DE10116786A1 - Tracing session or call in network environment e.g. when setting up IP multimedia sessions in GSM networks - Google Patents

Abstract

Involves transmitting a trace invocation from a control plane network element to another control plane network element or a user plane network element. A trace report is generated in the serving call state control function (S-CSCF) of the called party. Trace reports are subsequently generated in all the network functions involved in session set-up.

Description

The present invention relates to a method for tracing egg participant and / or a session in network elements that have an IP multimedia Manage session. Such a "session tracking" is one Extension of the subscriber defined by the ETSI TS 101 627 (GSM 12.08) and equipment tracking function. In addition, there will be an opportunity to activate tracking from a Multimedia Gateway Controller (MGC) or an MGC function (MGCF) to a multimedia gateway (MG) introduced.

The "session tracking" function is a good maintenance tool for troubleshooting or to test new functions. However, it is currently not for the Internet prototype coll (IP) multimedia subsystem (IMS) of the UMTS network defined. It is necessary, the network operator an opportunity to investigate subscriber-specific problems me to provide, for example after a complaint received.

The original GSM concept of subscriber and equipment tracking However, troubleshooting limits to a part of the network, namely to such networks elements that have a signaling connection with the user equipment. By introducing "session tracking" in the IMS, the network operator Infor mations of all networks involved in the establishment of an IP multimedia (IM) session collect elements / functions.

The "session tracking" should be called for "test conversations" (test sessions), led by participants under persecution, according to the part User and equipment tracking concept.

In addition to troubleshooting, the session tracking functionality can also assist a legal eavesdropping action with detailed session information become.

To use the subscriber and "session tracking" in a mobile AII-IP network, the following features should be provided in the network:

• 1. Central activation and / or deactivation of the "session tracking" in the Ho me Subscriber Server (HSS).
• 2. Activation of the "session tracking" starting from the HSS to the serving call State Control Function (S-CSCF) and the Proxy-CSCF (P-CSCF) of the persecuted Participant. The S-CSCF and the P-CSCF store subscriber-related data, so that the "session tracking" activation information is permanently there can be saved. In the P-CSCF can also be activated directly an administrative facility can be provided to ei to pursue the decision of the network operator visited.
• 3. Calling up the "session tracking" for the IM session in the other network function who participate in the IM session setup: S-CSCF and P-CSCF of the geru position, interrogating-CSCF (s) (I-CSCF, break-out gateway control function (BGCF), MGCF and MG. It is noted that the follow up call for subscriber tracking may only be required in the S-CSCF.
• 4. Generate the "session tracking" reports in the tracked session and send this to the operations and maintenance center (Operation and Maintenance Center, OMC). The "session tracking" reports contain identification information on the tracked participant / session. In the S-CSCF of the tracked participant can be the tracking reference ID, the private ID of the IM- Participant, the conversation ID of the Session Initiation Protocol (SIP) and the ID of the calling network operator, whereby in the case of the other network function the call ID of the SIP and the ID of the calling network operator delt. The "session tracking" reports can be sent to the ei in any operator network gene OMC system can be sent.
• 5. Process the "session tracking" reports in the OMC for an IM session by combining the network functions of the IMS implementie network elements received reports. The combination of the "Sessi "Tracking" reports is required only for session tracking.

The following specific aspects should be considered:

• 1. Multi-Vendor Networks:
  The standardized protocols should contain the message parameters required for the tracking call.
• 2. Setting up the IM session using a network of several network operators (only required for session tracking):
  The tracking activation may or may not be sent by the S-CSCF or the P-CSCF of another network, depending on the mutual agreements between the network operators.

The tracking call should be sent in the SIP messages across the network boundaries become. The tracking request information sent is intended to identify the Mo. Bilfunknetzes (Public Land Mobile Network, PLMN) included in the pursuit was activated. When evaluating this PLMN ID, the network elements should track Provide session reporting reports for the session or not, depending on a ge mutual tracking data provision agreement / cooperation between the Network operators (whether they cooperate in troubleshooting).

The "session tracking" function provides a good maintenance tool for troubleshooting or to test new functions. By separating the user level and Control level, the control level is managed by the MGC while the user level in the multimedia gateway (MG) is managed. The MG is to a new network element, the user level and the control level earlier were not separated. With the introduction of the MG, the control level and the User level now separated. So is a detailed information about the user Not available in the MGC, but available in the MG.

It is hardly feasible to have information about the physical resources of the MG collect in the MGC. The present standardizations only describe the way in which the MGC reserves logical resources of the MG. For the However, finding bugs or reporting on legal interventions are also information regarding the physical resources essential, for example the media type.

For troubleshooting and testing purposes, there is information about the user level and their physical resources required. Furthermore, the "Sessionver Follow "functionality in the MG for legal bug reports.

