Priority Switching Scheduler

Document Type Expired Internet-Draft (individual)
Authors Fred Baker  , Anaïs Finzi  , Fabrice Frances  , Nicolas Kuhn  , Emmanuel Lochin  , Ahlem Mifdaoui 
Last updated 2019-04-25 (latest revision 2018-10-22)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


We detail the implementation of a network rate scheduler based on both a packet-based implementation of the generalized processor sharing (GPS) and a strict priority policies. This credit based scheduler called Priority Switching Scheduler (PSS), inherits from the standard Strict Priority Scheduler (SP) but dynamically changes the priority of one or several queues. Usual scheduling architectures often combine rate schedulers with SP to implement DiffServ service classes. Furthermore, usual implementations of rate scheduler schemes (such as WRR, DRR, ...) do not allow to efficiently guarantee the capacity dedicated to both AF and DF DiffServ classes as they mostly provide soft bounds. This means excessive margin is used to ensure the capacity requested and this impacts the number of additional users that could be accepted in the network. PSS allows a more predictable output rate per traffic class and is a one fit all scheme allowing to enable both SP and rate scheduling policies within a single algorithm.


Fred Baker (
Anaïs Finzi (
Fabrice Frances (
Nicolas Kuhn (
Emmanuel Lochin (
Ahlem Mifdaoui (

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