1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T G.808.1 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2014) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Digital networks General aspects Generic protection switching Linear trail and subnetw
2、ork protection Recommendation ITU-T G.808.1 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARAC
3、TERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANS
4、MISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 General aspects G.800G.809 Design objectives for digital networks G.810G.819 Synchronization, quality and availability targets G.820G.829 Network capabilities and functions
5、 G.830G.839 SDH network characteristics G.840G.849 Management of transport network G.850G.859 SDH radio and satellite systems integration G.860G.869 Optical transport networks G.870G.879 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USE
6、R-RELATED ASPECTS G.1000G.1999 TRANSMISSION MEDIA CHARACTERISTICS G.6000G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.808.1 (05/2014)
7、 i Recommendation ITU-T G.808.1 Generic protection switching Linear trail and subnetwork protection Summary Recommendation ITU-T G.808.1 defines the generic functional models, characteristics and processes associated with various linear protection schemes for circuit-switched connection-oriented lay
8、er networks; e.g., optical transport networks (OTN), synchronous digital hierarchy (SDH) networks and packet-switched layer networks, e.g., asynchronous transfer mode (ATM) networks and Ethernet transport networks. It also defines the objectives and applications for these schemes. Protection schemes
9、 described in this Recommendation are trail protection and subnetwork connection protection with various monitoring alternatives for individual signals or groups of signals. Furthermore, survivability offered by the link capacity adjustment scheme (LCAS) is described. Generic functional models, char
10、acteristics and processes for ring protection and interconnected subnetwork (e.g., ring) protection schemes are defined in other Recommendations. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T G.808.1 2003-12-14 15 11.1002/1000/7063 1.1 ITU-T G.808.1 (2003) Amd. 1 2005-07-1
11、4 15 11.1002/1000/8541 2.0 ITU-T G.808.1 2006-03-29 15 11.1002/1000/8761 2.1 ITU-T G.808.1 (2006) Amd. 1 2009-01-13 15 11.1002/1000/9650 3.0 ITU-T G.808.1 2010-02-22 15 11.1002/1000/10401 3.1 ITU-T G.808.1 (2010) Amd. 1 2012-08-06 15 11.1002/1000/11491 3.2 ITU-T G.808.1 (2010) Amd. 2 2012-09-21 15 1
12、1.1002/1000/11781 4.0 ITU-T G.808.1 2014-05-14 15 11.1002/1000/12180 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T G.808.
13、1 (05/2014) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsi
14、ble 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 Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-
15、T study groups which, in turn, produce 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
16、basis with ISO and IEC. NOTE In this 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 mandat
17、ory provisions (to ensure, e.g., interoperability 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
18、 use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU 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
19、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, ITU had received notice of intellectual property, pr
20、otected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2014 All rights reserved. No par
21、t of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.808.1 (05/2014) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 2 3.1 Terms defined elsewhere 2 4 Abbreviations 6 5 Conventions 8 6 Individual and group p
22、rotection concept 8 7 Architecture types . 9 7.1 1+1 protection architecture . 10 7.2 1:n protection architecture 10 7.3 m:n protection architecture . 12 7.4 (1:1)n protection architecture 13 8 Switching types . 15 9 Operation types . 16 10 Protocol types . 16 11 Protection classes and subclasses .