The "session tracking" is related to a particular participant or Equipment activated, but the machine gun has no knowledge of the participant sits so that the "session tracking" cannot be activated locally in the MG.  

A possible solution is available if the MGC uses the "session tracking" Activation information at the beginning of the conversation about the H.248 protocol MG sends. When the MG receives the "session tracking" activation information it begins collecting detailed information about the users level and the physical resources of this conversation.

The "session tracking" activation information can be sent when the MGC requests the termination ID from the MG. In practice, this "session tracking" activation information can be sent to the ADD Command can be added.

Furthermore, a stand-alone procedure for informing the MG about the "Session tracking" may be provided. This standalone procedure is useful if reporting by the MG is required in an ongoing conversation. the This situation can usually occur in cases of a legal eavesdropping. Such stand-alone "session tracking" activation information can be found in the MODIFY command. The tracking enable in the MODIFY command is also required if the termination is removed from the context in the MG and one new termination is added to the same context (as in rebooking cases (Handover)).

The "session tracking" activation should be the tracking reference, the UE identity (IMSI or IMEI), the type of tracking (indicating what type of tracking is required and how the reports are transferred to the OMC) and the OMC ID for Identification purposes included.

The "session tracking" functionality can be disabled in the MG if the MGC requests that the reserved context be removed. Furthermore, can a stand-alone procedure for disabling tracking in the MG to be seen.

The tracking activation information should be defined in the GSM 12.08 standard Contained information.

The Third Generation Partnership Project (3GPP) has no tracking solution for that Specified IM sessions. Therefore, there is no tracking in multiple supplier networks possible. Furthermore, the current versions of the 3GPP  Standardizations have no specifications for tracking functionality in the IMS Universal Mobile Telecommunications System (UMTS) networks provided.

It is an object of the present invention to provide a "session tracking" functionality for IM sessions.

This task is solved by a method for tracking a session or a conversation in a multi-supplier network environment according to the patent entitlement.

According to the invention, two options for implementing the "session tracking" functionality are introduced:
The first option is a "subscriber tracking" similar to GSM tracking. This means tracking report generation in the S-CSCF of the called position. This avoids the lack of the possibility of providing detailed information about the interaction (interworking) between the user equipment (UE) and the IMS when setting up IP multimedia sessions.

The second option is "IM session tracking". This is about an extension of participant and equipment tracking capabilities that enables Creation of a tracking report in all networks involved in the session setup functions is enabled. Without this option, the network operators would be on one Information gathering restricted only by S-CSCF, d. H. You could investigate no problems in the P-CSCFs, the S-CSCF of the remote station, the I- CSCFs, the BGCF, the MGCF and the MG.

The old concept of subscriber and equipment tracking (existing for GSM) is improved in such a way that in the IMS of the UMTS network a broader range Applicability of the "session tracking" function is provided. Hence one Troubleshooting possible in the entire IMS.

By tracking in the MG, the tracking function can provide a detailed Information about the user level and the physical resources used  to be provided. This is especially useful when problems arise side of the user level.

In addition, the MG can provide detailed information about the user level and the physical resources used from the MG to the MGC for each Ge talk report, but there is a high load from the MGC and the cut between MG and MGC. By the present invention this burden can be avoided.

The invention is hereinafter described on the basis of a preferred embodiment game described in more detail with reference to the drawing figures. Show it:

FIG. 1 is a diagram of an IM subscriber registration with a tracking call in the P-CSCF;

Fig. 2 is a diagram of an IM session set-up, with the calling position being tracked;

Fig. 3 is a diagram of an IM session setup, the called position is under Ver;

Figure 4 is a diagram of a session setup when the call in the PSTN or a GSM network is ended and the calling party is under surveillance; and

Fig. 5 shows the session setup when the call is initiated in the PSTN or GSM network and the called party is under surveillance.

The preferred embodiment is below for the case of chase activation in the S-CSCF and P-CSCF described during registration. That is, the SIP INVITE message may contain the tracking call information in the IM session wear.

The figures show the most typical cases of session establishment with regard to the network size zen shown. Up to four different networks can be used in the IM session the network elements involved in the IM session setup also in the same network can be arranged. The I-CSCFs can be present or  not, for example depending on the decisions of the network operators on the ge mutual hiding of the internal network structure. In the case of from the PSTN or Sessions (conversations) originating from the GSM network can either be the connection point be located in the home network or the visited network of the IM subscriber, or it can also exist in a third-party network.

The network elements storing the tracking activation information are in the Figure distinguishable by hatched boxes.

Fig. 1 shows the registration in case the tracking is activated in the HSS before the customer starts the registration. The tracking call is sent to the visited network in the 200 OK SIP message.

