1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU SERIES I: INTEGRATED SERVICES DIGITAL NETWORK Main ten ance principles 1.630 (02199) ATM protection switching ITU-T Recommendation 1.630 (Previously CCITT Recommendation) STDmITU-T RECMN 1.b30-ENGL 1999 m 4b2
2、591 ObbOb98 734 ITU-T I-SERIES RECOMMENDATIONS INTEGRATED SERVICES DIGITAL NETWORK ;ENERAL STRUCTURE Terminology Description of ISDNs General modelling methods Telecommunication network and service attributes General description of asynchronous transfer mode Scope General aspects of services in ISDN
3、 Common aspects of services in the ISDN Bearer services supported by an ISDN Teleservices supported by an ISDN Supplementary services in ISDN Network functional principles Reference models Numbering, addressing and routing Connection types Performance objectives Protocol layer requirements General n
4、etwork requirements and functions Application of I-series Recommendations to ISDN user-network interfaces Layer 1 Recommendations Layer 2 Recommendations Layer 3 Recommendations Multiplexing, rate adaption and support of existing interfaces Aspects of ISDN affecting terminal requirements SERVICE CAP
5、ABILITIES 3VERALL NENVORKASPECTS AND FUNCTIONS ISDN USER-NETWORK INTERFACES INTERNETWORK INTERFACES MAINT B-ISDN EQUIPMENT ASPECTS ATM equipment Transport functions Management of ATM equipment 1.1 10-1.119 1.1 20-1.129 I. 130-1.139 I. 140-1.149 I. 1 50-1.199 I .200-1.209 1.21 04.21 9 1.220-1.229 1.2
6、30-1.239 I .240-1.249 I .250-1.299 I. 3 1 0-1.31 9 I. 320-1.329 I. 330-1.339 1.340-1.349 I. 3 5 0-1.3 5 9 I. 3604.369 I .370-1.399 I .420-1.429 1.430-1.439 I .440-1.449 1.450-1.459 I .460-1.469 1.470-1.499 1.500-1.599 1.600-1.699 1.730-1.739 1.740-1.749 1.750-1.799 For further details, please refer
7、to ITU-T List of Recommendations. STD-ITU-T RECMN 1-630-ENGL 3999 m 4b2591 ObbOb99 ia70 9 ITU-T RECOMMENDATION 1.630 ATM PROTECTION SWITCHING Summary This Recommendation “ATM Protection Switching“ provides architectures and mechanisms for protection switching at ATM layer. The architecture includes
8、the extent of the protected domain and arrangement of protected domain. The resource for protection entities is pre-allocated. The mechanism includes protection switching trigger, hold-off mechanisms and protection switching control protocol. This Recommendation describes individual VPNC protection
9、and group protection. The individual VPNC protection is a technique where a single network and/or subnetwork connection is used for working entity and protection entity. The group protection is a technique where a logical bundle of one or more network andor subnetwork connections is used for working
10、 entity and protection entity. Currently, this Recommendation describes 1+1 and 1 : 1 bidirectional protection switching as well as l+l unidirectional protection switching. Source ITU-T Recommendation 1.630 was prepared by ITU-T Study Group 13 (1997-2000) and was approved under the WTSC Resolution N
11、o. 1 procedure on the 26th of February 1999. 1 Recommendation 1.630 (02/99) STDmITU-T RECMN Imb30-ENGL 1999 48b259L Obb0700 liL2 FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization
12、 Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), wh
13、ich meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of informati
14、on technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public cor
15、respondence service. The terms Administration, ROA and public correspondence are defined in the Constitution of the ITU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed
16、Intellectual Property Right. The ITU takes no position concerning the evidence, 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, the ITU h
17、ad received notice of intellectual property, protected by patents, which may 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. O ITU 1999 All rights
18、 reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation 1.630 (02/99) STD-ITU-T RECMN Iab30-ENGL 1999 D 4862593 0660703 059 1 2 3 4
19、5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 6 6.1 6.2 7 7.1 7.2 CONTENTS Page Scope References Definitions Symbols and abbreviations . Protection switching principles 5.1.1 General principles . General requirements and objectives Examples of network protected domains Extent of the protected domain . 5.3.1 Tra
