1、INTERNATIONAL TELECOMMUNICATION UNIONITU-T Series QTELECOMMUNICATIONSTANDARDIZATION SECTOROF ITUSupplement 33(12/2000)SERIES Q: SWITCHING AND SIGNALLINGTechnical report TRQ.2401: Transport controlsignalling requirements Signallingrequirements for AAL type 2 link controlcapability set 2ITU-T Q-series
2、 Recommendations Supplement 33(Formerly CCITT Recommendations)ITU-T Q-SERIES RECOMMENDATIONSSWITCHING AND SIGNALLINGSIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN Q.60Q.99CLAUSES
3、APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 Q.120Q.249SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499DIGITAL EXCHANGES Q.500Q.599INTERWORKING
4、 OF SIGNALLING SYSTEMS Q.600Q.699SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799Q3 INTERFACE Q.800Q.849DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999PUBLIC LAND MOBILE NETWORK Q.1000Q.1099INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199INTELLIGENT NETWORK Q.1200Q.1699SIGNALLING RE
5、QUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799BROADBAND ISDN Q.2000Q.2999General aspects Q.2000Q.2099Signalling ATM adaptation layer (SAAL) Q.2100Q.2199Signalling network protocols Q.2200Q.2299Common aspects of B-ISDN application protocols for access signalling and network signallingand interwor
6、kingQ.2600Q.2699B-ISDN application protocols for the network signalling Q.2700Q.2899B-ISDN application protocols for access signalling Q.2900Q.2999For further details, please refer to the list of ITU-T Recommendations.Q series Supplement 33 (12/2000) iSupplement 33 to ITU-T Q-series RecommendationsT
7、echnical report TRQ.2401: Transport control signalling requirements Signallingrequirements for AAL type 2 link control capability set 2SummaryThis Supplement to the Q series of ITU-T Recommendations specifies the general aspects of AALtype 2 signalling requirements for the development of AAL type 2
8、signalling Capability Set 2(CS2). It should be read in conjunction with ITU-T Q-Series Supplement 8 realise the full set ofrequirements.This Supplement identifies what can be viewed as the capabilities for AAL type 2 Signalling. Inaddition, it describes the essential features and models useful for t
9、he development of functionalentity actions in support of AAL type 2 Signalling.SourceSupplement 33 to ITU-T Q-series Recommendations was prepared by ITU-T Study Group 11(2001-2004) and approved under the WTSA Resolution 5 procedure on 6 December 2000.ii Q series Supplement 33 (12/2000)FOREWORDThe In
10、ternational Telecommunication Union (ITU) is the United Nations specialized agency in the field oftelecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommend
11、ationson 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, produce Recommendations on thesetopics.The approval
12、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 areprepared on a collaborative basis with ISO and IEC.NOTEIn this publication, the expression “Administration“ is used
13、 for conciseness to indicate both atelecommunication administration and a recognized operating agency.INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publication may involve theuse of a claimed Intellectual Property Right. ITU takes no
14、position concerning the evidence, validity orapplicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside ofthe publication development process.As of the date of approval of this publication, ITU had not received notice of intellectual property, protectedb
15、y patents, which may be required to implement this publication. However, implementors are cautioned thatthis may not represent the latest information and are therefore strongly urged to consult the TSB patentdatabase. ITU 2001All rights reserved. No part of this publication may be reproduced or util
16、ized in any form or by any means,electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU.Q series Supplement 33 (12/2000) iiiCONTENTSPage1 Scope . 12 References 13 Definitions 14 Abbreviations . 15 Requirements . 25.1 General. 25.2 Routing 25.2.1 Suppor
17、t of AAL type 2 Service Specific Convergence Sublayer forNarrowband Services 2 . 25.2.2 Connection Resource Modification 25.2.3 AAL type 2 Path Types 35.2.4 CS2 to CS1 Interworking . 36 Architecture of AAL type 2 Signalling . 37 AAL type 2 Signalling Flows . 47.1 Successful AAL type 2 Connection Est
18、ablishment Information Flows 47.2 Unsuccessful AAL type 2 Connection Establishment Information Flows 67.3 Successful AAL type 2 Connection Resource Modification Information Flows 87.3 Unsuccessful AAL type 2 Connection Resource Modification Information Flows 97.5 Successful AAL type 2 Path Redirecti
