A policy map can be attached to one or more interfaces to specify a service policy. Configuration sources combined with context determines which QoS policy map is applied. The three configuration sources and their general order of precedence are as follows:
- Per-user (per-subscriber) configuration
- Service profile
- Interface configuration
This order of precedence shows the general condition, that is, service profiles and per-user configurations have higher priority than interface configurations.
However, a change of authorization (CoA) per-user push replaces the current per-user configuration for any overlapping or common feature. Similarly, when a new service logs in, its configuration replaces any overlapping feature, from previously configured service profiles, that is not already in effect from a per-user configuration source
If the new service then logs off, the previously existing configuration is reapplied if no higher-precedence configuration source is in effect.
Given those precedence qualifications, the policy map is determined as follows:
- If there is no policy map on the session, the incoming policy map is not applied.
- If an existing policy map is configured from a higher priority source than an incoming one, the incoming policy map is not applied.
- If an existing policy map is configured from a lower priority source than an incoming one, the incoming policy map replaces it.