2.1 Introduction
Low completion rate (especially for toll incoming calls) is a common network problem. To provide guidance for the maintenance engineers in improving the completion rate, we gather materials from multiple sources to form this
document, hoping it can be helpful in improving the completion rate of general sites.
In practice, if operations involve the modification of data, the maintenance engineers must be cautious and think it over. In addition, specific operations shall be done when the traffic is small, and modifications shall be carefully recorded. Also please back up the data before the modification and implement necessary dial test.
Many software parameter adjustments involved in this chapter are all aimed at the VMSC33 equipment of each company. Meanwhile, the meanings of software parameters vary with different equipment versions. So, if software parameters are involved in the modification, you must consult related technical support personnel of each company, and the equipment room maintenance personnel cannot operate on his own.
2.2 Establishment of the Call Model
- Objectives
To get a solution, you should first find the cause. So, by establishing the call model, we can learn about and analyze the called number data, route data, traffic measurement data, and state of surrounding offices, and can make clear the networking, call flow direction and structure of the local office. Also, by establishing a simple call model, we can see in which flow direction the completion rate is low and find the cause roughly.
- Operations
Analyze the route data, number analysis data and handover data of the local office. Communicate with the customer to make clear the call flow direction, signaling types in respective office directions, MAP version, CAP version, etc. of the local office.
Learn about the situation of surrounding offices (equipment manufacturer, and model, e.g. 1240) for the convenience of querying related history cases, as some manufacturers’ equipment has problems in signaling coordination.
Register the traffic measurement task for each flow direction to subdivide the completion rate according to the structure of flow direction of the local office. The
traffic measurement task types, which are often used, include the combination condition measurement and the bearer trunk traffic measurement. We can leave out useless measurement indices (a template can be formulated for use) according to the features of each call when registering a task. For example, remove some mobile-related measurement indices for the measurement task in the office direction of PSTN.
For the completion rate of the toll incoming call, to facilitate the monitoring and check at any time, we can take it as a basic item and register it as a permanent measurement task as it is very important. For the traffic measurement tasks to be registered for checking the completion rate of the toll incoming call, please refer to Appendix II.
- Analysis
Calculate the flow proportion in each flow direction according to the traffic measurement results, so as to get the call model diagram.
According to the traffic measurement results, find in which flow directions and of which types the call completion rate is low. Meanwhile, calculate their effect on the completion rate.
Since most of the exchanges have the traffic measurement optimization function, if there is a disparity between “combination condition measurement” and “bearer trunk traffic measurement”, the latter shall dominate. However, the former has more statistics information, and can provide abundant guidance data.
After MSC is upgraded to the target network, normally ”release while ringing” has a high ratio, occupying 25~30% of the toll incoming calls. This is within the normal range, caused by the change of the measurement point of MSC. For all the incoming calls, after MSC sends back ACM, the caller release will be regarded as a kind of “release while ringing”. Most of them give the signal tone. Normally the caller will not release the call immediately after listening to the signal tone. This type of call failure includes various failure tones and normal caller release while ringing, so it has a high ratio. Unless the proportion is especially high (>30%), this part cannot be eliminated.
Part of the exchanges have the failure of “no route to destination”, the cause for which may be: 1) the A interface circuit cannot be allocated; 2) since the configurations are inconsistent between the BSC side and the MSC side in part of cells, the cell ID carried in the mobile is different from that conFigured in MSC and thus the failure to query the GCI table occurs.
2.3 Common Methods for Completion rate Adjustment
2.3.1 Related Adjustment of Radio Network Data
I. Paging quality
- Objectives
By analyzing the paging 0uality, we can find in which location area the radio paging has a low success rate, thus to provide guidance to the network optimization or for MSC to adjust the VLR configuration parameters.
- Operations
Register the paging measurement task for all the location areas under the MSC:
Select [Traffic measurement of MSC basic services] for the measurement function type, and “Paging procedure measurement” for the measurement type,
and “all location areas” for the registry task parameter.
When it is found that the paging success rate is quite low, we can register the paging measurement task according to location areas to see which location area has a low paging success rate.
- Analysis
If the statistics show the paging success rate is relatively low, e.g. 50% or so, the problem normally lies in the BSC side. We must ask the customer to optimize the network of the location area with a low paging success rate, thus to improve the incoming call completion rate to a great extent. Meanwhile, we can check the MSC cell configuration and periodic location update data.
