1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 8 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU05“,)#G0G0$!4!G0G0.%47/2+3!$-).)342!4)6%G0G0!22!.%-%.43!$-).)342!4)6%G0G0!22!.%-%.43G0G0 amended at Melbourne, 1988)The CCITT,considering(a) that the permanent virtual circuit service is listed in Recommendat
2、ion X.2;(b) that the permanent virtual circuit service may not be available for all international connections and may notbe available for the maritime mobile services (as noted in Recommendation X.2);(c) that the international application of the permanent virtual circuit service depends on bilateral
3、 agreement (asnoted in Recommendation X.2);(d) that Recommendation X.25 defines the DTE/DCE interface characteristics and Recommendation X.75defines the procedures for international circuits between two STEs;(e) that there is a need to standardize administrative procedures for the exchange of inform
4、ation characterizingthe international permanent virtual circuit among Administrations concerned, in order to establish the internationalpermanent virtual circuit,unanimously recommends the following1 One of the two subscribers to be connected by the international PVC (hereafter called the “responsib
5、lesubscriber“) shall clearly be allocated the responsibility for all organizational matters relating to an international PVC.The responsible subscriber shall be nominated by the subscribers to be connected by the international PVC (see Note 1).2 The Administration of country housing this “responsibl
6、e subscriber“ (hereafter called the “sourceAdministration“) shall act as the controlling and coordinating Administration for that international PVC and shall carryout the discussions with the responsible subscriber about any changes to the international PVC.3 The source Administration will normally
7、gather information required for charging and accounting for theinternational PVC (see Note 2).4 The exchange of information for the provision of international PVCs will be as follows:4.1 Source Administration and destination Administration (the Administration housing the non-responsiblesubscriber) w
8、ill need to exchange information for the provision of the international PVC. This information shouldinclude:a) international numbers of both subscriber DTEs,b) throughput class (both directions),c) name of the international PVC (see Note 3),d) proposal on routing,e) quality of service parameters (se
9、e Note 4),f) service inauguration date and lifetime of the international PVC.4.2 If transit networks must be involved, the route should be agreed on among Administrations involved. For theefficiency of negotiation among Administrations, the source Administration may initiate the negotiation with its
10、 adjacentAdministration after which negotiation between subsequent Administrations follows, until the destination Administrationhas been reached. The information described in 4.1 should be conveyed to each transit Administration, and the routeshould be determined satisfying the requested throughput
11、classes and quality of service (see Note 4).2 Fascicle VIII.3 - Rec. X.1814.3 Between adjacent Administrations, information to be exchanged should include the following items in additionto the information described in 4.1:a) the identity of STE X/Y interface,b) logical channel group number and logic
12、al channel number,c) window size (both directions),d) packet size (both directions).5 The following procedures should apply for the interchange of information between Administrations andsubscribers of an international PVC. Where a subscriber has subscribed to more than one international PVC, theproc
13、edures in this Recommendation must be applied separately for each international PVC.5.1 A subscriber applying for the provision of an international PVC shall apply to his own Administration usingstandard application procedures. He should supply full details of the responsible subscriber.5.2 The Admi
14、nistration should, in case the request did not come from the responsible subscriber, pass details in astandard format to the source Administration as indicated in Annex A.5.3 The source Administration will then verify with the responsible subscriber whether the application can bepermitted.5.4 The so
15、urce Administration will then negotiate with the destination Administration and possibly transitAdministrations whether the application can be permitted, taking into account 4.5.5 If the conditions in 5.3 and 5.4 are accepted, the source Administration will agree with the subscriber on thelogical ch
16、annel group number and logical channel number to which the international PVC will be connected. Thedestination Administration will do so with the other subscriber.5.6 The source Administration will inform both subscribers involved when the international PVC is established.5.7 If, during the lifetime
17、 of the international PVC, rerouting of the international PVC is necessary, the responsiblesubscriber will be informed by the source Administration of any changes of either charging or quality of service of theinternational PVC (see Note 5).Note 1 - It is assumed that the responsible subscriber is o
18、ne of the two subscribers to be connected by theinternational PVC.Note 2 - Other arrangements are possible on a bilateral basis.Note 3 - A name of an international PVC should be unique among the Administrations involved, (e.g., thespecification of the international number, the logical channel group
19、number and the logical channel number to which theinternational PVC is connected for both subscribers).Note 4 - The parameters concerning quality of service are for further study.Note 5 - The impact of a possible inclusion of an automatic (re)establishment procedure is for further study.Fascicle VII
20、I.3 - Rec. X.181 3ANNEX A(to Recommendation X.181)The format and information to be passed to the source Administration following an application from asubscriber for the provision of an international PVC is as follows:1 Application for the establishment of an international permanent virtual circuit (
21、PVC) via several publicnetworks has been received from:FirmAddressCountryInternational numberDate of application2 The applicant as indicated in 1) above requests to be connected via an international PVC with:FirmAddressCountryInternational number3 The responsible subscribers international data number:4 The following is requested:- throughput class,- service inauguration date,- requested lifetime of the international PVC.
