1、)45G134 8 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU05“,)#G0G0$!4!G0G0.%47/2+3.%47/2+G0G0!30%#43#!,G0G002/#%33).G0G0$%,!93G0G0).05“,)#G0G0$!4!G0G0.%7/2+37(%.G0G002/6)$).G0G0).4%2.!4)/.!,39.#(2/./53G0G0#)2#5)4G1337)4#(%$!4!G0G03%26)#%3)45G134G0G0RecommendationG0G08 (Extract from the “LUEG0“OOK)INT
2、ERNATIONAL TELECOMMUNICATION UNIONNOTES1 ITU-T Recommendation X.130 was published in Fascicle VIII.3 of the Blue Book. This file is an extract fromthe Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identica
3、l to the Blue Book version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this
4、publication may be reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle VIII.3 - Rec. X.130 1Recommendation X.130Fascicle VIII.3 - Rec. X.130CALL PROCESSING DELAYS IN PUBLIC DATA NETWORK
5、S WHEN PROVIDINGINTERNATIONAL SYNCHRONOUS CIRCUIT-SWITCHED DATA SERVICES(Geneva, 1980; amended at Malaga-Torremolinos, 1984)The CCITT,considering(a) that Recommendation X.1 specifies the user classes of service applicable to networks offering public dataservices;(b) that Recommendation X.2 specifies
6、 the international user services and facilities to be offered by publicdata networks;(c) that Recommendations X.21 and X.21 bis define the DTE/DCE interface for circuit switched services;(d) that Recommendation X.60 specifies the common channel signalling for synchronous data networks;(e) that Recom
7、mendation X.71 specifies the channel associated signalling for synchronous data networks;(f) that Recommendation X.92 specifies the hypothetical reference connections for public data networks;(g) that Recommendation X.110 specifies the routing plan to be applied in the international portions of publ
8、icdata networks;(h) that Recommendation X.213 specifies the OSI Network Layer service;(i) that Recommendation X.140 specifies the user-oriented quality of service parameters applicable to dataservices,unanimously declaresthat when public data networks provide international synchronous circuit-switch
9、ed data services according toRecommendations X.21 and X.21 bis, the values of call processing delays specified in this Recommendation shall betaken as provisional worst-case values that should not be exceeded under the conditions specified therein.Introductory note - Design objectives that take into
10、 account both user needs and network costs are for furtherstudy.1 Introduction1.1 Quality of service in circuit-switched public data networks has been considered in five basic areas as follows:i) call processing delays (Recommendation X.130);ii) failures due to congestion (blocking) (Recommendation
11、X.131);iii) failures due to malfunction;iv) loss of service; andv) transmission performance (including throughput).This Recommendation specifies the objectives for i) above. Each of the other areas of circuit-switching qualityof service identified above will be the subject of a separate Recommendati
12、on in the X-series.1.2 In telecommunication networks it is necessary, for economic reasons, to limit the resources provided forcarrying the offered traffic. This limitation may affect the quality of service to the user of circuit-switched services intwo different ways: by call processing delays and
13、by blocking. Both of these aspects, that are consequences of the finite2 Fascicle VIII.3 - Rec. X.130traffic handling capacity of the network, constitute the grade of service. Grade of service together with malfunction, lossof service and transmission performance constitute the quality of service.1.
14、3 In this Recommendation the values for the network delay are quoted for two types of connection according toRecommendation X.92 as follows:Type 1: Typical terrestrial international connection of moderate length with no satellite circuits either in thenational or international portions (Internationa
15、l portion: 1000 km).Type 2: Long distance international connection with a satellite circuit in one national portion and two satellitecircuits in the international portion (International portion: 160 000 km).Where appropriate, values are also specified separately for the following network portions:-
16、originating national network,- international portion,- destination national network.The boundaries for these portions are shown in Figure 1/X.130.For the present, the values apply also to other normal routing options within the international portion.Following the allocation of a delay allowance to t
17、he international portion of an international transit connection,it will be necessary to further apportion the allowance to individual transit networks and/or their component parts withinthe international portion. The means by which useful and realistic constraints can be applied, consistent with mai
18、ntainingthe maximum possible freedom for each involved Administration in the design and implementation of its own network,is for further study.1.4 The values for call processing delays established in this Recommendation are to be considered as designobjectives in network planning together with the f
19、orecast traffic for the planned period. The actual delay performancethat will be obtained will depend on the accuracy of the traffic estimations. Normally, the actual delay performance willnot coincide with the one used as a basis for planning. Furthermore, if the network is planned for the traffic
20、forecast atthe end of the period considered, the actual delay performance of the network may be better than the design value,worsening gradually to the end of the planning period as traffic increases.The non-coincidence of busy hours in originating and destination national networks as well as in the
21、international network will improve the overall delay performance with respect to the sum of the nominal delays of theconstituent parts of the connection.1.5 Delays are specified under conditions of normal busy hour load and are expressed where appropriate in termsof mean and 95% probability values.
