1、ITU-T RECMN*F-BL3 95 4Bb259L Ob00309 217 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU OPERATIONS AND QUALITY OF SERVICE ISDN SERVICES F.813 (02/95) VIRTUAL PATH SERVICE FOR RESERVED AND PERMANENT COMMUNICATIONS ITU-T Recommendation F.813 (Previously “CC
2、ITT Recommendation”) ITU-T RECMN%F-B13 75 4862571 0600310 T39 FOREWORD The IT-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- da
3、tions on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. T
4、he approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC ResolutionNo. 1 (Helsinki, March 1-12, 1993). -T Recommendation F.813 was prepared by ITU-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 21st of Feb
5、ruary 1995. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1995 Ali rights reserved. No part of this publication may be reproduced or utilized in any form or by any mean
6、s, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECMN*F*813 95 = 4862591 Ob003L1 975 W CONTENTS 1 Definition . 2 Description . 2.1 General description . 2.2 Specific terminology . 2.3 Abbreviations 3 Procedures 3.1 Provision and wi
7、thdrawal . 3.2 Normal procedures 3.3 Exceptional procedures . 4 Interworking possibilities . Annex A - Attributes and values . A . 1 A.2 A.3 A.4 AS A.6 A.1 A . 8 A.9 A.10 A.ll A . 12 A . 13 Information transfer mode Information transfer rate . Information transfer capability of VP . Structure of Vps
8、 Establishment of communication Symmetry of W . Communication configuration Access protocols . QOS of Vps interworking possibilities . Operational and commercial aspects Access channels and rates . Supplementary services provided . Annex B . Normative references Annex C - Reference configuration Rec
9、ommendation F.813 (02/95) Page 1 1 1 2 3 3 3 6 10 10 10 10 11 11 11 11 11 11 11 11 12 12 12 12 12 13 i ITU-T RECMN*F.833 95 4862573 Ob00332 801 SUMMARY This Recommendation defines stage one of the broadband virtual path service for reserved and permanent communications (BVPS) for the public broadban
10、d integrated services digital network (B-ISDN). This Recommendation does not specify the additional requirements where the service is provided to the user via a telecommunication network that is not the B-ISDN, but does not preclude requirements for interworking between other networks and the B-ISDN
11、. The BVPS allows the transfer of unrestricted information between user-to-network reference points (UNRps). u Recommendation F.813 (02/95) Recommendation F.813 VIRTUAL PATH SERVICE FOR RESERVED AND PERMANENT COMMUNICATIONS (Geneva, 1994) 1 Definition According to Recommendation 1.130 4 , this Recom
12、mendation defines stage one of the Broadband Virtual Path Service for reserved and permanent communications (BVPS) for the public Broadband Integrated Services Digital Network (B- ISDN). The BVPS allows the transfer of unrestricted information between User-to-Network Reference Points (UNRPs). In the
13、 B-ISDN, the UNRP is TB. It does not preclude the applicability of the BVPS to S,. The establishment of communication is either reserved or permanent. The provision of the BVPS is based on ATM Vimial Path (VP) connections in the B-ISDN (see Recommenda- tion 1.340 lo. This Recommendation applies to s
14、tage two and stage three -T Recommendations (see Recommendation 1.130 4 for the BVPS. Charging Principles are outside the scope of this Recommendation, but could be contained in the appropriate IT-T Recommendation(s). 2 Description 2.1 General description The BVPS permits communication in both direc
15、tions between two users in a point-to-point configuration. The provision of the BVPS is based on VP connections in the B-ISDN. Several VPs can be multiplexed at a specific UNI (up to 256 VP can be allocated at the UNI of the B-ISDN according to Recommendation 1.361 121). The physical bit rate at the
16、 UNRP is defined by the existing UNIS according to Recommendation 1.432 141. The parameter Peak Cell Rate (PCR) is associated with each VP. A communication can be established in two different modes: either permanent or reserved (for non-periodic and periodic use). In permanent establishment of commu
17、nication, the subscriber can negotiate with the Service Provider (SP) any value of the PCR that is available at the UNRP and agreed by the SP. In reserved establishment of communication, the subscriber can negotiate with the SP any value of the maximum bandwidth that is available at the UNI and agre
