Call Source A call source refers to the t he subscriber or incoming trunk that originates a call. A call source name is specified for each call source. Generally, there are three types of call sources: A interface, Iu interface, and incoming trunk.
Based on the call originator, the MSC queries the corresponding table to obtain the call source name. The detailed number analysis procedure is as follows: If a call comes from the A interface (that is, from a 2G mobile subscriber who is visiting the local MSC), the local MSC queries the data about location area and cell to obtain the call source name based on the GCI. If a call comes from the Iu interface (that is, from a 3G mobile subscriber who is visiting the local MSC), the local MSC queries the data about location area and service area to obtain the call source name based on the SAI. If a call comes from the trunk t runk side (that is, from a fixed subscriber or a subscriber of other MSCs), the local MSC queries the office direction data to obtain the call source name for BICC trunks or queries the trunk group data to obtain the call source name for the other types of trunks, for example, ISUP, TUP, PRA, and SIP. A call source specifies the source of a call. The MSC processes calls differently depending on specific call sources. You can run ADD CALLSRC to configure a call source. When used as an input parameter, the call source name is referenced by many tables, including the Called Number Pre-analysis table (ADD CLDPREANA), Call Authority Check table (ADD CALLPRICHK), Auxiliary Signaling table (ADD AUSSIG), Service Check table (ADD SRVCHK), Caller Feature Analysis table (ADD CLICRTANA), Caller Number Analysis table (ADD CNACLR), Call Prefix Processing table (ADD PFXPRO), N-CSI Configuration table (ADD NCSICFG), Auxiliary Number Processing ta ble (ADD AIDNUMPRO), CLIP Processing table (ADD CLIPRO), and Out going Number Pre processing table (ADD OUTNUMPREPRO). OUTNUMPREPRO). Based on a call source name, the MSC can obtain other configurations related to the call source, such as DN set, route selection selecti on source name, and failure source name. In addition, based on a call source name, the MSC can check certain features of the call source, such as delay digit collection duration.
Office Direction and Route Figure 1 shows the trunk networking between office A and office D, where the real lines indicate the voice channels.
Figure 1 Trunk networking
Office Direction
If two offices have direct voice path, one office is called the office direction of the other. For example, there are direct voice channels between office A and office B, office A and off ice C, and office A and office D, as shown in Figure 1. It means that office B is an office direction of office A, office C is an office direction o f office A, and office D is an office direction of office A. In addition, because there is no direct voice channel between office B and office C, office C is not an office direction of office B. Also, office B is not an office direction of office C. In the MSOFTX3000, an office direction is defined by a unique name, so that it can be easily identified. For example, for office A in Figure 1, office direction from A to D can be defined as 1, office direction from A to B can be defined as 2, and office direction from A to C can be defined as 3.
Sub-Route
If a direct voice channel or an alternative channel exists between two offices, it means a sub-route exists between the two offices. The direct voice channel is the direct sub-route and the alternative channel is the alternative sub-route. For example, there are three sub-routes between office A and office D as shown in Figure 1:
Sub-route 1 is a direct sub-route from office A to of fice D. Sub-route 2 is an alternative sub-route from office A to office D thr ough office B. Sub-route 3 is an alternative sub-route from office A to office D thr ough office C.
Route
A route is a set of all sub-routes from local office to a destination office. A route contains multiple sub-routes and different routes may contain the same sub-routes. For example, in Figure 1:
The route from office A to office D contains sub-route 1, sub-route 2 and sub-route 3. The direct sub-route is sub-route 1. The route from office A to office B contains sub-route 1, sub-route 2 and sub-route 3. The direct sub-route is sub-route 2. The route from office A to office C contains sub-route 1, sub-route 2 and sub-route 3. The direct sub-route is sub-route 3.
Route Selection Source Name and Route Selection Name
A route selection source name is the name of the classification of the outgoing route selection policy configured for a call source. A route s election source name maps a call source. When different outgoing route selection policies are configured for different subscribers of an MSC, different route se lection source names can be defined for different call sources. A route selection source name is configured in the Call Source table (ADD CALLSRC).
A route selection name is the name of the route selection policy code configured for calls to called numbers with a specific prefix. During route analysis, a route selection name and a route selection source name co-derter mine an outgoing route. The route selection name is configured in the Route Analysis table ( ADD RTANA). The route selection source name is set for callers, and the route selection name is set for callees. Through the setting of route selection source names, different outgoing routes can be selected for the same route selection name.
Call Prefix and Dialed Number Set Call Prefix A call prefix is a prefix of a called number. It refers to one digit or several sequential digits starting from the first digit of the called number. It can also be equal to the entire called number. In other words, a call prefix is a subset of the called number.
