1、 International Telecommunication Union ITU-T O.211TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2006) SERIES O: SPECIFICATIONS OF MEASURING EQUIPMENT Equipment to perform measurements on IP networks Test and measurement equipment to perform tests at the IP layer ITU-T Recommendation O.211 ITU-
2、T O-SERIES RECOMMENDATIONS SPECIFICATIONS OF MEASURING EQUIPMENT General O.1O.9 Maintenance access O.10O.19 Automatic and semi-automatic measuring systems O.20O.39 Equipment for the measurement of analogue parameters O.40O.129 Equipment for the measurement of digital and analogue/digital parameters
3、O.130O.199 Equipment for the measurement of optical channel parameters O.200O.209 Equipment to perform measurements on IP networks O.210O.219 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. O.211 (01/2006) i ITU-T Recommendation O.211 Test and measurement equipment
4、 to perform tests at the IP layer Summary This Recommendation specifies an IP performance measurement signature (IPPMS) and test packets which may be used to measure the performance and the availability of IP network services across administrative areas, composite networks and among heterogeneous de
5、vices. The IPPMS may be used to support provisioning and maintenance of IPv4 as well as IPv6 networks. Source ITU-T Recommendation O.211 was approved on 13 January 2006 by ITU-T Study Group 4 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Active measurement, network performance.
6、ii ITU-T Rec. O.211 (01/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, opera
7、ting and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, pr
8、oduce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In t
9、his Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. in
10、teroperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest
11、 that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidenc
12、e, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may
13、be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2006 All rights reserved. No part of this publication may be reproduced, by any means whatsoev
14、er, without the prior written permission of ITU. ITU-T Rec. O.211 (01/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations 3 5 State of the art considerations. 5 5.1 ICMP PING users of this Recommendation are therefore encouraged to investigate the possibility of applyin
15、g the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 1 ITU-T
16、Recommendation M.2301 (2002), Performance objectives and procedures for provisioning and maintenance of IP-based networks. 2 ITU-T Recommendation O.181 (2002), Equipment to assess error performance on STM-N interfaces. 3 ITU-T Recommendation O.191 (2000), Equipment to measure the cell transfer perfo
17、rmance of ATM connections. 2 ITU-T Rec. O.211 (01/2006) 4 ITU-T Recommendation Y.1540 (2002), Internet protocol data communication service IP packet transfer and availability performance parameters. 5 ITU-T Recommendation Y.1541 (2006), Network performance objectives for IP-based services. 6 ITU-T R
18、ecommendation Y.1241 (2001), Support of IP-based services using IP transfer capabilities. 7 ITU-T Recommendation I.353 (1996), Reference events for defining ISDN and B-ISDN performance parameters. 8 ITU-T Recommendation G.7041/Y.1303 (2005), Generic framing procedure (GFP). 9 ITU-T Recommendation M.
19、1400 (2004), Designations for interconnections among operators networks. 10 IETF RFC 4148 (2005), IP Performance Metrics (IPPM) Metrics Registry. 11 ISO 3166-1:1997, Codes for the representation of names of countries and their subdivisions Part 1: Country codes. 3 Definitions The following definitio
20、ns are taken from ITU-T Rec. Y.1241 6: 3.1 IP-based service: An IP-based service is defined as a service provided by the service plane to an end user (e.g., a host (end system) or a network element) and which utilizes the IP transfer capabilities and associated control and management functions, for
21、delivery of the user information specified by the service level agreements. 3.2 IP network service: An IP network service is defined as a data transmission service in which the data passed across the interface between the user and provider is transferred in the form of IP (Internet protocol) packets
22、 (sometimes called datagrams). IP network service includes the service provided by using the IP transfer capabilities. 3.3 IP transfer capability: IP transfer capability is defined as the set of network capabilities provided by the IP layer. It may be characterized by the traffic contract as well as
23、 performance attributes supported by control and management functions of the underlying protocol layers. ITU-T Rec. Y.1540 4 defines end-to-end IP-service and measurement point (MP) as follows: 3.4 end-to-end IP service: For the purpose of this Recommendation, end-to-end IP service refers to the tra
24、nsfer of user-generated IP datagrams (referred to in this Recommendation as IP packets) between two end hosts as specified by their complete IP addresses. 3.5 measurement point (MP): The boundary between a host and an adjacent link at which performance reference events can be observed and measured.
