1、 TECHNICAL REPORT T1.TR.70-2001 Technical Report on Reliability/Availability Framework for IP-based Networks and Services Prepared by T1A1.2 Working Group on Network Survivability Performance Problem Solvers to the Telecommunications Industry A Word from ATIS and Committee T1 Established in February
2、 1984, Committee T1 develops technical standards, reports and requirements regarding interoperability of telecommunications networks at interfaces with end-user systems, carriers, information and enhanced-service providers, and customer premises equipment (CPE). Committee T1 is sponsored by ATIS and
3、 is accredited by ANSI. T1.TR.70-2001 Published by Alliance for Telecommunications Industry Solutions 1200 G Street, NW, Suite 500 Washington, DC 20005 Committee T1 is sponsored by the Alliance for Telecommunications Industry Solutions (ATIS) and accredited by the American National Standards Institu
4、te (ANSI). Copyright 2002 by Alliance for Telecommunications Industry Solutions All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. For information contact ATIS at 202.6
5、28.6380. ATIS is online at . Printed in the United States of America. T1.TR.70-2001 Technical Report Reliability/Availability Framework for IP-based Networks and Services Alliance for Telecommunications Industry Solutions Approved August 2001 Abstract This Technical Report (TR) addresses the growing
6、 concerns from the telecommunications community about the reliability/availability of Internet Protocol (IP)-based telecommunications networks, including the services provided under failure conditions. It is intended to provide a framework for designing and operating IP-based telecommunications netw
7、orks to meet users expectations regarding network reliability and service availability. T1.TR.70-2001 Foreword This Technical Report addresses the growing concerns from the telecommunications community about the reliability/availability of IP-based telecommunications networks, including the services
8、 provided under failure conditions. It is intended to provide a framework for designing and operating IP-based telecommunications networks that meet expectations regarding network reliability and service availability. This Technical Report is intended for providers of IP-based telecommunications net
9、works and services, and telecommunications equipment suppliers. Suggestions for enhancement of this report are welcome. These should be sent to the Alliance for Telecommunications Industry Solutions, Suite 500, 1200 G Street N.W., Washington, D.C. 20005. Working Group T1A1.2 on Network Survivability
10、 Performance, which developed this report, has the following officers and participants: S. Makris. T1A1.2 Chair O. Avellaneda, T1A1.2 Vice Chair F. Kaudel, T1A1.2 Chief Editor T1A1.2 Editors: R. Canaday, A. Nguyen, S. Makris, R. Paterson, and A. Webster Active Participants: O. Avellaneda J. Bennett
11、R. Canaday W. Chiles C. Dvorak F. Kaudel J. Lord S. Makris A. Nguyen R. Paterson J. Rupe P. Tarapore A. Webster ii T1.TR.70-2001 Table of Contents 0 Executive Summary .1 1 Purpose, Scope, Application, and Outline .1 1.1 Purpose 1 1.2 Scope .1 1.3 Application1 1.4 Outline 1 2 Related Work .2 2.1 T1A1
12、 Technical Subcommittee.2 2.2 Other T1 Technical Subcommittees .2 2.2.1 T1E1 Interfaces, Power Procedural Error Team to investigate the impact of procedural errors on telecommunication service outages; Facility Solutions Team to investigate the root causes of facility outages and issue Best Practice
13、s for mitigating cable dig-ups. For more information, see http:/www.atis.org/atis/nrsc/nrschome.htm. 2.6 U.S. National Security Telecommunications Advisory Committee (NSTAC) The President created the NSTAC by Executive Order (E.O.) 12382 in September 1982 to advise him on matters regarding National
14、Security/Emergency Preparedness (NS/EP) telecommunications. Four issues provided impetus for the establishment of the NSTAC: Divestiture of AT however, the nature of this threat is unclear. Without a clear and present danger, it is difficult for industry to justify spending additional dollars for au
15、gmenting protection of its systems. 2.6.3 Convergence Task Force Report, June 2001 This report anticipates unique network reliability and vulnerability concerns during the transitional period between the current network environment and the NGN, which is expected to be IP-centric and more dependent o
16、n wireless communications. As the NGN evolves, the U.S. Government is expected to serve an increasingly important role in working with industry and standards bodies to promote an understanding of National Security and Emergency Preparedness (NS/EP) requirements, including priority services, and to f
17、acilitate development and deployment of requisite NS/EP standards. Participation in standards bodies is of paramount importance as security considerations and other NS/EP requirements must be recognized and considered early in any network design process so that retrofitting is avoided. 9 T1.TR.70-20
