HP Enterprise File Services WAN Accelerator manual Neighbors in Connection Forwarding

Neighbors in

Connection

Forwarding

If you have one path (through HP EFS WAN Accelerator-2) from the client to the server and a different path (through HP EFS WAN Accelerator-3) from the server to the client, you need to enable in-path connection forwarding and configure the HP EFS WAN Accelerators to communicate with each other. These HP EFS WAN Accelerators are called neighbors and exchange connection information to redirect packets to each other.

Figure 5-1.Connection Forwarding in an Asymmetric Network

For example, in Figure 5-1packets from the Client to the Server go through HP EFS WAN Accelerator-2 while packets from the server to the Client go through HP EFS WAN Accelerator-3. The connection is intercepted by HP EFS WAN Accelerator-1 and HP EFS WAN Accelerator-2 because the first Transmission Control Protocol (TCP) packet went through HP EFS WAN Accelerator-2.

Because HP EFS WAN Accelerator-3 sees the packets but HP EFS WAN Accelerator- 2 has the relevant information to optimize them, HP EFS WAN Accelerator-3 redirects the packets from the Server to the Client back to HP EFS WAN Accelerator-2 so that the connection can be intercepted and optimized correctly by HP EFS WAN Accelerator-2.

Neighbors can be placed in the same physical site or in different sites but the latency between them should be small because the packets travelling between them are not optimized.

TIP: If the neighbors are placed on the same physical site, consider installing and configuring an HP EFS WAN Accelerator with multiple pairs of ports (for example, HP EFS N4c WAN Accelerator 4-port NIC Card) and connecting the multiple links to intercept all packets coming back from the server without performing connection forwarding.

Load-BalancingConnection forwarding can also be used in networks where there is packet load- balancing on the server-side, because it does not matter which path the packets take when they come back from the server. Connection forwarding cannot perform packet load-balancing on the client-side (that is, there is no redirection on the client-side).

40 5 - CONFIGURING CONNECTION FORWARDING