When the paging success rate is over 85%, as the space of adjustment is small (less than 5%), which has a limited effect on the completion rate of the toll incoming calls, we can suggest the customer to optimize the network, but the emphasis should be put on somewhere else. If the paging success rate is more than 90%, the radio quality is good and factors of this aspect can be ignored.
Add the paging times: modify the item “Max. paging times” in the “Software Parameter” table. By default, the value of this item is 3, which can be modified into 5 but less than 7 based on the actual situation. To increase the paging times too much will increase the call delay, which may cause the customer’s dissatisfaction. Note: increase of the paging times may bring a heavy load to the network, thus it shall be avoided where there is big traffic, so as to avoid accidents.
The adjustment of the switch-off times upon no answer of each cell can greatly improve the completion rate for the areas with a low paging success rate (modification is not suggested normally).
Adjust bit 4 of “VLR parameter 1”: control g_cSwitchSetDetach.
Meaning: g_cSwitchSetDetach = 1 means VDB actively sets the subscriber’s Attach state as “Detach” to end the next paging to the called party after the called subscriber does not answer for several consecutive times (subject to the subscriber type).
g_cSwitchSetDetach = 0 means that VDB does not set the subscriber’s Attach state as “Detach” after the called subscriber does not answer for several consecutive times (subject to the subscriber type).
Default setting: 0 (setting it to 1 can improve the completion rate).
Note: this parameter may have different meanings in different versions, so please modify it after confirmation.
II. Location update and periodic location update
- Objectives
By reducing the periodic location update time, we can decrease the call drop rate.
By adjusting software parameters and the settings related to location update, we can improve the completion rate.
- Operations
With the cooperation of the BSC side, modify the “Periodical location update time” domain of “VLR configuration table” to shorten the periodic location update time of MSC. But it must be ensured that this periodic location update time is 2-3 times bigger than that at the BSC side, so as to avoid the BSC load increase because of frequent location updates. As to the specific value of adjustment, there is not much experience data for reference yet. So, this shall be combined with the situation of the local office and consultation of the related Huawei personnel is required before you apply it. Since our MSC equipment supports pre-paging, the BSC load is very heavy already. So, if we set a too little value for the periodic location update time, disastrous consequences will be caused. So, when modifying this data, you must consult the related technical personnel of Huawei and then determine it according to the actual situation of the local office.
Adjust software parameters related to location update to improve the completion rate. Related software parameters are as follows (note: applicable to VMSC33 only):
Software parameter: VLR parameter 1
Bit 2: control g_cSwitchMSRNAllocate
Meaning:
g_cSwitchMSRNAllocate = 1 means when allocating the roaming number, VDB will not return any roaming number to this subscriber when he is busy and does not register the CW and CFB supplementary services.
g_cSwitchMSRNAllocate= 0 means when allocating the roaming number, VDB will still return a roaming number to this subscriber when he is busy.
Default setting: 0 (setting it to 1 can improve the completion rate, but the calling subscriber will hear the prompt tone about the subscriber unreachable when the subscriber is busy without other negative effects.)
Bit 3: control g_cSwitchClearStatus
Meaning:
g_cSwitchClearStatus= 1 means that when clearing the subscriber state during the calling subscriber location update, VDB only clears the RR state but does not clear the paging information, thus to ensure the called subscriber priority.
g_cSwitchClearStatus= 0 means that when clearing the subscriber state during the calling subscriber location update, VDB clears both the RR state and the paging information.
Default setting: 1 (setting it to 1 can improve the completion rate)
Bit 5: control g_cSwitchChangeLAI
Meaning:
g_cSwitchChangeLAI = 1 means when the subscriber implements the location update or makes a call, the subscriber LAI can be updated at any time.
g_cSwitchChangeLAI= 0 means when the subscriber implements the location update or make a call, the subscriber LAI cannot be randomly updated.
Default setting: Default setting: 0 (setting it to 1 can improve the completion rate).
Bit 6: control g_SwitchRestoreData
Meaning:
g_cSwitchRestoreData = 0: restore the database.
g_cSwitchRestoreData = 1: do not restore the database, but close the data restore procedure. This is a little bit beneficial to the completion rate, but is not a software parameter that may have an instant effect.
Default setting: 0
Eliminate all possible “Mobile does not match TMSI at the network side”, which causes paging failures; BIT3 of VLR parameter 1. Static TMSI or IMSI is used for paging. That is, no TMSI re-allocation is made during the location update or in the service flow.
