You can use either a software or a hardware load balancer to get the best performance out of your Relay Servers.
You should be able to use any hardware or software load balancer with the Relay Servers you have installed to support your SAP Mobile Platform cluster. This document describes how to use Apache, with proxy load balancing.
If you are using a hardware load balancer, see the product documentation for instructions on setting it up.
If you are using a software load balancer other than Apache, see the program documentation for instructions on setting it up.