Each forwarding class has an associated scheduler priority. Only two forwarding classes, best-effort and network-control (queue 0 and queue 3), are used in the JUNOS default scheduler configuration.
By default, the best-effort forwarding class (queue 0) receives 95 percent of the output link bandwidth and buffer space, and the network-control forwarding class (queue 3) receives 5 percent of the output link bandwidth and buffer space. The default drop profile causes the buffer to fill and then discard all packets until it again has space.
The expedited-forwarding and assured-forwarding classes have no schedulers, because by default no resources are assigned to queue 1 and queue 2. However, you can manually configure resources for expedited-forwarding and assured-forwarding.
The default scheduler settings are implicit in the configuration, although they do not appear in the output of the show class-of-service command.
- [edit class-of-service]
- schedulers {
-
- network-control {
- transmit-rate percent 5;
- buffer-size percent 5;
- priority low;
- drop-profile-map loss-priority any protocol any;
- drop-profile terminal;
- }
-
- best-effort {
- transmit-rate percent 95;
- buffer-size percent 95;
- priority low;
- drop-profile-map loss-priority any protocol any;
- drop-profile terminal;
- }
- }
- drop-profiles {
-
- terminal {
-
-
- fill-level 100 drop-probability 100;
- }
- }