Note: to use this parameter, the operation must be confirmed by the related technical personnel of each company!
- Analysis
The adjustment for both the location update and the periodic location update can take effect only in the case of poor radio quality.
- Cautions
If the paging quality is rather good, it is recommended that the method of adjusting the location update not be used.
The adjustment of the periodic location update time shall be cautiously implemented with the cooperation of the BSC side.
During the completion rate adjustment, normally you should not modify the VLR software parameters mentioned above unless some special cases.
When modifying bit 2 of VLR parameter 1, please note the negative effect of the operation (see the parameter description above).
III. Checking the location area and cell configurations
- Objectives
To check the LAI and GCI configurations at both the MSC and the BSC sides; to modify inconsistent configuration and omissions thus to reduce the failure of “no route to destination”.
- Operations
If BSC is non-Huawei equipment, the LAI and GCI configurations at the BSC side shall be obtained with the customer’s help. Then, based on these information, check the data in the “Location area cell table” of MSC.
If the BSC equipment is provided by Huawei, the DBF file containing the configurations of LAI and GCI at the BSC side (the file name can be obtained through Table.dbf of C:\OMC\BSC\BAM\dbf\system) shall be obtained with the customer’s help. Meanwhile, make a copy of the configuration file gsmlai.dbf of “Location area cell table” of MSC. Open two DBF files in Lotus 1-2-3 and copy the contents of them into a new 1-2-3 file (please delete some unimportant columns). Arrange them in two columns and then use Lotus 1-2-3 to check the configurations of the two sides (manual operation; with reference to the configurations of one side, align the lines of the other side with related lines of the reference side; mark inconsistent lines at the two sides with colors).
- Analysis
The check mainly focuses on if the MSC number of LAI, the total number of BSCs, respective subordinate BSC numbers and the BSC number of GCI are wrong, and if the call source exists in the call source table. Meanwhile, note if some cells of the local office that have been provisioned are not conFigured.
- Cautions & suggestions
Before modifying the data, please consult and confirm with the customer. And try to assist the customer in the dial test after modifying the data.
IV. Shortening the call proceeding time
- Objectives
By shortening the call proceeding time, we can reduce the subscriber pre-mature release and improve the completion rate.
- Operations
The method, which is known currently and has been adopted, is aimed at the single-frequency network: cooperate with BSC to delete the Classmark Request and Classmark Update flows. The major task is to adjust the BSC parameters, and shield this flow. And the MSC side only gives assistance in the operations. For different BSCs, the method may be different. In this case, it is necessary to consult the engineer of the BSC manufacturer.
If the proceeding time is relatively long, please trace the interfaces for the calling and called subscribers and implement the dial test. Calculate the proceeding time of each phase according to the Tick difference value of the information flow (such as the time from the call origination of the calling subscriber to the request of the roaming number, the time for sending the roaming number, the time taken from the moment the called party is connected to the moment he is paged, the time from called subscriber paging to paging response) One tick is 1/100 second. Repeat the test for several times to see the rough time distribution.
- Analysis
Unless the call proceeding time is too long, the adjustment of this item is of a little help to improving the completion rate, which may be taken as a method to improve the QoS.
When the call proceeding time is relatively long, which is mainly caused by the waiting time of multiple paging (if the first paging response succeeds, normally the paging phase takes 0.5 seconds only), it indicates the radio quality is poor. Also, it is possible that much time is spent in sending the roaming number (normally 1-2 seconds). Such problems shall be handled with coordination of the customer.
- Cautions & suggestions
The method to delete the Classmark Request/Update flow is intended to adjust the single-frequency network only.
2.3.2 Called Number Analysis, Route Data Check and Trunk Check
I.Checking the called analysis data configuration
- Objectives
ConFigure the number segment as detail and complete as possible, adjust the minimum number length of the local end and peer end, and reduce unallocated numbers, incorrect numbers and route errors.
- Operations
Trace the singling for respective major flow directions of toll incoming calls (except the local network) and register “Bearer trunk traffic measurement – outgoing trunk measurement” and “Combination condition traffic measurement (the call source is TMSC and the call type is tandem call)”.Check if there are too many failure times regarding unallocated numbers or incomplete addresses.
Trace the signaling for respective major flow directions of toll incoming calls (except the local network). For the information on use of the TUP signaling, use the signaling analysis software to count the proportion of ADI and UNN messages in outgoing calls. For the ISUP signaling links, use the function of “Analytical results of failure causes” to count the three failure causes “1”, “5” and “28” (the failure cause codes are “1, 5, 28”. For the meanings of respective failure causes, please refer to Appendix III).
