HP Enterprise File Services WAN Accelerator manual Enabling Asymmetric Routing Auto Detection

Enabling

Asymmetric

Routing Auto-

Detection

‹“Enabling Connection Forwarding” on page 68

‹“Enabling Encryption” on page 70

‹“Enabling Failover and Data Store Synchronization” on page 73

‹“Setting Peering Rules” on page 79

‹“Enabling Quality of Service” on page 81

‹“Modifying a QoS Class” on page 85

‹“Setting QoS Marking” on page 87

‹“Modifying QoS Marking Descriptions” on page 89

‹“Modifying Service Ports” on page 90

‹“Enabling Simplified Routing” on page 92

‹“Enabling WCCP Groups” on page 94

‹“Modifying WCCP Group Settings” on page 96

You enable asymmetric route auto-detection in the Advanced Networking - Asymmetric Routing page. Asymmetric route auto-detection detects and reports asymmetric routing conditions and caches this information to avoid losing connectivity between a client and a server.

When HP EFS WAN Accelerators are deployed in a network, all TCP traffic must flow through the same HP EFS WAN Accelerators in the forward and reverse direction. If traffic flows through an HP EFS WAN Accelerator in one direction and not the other, then TCP clients are unable to make connections to TCP servers. When deploying HP EFS WAN Accelerators into redundant networks, there is a possibility of traffic taking different forward and return paths so that traffic in one direction goes through HP EFS WAN Accelerators but traffic in the reverse direction does not.

If asymmetric routing is detected, the pair of IP addresses, defined by the client and server addresses of this connection, is cached on the HP EFS WAN Accelerator. Further connections between these hosts are not optimized until that particular asymmetric routing cache entry times out.

Detecting and caching asymmetric routes does not optimize these packets. If you want to optimize asymmetric routed packets you must make sure that packets going to the WAN always go through an HP EFS WAN Accelerator either by using a multi-port HP EFS WAN Accelerator, connection forwarding, or using external ways to redirect packets, such as WCCP or PBR.

For detailed information, see “Enabling Connection Forwarding” on page 68 or the HP StorageWorks Enterprise File Services WAN Accelerator Deployment Guide.

66 CONFIGURING THE HP EFS WAN ACCELERATOR