Configuration Guidelines for DiffServ Service Classes
RFC 4594
Network Working Group J. Babiarz
Request for Comments: 4594 K. Chan
Category: Informational Nortel Networks
F. Baker
Cisco Systems
August 2006
Configuration Guidelines for DiffServ Service Classes
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document describes service classes configured with Diffserv and
recommends how they can be used and how to construct them using
Differentiated Services Code Points (DSCPs), traffic conditioners,
Per-Hop Behaviors (PHBs), and Active Queue Management (AQM)
mechanisms. There is no intrinsic requirement that particular DSCPs,
traffic conditioners, PHBs, and AQM be used for a certain service
class, but as a policy and for interoperability it is useful to apply
them consistently.
Babiarz, et al. Informational [Page 1]
RFC 4594 Guidelines for DiffServ Service Classes August 2006
Table of Contents
1. Introduction ....................................................3
1.1. Requirements Notation ......................................4
1.2. Expected Use in the Network ................................4
1.3. Service Class Definition ...................................5
1.4. Key Differentiated Services Concepts .......................5
1.4.1. Queuing .............................................6
1.4.1.1. Priority Queuing ...........................6
1.4.1.2. Rate Queuing ...............................6
1.4.2. Active Queue Management .............................7
1.4.3. Traffic Conditioning ................................7
1.4.4. Differentiated Services Code Point (DSCP) ...........8
1.4.5. Per-Hop Behavior (PHB) ..............................8
1.5. Key Service Concepts .......................................8
1.5.1. Default Forwarding (DF) .............................9
1.5.2. Assured Forwarding (AF) .............................9
1.5.3. Expedited Forwarding (EF) ..........................10
1.5.4. Class Selector (CS) ................................10
1.5.5. Admission Control ..................................11
2. Service Differentiation ........................................11
2.1. Service Classes ...........................................12
2.2. Categorization of User Service Classes ....................13
2.3. Service Class Characteristics .............................16
2.4. Deployment Scenarios ......................................21
2.4.1. Example 1 ..........................................21
2.4.2. Example 2 ..........................................23
2.4.3. Example 3 ..........................................25
3. Network Control Traffic ........................................27
3.1. Current Practice in the Internet ..........................27
3.2. Network Control Service Class .............................27
3.3. OAM Service Class .........................................29
4. User Traffic ...................................................30
4.1. Telephony Service Class ...................................31
4.2. Signaling Service Class ...................................33
4.3. Multimedia Conferencing Service Class .....................35
4.4. Real-Time Interactive Service Class .......................37
4.5. Multimedia Streaming Service Class ........................39
4.6. Broadcast Video Service Class .............................41
4.7. Low-Latency Data Service Class ............................43
4.8. High-Throughput Data Service Class ........................45
4.9. Standard Service Class ....................................47
4.10. Low-Priority Data ........................................48
5. Additional Information on Service Class Usage ..................49
5.1. Mapping for Signaling .....................................49
5.2. Mapping for NTP ...........................................50
5.3. VPN Service Mapping .......................................50
6. Security Considerations ........................................51
Babiarz, et al. Informational [Page 2]
RFC 4594 Guidelines for DiffServ Service Classes August 2006
7. Acknowledgements ...............................................52
Show full document text