If respective statistics show much call loss due to the unallocated number exists, please check if the called number analysis data is consistent with the number segment configuration of office directions such as TMSC and PSTN. And try to conFigure the number segments as detailed and complete as possible (you can implement intended checks by using the called numbers of respective calls in the analytical results of the failure causes in step 2).
Adjust the minimum number length to make it the same at both sides. Try to reduce the sending of SAM and SAO messages from the local office, and strictly restrict the maximum number length of MSIDSN and MSRN/HON to avoid sending invalid numbers.
It is recommended that the minimum number length at the PSTN side be modified with coordination of the customer. In this way, the proportion of sending subsequent SAM and SAO messages can be reduced, thus improving the number of no dialing and in-dial abandon times.
Check the trunk bearer data to avoid the problems of cases 3 and 4 below.
- Analysis
If there are too many unallocated numbers and incorrect numbers, carefully check the called analysis data. The emphasis should be put on the number segment, the minimum and the maximum number lengths, and trunk bearer data.
- Cautions & suggestions
Please make clear the configuration purposes from the customer before modifying the data. Their approval should be obtained first before you modify the data. After modification, you should also make the dial test in time.
II. Removing alternating numbers (also called oscillation numbers)
- Objectives III. Link and trunk circuit check.
- Objectives
- Operations
Analyze the routing data of the local trunks, and the local office shall be able to realize load sharing. By querying the circuit according to the office direction, we can observe whether trunk selection of the local office and peer office is even. In some areas, the PSTN incoming calls are not even, which are centralized on several PCMs, thus affecting the routing to some extent.
Check if the link data of the local office is wrong. The emphasis should be put on the link selection of [MTP link set table] and the signaling link code of [MTP link table] (to avoid errors caused by human neglect).
Through two types of traffic measurements, i.e. [Bear trunk traffic measurement] or [Combination condition traffic measurement], we can get the trunk congestion proportion. Also, we can get general information by attaching a meter to analyze the signaling.
By tracing the signaling, we can know if there are many reset messages.
For the transmission fault and transmission quality, normally there will not be problems. And it is enough to inquire the customer about their conditions.
- Analysis
For most of the offices, the trunk load from them to PSTN is quite high, which shall be observed carefully.
When checking the routing data, please put the emphasis on the route selection module numbers and avoid neglecting the circuits of some modules. The checklist in Appendix K is recommended for the check.
IV. Checking the state of inter-office handover.
- Objectives
- Operations
If the failure rate of handover to this office is high, please assist the customer to implement the practical test on the handover to this office at night when the traffic is small. Meanwhile, trace the inter-office signaling and B interface (MSC--VLR) signaling.
- Analysis
V. Signal tone configuration
- Objectives
- Operations
- Analysis
- Cautions
VI. Checking the data configuration of forwarding registration in the local HLR
- Objectives
- Operations
Modify the “MAP function flow configuration table” of MSC/GMSC to enable MSC/GMSC to support all the PLMN user-defined types (select all the items of the ODB_SS domain), to avoid the call failure when MSs with some user-defined new services roam to the local place.
- Analysis
VII. Signaling Tracing and Analysis
- Objectives
- Operations
We can use the signaling tracing meter to trace the busy-hour signaling of the switch. Normally the signaling tracing meter supports the function of arranging together the tracing information of multiple links by calls. In this way, the analysis becomes very convenient. Also, we can measure the call failure causes by using these instruments.
When making the call analysis item by item, please save abnormal message flows (when using the tracing meter, please select to keep these messages instead of saving the information flows only, if conditions permit).
- Analysis
When only analyzing the calls not connected, make sure to observe if the failed numbers have certain rules. If yes, configuration errors of some number segments of the local office may exist.
Measure roughly the failure calls with cause values. For example, measure the ratio of failures due to causes such as CGC, ADI and LOS in the TUP message flow.
For the office direction of the TUP type, please observe if there are many IAM messages. If yes, please conFigure “Supplementary signaling flag” via the called number analysis table, so as to enable our equipment to use the IAI message to initiate calls. In this way, unnecessary load, which is caused when the peer office requests the calling number, can be avoided.
