HP Enterprise File Services WAN Accelerator manual Introduction to PBR, Overview of CDP

For detailed information about the factors you must consider before you design and deploy the HP EFS WAN Accelerator in a network environment, see “Design and Deployment Overview” on page 11.

Introduction to PBR

PBR is a router configuration that allows you to define policies to route packets instead of relying on routing protocols. It is enabled on an interface basis and packets coming into a PBR-enabled interface are checked to see if they match the defined policies. If they do match, the packets are applied as the rule defined for the policy. If they do not match, packets are routed based on the usual routing table. The rules redirect the packets to a specific IP address.

Typically, you configure PBR on the client-side of the network to redirect traffic to an

HP EFS WAN Accelerator.

IMPORTANT: PBR must be enabled on the interfaces where the client traffic is arriving and disabled on the interfaces corresponding to the HP EFS WAN Accelerator, to avoid an infinite loop. (The HP EFS WAN Accelerator can bounce back the packets it receives either because it is not configured to optimize that traffic or its admission control is refusing new connections.)

On the server-side, the HP EFS WAN Accelerator is configured as, an out-of-path device, although it can also be configured with a PBR router with a specific PBR rule or as an in-path device.

In all cases, the HP EFS WAN Accelerator that intercepts traffic redirected with PBR is configured with in-path support and PBR support enabled. PBR policies can be based on the source IP address, destination IP address, protocol (TCP only), source port, or destination port.

Overview of CDP

CDP is a protocol used by Cisco routers and switches to obtain neighbor IP addresses, model, IOS version, and so forth. The protocol runs at the Open System Interconnection (OSI) layer 2 using the 802.3 Ethernet frame.

HP EFS WAN Accelerators can be deployed in several ways: physically in path, virtually in path, or out of path. Virtual in-path deployments require that a network device redirect packets to the HP EFS WAN Accelerators. Network devices that are capable of redirection are layer-4 switches, WCCP enabled routers and switches, and PBR enabled routers.

46 6 - POLICY-BASED ROUTING DEPLOYMENTS