20、il protection 5.3.2 Subnetwork connection protection 5.3.3 1+1 non-intrusive monitored subnetwork connection protection (SNC/N) 5.3.4 Relationship between the protected domain and the extent of OAM flows General principles. requirements and objectives 5.1.2 Dependency on physical layer network confi
21、guration . Protection switching configurations . ( 1 + 1 ) configuration . 5.5.3 (1 :n) configuration . 5.5.4 (m:n) configuration . Protection switching perfonnance 5.5.1 5.5.2 (1 : 1) configuration . Hold-off function in ATM survivability escalation Protection switching control protocol ATM VPNC pr
22、otection switching . Protection switching trigger mechanism Trigger for signal fail Trigger for signal degrade . ATM VPNC Group protection switching . Specific requirements and objectives . Architecture 7.2.1 Introduction . 7.2.2 General Specific requirements and objectives . 6.2.1 Operator control
23、6.2.2 6.2.3 Recommendation 1.630 (02/99) . 1 1 2 5 8 8 9 10 11 12 12 12 12 12 12 12 13 13 13 14 14 14 14 15 15 15 15 15 15 16 . 111 STD-ITU-T RECMN 1.b30-ENGL 1999 4862591 Obb0702 T95 = 7.2.3 7.2.4 7.2.5 VPGNCG 1+1 protection architecture . VPGNCG 1 : 1 protection architecture VPGNCG 1 :N (N1) prote
24、ction architecture . 7.2.6 VPGNCG M:N protection architecture Protection switch trigger mechanism . 7.3.1 Operator control Trigger for signal fail Trigger for signal degrade . 7.3 7.3.2 7.3.3 Annex A - Protection switching coordination protocol for 1+1/1:1 configurations . A . 1 General introduction
25、 . A . 1.1 A . 1.2 1 + 1 /1: 1 Linear protection switching protocol A.2.1 Switch initiation criteria A.2.2 KlK.2 byte generation rules . A.2.3 1+1/1: 1 Linear protection switching algorithm . Application architecture Compliance with network objectives A.2 Annex B - 1 +1 unidirectional SNC and trail
26、protection switching operation . B . 1 Application architecture . B.2 Compliance with network objectives . B.3 Switch initiation criteria . B.3.1 Externally initiated commands B.3.2 Automatically initiated commands B.3.3 States . B.4 Protection switching protocol . B . 5 1 + 1 unidirectional protect
27、ion switching algorithm operation B . 5.1 Control of the bridge . B.5.2 Control ofthe selector . B S.3 Revertive mode . B.5.4 Non-revertive mode . Page 17 18 18 18 18 18 19 19 19 19 19 24 25 25 26 28 34 34 34 35 35 36 36 36 36 36 36 36 36 iv Recommendation 1.630 (02199) - - STDeITU-T RECMN Imb3O-ENG
28、L 3999 W 4862593 Obb0703 923 = Recommendation 1.630 ATM PROTECTION SWITCHING (Geneva, 1999) 1 Scope This Recommendation provides architectures and mechanisms of ATM VPNC protection switching and ATM VP group protection switching. The architecture includes the extent of the protected domain, arrangem
29、ent of protected domain, and resource allocation policies. The mechanism includes protection switching trigger, hold-off mechanisms and protection switching control protocol. The modelling methodology defined in Recommendations G.805 2 and 1.326 4 is used for describing the ATM VPNC protection switc
30、hing architecture and ATM VPNC group protection switching architecture given in this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publicatio
31、n, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of cur
32、rently valid ITU-T Recommendations is regularly published. i ITU-T Recommendation G.707 (1996), Network node interface for the synchronous digital hierarchy, (SDH). 2 ITU-T Recommendation G.805 (1 995), Generic functional architecture of transport networks. 3 ITU-T Recommendation G.841 (1998), Types
33、 and characteristics of SDH network protection architectures. 4 ITU-T Recommendation 1.326 (1 999, Functional architecture of transport networh based on ATM. 151 ITU-T Recommendation 1.610 (1 999), B-ISDN operation and maintenance principles and functions. 6 ITU-T Recommendation 1.732 (1 996), Funct
34、ional characteristics of ATM equipment. 7 CCITT Recommendation M.495 (1 988), Transmission restoration and transmission route diversity: terminology and general principles. 8 ITU-T Recommendation M.301 O (1 996), Principles for a telecommunications management network. 9 ITU-T Recommendation M.3300 (
35、1998), TMN F interface requirements. Recommendation 1.630 (02/99) 1 STD.ITU-T RECMN 1-630-ENGL 1779 m 4b257L ObbD704 Bb8 3 Definitions This Recommendation defines the following terms: 3.1 APS VCC: A VCC for control purposes, defined over the extent of the protected domain and contained within a VCG.
