IP stickiness on F5 with round-robin

It requires and understanding of HTTP 1.1 behaviour and how this interacts with the BIGIP. Version 1.1 keeps alive the connection to the BIGIP for however long the browser deems necessary. There is a timeout of 5 mins but this is rarely reached. Subsequent requests from the browser will reuse this connection. So when you request a HTML page the browser will open the 1st connection to get the html page. Then it will parse the html page and usually open a 2nd connection and then request the elements for that page such as images, css and the like down both connections.

Now the BIGIP load balances each TCP connection, not each request. This means if the connection does not close then subsequent requests down that same connection will always go back to the same server. So subsequent requests sent down the 1st connection will always go back to the same server. Requests sent down the second connection will be sent to wherever that connection was load balanced by the BIGIP. If you want to change this behaviour then turn on the oneconnect profile.