1、CEPT T/TE*OB-Ub*E 9 2326434 0033797 92 TTE 08-06 Page E 1 Recommendation T/TE 08-06 (Copenhagen 1987, revised in Edinburgh 1988) HARMONIZATION OF SWITCHED ACCESS TO A PACKET SWITCHED PUBLIC DATA NETWORK (PSPDN) FOR OS1 END SYSTEMS Recommendation proposed by Working Group T WG 10 ”Terminal equipment
2、(TE) Text of the Recommendation adopted by the “Telecommunications” Commission : “The Conference of European Post and Telecommunications Administrations. considering - that E-uropean Packet Switched Data Xetworks are in service and their interconnection has been carried out. - that CCITT Recommendat
3、ions X.2 and X.25 as weil as IS0 Standards IS0 7776 and IS0 8208 provide a large - that CCITT Recommendation X.32 provides a number of options. - that a harmonization of DTEs and networks is needed in order to provide the OS1 Connection-mode Setwork - that networks may provide additional options for
4、 other applications (see Recommendation T CD 08-02), number of options, Service in an efficient way, recommends to the members of CEPT that this Functional Standard should be applied for OS1 End System implementation as a minimum subset of options to be provided. and that networks should implement t
5、he functions necessary to support these OS1 End Systems in line with Recommendation T CD 08-03.” Edition of February 28, 1989 CEPT T/TE*OB-Ob*E 87 i23F16454 0055778 729 W TITE 08-06 E Page 2 FUNCTIONAL STANDARD T/32 PACKET SWITCHED DATA NETWORK SWITCHED ACCESS - Part 1 OS1 Connection-mode Transport
6、Service over a Connection-mede Network Service that satisfies CCIT Recom- mendation T.70. - Part 2 Note. Other parts may be added to define other protocol combinations or options that are included in future revisions of M-IT-02. An example would be the addition of a part that defines End Systems tha
7、t operate Class 2 of the Transport protocol and do not operate any non-multiplexing Class of the Transport protocol. OS1 Connection-mode Transport Service over the OS1 Connection-mode Network Service. FOREWORD The concept and structure of Functional Standards for information systems interconnection
8、are laid down in the CEN/CENELEC/CEPT Memorandum M-IT-01. The purpose of a Functional Standard is to recommend when and how certain information technology standards should be used. This Functional Standard specifies telecommunication function T/32 as defined in the CEN/CENELEC/CEPT Memorandum M-IT-0
9、2. This Functional Standard is in two parts. Part 1 ilejines: - The provision of the network independent basic Transport Service. as 5pecified in CCITT Recommendation T.70 (1984), between an End System (“The Reference End System“) which uses a Switched Telephone or Data Circuit to access a Packet Sw
10、itched Data Network (PSDN) and another End System (The Compatible End System”) which is accessible, by permanent or switched methods, either directly from the same PSDN, or indirectly through the provided Network Service. - The provision of a Connection-mode Network Service provided by the X.25 Netw
11、ork Layer, Link Layer, and Physical Layer Procedures in T.70 (1984). Part 2 dejines: - The provision of the OS1 Connection-mode Transport Service between an End System (“The Reference End System”) which uses a Switched Telephone or Data Circuit to access a Packet Switched Data Network (PSDN) and ano
