Access and Traffic handling

Access and Traffic handling this is designed to provide the student with knowledge about the traffic handling in AXE. Different ways to access the AXE are also mentioned. The analyses that are performed in TCS subsystem in order to set up a call are also described.

Access and Traffic handling ACCESS AND TRAFFIC HANDLING This chapter is designed to provide the student with knowledge about the traffic handling in AXE Different ways to access the AXE are also mentioned The analyses that are performed in TCS subsystem in order to set up a call are also described A number of services are named both for PSTN and ISDN connections and the differences between Bearer-, Tele- and supplementary services are clarified EN/LZT 101 1513 R4A – 283 – AXE Survey Intentionally Blank – 284 – EN/LZT 101 1513 R4A Access and Traffic handling GENERAL The AXE supports a wide range of access products that can be deployed by network operators to meet the service, bandwidth and mobility requirements of subscribers as economically and flexibly as possible AXE can be accessed by subscribers who are (see Figure 8-1) • Directly connected • Connected via a remote subscriber switch (RSS) • Connected via other Ericsson access products • Connected to other access networks which support the V5 interfaces Applications supported by the local exchange PSTN The AXE supports a full range of basic and advanced PSTN services Examples of basic services are alarm calls, abbreviated dialing and priority calls Examples of advanced services are call forwarding, malicious call identification, call completion to busy subscriber and three party calls PSTN/ISDN AXE supports ISDN and PSTN services in the same local exchange The Ericsson ISDN implementation is based on the European telecommunications standards institute (ETSI) standard, known as ISDN-E The combined PSTN/ISDN local exchange offers the subscriber access to a wide range of voice, data and multimedia services, all through a single connection It brings the local business and residential subscribers the benefits of speed and flexibility EN/LZT 101 1513 R4A – 285 – AXE Survey Rural Urban Cu RSS MUX RSM V5.1 Suburban Minilink RSS Freeset FTTC Cu PABX DIAmuX X.25 RSS RAS1000 Cu DRA 1900 Figure 8-1 Accesses to AXE Cu FTTC MUX PABX RSM RSS Copper Fiber to the curb Multiplexer Private automatic branch exchange Remote subscriber multiplexer Remote subscriber switch The different accesses will be described more in detail in chapter 10 In the next part a short description of the different PSTN and ISDN services follow – 286 – EN/LZT 101 1513 R4A Access and Traffic handling PSTN SERVICES Introduction The rapid development of telecommunications and the deregulation of the market have lead to increased competition for network operators Although other applications are growing, telephony services offered by the PSTN continue to be a major application Network operators can maximize their revenue from the PSTN by offering a broad range of services and stimulating use of the network The AXE supports a full range of PSTN services including: • Basic services • Call management services • Business support services • Custom local area signaling services (CLASS) PSTN basic services This service category includes the basic telephony service for the transmission of voice and data It also includes supplementary services such as abbreviated dialing or fixed destination calls Basic PSTN services made available to specific subscribers generate revenues for the operating company without incurring corresponding additional costs The services may not be used that very often, but when needed they have a high value for the subscriber Basic Services provides the facilities in a local exchange that ensure different supplementary services work together PSTN call management services These services provide the operating company with revenue opportunities by offering the end user increased control of and comfort in his telephone usage Services included are: EN/LZT 101 1513 R4A – 287 – AXE Survey • Remote control of supplementary services, which enables end-users to control remotely a service when they are away from their home or office • Distinctive alerting service, which allows four directory numbers, each with its own distinctive ringing, to be assigned to a single line • Change of keyword, which enables end-users to choose and change keywords if they have elected to use one to control PSTN services • Call barring services, which enable end-users to control which types of outgoing calls, can be made • Call forwarding services, which allows the end-users to direct incoming calls to another location • Three party service, which allows an end-user to consult third parties and add teleconferences without having to make several separate calls • Three party call with call transfer, which enables end-users to transfer a call to a third customer and then leave the call • Call waiting service, which informs an end-user, while he/she is having a conversation on the telephone, that another call is waiting • General deactivation service, which enables an end-user to deactivate all currently active subscriber services • Automatic meet me service, which offers end-users the possibility to set up and participate in conference calls without the aid of an operator PSTN business support services These services can be very valuable for