Pre-configuration tasks for WAN link load balancing
Before configuring WAN Link load balancing:
Disable NAT Web Cache Redirection. WAN Link load balancing and NAT Web Cache Redirection cannot be configured on the same WSM. See Application Redirection.
Make sure your ports are not configured into trunk groups. See Port management.
Make sure your WAN link load balancing is not configured with two or more WAN links connected through the same WSM port. This feature uses the proxy IP address of the destination port when translating the source IP address of the requests.