22、The term “mean“ is taken to be the expected value of delay in the statistical sense.The “95% probability“ value is taken as the limit within which 95% of the delays fall. Delays at higher loadings are forfurther study.Fascicle VIII.3 - Rec. X.130 31.6 Call processing delays are defined for a basic c
23、all which does not include any optional user facilities, e.g. thosedefined in Recommendation X.21.1.7 Where appropriate, separate limits are quoted for common channel signalling and channel associatedsignalling between DSEs.For common channel signalling, the values given in this Recommendation are a
24、lso applicable to lowersignalling rates (less than 4800 bit/s), when the associated mode of operation is used.1.8 The quality of service implications of regional or national satellite systems using demand assignment forresource allocation require further study.2 Call connection delaySee Annex A for
25、an explanation of the delay elements t1 to t6.2.1 Total call connection delay (TCCD)The total call connection delay (TCCD) is the time interval between the transmission of the call requestsignal and receipt of the ready for data signal by the calling DTE. A full explanation of the elements of TCCD i
26、scontained in Annex A. Objectives for the network-dependent components of TCCD are provided below.2.2 Call request delay (t1)Call request delay is considered to be a national matter and consequently the specification of its value is notappropriate to this Recommendation.2.3 Overall network post sele
27、ction delayOverall network post selection delay is the sum of t3 and t5. It should not exceed the values given in Tables1/X.130 and 2/X.130.If on any call the overall network post selection delay exceeds X seconds, the call will be considered forquality of service purposes to have failed. The precis
28、e value of X is for further study but it should be at least 30 seconds.2.4 Network portion post selection delays (t3 + t5)The contribution from each network portion to the overall network post selection delay should not exceed thevalues given in Tables 3/X.130 and 4/X.130.2.5 Ready for data delay (t
29、6)The need for specification of this parameter is for further study.3 Call clearing delays3.1 Clear request delay (CLRD)Clear request delay (CLRD) is the delay between transmission of a clear request signal and receipt of theDCE ready signal by the clearing DTE. Clear request delay is considered to
30、be a national matter and consequently thespecification of its value is not appropriate to this Recommendation.4 Fascicle VIII.3 - Rec. X.130TABLE 1/X.130Overall network post selection delay for common-channel signallingNote - See introductory note to this Recommendation.Delay (ms)User rate(bit/s)Sta
31、tistic Connection type12600 Mean 1800 350095% 2700 44002400 Mean 1500 320095% 2200 39004800 Mean 1300 300095% 1900 36009600 Mean 1300 300095% 1900 360048000 Mean 1300 300095% 1900 3600Fascicle VIII.3 - Rec. X.130 5TABLE 2/X.130Overall network post selection delay for channel-associated signallingNot
32、e - See introductory note to this Recommendation.Delay (ms)User rate(bit/s)Statistic Connection type12600 Mean 2200 400095% 3300 51002400 Mean 1800 360095% 2700 45004800 Mean 1700 350095% 2500 44009600 Mean 1600 340095% 2400 420048000 Mean 1500 330095% 2200 41006 Fascicle VIII.3 - Rec. X.130TABLE 3/
33、X.130Contributions to network post selection delays for common-channel signallingNote - See introductory note to this Recommendation.Originating nationalportion(ms)Destination nationalportion(ms)International portion (ms)User rate(bit/s)Statistic Number of satellites Number of satellites Connection
34、type010112600 Mean 700 1200 800 1300 300 150095% 1100 1600 1200 1800 500 17002400 Mean 600 1100 700 1200 200 140095% 900 1500 1100 1600 300 16004800 Mean 500 1000 600 1100 200 140095% 800 1300 900 1500 300 16009600 Mean 500 1000 600 1100 200 140095% 800 1300 900 1500 300 160048000 Mean 500 1000 600
35、1100 200 140095% 800 1300 900 1500 300 1600Fascicle VIII.3 - Rec. X.130 7TABLE 4/X.130Contributions to network post selection delays for channel-associated signallingNote - See introductory note to this Recommendation.Originating nationalportion(ms)Destination nationalportion(ms)International portio