especially business customers as they can increase their service level The services generate revenues for the network operator and also increase the utilization of the network Services included are: – 288 – • Changed number announcement service, which is intended for end-users who have moved or changed their telephone number All incoming calls are redirected to a variable announcement machine • Queue service, which enables callers receiving a busy signal to be placed in a queue EN/LZT 101 1513 R4A Access and Traffic handling Custom local area signaling services (CLASS) AXE offers a growing range of caller identification services, known as custom local area signaling services (CLASS) These services provide the basic telephony subscribers with a range of individual functions, features and information that help them get more out of their telephones The services provided with CLASS create subscriber satisfaction and extra revenue from conventional telephony services CLASS services can be charged to subscribers on the basis of a regular subscription or a fee each time a particular service is used Because CLASS services are based on information from the calling party, a switching and transport network, which supports the necessary signaling between exchanges, is required Some CLASS services can be accessed through standard telephones However a display capability is needed to fully exploit the services Dual tone multi frequency (DTMF) or frequency shift keying (FSK) signaling is required to transmit information about the calling subscriber to the called subscriber’s system terminal CLASS services include: EN/LZT 101 1513 R4A • Completion of calls to busy subscriber, which enables calls to a busy line to be completed when the line becomes free • Completion of calls on no reply, where a call receives no answer this service automatically monitors the called subscriber line when activated • Malicious call identification, which enables a customer to request a network operator to identify malicious, nuisance or obscene callers • Calling line identification presentation (CLIP), which enables the identity of a caller to be displayed on the called party’s telephone – 289 – AXE Survey FSK/DTMF A ISUP, TUP/MFC B CID Calling number Figure 8-2 CLIP CID DTMF FSK ISUP MFC TUP Calling identity unit Dual tone multi frequency Frequency shift keying ISDN user part Multi frequency compelled Telephony user part • Calling line identification restriction (CLIR), which enables an end-user to prevent the presentation of his/her number to a called party • Call answering service/message waiting indication enables end-users to have incoming calls directed to a voice mail box ISUP, TUP or TCAP Voice mail box AXE MWI CAS FSK DTMF Tone Figure 8-3 Call answering service/message waiting indication CAS DTMF FSK ISUP MWI TCAP TUP – 290 – Call answering service Dual tone multi frequency Frequency shift keying ISDN user part Message waiting indication Transaction capabilities application part Telephony user part EN/LZT 101 1513 R4A Access and Traffic handling TRAFFIC HANDLING GENERAL With the introduction of the AM concept in AXE system, the structure has been changed The Application Product contains the XSS (eXisting Source System), RMP (Resource Module Platform) and the AMs (Application Modules) The traffic control functions are then implemented in various parts of the system In XSS the Traffic Control Subsystem (TCS) controls and coordinates all the main activities in the various parts of the system involved in call setup, supervision and disconnection phases for both PSTN and old ISDN (non ISDN-E) subscribers In the AM adapted application, the ISDN User Service Application Module (IUSAM) and the Digital Access Service Application Module (DASAM) handle some of the respective procedures of the TCS for new ISDN subscribers, ISDN-E The remaining procedures are performed within XSS (in TCS) or coordinated by it i/c data Seizure phase -Storing of information Setup phase o/g data -Initial data -B-num analysis -Routing analysis -Subscriber analysis -End-of-selection analysis Active phase -End of call supervision analysis Release phase Figure 8-4 Survey of four phases in TCS Functionality such as Reception of Call Information, Analysis of Call Information, Seizure of Route/B-subscriber, Through Connection in the Group Switch, Sending of Call Information EN/LZT 101 1513 R4A – 291 – AXE Survey and Call supervision, release and coordination of functions are all either performed within TCS or coordinated by TCS The traffic control subsystem handles a number of phases in order to complete the call requests TCS is divided in a seizure phase, a setup phase, an active phase and a release phase The first phase for a new call is the seizure phase where data from incoming side are stored in TCS TCS will be passive until end of seizure is received At end of seizure TCS will go in to the setup phase by starting the below listed analyses and functions: • Originating Telecommunication Service analysis • Transmission Medium Requirement analysis • Generation of call reference (In AM environment) • Forced detailed billing • Call event (seizure of register) • Supervision of Register Holding Time • Originating Closed User group • Priority • Network call identification/reference • Flexible call processing (verification of DI) • Flexible call processing (call type derivation) • Equal access If