SonicOS 7.0 Rules and Policies for Policy mode
Table of Contents
PBR Metric-based Priority
SonicOS supports a metric weighted cost assigned to a route policy for policy-based routing (PBR) that allows the configured metric to take precedence in route prioritization over the route specificity that used by default. Metrics have a value between 0 and 255. Lower metrics are considered better and take precedence over higher ones.
The general prioritization (high to low) of PBR routes is as follows, based on the policy fields defined as anything other than Any, or zero for TOS:
- Destination, Source, Service, TOS
- Destination, Source, Service
- Destination, Source, TOS
- Destination, Source
- Destination, Service, TOS
- Destination, Service
- Destination, TOS
- Destination
- Source, Service, TOS
- Source, Service
- Source, TOS
- Source
- Service, TOS
- Service
- TOS
Within these 15 classifications, routes are further prioritized based on the cumulative specificity of the defined route entries. For the source and destination fields, specificity is measured by counting the number of IP addresses represented in the address object. For example, the network address object, 10.0.0.0/24, would include 256 IP addresses, while the network address object, 10.0.0.0/20, would represent 4096. The longer /24 (24 bit) network prefix represents fewer host IP addresses and is more specific.
The new metric-weighted option allows the configured metric to take precedence in prioritization over the route specificity. With the option enabled, the precedence used during prioritization is as follows (high to low):
- Route class (determined by the combination of source, destination, service, and TOS fields with values other than Any or zero)
- The value of the Metric
- The cumulative specificity of the source, destination, service, and TOS fields