- Cautions & suggestions
2.3.3 Some Adjustments Needing Approval of the Customer
Since the completion rate is an overall index, sometimes it is impossible to improve it continuously. So, we have to take some measures, which all have both negative effects and active effects. Therefore, the maintenance personnel shall think them over and again.
I.Enabling the conditional forwarding to the voice mailbox for the local mobile subscribers
- Objectives
- Operations
At the very beginning, the possibility of toll incoming call may be quite low among the selected numbers, with little effect on the completion rate. In this case, we can enable the conditional forwarding for more local mobile subscribers. To facilitate the
adjustment, the subscriber quantity shall be increased step by step. It is recommended to add the forwarding of 2000-4000 subscribers every day for observation.
Probably the HLRs of some manufactures do not support enabling the forwarding in batch. In this case, it is very time-consuming to operate one by one, so please coordinate and ask the customer’s maintenance personnel to implement it by themselves.
For the subscribers that have set the forwarding by themselves, please do not change their settings.
- Analysis
The defects of this method: the forwarding of these subscribers is enabled free of charge, so the customer may suffer a little loss in the fee income.
- Case
II. Alternating back part of the calls with high completion rate from TMSC.
- Objectives
- Operations
Modify the route data of the local office to send some calls to TMSC and then send them back via TMSC, thus to improve the completion rate of the toll incoming calls.
Common configuration methods: generating different routes according to the called number segments; using the call sources to form different routes. When the data is modified, it is necessary to avoid forming harmful oscillation calls between MSC and TMSC.
The configuration method of generating different routes according to the called number segments: when this method is adopted, the number segment sent to TMSC
shall be different from that alternated back from TMSC, which can be implemented by adopting the called number transform. Take the called number 0555-127 as an example:
First, modify the routing of the number segment 0555127 to TMSC as that to TMSC, and conFigure the called number transform. Meanwhile, insert a number before the number segment of this number and after its area code (e.g. to insert the number 9999, first verify that the local PSTN does not have this new number, and the number segment 05559999127 is not included in the called number analysis before the configuration). Finally, the called number sent to TMSC is thus 0555XXXX127.
Add the called number analysis for 0555XXXX127, which is an incoming call number segment from TMSC. The routing of this number segment is filled as that to PSTN. Meanwhile, conFigure the number transform for this number segment, and delete a number before the number segment of this number and after its area code (the handling is contrary to the operation of inserting a number as stated in step 1, e.g. delete the number 9999). Finally, the called number sent to PSTN is thus 0555127.
When modifying the number initial processing, the distribution of the call source of the local office shall be taken into account. Some offices have set different call sources for different areas, so the corresponding number initial processing must be conFigured for all the call sources in the local mobile network (or using the wildcard call source; refer to related cases for details). When the capacity of the number initial processing table is insufficient, the trunk bearer can be used to implement the number transform to avoid loading the host.
Set the data tables related to the called number analysis, number initial processing, number transform, etc. Then, please query the host to confirm if the setting succeeds. To reduce the impact on the subscribers during the setting period to the minimum, it is recommended to first set the number transform, then set the number initial processing, and finally set the called number analysis table.
Make the dial test on the number segment 0555-127 after modifying its route. Before this, trace the calling subscriber by using the maintenance console, so as to observe the signaling of the call and ensure its normal running.
The configuration method of using call sources to form different routes: this one is relatively simple, but the precondition is that all data of the local office is normative, and TMSC and the local mobile network have different call source codes and number initial sets. Otherwise, great changes in data need to be made, which is not what we desire. It is not reiterated here. Similarly, please confirm the setting succeeds and make the dial test after the modification.
- Analysis
The defects of this method: after the alternation, the generation of bills will change. It is necessary to confirm if the charging situation will be changed, so it must be confirmed by the maintenance personnel before the modification.
- Cautions & suggestions
When modifying the called number analysis table, make sure not to cause the phenomenon of alternation between the local office and TMSC. After modifying the data, please make the dial test to confirm the configuration is correct.
After using this method, please observe the change in the completion rate closely, and do not let the completion rate increase too much.
According to sources, China Mobile will adopt a new statistical rule for toll incoming calls. This new rule only measure the completion rate of toll calls to the local mobile subscribers. If so, this method will lose its meaning. If an office has adopted this method, this part of data shall be deleted.
III.Returning ANN (answer, no charge) upon failure processing
- Objectives
- Operations
In the failure processing table, conFigure “Send answer signal” for part of the tones (the failure source code is in the TMSC direction). Thus, The ANN messages will be returned when failure tones are played for incoming calls.