Fig. 2 and 3 show an IM session setup between two subscribers, and the manner in which that is sent to the sessio naufbau involved network elements of the tracking call via the chain.

Figure 2 shows the main use case of session tracking when the calling party is under tracking. The P-CSCF recognizes that the calling party is under tracking and inserts the tracking call in the SIP message INVITE. From this point on, all network elements / functions involved are responsible for forwarding the INVITE message with unchanged tracking information and checking it to create the tracking reports.

However, there may be cases where the P-CSCF does not have chase activation owns (for example, the participant wanders in a foreign PLMN in which none Agreement between the network operators for tracking exists, so that the Ver sequence activation was not sent from the S-CSCF to the P-CSCF). In this In this case, the S-CSCF should send the tracking call information to the SIP message INVITE insert. This means that the S-CSCF should continuously check its database whether tracking is enabled for the calling party.

It is noted that the tracking information is not always related to that called Position is sent, it is transmitted by the P-CSCF of the called position from the SIP INVITE message removed.  

Fig. 3 shows the case in which the called position was placed under pursuit. In this case, the pursuit should not be called up in the visited and home network of the calling agency. However, the S-CSCF should find the called position in its database that the tracking should be called for the called position. Therefore, it inserts the tracking call information into the SIP INVITE message. The tracking is called in the Interrogating CSCF (s) (I-CSCF (s)) and the P-CSCF of the called party, similar to the description in connection with FIG. 1.

Fig. 4 shows the session setup when the call ends in the Public Switched Telephone Network (PSTN) or in a GSM network and the calling party is under surveillance. Similar to the AII-IP-to-AII-IP session, the tracking call information is inserted by the P-CSCF (or by the S-CSCF) into the SIP message INVITE, cf. Fig. 2. The SIP message is forwarded to the MGCF with unchanged tracking information via the BGCF, I-CSCF (s) and MGCF. The signaling used on the further path is not SIP, so that the tracking call is not forwarded. Each network element checks the INVITE message for a tracking call and generates the report accordingly.

When the MGCF receives the chase call, it also calls the chase the MG. This is accomplished by inserting the tracking call information into the ADD- sent via the MEGACO interface (Media Gateway Control) Command.

Fig. 5 shows the session setup when the conversation is initiated in the PSTN or GSM network. This is the same as the case shown in FIG. 3. The S-CSCF of the called party reads in its database that the tracking for the called party is to be called and inserts the tracking call information into the SIP message INVITE. The tracking is then called in the I-CSCF (s) and the P-CSCF of the called party.

The signaling messages can be from a radio access network of the third genes ration (3G RAN) or a second generation base station system (2G BSS) originate and can be transparently transferred to the MGC in the MG become. The MGC controls the subordinate MGs via the H.248 protocol. Two MGCs can communicate with each other using the BICC (Bearer Independent Call Control) or SIP-T signaling.  

However, the user level does not send to the MGC, but is sent to the ATM (Asynchronous Transfer Mode) or IP backbone forwarded. In the case of an ATM Backbones is the user level, for example, between the two MGs below Use of AAL2 signaling (ATM Adaptation Layer 2).

A description of the details of the activation / deactivation and the following follows Calling session tracking.

1. Centralized tracking activation / deactivation

Similar to the tracking concept introduced by the GSM specification 12.08 tracking is enabled for participants. The activation / deactivation happens in the HSS, which is the central storage location for the subscriber's data.

Therefore, the usual subscriber management facilities can be used for example using the OMC.

An option to invoke tracking can also be provided in the HSS the packet-switched network domain (PS Network Domain) or exclusively in the IMS. The present embodiment is exclusively based on those in the IMS provided tracking function.

When tracking is activated, the network operator can provide a tracking reference Define, which serves as identification for the tracking reports.

2. Track activation / call a) Pursuit activation in the S-CSCF

During registration, the participant's data is transferred from a UMS to the S-CSCF downloaded and the tracking call data is said to be included there. In case of time-consuming pursuit activation / modification, it is accepted that there is a standardized operation / transaction in the Cx interface, which ensures that modifications of the data entered in the HSS of the part be replicated to the S-CSCF in near real time. The same facility can send ("replicate") the tracking activation data to the S-CSCF be used.  