18、01 According to this report, Government should also specify service level and assurance requirements in Government contracts with carriers. Furthermore, Government should specify NS/EP-related security, service availability and assurance requirements in IT and network-based procurements, as feasible
19、, to help ensure the NS/EP communitys needs are satisfied. 2.6.4 Information Sharing for Critical Infrastructure Protection (CIP) Task Force Report, June 2001 An important facet of the Nations strategy to protect critical infrastructures from cyber attacks is the development of mechanisms to facilit
20、ate public and private sector information sharing about actual threats and vulnerabilities. To address this concern, the National Security Telecommunications Advisory Committees (NSTAC) Industry Executive Subcommittee (IES) formed the Information Sharing/Critical Infrastructure Protection Task Force
21、 (ISCIPTF) in September 1999 to focus on various information-sharing issues associated with critical infrastructure protection. This report addresses three new charges from the NSTAC to the IES: 1. Provide input to Version 2.0 of the National Plan for Information Systems Protection 2. Address barrie
22、rs to information sharing for critical infrastructure protection, to include the Freedom of Information Act (FOIA) and possible law enforcement restrictions 3. Coordinate with United States Space Command (USSPACECOM) to further develop means for information sharing. 2.7 U.S. National Coordinating Ce
23、nter for Telecommunications (NCC) Presidential Decision Directive (PDD) 63: Protecting Americas Critical Infrastructures called for the creation of a private sector Information Sharing and Analysis Center (ISAC) to gather, analyze, appropriately sanitize and disseminate information regarding vulnera
24、bilities, threats, intrusions, and anomalies from the private sector to both industry and the National Infrastructure Protection Center. Since the issuance of PDD-63 in May 1998, several ISACs have been established (e.g., banking and finance, telecommunications, and government). The National Coordin
25、ating Center for Telecommunications (NCC) was designated as an ISAC for telecommunications in January 2000. The NCC-ISAC has developed a collection of automated systems and tools, collectively known as the Information Sharing and Analysis System (ISAS), to facilitate the collection, analysis, and ex
26、change of information on vulnerabilities, threats, intrusions, and anomalies affecting the telecommunications infrastructure. To achieve full operating capability as an ISAC, a minimum set of data elements must be considered for reporting cyber and physical events affecting telecommunications networ
27、ks. For more information, see http:/www.ncs.gov/ncc/. 2.8 Other Forums and Committees There are a multitude of other forums and committees that contribute to the work on IP network reliability/availability issues. Some of the more important organizations are discussed below. 2.8.1 The Telecommunicat
28、ions Management Forum (TMF) The TM Forum has produced an SLA-Management-Handbook that is very pertinent to the work on Network Reliability/Availability 9. See 8.3 for information on SLAs. 10 T1.TR.70-2001 For more information, see http:/www.nmf.org. 2.8.2 ETSI TIPHON (Telecommunications and Internet
29、 Protocol Harmonization Over Networks) From the ETSI TIPHON webpage: This projects objective is to support the market for voice communication and related voiceband communication (such as facsimile) between users. It will ensure that users connected to IP based networks can communicate with users in
30、Switched Circuit Networks (SCN such as PSTN /ISDN and GSM), and vice versa. The support comes in the production of appropriate ETSI deliverables: technical specifications and reports. In addition, the activity will include validation and demonstrations, in order to confirm the appropriateness of the
31、 solutions proposed. Several of the TIPHONs working groups produce results of interest for IP network reliability and availability. Examples are: Working Group 02 develops reference architecture models and interfaces. These are important for defining and measuring network reliability; Working Group
32、05 defines Quality of Service classes and develops measurement methodologies. These can be used in the development of SLAs; Working Group 08 addresses TIPHON Security. For more information, see http:/www.etsi.org/tiphon/. 2.8.3 The Internet Engineering Task Force (IETF) The IETF is concerned with al
33、most all aspects of IP-based networks and services. Below is a list of some of their working groups that have relevance to Reliability/Availability of IP-based networks and services. Internet Traffic Engineering (tewg) IP over Optical (ipo) IP over Resilient Packet Rings (iporpr) IP Performance Metr
