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A Proposed Flow Specification (RFC1363) Disclosure Number: IPCOM000002187D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 20 page(s) / 30K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Partridge: AUTHOR

Related Documents

10.17487/RFC1363: DOI

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 7% of the total text.

Network Working Group C. Partridge Request for Comments: 1363 BBN September 1992

A Proposed Flow Specification

Status of this Memo

This memo provides information for the Internet community. It does not specify an Internet standard. Distribution of this memo is unlimited.


A flow specification (or "flow spec") is a data structure used by internetwork hosts to request special services of the internetwork, often guarantees about how the internetwork will handle some of the hosts’ traffic. In the future, hosts are expected to have to request such services on behalf of distributed applications such as multimedia conferencing.

The flow specification defined in this memo is intended for information and possible experimentation (i.e., experimental use by consenting routers and applications only). This RFC is a product of the Internet Research Task Force (IRTF).


The Internet research community is currently studying the problems of supporting a new suite of distributed applications over internetworks. These applications, which include multimedia conferencing, data fusion, visualization, and virtual reality, have the property that they require the distributed system (the collection of hosts that support the applications along with the internetwork to which they are attached) be able to provide guarantees about the quality of communication between applications. For example, a video conference may require a certain minimum bandwidth to be sure that the video images are delivered in a timely way to all recipients.

One way for the distributed system to provide guarantees is for hosts to negotiate with the internetwork for rights to use a certain part of the internetwork’s resources. (An alternative is to have the internetwork infer the hosts’ needs from information embedded in the data traffic each host injects into the network. Currently, it is not clear how to make this scheme work except for a rather limited set of traffic classes.)

Partridge [Page 1]

RFC 1363 A Proposed Flow Specification September 1992

There are a number of ways to effect a negotiation. For example a negotiation can be done in-band or out-of-band. It can also be done in advance of sending data (possibly days in advance), as the first part of a connection setup, or concurrently with sending (i.e., a host starts sending data and starts a negotiation to try to ensure that it will allowed to continue sending). Insofar as is possible, this memo is agnostic with regard to the variety of negotiation that is to be done.

The purpose of this memo is to define a data structure, called a flow specification or flow spec, that can be used as part of the negotiation to describe the type of service that the hosts need from the internetwork. This memo defines the format of the fields of the data structure and their interpretation. It also briefly describes what purpose the different fields fill, and discusses why this set of fields is thought to be both necessary and sufficient.