In the software parameter table, set bit 1 of “Call internal parameter 1” to 0, so as to generate free bills [Bit 1: when the called number initial processing is set as “send signal tone”, it will control whether to charge when the signal tone is played (the caller subscriber has entered the conversation); when bit 1 is set to 1, charging will be applied; when it is set to 0, charging will not be applied, and the local office will generate free bills].
Note if 117 is conFigured in the local office. If yes, charging will not be applied when 117 is dialed.
Note that this is not allowed in many places.
- Analysis
Selecting different failure processing tones can make the completion rate stay within a certain range.
- Cautions & suggestions
This method is the last choice and care should be taken.
IV. Call Test
- Objectives
- Operations
Before the dial test, make various tracing preparations, e.g. opening the tracing of local mobile subscribers (which call local mobile subscribers), and attaching a meter to trace the signaling between TMSC and PSTN (tracing the state when foreign subscribers dial 17951 to call the local PSTN).
Coordinate the equipment room maintenance personnel at different places or use other resources to let the foreign mobile subscribers implement the dial test according to the dial test table.
Save messages and signaling traced.
Analyze the called number flow to find the abnormalities, or send messages traced to the R&D personnel of Huawei for analysis through proper approaches.
For offices with inter-office handover, please implement the inter-office handover test with the customer’s cooperation (handover to the local office).
- Analysis
V. Viewing Alarm and Logs
- Objectives
- Operations
View the log information. The emphasis shall be put on the information on the first call clear point to get some causes for the calls connected but failed.
- Analysis
The phenomenon of alternating numbers normally occurs between the local office and TMSC, or between the local office and PSTN. Thus, the failure of one call becomes multiple failures, which has a great effect on the completion rate. So it must be eliminated.
- Operations
Analyze the called number analysis and route data to find out the office direction and number segment where the phenomenon of alternating numbers may exist. The emphasis shall be put on checking the office directions from the local office to TMSC and to PSTN. The checking method is rather simple: check the called numbers of these office directions one by one to see if there is any possibility of these called numbers to be sent from them.
Register the traffic measurement task to check if the phenomenon of alternating numbers exists between the local office and the surrounding offices, supposing that two TMSCs are connected with the local office. Take TMSC1 for example, register the traffic measurement task of TMSC1 incoming/TMSC1 outgoing and that of TMSC1
incoming and TMSC2 outgoing. TMSC2 also has similar combinations. For others, the same rule applies:
Select to register [Combination condition object traffic measurement].
Register the task parameters:
Called number: null.
The office direction number of the call source: the office direction number of the TMSC1 toll office.
The office direction number of the outgoing end: the office direction number of the TMSC1 toll office.
Destination code: null.
Select “All calls”.
Analysis
Analyze the results of traffic measurement. Normally, if the phenomenon of alternating numbers exists, many of them can be measured together with a high failure rate.
If there are few phenomena of alternating numbers (e.g. 2-20 during the busy hour) and if the success rate is high, the cause may be that toll calls to a few subscribers are forwarded to foreign subscribers. And this is a normal phenomenon.
If there are signs indicating that alternating numbers exist, we can use the SS7 signaling analysis software to analyze it. The operation is as follows (take TMSC – MSC as an example):
First check the called number analysis table carefully to remove some obvious alternating number configuration.
Use the maintenance console to implement the signaling tracing for all the links from TMSC to MSC and save the tracing message in the disk. Meanwhile, implement the measurement within the tracing time segment by using the method mentioned above (20-30 minutes is recommended for the tracing time).
After the tracing is finished, if the statistics show that there is no alternating call within this time segment, please select proper re-tracing, till the alternating call is contained within the tracing time segment.
Use the signaling tracing software to analyze the signaling traced. Use its function of called number query to query all the number initials of the local office outgoing to TMSC one by one (select the outgoing call, query by the prefix, and fill in the number initial outgoing to TMSC). View the calling number of each outgoing call, which may be the alternating call if it is not a local subscriber. Carefully check the configuration related to the calling and called numbers (the calling number and called number analysis, number initial processing, bearer processing, etc.), to correct the configuration errors.
Modify the data configuration to eliminate the alternating number phenomenon.
Continuously observe the phenomenon of alternating numbers through the traffic measurement, to see if it has been eliminated.
- Cautions & suggestions
Please make clear the configuration purpose of the customer before modifying the data. Also please make the dial test after the modification.