23、18 11.1 Trail protection . 18 11.2 SNC protection . 22 11.3 Subnetwork connection group protection . 29 12 Survivability of inverse multiplexed link connections . 39 12.1 SIM functional model . 40 13 Protection switching performance 41 14 Hold-off timer . 42 15 Wait-to-restore timer 43 16 Automatic
24、protection switching signal . 44 17 Non-pre-emptible unprotected traffic . 44 18 Extra traffic (protection) transport entity overhead/OAM 44 19 External commands 45 19.1 External commands for CL-SNC . 45 19.2 External commands for ACL-SNC 46 20 Protection switching process states 46 21 Priority 47 2
25、2 SF and SD trigger conditions 47 22.1 Overview of SF conditions . 48 22.2 Overview of SD conditions 49 23 Working and protection allocation . 49 iv Rec. ITU-T G.808.1 (05/2014) Page 24 APS protocol . 50 24.1 1-phase 51 24.2 2-phase 51 24.3 3-phase 53 Appendix I Implementation of hold-off timer 55 A
26、ppendix II Automatic conditions (SF, SD) in group SNC protection 56 Appendix III Implementation observations 58 III.1 Analysis 58 Appendix IV An example of (1:1)n protection 62 Appendix V Examples of survivability of inverse multiplexed trails . 63 V.1 Survivability offered by LCAS 63 Appendix VI So
27、lution for SD triggered protection in PTN 64 Appendix VII Solution for service protection in DBN . 65 Rec. ITU-T G.808.1 (05/2014) 1 Recommendation ITU-T G.808.1 Generic protection switching Linear trail and subnetwork protection 1 Scope This Recommendation provides an overview of generic aspects of
28、 linear protection switching. It covers protection schemes applicable to circuit-switched and packet-switched layer networks; e.g., optical transport networks (OTNs), synchronous digital hierarchy (SDH), asynchronous transfer mode (ATM) and Ethernet transport based protection schemes. Overviews of r
29、ing protection and dual node subnetwork (e.g., ring) interconnection schemes will be provided in other Recommendations. 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
30、 time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; 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
31、. 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. ITU-T G.780 Recommendation ITU-T G.780/Y.1351 (2010), Terms and definitions for synchronou
32、s digital hierarchy (SDH) networks. ITU-T G.783 Recommendation ITU-T G.783 (2006), Characteristics of synchronous digital hierarchy (SDH) equipment functional blocks. ITU-T G.798 Recommendation ITU-T G.798 (2004), Characteristics of optical transport network hierarchy equipment functional blocks. IT
33、U-T G.805 Recommendation ITU-T G.805 (2000), Generic functional architecture of transport networks. ITU-T G.806 Recommendation ITU-T G.806 (2009), Characteristics of transport equipment Description methodology and generic functionality. ITU-T G.826 Recommendation ITU-T G.826 (2002), End-to-end error
34、 performance parameters and objectives for international, constant bit-rate digital paths and connections. ITU-T G.841 Recommendation ITU-T G.841 (1998), Types and characteristics of SDH network protection architectures. ITU-T G.842 Recommendation ITU-T G.842 (1997), Interworking of SDH network prot
35、ection architectures. ITU-T G.870 Recommendation ITU-T G.870/Y.1352 (2008), Terms and definitions for optical transport network (OTN). ITU-T G.873.1 Recommendation ITU-T G.873.1 (2006), Optical Transport Network (OTN): Linear protection. ITU-T I.610 Recommendation ITU-T I.610 (1999), B-ISDN operatio
36、n and maintenance principles and functions. ITU-T I.630 Recommendation ITU-T I.630 (1999), ATM protection switching. 2 Rec. ITU-T G.808.1 (05/2014) ITU-T I.732 Recommendation ITU-T I.732 (2000), Functional characteristics of ATM equipment. ITU-T M.495 Recommendation ITU-T M.495 (1988), Transmission
37、restoration and transmission route diversity: Terminology and general principles. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 General terms defined in ITU-T G.805: a) adapted information (AI). b) characteristic information (CI). c)
38、link connection. d) network. e) serial compound link connection. f) subnetwork. g) trail. 3.1.2 Action-related terms: 3.1.2.1 switch: ITU-T G.870. 3.1.3 APS protocol-related terms: 3.1.3.1 1-phase: ITU-T G.870. 3.1.3.2 2-phase: ITU-T G.870. 3.1.3.3 3-phase: ITU-T G.870. 3.1.4 Protection class-relate
39、d terms: 3.1.4.1 trail protection: ITU-T G.870. 3.1.4.2 subnetwork connection protection: ITU-T G.870. The determination of a fault condition on a serial compound link connection within the protected domain can be performed as follows: 3.1.4.2.1 sublayer monitored (/S): ITU-T G.870. 3.1.4.2.2 non-in
40、trusive monitored (/N): ITU-T G.870. 3.1.4.2.3 inherent monitored (/I): ITU-T G.870. 3.1.4.2.4 test monitored (/T): ITU-T G.870. 3.1.4.3 network connection protection: ITU-T G.870. 3.1.4.4 individual: ITU-T G.870. 3.1.4.5 group: ITU-T G.870. 3.1.5 Protection subclass-related terms: 3.1.5.1 end-to-en
41、d overhead/OAM (e): ITU-T G.870. 3.1.5.2 sublayer overhead/OAM (s): ITU-T G.870. 3.1.6 Component-related terms: Rec. ITU-T G.808.1 (05/2014) 3 3.1.6.1 protected domain: ITU-T G.870. 3.1.6.2 bridge: ITU-T G.870. 3.1.6.3 permanent bridge: ITU-T G.870. 3.1.6.4 broadcast bridge: ITU-T G.870. 3.1.6.5 sel
42、ector bridge: ITU-T G.870. 3.1.6.6 selector: ITU-T G.870. 3.1.6.7 selective selector: ITU-T G.870. 3.1.6.8 merging selector: ITU-T G.870. Figure 3-1 Protection selectors 3.1.6.9 head end: ITU-T G.870. 3.1.6.10 tail end: ITU-T G.870. 3.1.6.11 sink node: ITU-T G.870. 3.1.6.12 source node: ITU-T G.870.