25、Consistent with ITU-T Rec. I.353 7, the standard Internet protocols can be observed at IP measurement points. ITU-T Rec. I.353 provides more information about MPs for digital services. 3.6 Type-P: RFC 2330 defines a performance measurement framework. It introduces the notion of type of packet, the T
26、ype-P. It corresponds to the suite of protocols present in the IP and SUB-IP headers of the packet. A Type-P is represented as a list of protocol identifier names. Protocol identifiers names for IP are defined in RFC 2896. Specific protocol identifiers names for IPv6 are defined in RFC 3919. As an e
27、xample, the Type-P ip.udp.snmp differs from the Type-P ip.ip6.udp.snmp because the latter is not only an SNMP packet over IPv6 but is also an IPv6 packet encapsulated over IP. This definition is only used in this Recommendation to give clear encapsulation examples. ITU-T Rec. O.211 (01/2006) 3 3.7 I
28、P performance measurement signature (IPPMS): An IP test packet is a regular IP packet that contains a standardized block of fields needed to perform the measurement. This block of fields is named IP performance measurement signature (IPPMS). 4 Abbreviations This Recommendation uses the following abb
29、reviations: 3GPP Third Generation Partnership Project ATIS Alliance for Telecommunications Industry Solutions ATM Asynchronous Transfer Mode BGP Border Gateway Protocol CAC Connection Admission Control CIF Controller Identifier Format CRC Cyclic Redundancy Check CRC32 32-bit Cyclic Redundancy Check
30、DiffServ Differentiated Service DoS Denial of Service DSCP Differentiated Service Code Point DST Destination ETSI European Telecommunications Standards Institute EURESCOM European Institute for Research and Strategic Studies in Telecommunications FR Frame Relay FTP File Transfer Protocol HTTP Hyper
31、Text Transfer Protocol ICMP Internet Control Message Protocol ID Identifier IETF Internet Engineering Task Force IntServ Integrated Service IP Internet Protocol IPDR IP Packet Discard Rate IPDV IP Packet Delay Variation IPER IP Packet Error Ratio IPLR IP Packet Loss Ratio IPOD IP Operator Domain IPP
32、M IP Performance Metrics IPPMS IP Performance Measurement Signature IPRR IP Packet Reordering Ratio IPRTD IP Packet Round Trip Delay IPSLBR IP Packet Severe Loss Block Ratio 4 ITU-T Rec. O.211 (01/2006) IPTD IP Packet Transfer Delay IPv4 IP version 4 IPv6 IP version 6 LL Lower Layers MIB Management
33、Information Base MP Measurement Point MPEG Moving Picture Experts Group MTTR Mean Time To Restore NAT Network Address Translation NTP Network Termination Point OBGR Operator Border Gateway Router PAM Passive and Active Measurement PAT Protocol Address Translation PDH Plesiochronous Digital Hierarchy
34、 PDU Protocol Data Unit PING Packet Internetwork (Internet) Grouper PPP Point-to-Point Protocol QoS Quality of Service RMON Remote Network Monitoring RTP Real Time Transport Protocol SDH Synchronous Digital Hierarchy SDU Service Data Unit SLA Service Level Agreement SN Sequence Number SRC Source STM
35、-N Synchronous Transport Module, level N SUB-IP Sub IP Layer TCP Transmission Control Protocol TIPHON Telecommunications and Internet Protocol Harmonization Over Networks TSC Timestamp Control TSF Timestamp Format Tx Transmitter UDP User Datagram Protocol VoIP Voice over IP ITU-T Rec. O.211 (01/2006
36、) 5 5 State of the art considerations 5.1 ICMP PING the interface that has sent the packet; the identifier of the stream the packet belongs to; the absolute timestamp corresponding to the time the packet is sent; the sequence number of the packet; and a checksum or a CRC computed on the previous fie
37、lds or on the whole IP packet. Existing implementations insert the test information either at the beginning or at the end of the SDU of the IP test packet. This Recommendation covers these two designs. 6 Requirements and benefits of a standard IP test packet This Recommendation specifies an IP test
38、packet format to be used when doing network provisioning and maintenance tests in order to verify the IP-transfer performance requirements of IP-based services by measuring the IP metrics defined in ITU-T Recs Y.1540 4 and M.2301 1. This clause discusses general requirements and benefits of a standa
39、rd test packet. 6.1 General requirements ITU-T Rec. M.2301 1 presents two basic measurement approaches intrusive and non-intrusive. Intrusive measurements use IP test packet streams to create IP flows on the path to be tested. These test packets are interleaved with the normal traffic flows between
40、two measurement points (MPs), or transmitted as a continuous stream of pseudo-customer traffic. Non-intrusive measurements use one of two methods: Monitoring and collecting of MIB data from network elements such as routers for performance assessment and maintenance; Measuring the network performance
41、 for customer IP packets. 6 ITU-T Rec. O.211 (01/2006) Non-intrusive measurements monitor not only customer IP packets, they also monitor IP test packets as regular IP traffic. Therefore, a passive and active measurement approach, named PAM, exits. This might be thought of as a “mixed mode“ where th
42、e test packets are inserted intrusively, but they are monitored non-intrusively. As an example, non-intrusive probes attached at key MPs in the network such as gateway routers may monitor the test packets to measure inter-domain performance. To measure the quality of service, it is important to have
43、 operational interoperability among heterogeneous manufacturers and to perform one-way delay and one-way packet loss measurement across administrative areas or over composite networks for different Type-P packets. Consequently, this Recommendation considers two main points: When doing network provis
44、ioning and service turn-up tests, it is crucial to use an IP test packet stream that simulates the kinds of application services to be supported. IP data are never carried directly over IP. User traffic is carried mainly on top of UDP or TCP, but not exclusively. 6.2 Benefits of standardizing an IP
45、test packet Standardizing an IP test packet has a number of advantages, including the following: IP-based services can be provisioned and activated consistently, and QoS established against negotiated SLAs; network performance and QoS can be monitored consistently, and measurement results compared a
46、gainst SLAs and correlated between different MPs and instruments; interoperability between instruments of different manufacturers can be evaluated; interoperability of measurement between administrative domains and over composite networks can be evaluated. 6.3 Interoperability The definition of the
47、IP test packet must offer interoperability among heterogeneous manufacturers in order to perform metric measurements across administrative areas and among composite networks. Currently, in a test involving heterogeneous equipment and/or administrative areas, the identifier of the measurement set by
48、the source (essentially, the identification of the source) has no meaning for the sink. To gain interoperability, the IP test packet must carry information to unambiguously identify the controller of the measure. 6.4 IP multicast and mobility The definition of the IP test packet must consider the me
49、asurement of the performance of multicast services, mobile IP services. 6.5 IPv4 and IPv6 coexistence To permit end-to-end measurement, the test packet must not depend on either IPv4 or IPv6. The protocol translation mechanisms between, IPv4 and IPv6 and the coexistence of, IPv4 and IPv6 are potential sources of non-interoperability of the measurements. Whenever possible the test packet should not be rejected by IPv6/IPv4 translation or transition mechanisms. ITU-T Rec. O.211 (01/2006) 7 6.6 Transport protocol Figur