any of the analyses or functions detects that a special action is needed it is done by generating an EOS-code and go directly to the end of selection analysis TRAFFIC CONTROL FEATURES The TCS is capable of handling both PSTN and ISDN calls It supports, also, interworking with subscriber and Intelligent Network (IN) services as well as the group switch with more than 64k MUPs With the introduction of the Application Modularity (AM) concept and the ISDN-E realization, two implementations of ISDN are present: “Old-ISDN”, implemented in the XSS – 292 – EN/LZT 101 1513 R4A AXE Survey At the end of the seizure phase and when the setup phase starts the originating Telecommunication Service Analysis (TSA) and Transmission Medium Requirement Analysis (TMR) are performed in the block TECA The telecommunications service analysis is performed for an originating call It is a function, which is used to analyze the received information and compile the parameters into a few simple service identifiers, which from a network point of view represent a unique service description Telecommunication Service Analysis yields a Telecommunication Service Code, TSC as a result This TSC code is used by other analysis functions, for example in Charging analysis Each TSC code can be defined to identify a specific service For example TSC=2 can be defined to represent the teleservice telephony The Transmission Medium Requirement, TMR analysis is performed for incoming trunk and originating PSTN calls This analysis will define the transmission media that is required in order to provide the specific service defined by the parameter TSC Besides the analysis in TECA block will also define the parameter WSIG, Wanted signaling, in order to define the signaling that is required for the specific service described by the parameter TSC That means that the TECA block will be used in order to identify the required service the transmission requirements in order to provide the service and the required signaling The result of the analysis in TECA block is sent to the RE, Register block that open a record and keep all the results regarding the specific call The RE block also keep the number that is dialed the so-called B-number (A-number is the number of the subscriber that makes the call and B-number is the number of the subscriber that receives the call) The next step should be to perform B-number analysis in order to find out how to make the further connection via the exchange to the right B-subscriber Since the B-number table located in block DA could be quite big it is essential to start the analysis at a point that should give the fastest result In order to find the entry point in the Bnumber table we perform what we call pre-analysis – 296 – EN/LZT 101 1513 R4A Access and Traffic handling This is performed in block PREA The result of the PREA block is a parameter called OBA and that means Origin for B-number Analysis In other words the parameter OBA indicates the entry point in the B-number table The result of the B-number analysis could be that the Bsubscriber is connected in another exchange and that means we have to find how to make connection to that exchange that means we have to find a route going to the other exchange If the result of the B-number indicates that the call is terminated then it means that both A- and B-and B-subscriber are connected to the own exchange and we don’t need to perform route analysis Before a connection to the right B-subscriber can be done we have to check that the B-subscriber has the required service and can receive the information This is done with the aid of blocks SC and SUA One of the results in DA block should be what we call Routing Case, RC The RC indicates where we want to be connected to, the destination If the A-subscriber is in Stockholm and Bsubscriber is in Oslo then the parameter RC will have a value that corresponds the destination Oslo But the call can be connected to Oslo in different ways for example: • From Stockholm to Oslo directly • From Stockholm to Gothenburg and then to Oslo • From Stockholm to Copenhagen and then to Oslo The different alternatives above represent s different routes that carry traffic to the same destination The different routes have different characteristics One route can use as transmission media fiber the other co-axial cable One route can use a CAS signaling system the other one SS7 signaling system Depending on the required service TSC and the corresponding parameters TMR and WSIG, the right route can be selected This is achieved by doing a compatibility check in block TECA This compatibility check means that we compare the parameters for the route with the parameters TMR and WSIG If we find a route where the parameters match each other then we reserve capacity to establish speech connection with the remote side The defined route is a speech route Before this can be done we have to inform the remote side (Bside) that we intend to make a call in order to be prepared for EN/LZT 101 1513 R4A – 297 – AXE Survey digit reception Depending on the signaling system used by the speech route we send the corresponding signaling information The block RE is responsible to make connection to the right block used for signaling and order that block to send signaling information to the remote side First a signaling connection is established between A- and Bexchange and after that the speech