34、ics (ippm) Multiprotocol Label Switching (mpls) Differentiated Services (diffserv) Media Gateway Control (megaco) Resource Reservation Protocol (rsvp) Policy Framework (policy) Mobile Routing for Wireless/Mobile Hosts (mobileip) Session Initiation Protocol (sip) Instant messaging and Presence Protoc
35、ol (impp) LDAP Extensions (ldapext) Zero Configuration Networking (zeroconf) Next Generation Transition (ngtrans) 11 T1.TR.70-2001 Internet Protocol Telephony (iptel) PSTN and Internet Internetworking (pint) Services in the PSTN/IN Requesting Internet Service (spirits) Common Control and Measurement
36、 Plane (ccamp). For more information, see http:/www.ietf.org. 2.8.4 Institute of Electrical and Electronic Engineering (IEEE) 802.17 is a relatively new working group under IEEE 802, which is tasked with developing a Resilient Packet Ring (RPR) Media Access Control (MAC) layer. This MAC will offer a
37、 both a competing technology to traditional 802.3 Ethernet and a way of extending Ethernet-based services out from the LAN to the MAN network. RPR proposes to bring SONET-like reliability and OAMP monitoring with a packet-based Ethernet extension to a dual counter-rotating fiber ring topology. RPR p
38、roposes to improve fiber BW utilization while supporting both SONET/SDH and best effort connectionless packet data transport. There are RPR vendors already contemplating offering circuit-emulation services at OC-3 to OC-48 speeds without using the frame structure of SONET in order to be more bandwid
39、th efficient, to better support bursty packet data and to push LAN services out to the MAN. The Technical Committee on Communications Quality and Reliability (CQR) focuses on and advocates worldwide communications and reliability on behalf of, and within, the IEEE Communications Society. CQR serves
40、as the catalyst for global awareness and the exchange of information relative to technical and management-related aspects of communications quality and reliability. 2.9 Emergency Communications Services The following are two emergency services that provide priority communications for governmental, c
41、ivil, and other essential users of public telecommunications services in crisis situations, such as earthquakes, severe storms, and floods. Telecommunication services are often restricted during these events due to damage, congestion, and failures. 2.9.1 ITU-T Recommendation E.106 International Emer
42、gency Preference Scheme (IEPS) This Recommendation from ITU-T Study Group 2 describes an International emergency Preference Scheme for telecommunications services that will support recovery activities during crisis situations. The Recommendation deals with making emergency telephone calls over the P
43、ublic Switched Telecommunications Network (PSTN) and Integrated Services Digital Network (ISDN). The essential features described by E.106 for the successful operation of IEPS are: Priority dial tone Priority call set-up, including priority queuing schemes Exemption from restrictive management contr
44、ols. Public telecommunications services in the United States have long had such a scheme (e.g., GETS-Government Emergency Telecommunications Service), to ensure priority handling of telephone communications, such as during natural disasters. 12 T1.TR.70-2001 2.9.2 ITU-T Recommendation F.706: Service
45、 Description for an International Emergency Multimedia Service (IEMS) This Recommendation from ITU-T Study Group 16 provides a core service capability for identifying and authenticating IEMS communications. This core service also provides priority routing and processing through the participating int
46、ernational network infrastructures, and alerting the receiving location that an IEMS communication is pending. The Administrations and other essential users of public telecommunications can use the IEMS service during crisis situation when normal communications facilities are restricted due to physi
47、cal damage, equipment failure, or unusually high-traffic volume. 2.9.3 ITU-T Draft Recommendation M.ieps: Service Management Functions Across the X-Interface for IEPS Communications over Internet-based Multimedia Services This draft Recommendation in ITU-T Study Group 4 describes the service managem
48、ent functions of the IEPS traffic over the IP-based Multimedia service. 3 Introduction This document addresses the growing concerns from the telecommunications community about the reliability/availability of IP-based telecommunications networks, including the services provided under failure conditio
49、ns. It provides a basis for designing and operating IP-based telecommunications networks to meet users expectations regarding network reliability and service availability. The public carrier network is rapidly evolving to an IP-centric network that is providing an expanding set of diverse services across multiple network domains. Traditional network service providers face a tremendous challenge to build and integrate these multi-supplier networks so that they meet the diverse reliability service needs of their custome
