can easily control your HTTP traffic by implementing a BIG-IP system feature known as an HTTP profile. An HTTP profile is a group of settings that affect the behavior of HTTP traffic. An HTTP profile defines the way that you want the BIG-IP system to manage HTTP traffic.

You can use the default HTTP profile, with all of its default values, or you can create a custom HTTP profile. This particular implementation uses the default HTTP profile.

When you configure the BIG-IP system to manage HTTP traffic, you can also implement simple session persistence, also known as source address affinity persistence. Source address affinity persistence directs session requests to the same server based solely on the source IP address of a packet. To implement source address affinity persistence, the BIG-IP system offers a default persistence profile that you can implement. Just as for HTTP, you can use the default profile, or you can create a custom simple persistence profile.

For a very simple example you can usderstand it this way, suppose you are doing a shopping on an e-commerce website.

So based on your Source IP address persistence the LB for that particular VIP on that site will send your request to the same server to serve your request and other future request , when you add items to a cart , else what will happne you can have multiple shopping carts if the LB keep sending your multiple request to multiple backend pool memeber servers, this way your shopping experince can be destroyed and you feel lost where are your old items in the cart have gone kind of experience. (this example is just for an understanding)

HTH

This example is just for simple understanding of why or where we can implement Source IP address persistence