18、ed by the SP. Then, the manager can negotiate with the Service Management Entity (SME) any available value of the PCR within the subscribed maximum bandwidth. The SP shaii enforce user cells according to the Peak Cell Rate (PCR) reference algorithm specified in Recommendation 1.371 13. According to
19、the PCR reference algorithm in RecommendationI.371 13, the cell conformance is defined with reference to the pair (T, z) where T is the Peak Emission interval (PEI) and z is the Ceil Delay Variation (CDV) tolerance. The SP shall provide the user the values of PEI and CDV tolerance that are part of t
20、he traffic contract. User information transfer is unresmcted. It is structured in ATM cells. The cell format is of the User-to-Network Interface (UNI) type as defined in 2.2A.361 12. The bit rate of the source can be CBR or VBR. The effective availability of the constant value of PCR (greater than z
21、ero) for a VP corresponds to a time slot as defined within this Recommendation. Recommendation F.813 (02/95) 1 ITU-T RECMN*F.B13 95 4862571 0600314 684 In permanent establishment of communication, periodic or non-periodic VPs are possible. A permanent VP, either periodic or non-periodic, is subscrib
22、ed providing all the parameters necessary for its establishment. A permanent VP is registered at subscription. in reserved establishment of communication, periodic or non-periodic VPs are possible. The subscriber subscribes to the BVPS in reserved establishment of communication providing general ser
23、vice parameters (see 3.1.3), e.g. listing only the users involved in the use of the BVPS and the maximum number of VPs that can be established among these users in any configuration at the same time. Every reserved VP, either periodic or non-periodic, is established after a registration procedure. D
24、uring this phase the parameters of the VP between the two involved users are negotiated. 2.2 Specific terminology For the purpose of this Recommendation, the following definitions apply: 2.2.1 integrated services digital network: See 2.3h.112 2, definition 308. 2.2.2 broadband: See 2.1fl.113 3, defi
25、nition 101. 2.2.3 service, telecommunication service: See 2.2fl.112 2, definition 201. 2.2.4 asynchronous transfer mode: See 2.2fl.113 3, definition 204. 22.5 virtual channel: See 4h.113 3, definition 401. 2.2.6 virtual channel identifier: A number that identifies locally a specific Virtual Channel
26、(VC) at a UNI. 2.2.7 bidirectional transport of ATM cells belonging to VCs that are associated by a common VPI. virtual path: From the users point of view, a virtual end-to-end connection that ensures unidirectional or 22.8 virtual path identifier: A number that identifies locally a specific VP at a
27、 UM. 2.2.9 the Service Management Entity (SME) for the management of the complete VP. global virtual path identifier: The Global Virtual Path Identifier (GVPI) identifies a specific VP. It is used by 2.2.10 modification requests and interrogation requests are addressed (see Figure C.1). service mana
28、gement entity: The functional entity (SME) to which managers VP registration requests, VP 2.2.11 manager (see Figure C.1). service management reference point: This reference point (SMRP) is defined between the SME and the 2.2.12 and one or more related users. subscriber: The logic entity that subscr
29、ibes to the BVPS. The subscriber shall declare one manager at most 22.13 manager: The functional entity authorised to perform through SMRP all the service management functions, including VP registration requests, VP modification requests and interrogation requests, on behalf of the users to which it
30、 is related at subscription time (see Figure C.1). 2.2.14 sending and receiving User Information (see Figure C.1). user: The functional entity authorised to perform through UNRP all the User plane functions, including 2.2.15 capabilities (see Figure C.1). It is equal to TB. This does not preclude th
31、e applicability of the BVPS to SB. user-to-network reference point: This reference point CUNRp) is defined between the user and the ATM 2.2.16 initiating manager: The manager issuing a request to the SME. 2.2.17 involved manager: The manager receiving a request issued by another initiating manager.