In the case of local tracking activation, the means for activating are Tracking function for visitor participants at the network operator of the visited Net zes by his own decision. This can be done through administrative Commands are given. This tracking function can be in an actively pending state if the participant in question is not registered in this P-CSCF is, and can be activated when performing such a registration.

b) Pursuit activation in the P-CSCF (only required for session tracking)

During registration after downloading the participant data to the S- CSCF can check the S-CSCF for any tracking activation included in it is. If so, the S-CSCF inserts this information into the SIP message 200 OK and sends it back to the registrant. Therefore, an optional SIP Head (SIP header) can be used. As an alternative, it can also be used in the payload be included in the SIP message. If the P-CSCF forwards the message 200 OK it checks for the presence of the tracking activation information and the P- CSCF stores them locally (together with other subscriber-related data, e.g. S-CSCF address), if it exists, so that it can track reports for can provide the participant's relevant sessions. It is noted that the P-CSCF removes the tracking information from the 200 OK message, so that the participant does not receive them.

In the case of time-consuming pursuit activation / modification, the in the S- CSCF received tracking activation information forwarded to the P-CSCF are made using a similar procedure (protocol) as between the HSS and the S-CSCF. If such an interface is not defined, the tracking activation arriving at the S-CSCF can only be activated with an active forwarded during the session, d. H. if SIP messages between the part be sent to subscribers. Using this path, the S-CSCF can Tracking activation information in each (e.g., the first) SIP message insert and thus forward to the P-CSCF. For this purpose, an optional SIP message headers can be used.

c) Pursuit call in the I-CSCF (s), in the S-CSCF and in the P-CSCF of the geru open position in IM sessions

If the position called is under tracking, none of the aforementioned will be saved Network elements the tracking call data. Hence the persecution in these Network elements called in the session itself. If the persecution in the S-CSCF  and the P-CSCF has been activated, this can be done by inserting at the beginning of the session the tracking call information into the SIP message INVITE. Comes the Tracking activation during an active session, so this information inserted by the S-CSCF in the first SIP message. In both cases one can optional header can be used in the SIP message. This enables tracking call even if not all of the network elements involved track the function. Those who don't interpret this optional head will not generate the persecution report, but the persecutor forward formation. It is believed that the main application of the track function is the activation of the tracking function for the calling party. In this case, tracking can be involved in all of the SIM session setup Network elements can be called. However, it is also possible for those called Place activated tracking to use, but tracking in this case is only called in the network elements that the S-CSCF of the called position are subordinate in the session setup chain.

d) Pursuit call in the I-CSCF (s), the BGCF, the MGCF in IM sessions, that end in PSTN or GSM

Neither of these network elements stores the tracking call data. Hence the Tracking in these network elements called in the session itself. This is done in same way as for the IM sessions described above.

e) Pursuit call in the MG for IM sessions that end in the PSTN or GSM

The MGCF can receive the tracking activation in the SIP INVITE message. After selecting the appropriate MG for the conversation, she prompts you User level connection establishment, by sending a MEGACO- (H.248) - ADD command via the Mc interface. The tracking call information is in inserted this command. The tracking activation comes at the S-CSCF (consequently at the MGCF) during an active session, so tracking activation be inserted into a MODIFY command that is sent to the MG.

3. Persecution deactivation

In S-CSCF and P-CSCF, tracking is deactivated by deregistration.

In the S-CSCF, tracking can be disabled at any time if this information is received via the Cx interface in the subscriber data.  

Compared to P-CSCF, the same chase activation mechanism can be used be used, or if no interface is to be defined. He can start the next active session. If the persecution deactivation arrives with the first message of a session, the P-CSCF should not follow Provide the performance report for this session.

IM session tracking is automatically performed at the end of a session in I-CSCF, the BCGF and MGCF, or in the S-CSCF and P-CSCF of the others (i.e. not tracked) point "deactivated". Tracking is deactivated in the MG when the MGCF requests that the reserved context be resolved.

4. Creation of the tracking report

When determining that a participant is under persecution, or at Reception of tracking activation should include all of the above network functions begin collecting detailed information about the session being tracked.

At the end of the session or immediately after the specific events, these will be Reports are sent to the OMC for analysis so that the OMC can go through multiple Network functions can combine data sent. The call ID of the SIP can included in the persecution reports. The call ID of the SIP can also be made via MEGACO to be sent to the MG.

The S-CSCF can also record the private ID of the tracked participant and the tracker Include the reference in the reports.

The "session tracking" function can be done by building a tracking report Generation intelligence are implemented in the network elements, whereby the pre called network functions are implemented, or the / the pursuit activation / standardized in the aforementioned protocols. The persecution act Identification information can be included in the ADD transaction in the H-248 protocol his. Typically, the MGC requests the transaction ID reservation from the MG using this ADD transaction.

It is noted that the present invention is not limited to the above written embodiment is limited, and to track a session /  Conversation can be used in any multi-supplier network environment can.

Claims (1)

Procedure for tracking a session or conversation in a multi specialist supplier network environment, with the steps of activating a track function in a network element with a gateway functionality Send tracking activation information to the network element.