The MSOFTX3000 matches a called number with a call prefix by following the maximum match method. That is, the MSOFTX3000 searches a list of call prefixes for the call prefix that best matches the called number. Based on the matched call prefix, the MSOFTX3000 checks a data table for call attributes such as service category and route selection name. For example, among the c all prefixes 139, 138, 13900278, and 61 39, the MSOFTX3000 automatically selects the call prefix 13900278 as the best match for the called number 13900278310.
Dialed Number Set
Dialed number (DN) set is a collection of number initials or prefixes. The DN set is directly associated with call prefixes. It is first used for dif ferentiated analysis on the same call prefix, and with the passage of time it is steadily recognized as a f lexible means of call prefix analysis. One call source maps only one DN set, but one DN set can be shared by multiple call sources. Thus, the concept of DN set is greater than call source. You can configure the same DN set for different call sources, and you do not need to configure multiple data records for different call sources. This reduces the amount of data greatly. A prefix is a key factor that determines various services related to a call. Different subscribers or trunk groups may share one prefix, but the calls sharing the same call prefix may be processed in different ways.
Failure Source Name and Failure Processing Failure Source Name
A failure source name denotes the source of a call. The system can perform different failure processing operations based on different call sources. When a call from a certain call source fails, the system can select a corresponding failure processing mode based on the failure source name. Failure Processing
Failure processing refers to the processing of a call failure. If no failure processing data is configured, the system directly releases the call or plays the failure announcement to the caller by default in the case of a call failure. If the default failure processing setting is to play the failure announcement to t he caller, only several common failure announcements can be played, such as the bus y tone, callee poweroff announcement, or callee no reply announcement. For most call failures, the system directly releases the calls by default. In this case, a caller cannot know the real cause for the call failure, and may try to place calls again and again, which reduces the call completion rate of the system. If the system performs a failure processing operation based on the setting when a call fails, for example, playing the failure announcement to the caller, s ending USSD characters, reselecting a route automatically, or forwarding the call to a voice mailbox, the number of invalid calls can be reduced and the call completion rate can be increased.
Route Analysis The route analysis is a process of table query and data analysis. Figure 1 illustrates the process for analyzing how to route an outgoing call over ISUP trunks.
Figure 1 Route analysis process
Assuming that a local subscriber has originated an outgoing call, the MSOFTX3000 performs route analysis in the following way: 1. The MSOFTX3000 looks up the Call Prefix table for Route selection name of the called prefix, that is, the route selection strategy planned for the called prefix. 2. The MSOFTX3000 looks up the Route Analysis table for a record that matches Route selection name. By analyzing Route selection source name, Caller category, Address information indicator, Transmission capability, and Time segment name in the record, the MSOFTX3000 decides whether to grant a route to the current call and which route is to be granted. If the analysis is successful, the MSOFTX3000 obtains the name of the selected route. 3. The MSOFTX3000 looks up the Route table for a record that matches the route name. According to the subroute selection strategy in the record, the MSOFTX3000 selects the subroute to be used and obtains the name of the selected subroute. There are two strategies for subroute selection: sequential selection and percentage-based selection. 4. The MSOFTX3000 looks up the Sub-Route table for a record that matches the subroute name. According to the trunk group selection strategy in the record, the MSOFTX3000 selects the trunk group to be used and obtains the number of the selected trunk group. There are two strategies for trunk group selection: cyclic selection and random selection.
5. The MSOFTX3000 looks up the SS7 Trunk Group table for a record that matches the trunk group number. It then analyzes the record to select a trunk circuit on a particular MGW. It also obtains the internal number (circuit number) of the selected trunk circuit. NOTE: The commonly used circuit selection modes are Maximum, Minimum, Master/slave, and Cycle. Maximum: Among the available circuits, the system always selects the circuit with the maximum circuit number on the WCCU/WCSU with the largest module number. Minimum: Among the available circuits, the system always selects the circuit with o the minimum circuit number on the WCCU/WCSU with the smallest module number. Cycle: Among the available circuits, the system always selects the circuit that is first o released. The circuit selection is based o n the circuit numbers (which are numbered within one module) but not the CICs, and thus you must configure the circuit with a smaller CIC to the module with a smaller module number if the circuits in an office direction must be configured to multiple modules. This ensures that circuits can be selected based on the CICs. Master/slave: If a master circuit is available, the system always selects the master o circuit. The system selects the slave circuit only when no master circuit is available. Therefore, coordinate with the peer MSC server when setting the Master/slave circuit selection mode. If the peer MSC server uses the even master circuit selection mode, the local MSC server must use the odd master circuit selection mode. If the circuit selection mode of the local MSC server does not match that of the peer MSC server, circuit dual-seizure occurs frequently and the call completion rate is affected. 6. The MSOFTX3000 looks up the SS7 Trunk Group table or a record that matches t he trunk circuit number. From the record, it obtains the E1 timeslot ID (TID) that is mapped to the trunk circuit number. 7. The MSOFTX3000 sends an H.248 message with the TID to instruct the MGW to select the required trunk circuit. o
Number Match Rule Maximum matching means that the MSC searches all lists of call prefixes for the best match with a called number, and then the MSC determines such call attributes as service category, service attributes, route selection, and called number type based on the matched call prefix. Assume that a subscriber dials 13901234567. Among the prefixes 13, 139, 13901, and 1390123, the MSC determines that the best match is 1390123 according to the maximum matching method.