32、2.2.18 second. peak cell rate: See Recommendation 1.371 13. The PCR is expressed as an integer number of cell(s) per The network shall allocate the appropriate resources using the PCR value. There is no statistical multiplexing. 2 Recommendation F.813 (02/95) ITU-T RECMN*F.L3 95 M 4b2591 Ob00315 510
33、 m 2.2.19 peak emission interval: According to Recommendation 1.371 13, the PEI is the inverse of the PCR, i.e. PEI corresponds to the minimum time interval T between two successive cells emission times, when these cells are emitted perfectly periodically by the user. 2.2.20 perfectly periodic cell
34、stream emitted at period T (see PEI definition) and the conforming user cell stream. 2.2.21 time slot: The time interval between the activation and the following deactivation of a VP. The duration of an i* time slot Dei is defined by Dei = Demin + y * P where De, is the minimum duration of the time
35、slot, M, is an integer and P is a fixed duration of time. De, and P are service constants. cell delay variation tolerance: The CDV tolerance z corresponds to the maximum time variation between a 23 Abbreviations For the purposes of this Recommendation, the following abbreviations are used: ATM Async
36、hronous Transfer Mode B-ISDN BVPS CBR Constant Bit Rate CDV Cell Delay Variation GVPI Global Virtual Path Identifier NMRP Network Management Reference Point PCR Peak Cell Rate PEI Peak Emission Interval SME Service Management Entity SMRP Service Management Reference Point SP Service Provider UMRP Us
37、er Management Reference Point UNI User-to-Network Interface UNRP User-to-Network Reference Point VBR Variable Bit Rate vc Virtual Channel VCI Virtual Channel Identifier VP Virtual Path VPI Virtual Path Identifier Broadband Integrated Services Digital Network Broadband Virtual Path Service for reserv
38、ed and permanent communications 3 Procedures 3.1 Provision and withdrawal 3.1.1 General principles The BVPS is provided after arrangement with the SP. The BVPS permits either reserved or permanent establishment of communications between two UNIS. Subscriptions of reserved and permanent establishment
39、s of communications can coexist on the same UNI. The subscription states the maximum number Nb, of VPs per UNI. According to Recommendation 1.361 12, the number of VPs available at the UNI is less than or equal to 256. Hence, Nb, is evaluated taking these constraints into account. Recommendation F.8
40、13 (02/95) 3 ITU-T RECMNMF-813 95 = 4862593 Ob00316 457 Provision and withdrawal processes are based on Figure 1. t0 tl t2 t3 TO1 03410-94ldO1 to t, t2 tg Time at which subscription to the BVPS is requested Time at which the BVPS is available Time at which Subscription to the BVPS is requested to be
41、 termimted Time at which subscription to the BVPS is effectively terminated FIGURE 1P.813 Schedule 1 The notification time Ta = tl - to is necessary greater than or equal to a minimum time Ta-. The availability of service Da = t3 - tl corresponds to the duration of subscription. Da varies between th
42、e minimum duration of subscription Da, and the maximum duration of subscription DhaX. If t3 is not indicated Da is assumed equal to Dhax. The values of Th, Da,h and Dh, are fKed by the SP. 3.1.2 Permanent establishment of communication The permanent establishment of communication is defined in Recom
43、mendation 1.140 51. Each VP is available at the subscribed PCR during a period Da. The subscription is renewable per periods of Da,;. Either non-periodic or periodic VP can be subscribed. For a non-periodic VP, values of PCR and QOS are constant for the duration of subscription. For a penodic VP, th
44、e same values of PCR and QOS scheme are repeated within each period for the duration of the subscription. At the subscription, the SP and the subscriber negotiate the values of service parameters for each VP. For a non-periodic VP, 3.1.2.1 applies. For a periodic VP, 3.1.2.2 applies. The following p
45、arameters are defined per VP. 3.1.2.1 Non-periodic VP 3.1.2.1.1 Mandatory subscription parameters a) users E.164 i numbers: b) subscription beginning time: tl; c) d) symmetry: unidirectional, bidirectional symmetric or bidirectional asymmetric; PCR: in each direction for a bidirectional asymmetric V
46、P. 3.1.2.1.2 Optional subscription parameters a) subscription end time: t3; b) c) values of VPIs (as a SP option): value of QOS: in each direction for a bidirectional asymmetric VP. 4 Recommendation F.813 (02/95) 3.1.2.2 Periodic VP This subscription aiiows the specification of a period and of a num
47、ber N of time slots within the period (see Figure 2). The number N of time slots shall be within 1 and N, (fixed by the SP). Time slot, Time slot,+l Time slotl+p TO1 03420-M/ b) subscription beginning time: tl; c) period: day, week or month; d) activation time for each time slot: TA, (with 1 I i I N
48、); e) f) g) deactivation time for each time slot: TDi (with 1 I i 5 N); symmetry: unidirectional, bidirectional symmetric or bidirectional asymmetric; PCR for each time slot: in each direction for a bidirectional asymmetric VP. 3.1.2.2.2 Optional subscription parameters a) b) subscription end time:
49、t3 that corresponds to the end time of the last period; values of VPIs (as a SP option); c) value of QOS for each time slot: in each direction for a bidirectional asymmetric VP. Recommendation F.813 (02/95) 5 3.1.3 Reserved establishment of communication The definition of the reserved establishment of communication is based on Recommendation I. 140 IS. The manager obtains at time tl (see Figure 1) the authorisation to use the BVPS, i.e. to issue registration request to the SME to reserve VP(s). Two types of reservations are possible (as des
