strict-priority-scheduler

Syntax

Hierarchy Level

Description

On PTX Series routers only, enable strict-priority scheduling for all scheduler maps within the traffic control profile.

Physical interfaces on PTX Series routers support two mutually exclusive scheduling processes:

• normal scheduling (default mode) — A queue’s transmit-rate is used to determine whether it is operating within the guaranteed region or in the excess region.

  Within the guaranteed region (transmit-rates credits are positive), the scheduler uses the transmit rates to decide the bandwidth allocation. Queues that are at priority-level low or higher and have transmit-rate credits are serviced first by priority order and then within a priority level using packet round robin algorithm.

• strict-priority scheduling — Queues are processed in strict-priority order. There is no concept of guaranteed region and excess region. The packet scheduler is always operating in the guaranteed region, with the exception of priority low, which is always assigned to the excess priority level. The configured transmit-rate does not affect how the queue is serviced because packets are processed in order of queue priority. Among queues that are configured low priority, if excess-rate weights are configured, they are used by the hardware to perform WRR. Queues that are mapped to the same hardware priority or that have the same configured priority other than low are serviced in a packet round-robin fashion.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 13.3.