1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 8 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU).4%27/2+).G0G0“%47%.G0G0.%47/2+3%.%2!,%.%2!,G0G0!22!.%-%.43G0G0(b) that Recommendation X.301 defines the general arrangements for call control within a subnetwork andbetween subnetworks for the provision of
2、data transmission services;(c) that Recommendation X.302 defines the general arrangements for internal network utilities within asubnetwork and between subnetworks for the provision of data transmission services;(d) that Recommendation X.75 specifies packet switching signalling system between public
3、 networksproviding data transmission services;(e) that Recommendation X.10 describes categories of access to PSPDNs and ISDNs for the provision of datatransmission services;(f) that Recommendation X.213 describes the network service definition for open systems interconnection forCCITT applications;(
4、g) that Recommendation X.305 describes functionalities of subnetworks relating to the support of the OSInetwork service,(h) the need for arrangements when interworking between ISDNs and PSPDNs for the provision of datatransmission services,unanimously recommendsthat arrangements for the interworking
5、 between PSPDNs for the provision of data transmission services be inaccordance with the principles and arrangements specified in this Recommendation.CONTENTS0 Introduction1 Scope and field of application2 References3 Definitions4 Abbreviations5 General aspects6 Specific interworking arrangements2 F
6、ascicle VIII.6 - Rec. X.3230 IntroductionThis Recommendation is one of a set of Recommendations produced to facilitate considerations of interworkingbetween networks. It is based on Recommendation X.300 which defines the general principles for interworking betweenpublic data networks and between pub
7、lic data networks and other networks. Recommendation X.300 indicates inparticular how collections of physical equipment can be represented as “subnetworks“ for consideration in interworkingsituations.This Recommendation describes the interworking arrangements between PSPDNs for the provision of data
8、transmission services. These interworking arrangements should include all the capabilities required to support thenetwork service for open systems interconnection for CCITT applications as described in Recommendation X.213.1 Scope and field of applicationThe purpose of this Recommendation is to desc
9、ribe the general arrangements for interworking between PSPDNsfor the provision of data transmission services. These arrangements are applicable only to the interworking involvingtransmission capabilities, and not to interworking involving communication capabilities as described inRecommendation X.30
10、0.2 References1 Recommendation X.3002 Recommendation X.3013 Recommendation X.3024 Recommendation X.3055 Recommendation X.316 Recommendation X.757 Recommendation X.18 Recommendation X.29 Recommendation X.1010 Recommendation I.21111 Recommendation I.50012 Recommendation X.12113 Recommendation E.1643 D
11、efinitionsThis Recommendation makes use of the following terms defined in Recommendation X.300:a) transmission capability,b) communication capability,c) subnetwork functionality,d) data transmission service.Fascicle VIII.6 - Rec. X.323 34 AbbreviationsCNIC Clearing Network Identification CodeCUG Clo
12、sed User GroupCUG/OA CUG with outgoing accessDTE Data Terminal EquipmentIWF Interworking FunctionPSPDN Packet Switched Public Data NetworkTNIC Transit Network Identification Code5 General aspectsThis Recommendation, in describing arrangements between two subnetworks for the provision of datatransmis
13、sion services, adheres to the general principles of Recommendation X.300. The environments of these twosubnetworks are described in the following sections.5.1 PSPDNThe PSPDN provides packet-switched data transmission services as defined in Recommendations X.1 and X.2for the provision of data transmi
14、ssion services. The PSPDN may be accessed by DTEs by the categories of access C andD as defined in Recommendation X.10.5.2 Call control between the PSPDNsThe general arrangements for call control between the PSPDNs are as defined in Recommendation X.301.Network utilities used between the PSPDNs are
15、as defined in Recommendation X.302 (not visible for users).6 Specific interworking arrangements6.1 Interworking between PSPDNsThe detailed procedures for interworking are defined in Recommendation X.75. In particular, the followingapplies:6.1.1 Transfer of addressing informationThe considerations on
16、 the transfer of addressing information as described in Recommendation X.301 mayapply.6.1.2 Arrangements for facilities related to the QOS of the callThese arrangements are described in Recommendation X.301.6.1.3 Arrangements for facilities related to protection mechanisms requested by the user of a callThese arrangements are described in Recommendation X.301.6.1.4 Arrangements for internal network utilities (not visible for users)These arrangements are as described in Recommendation X.302.