connection is done When block RE in exchange A- receives an answer from exchange Bthat everything is ready it orders the GS to establish a speech connection between the incoming and outgoing side of the call When the call has been established the block CLCOF takes over from the block RE and is responsible for the supervision and disconnection of the call The End of Selection Code, EOS describes an action to be taken in the exchange For example when we make a call to a subscriber that has the service call transfer, it means that the receiving exchange has to make a new analysis for the Bsubscriber in order to find where to divert the call That action, the further analysis, will be caused by an EOS code When we call a subscriber and we are connected to an announcement machine this is also caused by an EOS code • Service Indicator Code analysis Service Indicator Code (SIC) analysis offers the possibility for a non-ISDN calling subscriber to use ISDN Bearer services and Teleservices – 298 – EN/LZT 101 1513 R4A Access and Traffic handling ISDN SERVICES General Integrated services digital network (ISDN) provides end-to-end digital connections to support voice, data and video applications in the same network ISDN supports both switched and semi-permanent connections The switched connections include both circuit switched and packet switched connections, which can be handled simultaneously AXE implements ISDN as defined by the European Telecommunications Standards Institute (ETSI) Then it is referred to as ISDN-E The AXE implementation of ISDN in the Local Exchange offers subscribers a range of bearer, tele- and supplementary services Bearer services The Bearer services provide the basic transmission capabilities in the network The range of bearer services that AXE supports are: EN/LZT 101 1513 R4A • Circuit mode speech, which is the bearer service for normal audio quality voice communications • 3.1 KHz audio, which is the bearer service for equipment such as modems and fax • Circuit mode 64 kbps unrestricted, which features no use of echo cancellers or compression and is the bearer service for, for example data communications • Circuit mode 64 kbps restricted, which corresponds to the unrestricted service, however echo cancellers and compression may be used • Packet mode data, which is the bearer service for packet switched data – 299 – AXE Survey Teleservices These services incorporate all aspects of communication between subscribers They include the terminal equipment functions as well as the network functions Examples are telephone and fax Supplementary services These are enhanced services for subscribers, additional to the bearer- and teleservices These services cannot be offered as stand-alone services, and are an important potential source of revenue for network operators Examples include: – 300 – • Direct dialing in (DDI), which enables a caller on a public network to dial in directly to an extension on a private network • Closed user group (CUG), which enables end-users to form groups with different access restrictions • Meet me conference (MMC), which enables an end-user to arrange for a call between more than two participants EN/LZT 101 1513 R4A Access and Traffic handling TRAFFIC HANDLING IN ISDN General This section describes an ISDN-E basic access (2B+D) call between subscribers connected to different exchanges Speech and data may be sent over the B-channels simultaneously, while the signaling messages are sent on the D-channel The description uses the application modularity concept The call case shown in this section describes the call at AM level rather than block level, since the ISDN call handling is a variation of the same general principle used for PSTN calls ISDN-E to ISDN-E call For simplicity we will split the call into three phases: • Basic call setup • Basic call establishment • Basic call disconnection Basic call setup SYSOMAM ISOMAM XSS IUSAM DASAM FOAM APSI RMP DSA AP APZ Figure 8-7 Handling of call by DSA on originating side EN/LZT 101 1513 R4A – 301 – AXE Survey AP APSI DASAM DSA FOAM ISOMAM IUSAM RMP SYSOMAM XSS Application platform Application platform service interface Digital access services application module Digital subscriber access service Formatting and output application module ISDN operation and maintenance application module ISDN user services application module Resource module platform System operation and Maintenance application module Existing source system Handling of call by DSA on originating side The call set-up begins when the user (A-subscriber) lifts the telephone handset This is referred to as OFFHOOK The terminal/telephone sends a SETUP message to the digital subscriber access service (DSA), which is implemented in the existing source system (XSS) (1) The SETUP message indicates the wish to set up the call See Figure 8-7 The digital subscriber signaling system (DSS1) defined SETUP message is a user to network D channel message At reception of the SETUP message, the DSA complex performs syntax check of the message, and informs digital access services AM (DASAM) about the received message (2) The SETUP contains for example calling/called party number and bearer capability information Handling of the call by the originating DASAM At the reception of a new call establishment request from DSA, DASAM requests processor capacity from the application platform service interface (APSI) load