19、on Information Flows. 10Q series Supplement 33 (12/2000) 1Supplement 33 to ITU-T Q-series RecommendationsTechnical report TRQ.2401: Transport control signalling requirements Signallingrequirements for AAL type 2 link control capability set 21ScopeThis Supplement contains the signalling requirements
20、for the AAL type 2 connection signalling forthe capability set 2 (CS2) to extend the CS1 signalling requirements specified in ITU-T Q-seriesSupplement 8 1. Only additional or changed requirements to those described in ITU-T Q-seriesSupplement 8 1 are shown.The main new features introduced in this ca
21、pability set are: Support of the latest version of AAL type 2 SSCS for Narrowband Services, Connection Resource Modification, AAL type 2 Path Type Selection, and AAL type 2 Path Redirection Request.2 References1 ITU-T Q-series Supplement 8 (1999), Technical report TRQ.2400: Transport controlsignalli
22、ng requirements Signalling requirements for AAL Type 2 link control capabilityset 1.2 ITU-T I.366.2 (2000), AAL type 2 service specific convergence sublayer for narrowbandservices.3 ITU-T I.356 (2000), BISDN ATM layer cell transfer performance.3 DefinitionsFor the purpose of this Supplement the defi
23、nitions in clause 3 of ITU-T Q-Series Supplement 8 1apply, with the addition of :3.1 AAL type 2 Connection Resource: Describes the attributes of the AAL type 2 links makingup the connection, and the Service Specific Convergence Sublayer resources used at the AAL type 2end points.3.2 AAL type 2 Path
24、Characteristics: Describes the AAL type 2 path type.3.3 AAL type 2 Preferred Link Characteristics: Link Characteristics to be used at connectionestablishment for nodes supporting connection resource modification capabilities.3.4 modified SSI attributes: SSI profile or multiplier n, for n 64 kbit/s.
25、Preferred SSIattributes. SSI attributes to be used at connection establishment for nodes supporting connectionresource modification capabilities.4 AbbreviationsFor the purpose of this Supplement the abbreviations in clause 4 of ITU-T Q-series Supplement 8 1apply, with the addition of:M_SSI Modified
26、SSI attributes2 Q series Supplement 33 (12/2000)P_SSI Preferred SSI attributesSSI Service Specific Convergence Sublayer Information5 RequirementsThe additional / modified AAL type 2 signalling requirements for capability set 2 (CS2) areprovided in this clause to extend those in clause 5 of ITU-T Q-s
27、eries Supplement 8 1.5.1 GeneralThe AAL type 2 Signalling Endpoint shall include mechanisms for the establishment and clearing ofAAL type 2 links.In support of general signalling requirements for the establishment of AAL type 2 links, the AALtype 2 Signalling Endpoint shall provide:the transparent t
28、ransfer of the AAL type 2 served user generated reference to the AAL type 2served user in the forward direction in the establishment phase;NOTE the AAL type 2 served user generated reference may include, for example, a reference to anaccess channel or radio link.the Service Specific Convergence Subl
29、ayer type and any relevant Service SpecificConvergence Sublayer parameters;the AAL type 2 link characteristics; andthe AAL type 2 path types.5.2 RoutingThe AAL type 2 Signalling shall support hop-by-hop routing.Routing typically is based on addressing information (in the switched case); path and lin
30、kcharacteristics/SSCS (at a AAL type 2 endpoint) reflecting the resources required, eg. bandwidth;path type and other information. The information used for describing the link characteristics shall bedefined in such a way to allow efficient routing with minimal delay and processing burden. Routingal
31、gorithms are implementation specific.Rerouting at an AAL type 2 node may be based on information received from an AAL type 2terminating endpoint.5.2.1 Support of AAL type 2 Service Specific Convergence Sublayer for NarrowbandServices 2The AAL type 2 Signalling Endpoint shall provide the Service Spec
32、ific Convergence Sublayer typeand any relevant Service Specific Convergence Sublayer parameters5.2.2 Connection Resource ModificationEither AAL type 2 Served User shall be able to modify the resources associated with an active AALtype 2 connection, represented by the information contained in the AAL
33、 type 2 Link Characteristicor the Service Specific Convergence Sublayer information, Profile or Multiplier n for n 64 kbit/s.NOTE This modification of AAL type 2 connection resources only involves Connection Admission Control(CAC).Collision of connection resource modification requests shall be avoid
34、ed by the AAL type 2 ServedUser.Modification shall be performed with no loss of CPS-SDU information.Q series Supplement 33 (12/2000) 3Use of inband procedures are not excluded.The use of the preferred AAL type 2 Link Characteristics and preferred AAL type 2 SSCS are toavoid the need of a subsequent
