MIP DT Infomodel

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<p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>1 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>MSC in POOLAbstract This document describes FAJ 121 297 R2 - MSC in Pool from a DataTranscript point of view.</p> <p>Content 1 2 2.1 2.2 2.3 2.4 2.4.1 2.4.2 2.4.3 2.5 2.5.1 2.5.2 2.5.3 2.5.4 2.5.5 2.6 2.6.1 2.6.2 3 3.1 3.2 3.2.1 3.2.2 3.2.3 4 4.1 4.1.1 4.1.2 5</p> <p>Revision Information............................................................................3 Description ..........................................................................................3 Abbreviations.......................................................................................3 Concepts .............................................................................................4 Concerned Nodes ...............................................................................5 Prerequisites .......................................................................................5 Network ...............................................................................................5 Feature included..................................................................................8 Software level ......................................................................................8 General................................................................................................8 Neighbouring MSC Group ...................................................................9 Network Resource Indicator (NRI):......................................................9 MSC Pool Area..................................................................................10 Overlapping Pool Area ......................................................................11 Proxy MSC ........................................................................................12 Technical Solution .............................................................................13 MSC in Pool function.........................................................................13 Building a pool network: ....................................................................15 Traffic Case .......................................................................................22 Location update in MSC in pool area ................................................22 Handover / SRNS Relocation ............................................................23 Neighboring MSC groups ..................................................................24 Subsequent Handover/SRNS Relocation to Third MSC, Anchor MSC24 Handling of Handover/SRNS Relocation in Non-anchor MSC ..........25 Data Transcript Impacts MSC ........................................................26 AXE Parametrs..................................................................................26 Subfile 10000 Size Alteration APT ....................................................27 Subfile 77200 MSC Pool ...................................................................28 Data Transcript Impacts- HLR ...........................................................28</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>2 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>6 7</p> <p>Miscellaneous information .................................................................28 Class .................................................................................................29</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>3 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>1</p> <p>Revision Information</p> <p>Revision</p> <p>Impacts</p> <p>Prepared</p> <p>Date</p> <p>A PA3 PA2 PA1</p> <p>Release Update after review SIGTRAN added Mixed netw. BSC/RNC added New document</p> <p>ethcsir ethcsir ethcsir ethcsir</p> <p>17-10-05 28-09-05 08-07-05 09-05-05</p> <p>2</p> <p>Description</p> <p>2.1</p> <p>AbbreviationsBSC CDR HLR ISP LA MSC MS MSISDN NRI PLMN RNC SMS TMSI Base station Services Switching Centre Call Data Record Home Location Register In Service Performance Location Area Mobile Services Switching Centre Mobile Subscriber Mobile Station ISDN number Network Resource Indicator Public Land Mobile Network Radio Network Controller Short Message Service Temporary Mobile Station Identity</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>4 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>UE VLR</p> <p>User Equipment Visitor Location Register</p> <p>2.2</p> <p>ConceptsA MSC Pool is defined as a pool of MSC nodes linked to a number of BSC and/or RNC nodes. Each BSC/RNC is connected to each MSC node of the pool.</p> <p>Figure 1: Example of a Configuration of an MSC Pool All MSCs within a pool need to be connected to all BSCs/RNCs, so links need to be set up between the nodes. All MSCs within a pool need to have the same BSC/cell RNC/SAI related settings. An MSC of the pool has no knowledge about the behaviour of the surrounding MSC nodes, whether they belong to the same MSC pool or not. The MSC pool concept is mainly applicable for the BSC/RNC, as the BSC/RNC can see a pool of MSC nodes. Each MSC node in a pool shares the same service area with all other MSCs in the pool. If an MSC is removed from the pool the subscribers of the removed MSC will be distributed to the other MSCs of the pool. This feature provides MSC redundancy and improved network service availability. This feature requires a fully meshed network of A-interfaces / IuCS interfaces between all the BSC / RNC nodes of a pool service area and all the MSC nodes of this pool.</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>5 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>This means that all MSC nodes of a pool can have access to a GSM service area and a WCDMA service area at the same time. Note: It has to be noted that all MSCs in the pool should provide the same level of functionality (HW&amp;SW&amp;activation of functions), otherwise the enduser can get different level of service depending on which MSC she/he is connected to. Anchor-MSC Anchor-MSC is the MSC where the transaction is originally established.</p> <p>2.3</p> <p>Concerned NodesMSC/VLR MSC/MGW MSC server BSC RNC</p> <p>2.4</p> <p>Prerequisites</p> <p>2.4.1</p> <p>Network The network service availability is improved for UEs roaming in the WCDMA service area of the MSC pool. This is due to the fact that if an MSC fails its subscribers will be reallocated to another MSC node of the pool. The feature eases a change of the network infrastructure and improves horizontal scalability, availability and in-service performance (ISP). Less relocation and location update cases with registration to the HLR reduce the signalling load. Some assumptions that an operator should take into account for the MSC in pool function are the following: The network topology should be a fully meshed network. This means that each MSC shall be logically connected to all BSCs/RNCs in the MSC pool service area.