regulation service in the resource module platform (RMP) (3) In the request for capacity, DASAM sets the priority value It does this, according to the priority value stored as access data on the access instance, where the call set-up is requested This priority value will determine whether processor capacity is granted at times when traffic is high in the network DASAM itself seizes a message buffer in the RMP and informs DSA (indicating the message buffer pointer and key) to which the SETUP data should be sent in order to continue the call (4) The DSA complex will proceed by storing the received SETUP message, with some additional information, to make it SETUP in the seized message buffer This SETUP message is then forwarded by DSA to DASAM (5) – 302 – EN/LZT 101 1513 R4A Access and Traffic handling DASAM continues the call processing by validating the calling party number received in the SETUP message It checks whether this number is valid for the access or not Using the calling party number and access data, DASAM can determine the list of all B-channels available for the call DASAM can then seize a free B-channel, if one exists, leading to the calling party number (otherwise the call is released)(6) DASAM also seizes an access switch view for the DASAM part of the call See Figure 8-8 SYSOMAM ISOMAM XSS IUSAM DSA FOAM DASAM Message Buffer APSI RMP AP APZ Figure 8-8 Handling of the call by the originating DASAM Handling of the call by the originating IUSAM A SETUP message is then sent by DASAM to the ISDN user services AM (IUSAM) The SETUP message contains for example calling/called party number, priority indicator, terminal identity, message buffer administrative data, channel identification and bearer capability (7) IUSAM compares the received priority indicator with the one stored for DASAM This is done to check if the two values are different If they are different a new check has to be done with the APSI load regulation service (8) IUSAM opens a charging view for the call in the charging service subsystem in the RMP There it stores initial call data, for example register seizure time, in the charging log (9) IUSAM also performs basic service analysis, and stores the basic service, and all output from the basic service analysis, in a EN/LZT 101 1513 R4A – 303 – AXE Survey message buffer in the RMP (10) Next it checks if the subscriber is allowed to use the basic service requested IUSAM then seizes a switching view for the basic call, and connects it to the received access switch view (11) IUSAM orders the switch view to be asymmetric through connected, that is only connected in the terminating — originating direction See Figure 8-9 SYSOMAM ISOMAM XSS IUSAM DASAM FOAM 11 10 APSI RMP AP APZ Figure 8-9 Handling of the call by the originating IUSAM IUSAM checks the basic call subscription properties to be used for the call Then it checks if any default calling party number should be located into the message buffer It also checks if any supplementary service should be invoked due to the reception of a SETUP message Handling of the call by the XSS Since the call originates from a DSS1 ISDN subscriber, IUSAM sends the Initial address message (IAM) to an incoming DJ block in the XSS (12) – 304 – EN/LZT 101 1513 R4A Access and Traffic handling SYSOMAM ISOMAM 12 XSS IUSAM DASAM FOAM APSI RMP 13 AP APZ Figure 8-10 Handling of the call by the XSS To this, IUSAM uses the IUS-XSS or ISDN user part (ISUP) protocol Certain information received in the IAM message enables the XSS to act as an AM such as: • A pointer to the message buffer service where further information is stored • A pointer to the switch views in the connection service • A pointer to the charging view which has been opened in the RMP The connection service for XSS (CXSE), enables the XSS to select, operate and release on-demand, speech paths in the group switch It is the TCS in the XSS, which uses this CXSE service (13) The CXSE service allows the TCS to work with the logical model created by the AMs, in order to establish connections involving ordinary PSTN subscribers, and AMs as users In the XSS the physical path is established using multiple positions (MUPs) The physical path in an AM world is established using switch views Since the XSS must be viewed as an AM according to the AM modeling concept, the conflict between switch views must be resolved To so, we have the logical multiple position switch view (LSV) and logical multiple position (LMUP) EN/LZT 101 1513 R4A – 305 – AXE Survey An LMUP is a cross between switch views and MUPs It acts as a bridge between the XSS and the connection service The XSS views the LMUP as any real MUP, and allows the connection service to translate from logical MUP to real MUP and vice versa Handling of a call in the terminating IUSAM The only difference between the terminating IAM message and the originating IAM is that it passes the terminating logical MUP switch data The terminating IUSAM (14) carries out similar tasks as the originating IUSAM It does basic service analysis, it seizes a terminating switch view The switch view is not through connected It checks if the terminating subscriber is allowed to use the specific basic service The IUSAM also finds the access AM, for example DASAM IUSAM checks if any supplementary services are to be invoked due to reception of the IAM from the originating side A supplementary service can