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Something a host could do with source quench: The Source Quench Introduced Delay (SQuID) (RFC1016)

IP.com Disclosure Number: IPCOM000001820D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 15 page(s) / 44K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

W. Prue: AUTHOR [+2]

Abstract

A gateway may discard Internet datagrams if it does not have the buffer space needed to queue the datagrams for output to the next network on the route to the destination network. If a gateway discards a datagram, it may send a source quench message to the Internet source host of the datagram. A destination host may also send a source quench message if datagrams arrive too fast to be processed. The source quench message is a request to the host to cut back the rate at which it is sending traffic to the Internet destination. The gateway may send a source quench message for every message that it discards. On receipt of a source quench message, the source host should cut back the rate at which it is sending traffic to the specified destination until it no longer receives source quench messages from the gateway. The source host can then gradually increase the rate at which it sends traffic to the destination until it again receives source quench messages [1,2].

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 7% of the total text.

Network Working Group W. Prue

Request for Comments: 1016 J. Postel

ISI

July 1987

Something a Host Could Do with Source Quench:

The Source Quench Introduced Delay (SQuID)

Status of this Memo

This memo is intended to explore the issue of what a host could do

with a source quench. The proposal is for each source host IP module

to introduce some delay between datagrams sent to the same

destination host. This is an "crazy idea paper" and discussion is

essential. Distribution of this memo is unlimited.

Introduction

A gateway may discard Internet datagrams if it does not have the

buffer space needed to queue the datagrams for output to the next

network on the route to the destination network. If a gateway

discards a datagram, it may send a source quench message to the

Internet source host of the datagram. A destination host may also

send a source quench message if datagrams arrive too fast to be

processed. The source quench message is a request to the host to cut

back the rate at which it is sending traffic to the Internet

destination. The gateway may send a source quench message for every

message that it discards. On receipt of a source quench message, the

source host should cut back the rate at which it is sending traffic

to the specified destination until it no longer receives source

quench messages from the gateway. The source host can then gradually

increase the rate at which it sends traffic to the destination until

it again receives source quench messages [1,2].

The gateway or host may send the source quench message when it

approaches its capacity limit rather than waiting until the capacity

is exceeded. This means that the data datagram which triggered the

source quench message may be delivered.

The SQuID Concept

Suppose the IP module at the datagram source has a queue of datagrams

to send, and the IP module has a parameter "D". D is the introduced

delay between sending datagrams from the queue to the network. That

is, when the IP module discovers a datagram waiting to be sent to the

network, it sends it to the network then waits time D before even

looking at the datagram queue again. Normally, the value of D is

zero.

Imagine that when a source quench is received (or any other signal is

received that the host should slow down its transmissions to the

network), the value of D is increased. As time goes by, the value of

D is decreased.

The SQuID Algorithm

on increase event:

D <-- maximum (D + K, I)

(where K = .020 second,

I = .075 second)

on decrease event:

D <-- maximum (D - J, 0)

...