What is this Irule doing?

The "incr ::c" command ensures that subsequent HTTP requests will go to port 87 and then 86, either within same connection or across multiple connections. Then after it hits port 86 the ::c variable is reset to 0 and it all starts again.

In other words, this irule sends HTTP requests in a round robin fashion between ports 88, 87, and 86.

One problem is that this irule disables CMP on the virtual because it uses a non-static global variable.