36、 Its purpose is to assist in the evaluation of the quality of the associated VCG and to serve as a conduit for protection switching control protocol messages. There is an APS VCC associated with each VCG-W and an APS VCC associated with each VCG-P. The transmission of protection switching control pr
37、otocol messages is always over the VCG-P APS vcc. 3.2 APS VPC: A VPC for control purposes, defined over the extent of the protected domain and contained within a VPG. Its purpose is to assist in the evaluation of the quality of the associated VPG and to serve as a conduit for protection switching co
38、ntrol protocol messages. There is an APS VPC associated with each VPG-W and an APS VPC associated with each VPG P. The transmission of protection switching control protocol messages is always over the VPG-P A6 VPC. 3.3 bidirectional protection switching: A protection switching architecture in which,
39、 for a unidirectional failure, both directions (of the “trail“, “subnetwork connection“, etc.), including the affected direction and the unaffected direction, are switched to protection. 3.4 bridge: (For 1+1 configuration) The action or function of transmitting identical traffic on both the working
40、and protection entities. (For 1 :n configuration) To be defined. 3.5 Connection Point (CP): (See Note 2 in 3.38.) Reference points which are defined along a network connection defined at a given network layer. CPs defined at the ATM layer along a VP (or VC) connection are located at the ingress and
41、egress of an ATM network element (or customer equipment), where VP (or VC) link termination functions operate. 3.6 dedicated protection resource allocation: A resource allocation policy where both the route and the bandwidth for the protection entity are pre-allocated. 3.7 egress: The egress point o
42、f an ATM network element is illustrated in Figure 1. ATMnode I _. 4 ,- ; i I“I - TI31 3940-98 ingress 0 egress + direction of a connection Figure 1fi.630 - Usage of ingress and egress terms in Recommendation 1.630 3.8 escalation: A network survivability action caused when the survivability function
43、in lower layers has not been carried out. 3.9 extra traffic: A lower priority traffic with respect to the one being carried by the working entity. It is carried over the protection entity while the working entity is active. The extra traffic is not protected, i.e. when the protection entity is requi
44、red to protect the traffic that is being carried over the working entity (due to a failure or forced switcWmanua1 switch operation in this last one), the extra traffic is pre-empted. 2 Recommendation 1.630 (02/99) STD-ITU-T RECMN 1.630-ENGL 1999 W 4862591 Ob60705 7TLi 3.10 forced switch for working
45、entity #n: A switch action initiated by an operator command. Switch action is conducted except when signal fail condition exists for the protection entity to switch over. 3.11 hitless protection switch: A protection switch which does not cause cell loss, cell duplication, cell disorder, or bit error
46、s upon protection switching action. 3.12 hold-off time: The time interval between the detection of an SF or SD and its confirmation as a condition requiring the protection switching procedure. 3.13 impairment: A defect or performance degradation which may lead to SF or SD trigger. 3.14 ingress: The
47、ingress point of an ATM network element is illustrated in Figure 1. 3.15 intermediate node: A node on either the working entity physical route or the protection entity physical route in between the source and sink of the corresponding protected domain. 3.16 link connection: Definition is provided in
48、 Recommendation G.805. As an example a VP link connection is delimited by the CPs located in two consecutive ATM network elements operating at VP level. 3.17 manual switch: A switch action initiated by an operator command. Switch action is conducted unless a higher priority request is in effect. 3.1
49、8 matrix connection: Subnetwork connection delimited, for the ATM layer, by the CPs located at the ingress and egress of an ATM network element (see Note 2 in 3.38). 3.19 network connection: Transport entity used for transferring user and OAM information between the endpoints of the connection (TCPs) (see Note 2 in 3.38). 3.20 network survivability: The set of capabilities that allow a network to restore affected traffic in the event of a failure. The degree of survivability is determined by the networks capability to survive single fa