43、 3.1.6.13 intermediate node: ITU-T G.870. 3.1.7 Fault condition-related terms: 3.1.7.1 signal degrade (SD): ITU-T G.805. 3.1.7.2 signal fail (SF): ITU-T G.805. 3.1.7.3 signal degrade group (SDG): ITU-T G.870. 3.1.7.4 signal fail group (SFG): ITU-T G.870. 3.1.7.5 server signal degrade (SSD): ITU-T G.
44、806. 3.1.7.6 server signal fail (SSF): ITU-T G.806. 3.1.7.7 trail signal degrade (TSD): ITU-T G.806. 3.1.7.8 trail signal fail (TSF): ITU-T G.806. 3.1.8 Architecture-related terms: 3.1.8.1 1+1 (protection) architecture: ITU-T G.870. 3.1.8.2 1:n (protection) architecture (n 1): ITU-T G.870. 3.1.8.3 m
45、:n (protection) architecture: ITU-T G.870. 4 Rec. ITU-T G.808.1 (05/2014) 3.1.8.4 (1:1)n protection architecture: ITU-T G.870. 3.1.9 External commands-related terms: 3.1.9.1 lockout of protection transport entity #i (LO #i): ITU-T G.870. 3.1.9.2 lockout of normal traffic signal #i: ITU-T G.870. 3.1.
46、9.3 clear lockout of normal traffic signal #i: ITU-T G.870. 3.1.9.4 freeze: ITU-T G.870. 3.1.9.5 forced switch for normal traffic signal #i (FS #i): ITU-T G.870. 3.1.9.6 forced switch for null signal (FS #0): ITU-T G.870. 3.1.9.7 forced switch for extra traffic signal (FS #ExtraTrafficSignalNumber):
47、 ITU-T G.870. 3.1.9.8 manual switch for normal traffic signal #i (MS #i): ITU-T G.870. 3.1.9.9 manual switch for null signal (MS #0): ITU-T G.870. 3.1.9.10 manual switch for extra traffic signal (MS #ExtraTrafficSignalNumber): ITU-T G.870. 3.1.9.11 exercise signal #i (EX): ITU-T G.870. 3.1.9.12 clea
48、r (CLR): ITU-T G.870. 3.1.10 State-related terms: 3.1.10.1 do not revert normal traffic signal #i (DNR #i): ITU-T G.870. 3.1.10.2 no request (NR): ITU-T G.870. 3.1.10.3 wait-to-restore normal traffic signal #i (WtR): ITU-T G.870. 3.1.11 Operation-related terms: 3.1.11.1 revertive (protection) operat
49、ion: ITU-T G.870. 3.1.11.2 non-revertive (protection) operation: ITU-T G.870. 3.1.12 Signal-related terms: 3.1.12.1 traffic signal: ITU-T G.870. 3.1.12.2 normal traffic signal: ITU-T G.870. 3.1.12.3 extra traffic signal: ITU-T G.870. 3.1.12.4 null signal: ITU-T G.870. 3.1.13 Switching-related terms: 3.1.13.1 bidirectional (protection) swit
