HP Enterprise File Services WAN Accelerator manual Failover Support on

The HP EFS WAN Accelerators use the following methods to communicate with routers:

‹ Unicast (User Datagram Protocol Packets). The HP EFS WAN Accelerator is

configured with the IP address of each router. If additional routers are added to the service group, they must be added on each HP EFS WAN Accelerator.

‹ Multicast. The HP EFS WAN Accelerator is configured with a multicast group. If additional routers are added, you do not need to add or change configuration settings on the HP EFS WAN Accelerators.

All Transmission Control Traffic (TCP) traffic is redirected by default. You can configure specific source or destination ports to be redirected. For detailed information, see “TCP Port Redirection” on page 80.

For other types of redirection filtering such as the Internet Protocol (IP) address, you configure Access Control Lists (ACLs) on the routers and add it to the service group. For detailed information, see “Specific Traffic Redirection” on page 81.

Traffic is redirected using one of the following schemes:

‹ gre (Generic Routing Encapsulation). Each data packet is encapsulated in a

GRE packet with the HP EFS WAN Accelerator IP address configured as the destination. This scheme is applicable to any network.

‹ l2 (Layer-2). Each packet Media Access Control (MAC) address is rewritten with an HP EFS WAN Accelerator MAC address. This scheme is possible only if the HP EFS WAN Accelerator is connected to a router at Layer-2.

‹ either. The either value uses l2 (Layer-2) first—if Layer-2 is not supported, gre is used.

	You can load-balance using WCCP. Traffic is redirected based on a hashing scheme
	and the weight of the HP EFS WAN Accelerators. You can hash on a combination of
	the source IP address, destination IP address, source port, or destination port. The
	default weight is based on the HP EFS WAN Accelerator model number. (The weight
	is heavier for models that support more connections.) You can modify the default
	weight. For detailed information, see “Load Balancing” on page 81.
	You can also provide failover support using WCCP. In a failover configuration, the HP
	EFS WAN Accelerators periodically announce themselves to the routers. If an HP EFS
	WAN Accelerator fails, traffic is redirected to the working HP EFS WAN Accelerators.
	To configure failover support where the passive HP EFS WAN Accelerator takes over
	if there is a failure in the active HP EFS WAN Accelerator, you simply configure the
	weight for the backup HP EFS WAN Accelerator to be 0. For detailed information, see
	“Failover Support” on page 81.
Basic Steps	The following steps summarize how to configure WCCP on a client-side HP EFS
	WAN Accelerator with an out-of-path server-side HP EFS WAN Accelerator.
	IMPORTANT: This is an example of one type of WCCP deployment. You can also have
	deployments with both HP EFS WAN Accelerators configured as in-path devices and WCCP
	configured on one of them. Contact HP technical support for further information at http://
	www.hp.com.
HP STORAGEWORKS ENTERPRISE FILE SERVICES WAN ACCELERATOR 2.1.5 DEPLOYMENT GUIDE		65

7 - WCCP DEPLOYMENTS