About path selection
You define a path, called an uplink, by specifying a WAN egress point and providing a direction for the egressing packets to take. These steps provide the suggested workflow for configuring path selection:
1. Define applications. Attach a business relevancy to all traffic that goes through your network. Use the preexisting default definitions to identify applications. If the application doesn’t appear in the preexisting application list, you can define a custom application.
2. Define a view of all available networks. The network definition is simply a name (for example, MPLS).
3. Define sites. Provides the SteelHead with the IP addresses of all subnets existing within a site (this applies to non-SteelHead sites as well). It’s important to define all remote subnets in the enterprise so they can be matched with the correct rules. You must define local and remote sites. The site definitions include a list of IP subnets that path selection will use to identify the site. Every subnet must be globally unique, although they can overlap. You also define the default site as a catch-all for traffic that is not assigned to another site. Specify the appliance peers to use for path monitoring. Peers are select distinct IP addresses you choose to poll, in order, to verify path availability.
4. Define uplinks that join the sites to the networks. You must define the local site with the gateway IP address and the in-path interface the uplinks will use to connect to the network. On the SteelHead you are configuring, the local default gateway is the in-path interface. When you configure path selection, if the default gateway is pointing to the LAN side of the SteelHead, we recommend changing the interface to point the gateway to the WAN side of the SteelHead to avoid packet ricochet. The order of sites isn’t important because the longest prefix in the site subnet is matched first.
5. Enable path selection. Choose Network > Network Services: Path Selection, and select Enable Path Selection.
6. Configure path selection rules. Path selection rules direct matching traffic onto specific uplinks. Traffic is matched by a combination of application and destination site.