WAN Optimization via IPsec
WAN Optimization can work with IPsec as long as the traffic is optimized before it enters the IPsec tunnel. Optimization before encryption is the minimum requirement to get optimization working over the IPsec VPN.
Example Diagram:
Head-Office-Server
|
Wanos 1
|
Ipsec-VPN
|
Internet
|
Ipsec-VPN
|
Wanos 2
|
Branch-Server
Some Cisco IOS versions drop protocol 108 over IPsec GRE tunnels. The workaround is to use a different Encapsulation (e.g. using GRE only without IPsec VPN) or enable UDP encapsulation in Wanos.
Although very rarely an obstacle, note that tunnels could introduce additional MTU considerations.