be invoked both on information coming from the IAM, and/or subscription data stored in IUSAM IUSAM checks if the called party number should be sent in the SETUP to DASAM SYSOMAM ISOMAM XSS 14 IUSAM 15 DASAM FOAM APSI RMP 16 DSA AP APZ Figure 8-11 Handling of a call in the terminating IUSAM, DASAM and DSA – 306 – EN/LZT 101 1513 R4A Access and Traffic handling Mapping of elements received from XSS in IAMACM on the ISUP’ protocol to elements sent to DASAM in SETUP on the DSS1’ protocol occurs in IUSAM A SETUP message is then sent via the message buffer to DASAM See Figure 8-11 Handling of a call in the terminating DASAM DASAM selects a B-channel, seizes an access switch view and orders it to be through connected Then it sends the setup information to DSA, and orders DSA to generate a SETUP message to the end user (15) DASAM also starts timers to check that the DSA, and end user, responds within a certain time DASAM informs IUSAM with SETUP SENTANM that the SETUP is sent to the DSA Handling of a call in the terminating DSA DSA translates the received SETUPSETUP SENT message into DSS1 format (16) DSA sends SETUP SENT to DASAM, to indicate that SETUP is sent to the end user See Figure 8-11 Basic call establishment When the B subscriber’s terminal (phone) rings, it responds to the network with an ALERTING message The information contained in the ALERTING message is transferred across the network to the A-subscriber’s user network interface in the form of an address complete message (ACM) The ACM indicates that all the address signals required for routing the call have been received The ACM message also contains information like: • Charging or no charging • The status of the called party • B-party is ordinary subscriber or pay phone • Terminating access is ISDN or not ISDN Once the ACM message has been sent and the data received from the called party has been transmitted to the calling party, the call is said to be in RINGING or ALERTING state When the B-subscriber has answered the call a CONNECT message is sent across the user-network interface, to indicate call acceptance by the called user The CONNect ACK message EN/LZT 101 1513 R4A – 307 – AXE Survey acknowledges reception of the CONNECT message to the called subscriber DSS1 DSS1 DSS1 ISUP ISUP Alerting Alerting Alerting ACM ACM DSS1 Alerting DSS1 DSS1 Alerting Alerting XSS DSA DSA A-sub Connect Connect ack B-sub Connect Connect Connect ack Connect ack ANM ANM Connect Connect Connect Connect ack ack Connect Connect ack Figure 8-12 Basic call establishment ACM ANM ACK DSS1 Address complete message Answer message Acknowledge Digital subscriber signaling system The information contained in the CONNECT message is transferred across the network in an answer message (ANM) towards the A side The A side acknowledges reception of the CONNECT message to the called subscriber by sending a CONNect ACK message The ANM can contain the same type of information as the ACMSETUP It also contains the connected B-party number The ANMREL is the answer message after ringing The call is now established and the A and B subscriber can talk to each other The call is said to be in the ACTIVE state, and charging is started Basic call disconnection When the user replaces the handset, this is referred to as ONHOOK The call disconnection may be initiated by one of the users involved in the call However, if a fault occurs in the communication process, it is the network, which initiates the call disconnection The A terminal/phone sends the DISCONNECT message which indicates that the A subscriber wishes to end the call The – 308 – EN/LZT 101 1513 R4A Access and Traffic handling information in the DISCONNECT message is transferred across the network to the B-subscriber user-network interface in the form of a release message (REL) DSS1 DSS1 DSS1 ISUP ISUP Disconnect Disconnect Disconnect REL REL DSA DSS1 Disconnect DSS1 DSS1 Disconnect Disconnect XSS DSA A-sub Release Relcomp B-sub Release Release RLC RLC Relcomp Relcomp Release Release Release Relcomp Relcomp Relcomp Figure 8-13 Release of the call from the A-side REL RLC Release Release complete The REL message always contains a cause indicator with a cause value The cause value gives the reason for sending the REL message The network responds with a RELEASE message which indicates that the channel and call reference are released The RELEASE message is transferred across the network to the Aside in the form of a RLC message The RLC is the response message to REL The terminal does not release the D-channel until the RELEASE message is received The call connection is then broken The RELEASE message is acknowledged with a RELRLC COMPlete message See Figure 8-13 EN/LZT 101 1513 R4A – 309 – AXE Survey Intentionally Blank – 310 – EN/LZT 101 1513 R4A ... different access restrictions • Meet me conference (MMC), which enables an end-user to arrange for a call between more than two participants EN/LZT 101 1513 R4A Access and Traffic handling TRAFFIC HANDLING. .. Transaction capabilities application part Telephony user part EN/LZT 101 1513 R4A Access and Traffic handling TRAFFIC HANDLING GENERAL With the introduction of the AM concept in AXE system, the structure... EN/LZT 101 1513 R4A Access and Traffic handling GENERAL The AXE supports a wide range of access products that can be deployed by network operators to meet the service, bandwidth and mobility requirements