WAN policies define how to route outgoing traffic to optimize application performance across multiple paths. Each policy specifies which Internet path to use based on a set of performance metrics or specific criteria. A WAN Policy becomes active when it is set as an action in a WAN Rule.
Example WAN Policies:
- Use the WAN with the lowest latency.
- Balance across all WANs and favor the WAN with the most available bandwidth.
- Balance evenly among the WANs that have less than 100ms latency.
- Use a specific WAN such as a VPN Tunnel.
When assigning WAN Rules to the above WAN Policy examples, you can configure Untangle SD-WAN Router to optimize bandwidth as follows:
- For VoIP traffic use the WAN with the lowest latency.
- For Skype application balance across all WANs and favor the WAN with the most available bandwidth.
- For other web traffic balance evenly among the WANs that have less than 100 ms latency.
- For HTTP and HTTPS traffic always use a specific VPN Tunnel.
To configure WAN Policies, go to Settings > Routing > WAN Policies.
WAN Policy Parameters
A WAN Policy consists of the following parameters:
|A description of the policy. This can be anything you like that identifies the policy & its purpose.|
|Whether to enable or disable the policy. When disabled, any rule that uses the policy is skipped.|
WAN Type Parameters
The Best WAN and Balance types require additional settings:
|Metric - the metric used to identify which WAN is the "best" at the time a rule is evaluated.
|Algorithm - the algorithm used to balance across multiple WANs.
WANs - This defines the set of WANs from which to balance.
WAN Type Criteria
Both "Balance" and "Best WAN" type WAN policies support criteria. By adding criteria you can set "Service Level Agreements" so that any WAN in the policy is dynamically removed (made unavailable) at the time of WAN policy processing.
For example, a policy to balance among all WANs can include criteria to balance among all WANs with less than 100ms latency.
There are several types of criteria:
Can be used to "rule out" interfaces which do not have active internet connectivity.
It is possible that based on the constraints of a WAN policy, there is no suitable route. For example, a WAN policy may be set to use a Best WAN, however at the time of processing, all WAN links enabled in the policy are down. In this case, the policy is considered defunct.
When a policy is defunct, all WAN Rules that refer to the policy are skipped. In other words, WAN Rules that refer to defunct WAN policies have no action and the execution of rules continues until the next matching rule is found. Therefore, the order of WAN Rules is important for defining how traffic is handled when a policy becomes defunct.
Defunct processing allows an administrator to define a fallback behavior. For example, a WAN Rule can send traffic from the VoIP server to "Balance among all WANs with less than 100ms latency". If this policy becomes defunct because no WANs have less than 100ms latency, then a second rule can send traffic from the VoIP server to the "Best WAN" with the lowest latency.
Important: WAN Failover works best when the Policy Type uses Best WAN or Balance scenarios with specific WANs selected within those schemes.
Rules where the Policy Type uses Specific WAN do not failover unless the link is physically disconnected.