35、modification of the connection resources immediately after theconnection establishment.The capability to modify AAL type 2 SSCS or AAL type 2 Link Characteristics, for an AAL type 2connection must be indicated by the originating AAL type 2 endpoint. Each AAL type 2 node mustsupport the modification
36、capability of AAL type 2 Link Characteristics. Only the terminating AALtype 2 endpoint need support the modification capability of the AAL type 2 SSCS.This capability uses the following objects: SSI Modification Support Request, AAL type 2 Link Characteristics Modification Support Request, SSI Modif
37、ication Support Response, and AAL type 2 Link Characteristics Modification Support Response.5.2.3 AAL type 2 Path TypesAAL type 2 path types shall include:Path Type, tolerant.Path Type, stringent.The above information is only used for AAL type 2 path selection.The attributes of stringent and toleran
38、t shall be those as defined in ITU-T I.356 3.5.2.4 CS2toCS1InterworkingAAL type 2 path type SelectionIt is assumed that a CS1 node operates in a stringent mode, therefore the information shall bepassed on transparently through an AAL type 2 switch.AAL type 2 Path RedirectionA CS1 node receiving an A
39、AL type 2 path redirection request, shall ignore the request.Connection Resource ModificationCS1 nodes receiving the AAL type 2 Link Characteristics Modification Support Requestinformation relating to connection resource modification, shall discard that information.CS1 switches receiving the SSI Mod
40、ification Support Request information relating to connectionresource modification, shall pass on transparently this information.AAL type 2 Service Specific Convergence Sublayer for Narrowband ServicesThe information shall be passed on transparently through an AAL type 2 switch (both CS1 andCS2).6 Ar
41、chitecture of AAL type 2 SignallingFor the purpose of this Supplement the architecture in clause 6 of ITU-T Q-series Supplement 8 1apply.4 Q series Supplement 33 (12/2000)7 AAL type 2 Signalling FlowsThe following diagrams illustrate the modification of AAL type 2 connection resource (successfuland
42、unsuccessful).7.1 Successful AAL type 2 Connection Establishment Information FlowsT11112930-01A B123456RequestingAAL type 2End PointAAL type 2SwitchingNodeAAL type 2SwitchingNodeAddressedAAL type 2End PointFigure 1 Successful AAL type 2 ConnectionEstablishment Information FlowsThe flows illustrated
43、in Figure 1 are as follows:1 AAL type 2 Setup-Request.ready Requesting End Point to Switching NodeUser information Connection information Link informationAAL type 2 served user generatedreference = 1Served User Transport InformationP_SSI (optional)SSI Modification Support RequestSSIEnd Pt. Address =
44、 B,AAL type 2 LinkCharacteristicsAAL type 2 PreferredLink Characteristics(optional)AAL type 2 LinkCharacteristicsModification SupportRequestAAL type 2 Path TypeCID = 15,AAL type 2 PathIdentifier = 27Initiation of information flow: The requesting end point starts to establish an AAL type 2 networkcon
45、nection.Pocessing upon receipt: The switching node selects a route towards the addressed end point that canprovide enough resources to carry the AAL type 2 network connection to be established. It thenissues Information Flow 2.Q series Supplement 33 (12/2000) 52 AAL type 2 Setup-Request.ready Switch
46、ing Node to Switching NodeUser information Connection information Link informationAAL type 2 served user generatedreference = 1Served User Transport InformationP_SSI (optional)SSI Modification SupportRequestSSIEnd Pt. Address = B,AAL type 2 LinkCharacteristicsAAL type 2 Preferred LinkCharacteristics
47、 (optional)AAL type 2 LinkCharacteristics ModificationSupport RequestAAL type 2 Path TypeCID = 25,AAL type 2 PathIdentifier = 18Processing upon receipt: The switching node selects a route towards the addressed end point thatcan provide enough resources to carry the AAL type 2 network connection to b
48、e established. It thenissues Information Flow 3.3 AAL type 2 Setup-Request.ready Switching Node to Addressed End PointUser information Connection information Link informationAAL type 2 served user generatedreference = 1Served User Transport InformationP_SSI (optional)SSI Modification Support Request
49、SSIEnd Pt. Address = B,AAL type 2 LinkCharacteristicsAAL type 2 PreferredLink Characteristics(optional)AAL type 2 LinkCharacteristicsModification SupportRequestAAL type 2 Path TypeCID = 10,AAL type 2 PathIdentifier = 55Processing upon receipt: The addressed end point assures that enough resources in the end pointremain for the new AAL type 2 network connection. It then issues Information Flow 4 to confirm theestablishment. Finally, the AAL type 2 signalling served user is informed a