IMSI Number An international mobile subscriber identity (IMSI) identifies a mobile station (MS) in the global system for mobile communications (GSM) network uniquely. IMSIs are encoded in E.212 format, stored in the subscriber identity module (SIM) card, HLR, and VLR, and transmitted over the wireless interface and Mobile Application Part (MAP) interface.
Figure 1 IMSI structure
MCC: It is short for mobile country code and is composed of three digits, for example, 460 for China. MNC: It is short for mobile network code and is composed of two digits, for example, 00 for a carrier. MSIN: It is short for mobile subscriber identification number and is a unique identification for an MS in a PLMN. NMSI: It is short for national mobile subscriber identification and is a unique identification fo r an MS in a country. A typical IMSI example is 460-00-4777770001. The principles for IMSI allocation are as follows:
An IMSI can contain up to 15 digits. MCCs are allocated uniformly worldwide, but NMSIs are allocated by carriers of different countries. If more than one GSM PLMN exists in a country, a unique MNC must be allocated to each PLMN. For IMSI allocation, it is required that addressing in PLMNs of foreign countries be successful after analysis of only MCC, or only MNC, or MCC+MNC.
The operations UpdateLocation, PurgeMS, and SendAuthenticationInfo must use IMSIs for addressing at the first time. Generally, the operation RestoreData uses IMSIs for addressing. At present, all messages related to supplementary service operations sent to t he HLR use IMSIs for addressing.
TMSI Number Temporary mobile station identities (TMSIs) are allocated within a VLR for enhancing the system security. A TMSI corresponds to an IMSI uniquely within a VLR. The structure of TMSI can be codetermined by the carrier and the equipment provider. The principles for TMSI allocation are as follows:
A TMSI is composed of four bytes, which can be eight hexadecimals. The 32 bits of a TMSI cannot be all ones, because an all-one TMSI in a S IM card indicates an invalid TMSI.
A typical example of TMSI is 60340039.
MSISDN/MSRN/HON Number MSISDN Number A mobile station international ISDN number (MSISDN) is a number dialed by a subscriber to call an MS within the PLMN. The function of an MSISDN is equivalent to that of a PSTN number. MSISDNs are encoded in E.164 format, stored in the HLR and VLR, and used for addressing of the MAP interface.
Figure 1 MSISDN structure
A country code (CC) specifies the code of the country where an MSC is located according to the international PSTN numbering plan. CCs are allocated uniformly worldwide by the International Telecommunication Union - Telecommunication Standardization Sector (ITUT). Its maximum length is three digits. For example, the CC of China is 86, and the CC of the Great Britain is 44. A national destination code (NDC), also called a mobile service access code, is a PLMN number. Its maximum length is three digits. NDCs are allocated uniformly within a country by the telecom management department. A subscriber number (SN) is a number of an MS in a PLMN. SNs are allocated uniformly by a carrier in a PLMN. The coding format of an SN is H 0H1H2ABCD or H0H1H2H3ABCD. For example, China Mobile uses the coding format H 0H1H2H3ABCD for SNs, in which H0H1H2H3 stands for the HLR number of the local mobile network, and ABCD stands fo r the number of an MS.
The general format of an MSISDN is 86-139-H1 H2 H3 ABCD. A typical MSISDN example is 861394770001. Both operations SendRoutingInfo and SendIMSI use MSISDNs for addressing.
MSRN Number
When an MS is called, a mobile station roaming number (MSRN) is temporarily allocated by a currently-visited VLR to the MS, so that the VMSC or GMSC at the caller side can route the call to the MSC/VLR to which the MS registers at present. This MSRN contains the information of routing in the PLMN. An MSRN can also be used as the global title (GT) of Signaling Connection Control Part (SCCP) signaling for searching for the MSC visited by a roaming subscriber at present. It is unique within the coverage of a VLR.
The coding scheme of an MSRN is the same as that of an MSISDN, shown as in Figure 1. A typical MSRN example is 86139025553.