36、n (ms)User rate(bit/s)Statistic Number of satellites Number of satellites Connection type010112600 Mean 800 1300 1000 1500 400 170095% 1200 1800 1500 2100 600 20002400 Mean 700 1200 800 1300 300 160095% 1100 1600 1200 1800 500 19004800 Mean 600 1100 800 1300 300 160095% 900 1500 1200 1800 500 190096
37、00 Mean 600 1100 700 1200 300 160095% 900 1500 1100 1600 500 190048000 Mean 600 1100 700 1200 200 150095% 900 1500 1100 1600 400 17008 Fascicle VIII.3 - Rec. X.1303.2 Network clear indication delay (NCID)Network clear indication delay (NCID) is the delay between transmission of a clear request signa
38、l by theclearing DTE and the receipt of the DCE clear indication signal by the cleared DTE. It should not exceed the valuesgiven in Tables 5/X.130 and 6/X.130.If on any call the overall network clear indication delay exceeds Y seconds the call will be considered forquality of service purposes to hav
39、e failed. The precise value of Y is for further study but it should be at least 30 seconds.TABLE 5/X.130Overall network clear indication delay for common-channel signallingNote - See introductory note to this Recommendation.Delay (ms)User rate(bit/s)Statistic Connection type12600 Mean 900 190095% 13
40、00 24002400 Mean 700 170095% 1100 21004800 Mean 600 160095% 900 19009600 Mean 600 160095% 900 190048000 Mean 600 160095% 900 1900Fascicle VIII.3 - Rec. X.130 9TABLE 6/X.130Overall network clear indication delay for channel-associated signallingNote - See introductory note to this RecommendationDelay
41、 (ms)User rate(bit/s)Statistic Connection type12600 Mean 1100 210095% 1600 27002400 Mean 900 190095% 1300 24004800 Mean 800 180095% 1200 23009600 Mean 800 180095% 1200 230048000 Mean 800 180095% 1200 230010 Fascicle VIII.3 - Rec. X.1303.3 Network portion clear indication delay (NPCID)The contributio
42、n from each network portion to the overall network clear indication delay should not exceed thevalues given in Tables 7/X.130 and 8/X.130.TABLE 7/X.130Contributions to network clear indication delay for common-channel signallingNote - See introductory note to this RecommendationOriginating nationalp
43、ortion(ms)Destination nationalportion(ms)International portion (ms)User rate(bit/s)Statistic Number of satellites Number of satellites Connection type010112600 Mean 300 600 400 700 200 90095% 500 800 600 900 300 11002400 Mean 200 500 300 600 200 90095% 300 600 500 800 300 11004800 Mean 200 500 300 6
44、00 100 80095% 300 600 500 800 200 9009600 Mean 200 500 300 600 100 80095% 300 600 500 800 200 90048000 Mean 200 500 300 600 100 80095% 300 600 500 800 200 900Fascicle VIII.3 - Rec. X.130 11TABLE 8/X.130Contributions to network clear indication delay for channel-associated signallingNote - See introd
45、uctory note to this Recommendation.Originating nationalportion(ms)Destination nationalportion(ms)International portion (ms)User rate(bit/s)Statistic Number of satellites Number of satellites Connection type010112600 Mean 400 700 500 800 200 90095 % 600 900 800 1100 300 11002400 Mean 300 600 400 700
46、200 90095 % 500 800 600 900 300 11004800 Mean 300 600 300 600 200 90095 % 500 800 500 800 300 11009600 Mean 300 600 300 600 200 90095 % 500 800 500 800 300 110048000 Mean 300 600 300 600 200 90095 % 500 800 500 800 300 110012 Fascicle VIII.3 - Rec. X.1303.4 Clear confirmation delay (CLCD)Clear confi
47、rmation delay (CLCD) is the delay between transmission of a DTE clear confirmation signal andreceipt of a DCE ready signal by the cleared DTE. Clear confirmation delay is considered to be a national matter andconsequently the specification of its value is not appropriate to this Recommendation.ANNEX
48、 A(to Recommendation X.130)A.1 Total call connection delay (TCCD) elementsThe total call connection delay is the sum of the following elements (see Figure A- I /X. 1 30):t1: delay between transmission of the call request signal and receipt of the proceed to select signal by thecalling DTE.t2: time b
49、etween receipt of the proceed to select signal and transmission of the end of selection signal by thecalling DTE.t3: delay between transmission of the end of selection signal by the calling DTE and receipt of the incomingcall signal by the called DTE.t4: delay between receipt of the incoming call signal and transmission of the call accepted signal by the calledDTE.and if t5 t6,t5: delay between transmission of the call accepted signal by the called DTE and receipt of the ready for datasignal by the calling DTE.or if t5 t6,t6: delay between transmission of the call accepted signal and re
