Signaled Preemption Priority Policy Element (RFC3181)

Network Working Group                                          S. Herzog

Request for Comments: 3181                          PolicyConsulting.Com

Obsoletes: 2751                                             October 2001

Category: Standards Track

              Signaled Preemption Priority Policy Element

Status of this Memo

   This document specifies an Internet standards track protocol for the

   Internet community, and requests discussion and suggestions for

   improvements.  Please refer to the current edition of the "Internet

   Official Protocol Standards" (STD 1) for the standardization state

   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This document describes a preemption priority policy element for use

   by signaled policy based admission protocols (such as the Resource

   ReSerVation Protocol (RSVP) and Common Open Policy Service (COPS).

   Preemption priority defines a relative importance (rank) within the

   set of flows competing to be admitted into the network. Rather than

   admitting flows by order of arrival (First Come First Admitted)

   network nodes may consider priorities to preempt some previously

   admitted low priority flows in order to make room for a newer, high-

   priority flow.

   This memo corrects an RSVP POLICY_DATA P-Type codepoint assignment

   error in RFC 2751.

Herzog                      Standards Track                     [Page 1]

RFC 3181      Signaled Preemption Priority Policy Element   October 2001

Table of Contents

   1 Introduction .....................................................2

   2 Scope and Applicability ..........................................3

   3 Stateless Policy .................................................3

   4 Policy Element Format ............................................4

   5 Priority Merging Issues ..........................................5

   5.1  Priority Merging Strategies ...................................6

   5.1.1 Take priority of highest QoS .................................6

   5.1.2 Take highest priority ........................................7

   5.1.3 Force error on heterogeneous merge ...........................7

   5.2  Modifying Priority Elements ...................................7

   6 Error Processing .................................................8

   7 IANA Considerations ..............................................8

   8 Security Considerations ..........................................8

   9 References .......................................................9

   10  Author's Address ...............................................9

   Appendix A: Example ...............................................10

   A.1  Computing Merged Priority ....................................10

   A.2  Translation (Compression) of Priority Elements ...............11

   Full Copyright Statement ..........................................12

1  Introduction

   This document describes a preemption priority policy element for use

   by signaled policy based admission protocols (such as [RSVP] and

   [COPS]).

   Traditional Capacity based Admission Control (CAC) indiscriminately

   admits new flows until capacity is exhausted (First Come First

   Adm...