12、ther End System (“The Compatible End System”) which is accessible, by permanent or switched methods, either directly from the same PSDN, or indirectly through the provided OS1 Connection-mode Network Service. -The provision of the OS1 Connection-mode Network Service between the Reference End System
13、and the Compatible End System, using the X.25 subnetwork access procedures to a PSDN. Part 1 is applicable to environments which support the CCITT defined Telematic Services. Part 2 is applicable to environments which support the OS1 Network Service. Two options are defined. Implementa- tion of the
14、first option (Class O only) requires that the End System does not operate any of the multiplexing Classes (Classes 2, 3 or 4) of the Transport Protocol procedures. Such End Systems will only interwork with End Systems that also implement Class O Transport Protocol procedures. Implementation of the s
15、econd option (Classes O and 2) in an End System enables that End System to interwork with any End System conforming to either X.224 or IS0 8073. Parts 1 and 2 of this Functional Standard each specify a set of protocols to provide the function defined above. Part 1 and/or Part 2 do not specify total
16、End System capability. The requirements placed on an End System in Parts 1 and 2 of this Functional Standard are solely those necessary for operation of the protocol sets specified in Parts 1 and 2. BRIEF HISTORY This European Prestandard (ENV) wus drawn up by Working Group TE of CEPT as requested b
17、y the CEN/ CENELEC/CEPT Information Technology Steering Committee (ITSTC) on 1985-07-17. This ENV was adopted by CEN/CENELEC on the strength of its acceptance by the following member countries: Austria, Belgium, Denmark, Finland, France, Greece. Ireland, Italy. Portugal, Spain, Sweden and United Kin
18、gdom through a voting procedure by correspondence which ended on 1987-10-15. Further editorial improvements were made during a joint meeting with CEPT on 1988-01-14. Edition of February 28. 1989 CEPT T/TE*O-Ob*E 9 m 23261134 0033799 665 m 1 . 1 .o. 1.1. 1.2. 1.2.1. 1.2.2. 1.2.3. 1.3. 1.3.1. 1.3.2. 1
19、.3.3. 1.3.4. 1.3.5. 1.3.6. 1.4. 1.5. 1.5.1. 1.5.2. 1.6. 1.6.1. 1.6.2. 1.6.3. 1.6.4. 1.6.5. 1.6.6. 1.7. 1.7.1. 1.7.2. 1.7.3. 1.7.4. 1.7.5. 1.7.6. 1.7.7. 1.7.8. 1.7.9. 1.7.10. 1.8. 1.8.1. 1.8.2. 1.8.3. 1.8.4. 1.8.5. 1.8.6. 1.8.7. 1.9. 1.9.1. 1.9.2. 1.9.3. 1.9.4. 1.9.5. 1.10. 1.10.1. 1.10.2. 1.10.3. 1.
20、10.4. 1.11. 1.11.1. 1.11.2. 1.11.3. 1.11.4. 1.11.5. 1.11.6. 1.11.7. T/TE 08-06 E Page 3 Table of Contents PART1 6 Introduction 6 Scopeandfieldofapplication . 6 References . 6 General reference documents . 6 National network attachment specijcations . 6 Additional references 7 Definitions . 7 EndSyst
21、em 7 Functional Standard Option . 7 Connection-mode network service . 7 Data Circuit 7 Access Network 7 Accessed Network . 7 Abbreviations . 7 Scenario description and Model description . 8 Scenario description . 8 Model description 8 Conformity 8 Conformity principles 8 Conformity at Layer 4 . 9 Co
22、nformity at Lajqer 3 . 9 Conformity at Layer 2 . 10 Conformity at Layer I . 10 Conformity for X.32 dejned features . 10 Strategy for implementation . 10 Options to be used . 10 Recommended parameter values 10 Addressing . 10 Class negotiation 11 Quality of Service QOS) 11 Management of network conne
23、ctions Transport protocol identijcation . 11 Use of the network service 11 Protocol errors . 11 Layer 3 11 Strategy for implementation . 11 Establishment of the Circuit . 11 Relationships between Circuit and Packet Level . Packet Switched Optional User jcilities Addressing . 14 Quality of Service fQ
