1、 ETSI TS 183 022 V1.1.1 (2005-06)Technical Specification Telecommunications and Internet converged Services andProtocols for Advanced Networking (TISPAN);MGC Information PackageETSI ETSI TS 183 022 V1.1.1 (2005-06) 2 Reference DTS/TISPAN-03045-NGN-R1 Keywords H.248, MGC ETSI 650 Route des Lucioles F
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6、oregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2005. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTMand the TIPHON logo are Trade Marks currently being registere
7、d by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI TS 183 022 V1.1.1 (2005-06) 3 Contents Intellectual Property Rights4 Foreword.4 1 Scope 5 2 References 5 3 Abbreviations .5 4 MGC info
8、rmation package.6 4.1 Properties6 4.2 Events.6 4.3 Signals 6 4.4 Statistics .6 4.5 Procedures 6 4.5.1 Setting the property.6 4.5.2 Resetting the property.6 4.5.3 Retreiving the property .7 4.5.4 Example scenario7 History 8 ETSI ETSI TS 183 022 V1.1.1 (2005-06) 4 Intellectual Property Rights IPRs ess
9、ential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potenti
10、ally Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out
11、 by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Specification (TS) has been produced by ETSI Technical Commi
12、ttee Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN). ETSI ETSI TS 183 022 V1.1.1 (2005-06) 5 1 Scope The present document describes an extension to ITU-T Recommendation H.248.1 1 gateway protocol to enable a Call Agent/MGC to store data on a MG that
13、 can be subsequently retrieved to facilitate MGC recovery action. The standard H248 audit mechanism permits a MGC to retrieve data from an associated MG in order to re-synchronize connection data/state between a MGC and MG. In terms of identifying the other end of this connection, the SDP RD (Remote
14、 Descriptor) that is associated with the ephemeral termination enables the other end of the connection to be identified albeit not in a format that may be convenient for the MGC to use. In many cases the RD may not enable the other end to be identified (e.g. some GWs may use different control and me
15、dia addresses). In order to achieve a co-ordinated recovery action, whereby both GW connections in a single call/end-end connection can be torn down in parallel, it is proposed to define a new H248 package to enable the MGC to store a block of data on a MG which enables the MGC to identify the other
16、 end of the connection. The structure of the stored data is understood only by the MGC and is opaque to the MG. Thus, the MGC is now able, via standard H248 audit mechanisms, to retrieve the previously stored data block in the event of a MGC failure. The MGC is now able to identify the other end of
17、the connection (e.g. typically on separate MG) and thus provide a co-ordinated clean-up of the related connections on the separate MGs. The MGC is at liberty to define the contents of the string in a proprietary manner that is most convenient for its own usage. 2 References The following documents c
18、ontain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-s
19、pecific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. 1 ITU-T Recommendation H.248.1: “Gateway Control Protocol: Version 2“. 3 Abbreviations For the purposes of the
20、present document, the following abbreviations apply: AGW Access GateWay CIC Call Identification Code GW GateWay ISUP ISDN User Part LCD Local Control Descriptor MG Media Gateway MGC Media Gateway Controller REL RELease message SDP Session Description Protocol SS7 Signalling System No. 7 TGW Trunk Ga
21、teWay ETSI ETSI TS 183 022 V1.1.1 (2005-06) 6 4 MGC information package PackageID: MGCInfo (0xTBA). Version: 1. Description: This package enables the MGC to store an opaque data block against a physical or ephemeral termination in the MG. Extends: None. 4.1 Properties Data Block PropertyID: db (0x00
22、01). Description: This property holds the MGC Recovery Information data block. Type: Octet String. Possible Values: A range of 0 to 128 characters. The range can be modified in the appropriate H248 profile which defines the application which utilizes this property. Defined In: Local Control. Default
23、 Value: An empty string. Characteristics: Read/Write. 4.2 Events None. 4.3 Signals None. 4.4 Statistics None. 4.5 Procedures 4.5.1 Setting the property The property is set by the MGC when a termination (either physical or ephemeral) is placed into a non-null context. Having been initially set, it is
24、 permissible for the MGC to subsequently modify the property by overwriting the previous setting. 4.5.2 Resetting the property The property is reset to its default value when a physical termination is moved into the null context. For ephemeral terminations, the property shall be set to the default v
25、alue when the ephemeral is created and no string has been supplied by the MGC. ETSI ETSI TS 183 022 V1.1.1 (2005-06) 7 4.5.3 Retreiving the property The property is retrieved by the MGC in the event of an MGC failure. The retrieval is performed via the H248 audit mechanism. The property is part of t
26、he Local Control Descriptor (LCD) and is thus retrieved using the AuditValue command that specifies a specific termination id and theMedia Descriptor (which contains the LCD). 4.5.4 Example scenario Consider a stable call/connection between a TGW and an AGW both GWs being under the control of a sing
27、le MGC. During the supervision phase, the MGC suffers a failure/disturbance and loses its transient memory. H248 H248 IP N/W GW GW MGC Figure 1: Example of scenario where GWs are controlled by MGC As part of its normal recovery action, the MGC would typically perform H248 audits on its GWs to re-syn
28、chronize its lost data. This is typically done as a background activity. In addition, call signalling messages will also be received which will also initiate H248 audit activity. Consider that an ISUP-REL is received for the active call. The MGC will now : 1) Translate the SS7 CIC identity to corres
29、ponding TGW and endpoint identity. 2) The H248 audit mechanism enables the MGC to determine that the endpoint is connected (in a non-null context) and also the related ephemeral endpoint identity. 3) In terms of identifying the other end of this connection, the MGC also retrieves the MGC information
30、 string (that was previously stored when the connection was established). The string may be stored/retrieved via either a physical or ephemeral termination. 4) The MGC is now able to interpret the previously stored string as identifying the associated AGW termination. As a result the call may be tor
31、n down in a co-ordinated manner dealing with both GWs concerned. The MGC information string thus permits a faster and better co-ordinated recovery by the MGC. This approach can be extended to any number of terminations within a context e.g. each termination within a 3-way connection/context may each be provided with a separate MGC Information string. ETSI ETSI TS 183 022 V1.1.1 (2005-06) 8 History Document history V1.1.1 June 2005 Publication
