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Active Queue Management and Packet Scheduling
charter-ietf-aqm-00-00

The information below is for an older proposed charter
Document Proposed charter Active Queue Management and Packet Scheduling WG (aqm) Snapshot
Title Active Queue Management and Packet Scheduling
Last updated 2013-08-20
State Start Chartering/Rechartering (Internal Steering Group/IAB Review)
WG State Proposed
IESG Responsible AD Mirja Kühlewind
Charter edit AD Martin Stiemerling
Send notices to wes@mti-systems.com, rs@netapp.com

charter-ietf-aqm-00-00

Internet routers, lower-layer switches, end-host operating
systems, device drivers, and many types of additional
middleboxes include memory buffers in which they implement
queues to hold packets that require processing or otherwise
need to wait for forwarding to the next hop.

The queues are intended to absorb bursts of traffic that may
naturally occur, and avoid unneccessary losses. However, queues
also cause latency and jitter in the eventual arrival times of
packets. This can create issues and complications for interactive
applications.

Extremely large unmanaged buffers have been noticed in some
software and equipment. When these buffers fill, interactive
applications and other traffic can be severely impacted or
completely broken, due to high and potentially oscillating delays.

The Active Queue Management and Packet Scheduling working group
(AQM) works on algorithms for managing queues in order to:

(1) minimize standing queues; helping to reduce delay for
interactive applications

(2) help flow sources control their sending rates without
unnecessary losses, e.g. through ECN

(3) consider the merits of various techniques to protect flows
from negative impacts of other more aggressive or misbehaving
flows

(4) help avoid global synchronization of flows sharing a
bottleneck

The AQM working group will publish Informational and Best Current
Practices documents that cover the design, use, and configuration
of algorithms for managing queues in Internet devices and software.
The scope includes both how to best configure existing equipment
and software, as well as recommendations on designing new equipment
and software.

The AQM working group will also publish algorithm specifications
that are found to be broadly applicable and beneficial. Evaluating
these algorithms shall be done in coordination with the Internet
Congestion Control Research Group (ICCRG) in order to select and
assess the relevant criteria, scenarios, and metrics.

The working group will also explore the merits of whether to
isolate flows, and mechanisms for performing this function. Note
that isolation and potentially policing of flows implies some policy
beyond what is required to simply minimize queues. This topic
requires significant attention in the working group.

AQM algorithms do not have to be implemented universally in order
to be effective. Specifications will aid in producing proper
implementations that avoid potential ambiguities and corner cases.
"Interoperability" of algorithms and implementations of them is
not the reason for creating these specifications; correctness is
the primary motivation.

The working group will not make changes to ECN, DiffServ, or other
IETF protocols, though existing ECN, DiffServ, and other mechanisms
may be used within the algorithms proposed. As their implementation
is likely to be entwined with AQM algorithms, there is expected to be
close coordination between both TSVWG and AQM groups.

Many AQM algorithms have been proposed in academic literature, but
a smaller number are widely implemented and deployed. The goal of the
working group is to produce recommendations that will actually be used,
and algorithms that will actually be implemented, deployed in equipment,
and enabled. Towards these ends, the group actively encourages
participation from operators and implementers, and will coordinate with
the IETF OPS area and other relevant parts of the IETF and Internet
community. Wider research and evaluation of AQM mechanisms shall be
coordinated with the IRTF/ICCRG, and significant participation in this
WG from the academic and research community is highly desirable, when it
is directly relevant to implementation and deployment.

Combined Queue Management / Packet Scheduling algorithms are in-scope,
provided their benefit have been evaluated against the established
requirements for an AQM algorithm. It is expected that some classes of
algorithms will focus on software implementations, while others on
existing or new hardware deployments, and algorithms may be specific
to distinct scenarios.