</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>6 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>TMSI allocation shall always be performed even after a reload. All MSCs within a pool need to have the same BSC/cell, RNC, and area cluster related settings. For the MSCs that serve also BSCs/RNCs outside the pool, additional settings are needed. When a new MSC (without connected BSCs/RNCs) is installed in the pool, the data of BSCs/RNCs in the pool should be copied to the new MSC. When a new MSC (with connected BSCs/RNCs) is installed in the pool the cell/RNC and area cluster (if available and used) data needs to be copied from the MSC to all MSCs in order to have the same radio data definition. This copy procedure has to be done following some order and rules that are described reference [3]. If an MSC pool is configured for GSM traffic only and some of the MSCs in the pool also serve for WCDMA traffic, then these MSCs should be offloaded from the GSM traffic distributed in the MSC pool. This means that less subscribers will be routed to this MSC from the BSC, by using the MSC selection function. The opposite case (MSC pool configured for WCDMA only with some MSCs in the pool serving GSM traffic) should be considered in the same way. The NRI length should not change during normal operation because all the previously stored NRI values in the MSC are physically deleted from the MSC immediately. The BSCs/RNCs and the MSCs need to have consistent NRI length.</p> <p>Physical location MSC pool members can be placed in the same site (centralized configuration) or they can be placed in different physical sites (distributed configuration). When deciding about the physical location of the nodes (centralized/distributed) it is important to take into consideration the security aspects, the network architecture (layered, non-layered), the transmission cost aspects and the operational aspects. For example, an MSC pool where all the MSC pool members and the BSCs are placed in the same site has a low transmission cost, an easier operation but it is vulnerable for a site failure (for example: fire, power cut). If the MSC pool members are distributed in different sites, it is possible to achieve the required network availability even if one of the sites fails completely.</p> <p>Layered network architecture The layered network architecture enables the distribution of MSC pool members and BSCs in multiple sites with optimal transmission usage (Ainterface transmission).</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>7 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>E-interface (MSCMSC) There is no inter-MSC handover among the MSC pool members if all the MSC pool members are only serving the BSCs in the same MSC pool area. That is, as long as the subscribers move inside the MSC pool area, there are only intra MSC handovers. In this case, there is no need for E-interface among the MSC pool members. D-interface (MSC/VLRHLR) In a normal pool operation, the signaling capacity in the D-interface is decreased because there is no location-updating request towards the HLR as long as the subscriber roams inside the MSC pool area. However the dimensioning of the D-interface must take into consideration the MSC pool member failure cases where a large number of subscribers are moved from the failed MSC pool member to the other MSC pool members. The consequences are a large amount of transactions to the HLR through the Dinterface. Global paging The MSC pool area in a large MSC pool can contain a very large amount of location areas. The global paging distributed to a large number of location areas decreases the BSC nodes capacity in the MSC pool area. Therefore the MSC pool members should be configured to support first and second local paging as the preferred paging option in normal traffic. The MSC parameter PAGREP1LA enables/disables the global paging. Note that an MSC pool member will always generate global paging for the subscribers with unknown LA. For example, the LA information is lost during the restoration procedures (after a large restart) if the function retaining MSC/VLR data after system large restart is not available. The LA information is always lost after a reload followed by a system large restart.</p> <p>MSC pool area coverage The definition of the MSC pool area should take into consideration the geographical traffic patterns and flow in the network in order to optimize the utilization of network resources. For example, there is a traffic pattern from the housing area/suburb to a central business area (large number of subscribers moves in the morning from the suburb into the business area and back to the suburb in the evening). If the MSC pool area covers the housing area/suburb, the central business area and the main roads in between, it minimizes inter MSC handover cases (inter-MSC handover to MSC/VLRs outside the MSC pool or vice-versa). It minimizes also the number of subscribers that perform location updates in/out of the MSC pool area (HLR signaling).</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>8 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>2.4.2</p> <p>Feature included This document describes the following features: MSC in POOL FAJ 121 297 R2</p> <p>2.4.3</p> <p>Software level The feature MSC in Pool for GSM was introduced in R11, MSC in pool with access to WCDMA service areas is supported in R12.</p> <p>2.5</p> <p>GeneralEach BSC / RNC in the pool is connected via the A interface / IuCS interface to each MSC/VLR's of the pool. When a subscriber roams into a MSC Pool Service Area, the involved BSC selects one of the MSC's in the pool according to pre-defined traffic distribution algorithm based on the capacity figures of the MSCs in the Pool. The subscriber registers in the selected MSC and remains registered in the same MSC until he moves out of the MSC Pool Service Area. When the subscriber moves from one location area to another within the MSC Pool Service Area, the new BSC will be informed by the MS about the identity of the MSC where it is registered. In order to implement this functionality without impacts on the Mobile Stations, the TMSI is modified to carry the NRI. In case MS has roamed outside the MSC Pool Area there may be a need to fetch the IMSI and the security related data from the previous MSC. In order to find out the correct co-operating MSC within the pool, the old TMSI (NRI) is analyzed in the new MSC. In case the previous MSC is part of a MSC pool, then TMSI points out to so called proxy MSC of that MSC pool, which has knowledge of all MSCs in this MSC pool. This proxy MSC relays the signaling between new MSC and the correct previous MSC. Note: BSC/RNC configurations have to be adapted to the MSC-Pool concepts.</p> <p>Ericssonwide Internal DT FEATURE DESCRIPTIONPrepared (also subject responsible if other) No.</p> <p>9 (29)</p> <p>ETH/GS Irn CsiszrApproved Checked</p> <p>4/190 46-FAD 104 50Date Rev Reference</p> <p>ETH\GSC</p> <p>ETHBYP</p> <p>2005-10-17</p> <p>A</p> <p>2.5.1</p> <p>Neighbouring MSC Group The MSCs in the neighbouring MSC group are grouped together (max.16) for administration purposes to distribute the inter-MSC handover/SRNS relocation (from outside the pool) in order to achieve...</p>