24、OS) 14 Details on the protocol . 14 Layer 2 14 Strategy for implementation . 14 Underlying transmission facilit? 14 Link level address assignment . Default parameter salues . 14 Use of XID frame . 14 Layer4 10 11 11 11 14 Layer 1 Strategy for implementation . Physical interface Data Signalling Rates
25、 End System identijcation method . Connectors . X.32 defined features Accessed Net work iden t ijca t ion nie th od Services X.32 optional user facilities . X.32 parameters Dial mode . Security grade 2 method . 15 15 15 15 15 15 15 15 16 16 16 16 16 Edition of February 28. 1989 CEPT T/TE*O-Ob*E 89 2
26、32b414 0051t300 507 T/TE 08-06 E Page 4 2 . PART2 11 2.0. Introduction 11 2.1. Scope and field of application . 17 2.2. References . 17 2.2.1. General reference rlocunienrs . 17 2.2.2. Nutionti1 network attachnient spec$cution.s . 18 2.2.3. Adlitioncil rejkrences 18 2.3. Definitions . 18 2.3.1. End
27、System 18 2.3.2. Firnctional Standnrd Option . 18 2.3.3. Datu Circuir 18 2.3.4. Access Network 18 2.3.5. Accessctl Network . 19 2.4. Abbreviations . 19 2.5. Scenario description and Model description . 19 2.5.1. Scenario description . 19 2.5.2. Model description 19 2.6. Conformity 20 2.6.1. Conformi
28、ty principles 20 2.6.2. Conforniity UI Luyer 4 . 20 2.6.3. Conformity at Layer 3 . 20 2.6.4. Conformity at Layer 2 . 21 2.6.5. Conforidly ut Layer 1 . 21 2.6.6. Coriforiwlyfr X.32 deJined.fkutiire.s . 21 2.1. Layer4 22 2.1.1. Stroregy for impl?ienttitioIi . 22 2.1.3. Recontmended parameter vuluw 22
29、2.1.4. Addressing . 22 2.1.5. Cluxs negotittion 23 2.1.6. Quality of Scrcice (QOS) 23 2.1.1. Mantigenient of network connections 23 2.1.8. Trunsporl protocol idetitiJiculion . 23 2.7.9. Use of the network service 23 2.1.10. Protocol errors . 23 2.8. Layer3 23 2.8.1. Strategy for iizleniaites no qes
30、no ( 2) yes no (2) yes no (2) !es no (1) les no (1) )es no (1) es no (1) yes no (1) ves no 1.6.2. 1.6.2.1. 1.6.2.2. 1.6.3. 1.6.3.1. The claim of conformity shall indicate that the End System conforms to Part 1 of this Functional Standard. A claim of conformity to this part of the Functional Standard
31、 is a claim that all requirements in the body of this part of the Functional Standard are satisfied. For each layer, the claim of conformity shall indicate: - the supported options defined in this part of the Functional Standard. - the general conformity requirements related to the base standards. C
32、onformity at Layer 4 Options related to this part of the Functional Standard The End System claiming conformity to this part of the Functional Standard shall state which Transport Protocol Identification procedure is supported according to 1.7.8.: Option FSO PID X or FSO PID T. General conformity re
33、quirements An End System claiming conformity to this part of the Functional Standard shall state: - whether it is capable of initiating or responding to CR TPDUs or both; - the maximum TPDU size implemented. Conformity at Layer 3 Options related to this part of the Functional Standard The claim of c
34、onformity shall indicate the implemented circuit switched optional user facilities among those qualified “local choice“ in Table 1.4 (T TE 08-06) of section 1.8 (see Table 1.1 (T TE 08-06). Table 1.1 (T TE 08-06). facilities. Note 1. Optional user facility related to interworking capabilitq. Nute 2.