HON Number
During the handover between two MSCs, a handover number (HON) is temporarily allocated by the VLR to an MS for setting up a speech channel between the two MSCs. In applications, the composition of a HON is the same as that of an MS RN. Therefore, the MSRNs and HONs that can be used by the MSC Server are uniformly managed and allocated by the VLR. The coding scheme of a HON is the same as that of an MSISDN, shown as in Figure 1. A typical HON example is 86139025553.
PSTN Number PSTN is short for public switched telephony network. To call a subscriber within the PSTN, the caller needs to dial the PSTN number of the callee. If the called number type mapping a call prefix is set to PSTN on the MSOFTX3000 , all calls to the numbers with the prefix are routed out of the office through trunks. PSTNs are encoded in E.164 format.
Figure 1 PSTN structure
A country code (CC) specifies the code of the country where an MSC is located according to the international PSTN numbering plan. CCs are allocated uniformly worldwide by the International Telecommunication Union - Telecommunication Standardization Sector (ITUT). Its maximum length is three digits. For example, the CC of China is 86, and t he CC of the Great Britain is 44. A national destination code (NDC), is a PLMN number. Its maximum length is three digits. NDCs are allocated uniformly within a country by the telecom management department. A subscriber number (SN) is a number of a user in a PLMN. SNs are allocated uniformly by a carrier in a PLMN. The coding format of an SN is H 0H1H2ABCD or H0H1H2H3ABCD.
LAI/GCI/SAI Number
LAI Number
A location area identification (LAI) identifies a GSM location area uniquely worldwide, and it is used for detecting location update. Figure 1 LAI structure
MCC: mobile country code, for example, 460 for China. MNC: mobile network code, for example, 00 for China Mobile and 01 for China Unicom. LAC: location area code. It identifies a location area. It is composed of hexadecimals of twobyte length. It is in format of X1X2X3X4, in which X1X2 is specified by the telecom management department, and X3X4 is customized by a carrier. Note that 0000 and FFFE cannot be used.
A typical LAI example is 460-00-4777.
GCI/SAI Number
In the GSM network, a cell is a wireless coverage area identified by the GCI. The system uses the GCI to uniquely identify a cell in the PLMN. If the omni-directional antenna is used, a cell is a BSC area. In the UMTS network, a cell is a wireless coverage area identified by the SAI. The system uses the SAI to uniquely identify a service area in the PLMN. If the structure of omnidirectional antenna is used, a cell is an RNC area.
The coding scheme of the GCI and the SAI are LAI + CI. CI: It is short for cell identity. A CI is a two-byte-length hexadecimal BCD code allocated by a carrier. A typical GCI/SAIexample is 460-00-4777-0101.
PSTN Number PSTN is short for public switched telephony network. To call a subscriber within the PSTN, the caller needs to dial the PSTN number of the callee. If the called number type mapping a call prefix is set to PSTN on the MSOFTX3000 , all calls to the numbers with the prefix are routed out of the office through trunks. PSTNs are encoded in E.164 format.
Figure 1 PSTN structure
A country code (CC) specifies the code of the country where an MSC is located according to the international PSTN numbering plan. CCs are allocated uniformly worldwide by the International Telecommunication Union - Telecommunication Standardization Sector (ITU-
T). Its maximum length is three digits. For example, the CC of China is 86, and the CC of the Great Britain is 44. A national destination code (NDC), is a PLMN number. Its maximum length is three digits. NDCs are allocated uniformly within a country by the telecom management department. A subscriber number (SN) is a number of a user in a PLMN. SNs are allocated uniformly by a carrier in a PLMN. The coding format of an SN is H 0H1H2ABCD or H0H1H2H3ABCD.
MSC/VLR Number
MSC Number
An MSC number identifies an MSC entity uniquely. It is coded in E.164 format.
Figure 1 MSC structure
A country code (CC) specifies the code of the country where an MSC is located according to the international PSTN numbering plan. CCs are allocated uniformly worldwide by the International Telecommunication Union - Telecommunication Standardization Sector (ITUT). Its maximum length is three digits. For example, the CC of China is 86, and the CC of the Great Britain is 44. A national destination code (NDC), also called a mobile service access code, is a PLMN number. Its maximum length is three digits. NDCs are allocated uniformly within a country by the telecom management department. A locally significant part (LSP), it's allocated by carriers.
Detail: A typical MSC number example is 86-139-0477. Both operations PerformHandover and PrepareHandover use MSC numbers for addressing.
VLR Number
A VLR number identifies a VLR uniquely. In applications, the VLR and MSC are i ntegrated, so the VLR number is set to the same value as the MSC number generally.