35、 Optional user facility related to performance. The claim of conformity shall indicate the implemented packet switched optional user facilities among those qualified “local choice“ in Table 1.5 (T TE 08-06) of section 1.8 (see Table 1.2 (T TE 08-06). Example for a conformity statement related to cir
36、cuit snitched optional user Identified or non-Identified - - qes no es no yes no yes no - yes no - Customized es no es no qes no qes no es no es no Table 1.2 (TTE 08-06). facilities. iVote 1. Optional user facility related to interworking capabilitq Nute 2. Optional user facilit! related to performa
37、nce. Example for a conformity statement related to packet switched optional user Edition of February 28. i989 CEPT T/TE*ti-b*E 9 232bliliY 05lib b25 T/TE 08-06 E Page 1 O 1.6.3.2. 1.6.4. 1.6.4.1. 1.6.4.2. 1.6.5. 1.6.5.1. 1.6.6. 1.6.6.1. 1.7. 1.7.1. 1.7.2. 1.7.3. 1.7.4. General conformity requirement
38、s An End System claiming conformity to this part of the Functional Standard shall state: - the packet size(s) implemented; - the window size( implemented; - whether it is capable of initiating or accepting network connections or both. Conforttiity at Laper 2 Options related to this part of the Funct
39、ional Standard An End System conforming to this part of the Functional Standard shall state: - whether the T.70, X.25 or both of these methods for link level address assignment are supported; - whether the underlying transmission facility is duplex, half-duplex. or both; - if the FSO XID frame is su
40、pported. General conformity requirements An End System claiming conformity to this part of the Functional Standard shall state: - the supported value of parameter NI (maximum frame length). Conforiziity at Layer 1 Options related to this part of the Functional Standard The claim of conformity shall
41、indicate: - which physical interfidce(s) is (are) supported section 1.10.2.); - which data signalling rate(s is (are) supported (section 1.10.3.); - which connector(s) is (are) supported (section 1.10.4.). Coilforniity far lie X.32 iqnei.fiaturcs Options related to this part of the Functional Standa
42、rd An End System claiming conformity to this part of the Functional Standard shall indicate: whether identification is provided and if so which methodh) is (are) supported (see Table 1.3 - whether FSO Grade 2 Method option is supported. and if so which algorithm(s) is (are) supported; - whether dial
43、-out-by-the-PSDN option is supported. (T/TE 08-06); I 1 Methad B (XID) implemented I See section 1.9. I yeC:no I Method C (NUI) implemented I Se section 1.8. Table 1.3 (T/TE 08-06). Example for a conformity statement related to identification. Layer 4 Slrategy jhr inplermwtution The transport servic
44、e provided is as described in IS0 89721 and X.214. The transport protocol procedures shall be as described in IS0 80731 and X.224. According to T.70, only transport Clas 8 procedures shall be implemented. Options to he irsed Options as specified in IS0 80731. No options. Reconintendcd parmetcr salir
45、w - TS 1 timer: 60 seconds, - TS 2 timer: 60 seconds. Note. Parameters should be tunable. and timers should be capable of taking values of the abovc order of magnitude, which may be considered as typical for working over u public PSDN. Addressiig Note. Further detailed study is required and details
46、will be provided in u separate document. Flexibility is recommended in implementation to allow for future developments. End Systems conforming to this part of the Functional Standard may use Transport Selectors for identifica- tion of their TSAPs. End Systems shall be capable of transmitting and rec
47、eiving TSAP-ID fields of variable size up to 32 octets. The encoding shall be as described in p.70 section 5.5.4.2. O Edition of February 28, 1989 CEPT T/TE*OB-Ob*E 89 2326434 0031807 562 1.7.5. 1.7.6. 1.7.7. 1.7.8. 1.7.9. 1.7.10. 1.8. 1.8.1. 1.8.2. 1.8.3. 1.8.4. T/TE 08-06 E Page 11 Class negotiati
48、on Class negotiation takes place as defined in T.70. To conform with the rules described in IS0 80731, an End System should accept the Transport Connection only if Class O is proposed as the preferred or the alternative class in the CR TPDU. Note. An End System receiving user data in a CR TPDU may r
49、espond either: - with a CC TPDU indicating Class O. the user data being ignored: - or by a connection refusal. Quality of Service QOS) The use of QOS does not imply or guarantee that the agreed QOS will be provided in all cases. No QOS parameters are required to be signalled in CR TPDCs and CC TPDUs in this part of the Functional Standard. Received QOS parameters must therefore be ignored if not supported. Note. Information related to Quality of Service from the Transport Service user may be used within an End System by a trans
