Telefonaktiebolaget Lm Ericsson (publ)

Lars-G&ouml;ran Petersen

Mattias &Ouml;stman

Arne Lundb&auml;ck

Ulf Erik Ekstedt

Patrik Wiss

Gunnar Larsson

Karl Anders N&auml;sman

Johan Mikael Agnevik

Lars G&ouml;ran Vilhelm Eneroth

Staffan Andersson

Peter Carl Birger Lundh

Hans Magnus Broberg

Ola Dagberg

Hans Peter Lippelt

Per Erik Filip Sydhoff

Ola Engstr&ouml;m

A communications network ( ) has ATM cells with AAL2 protocol packets carried on a first interface ( ) between two nodes ( ) of the network. Using the AAL2 protocol packets, many user channels are multiplexed onto one ATM VC between the two nodes. In one of the two nodes designated as a control node ( ), user channels are terminated by mapping AAL2 packets of the user channels into modified ATM cells having a AAL protocol different than AAL2. The AAL protocol utilized for the modified ATM cells, termed AAL2 prime, requires that AAL2 packets carried in the ATM cell payload be whole packets and that the ATM payload not have an AAL2-type start field. Preferably, in the AAL2 prime protocol only one whole AAL2 packet is carried per ATM cell payload. Termination of the AAL2 user channels at the control node preferably occurs at a pooled and centralized resource termed a cell handling unit ( ). The provision of the cell handling unit ( ) and the AAL2 prime protocol advantageously allows standard ATM equipment, e.g., an ATM switch ( ), to be employed. A mobile telecommunications network is provided as an example illustrated embodiment.

Asynchronous transfer mode system handling differing AAL protocols

A gateway (MG ) interconnects telecom networks (N ,N ) of different types with different signal formats (ATM,IP). A first control unit (CC ), connected (C ) to a server, controls connection set up. A second control unit (RC ) provides telecom functions (F -F ), such as speech coder/decoder or echo extinguisher, to the connection. A third control unit (BC ) establishes connections and sets up switch functions (CP -CP ) corresponding to the different signal formats (ATM,IP). A signal format converter (CP ) converts to/from a common signal format (COM ) that the telecom functions uses. A speech request goes via the server to the first control unit (CC ), which requests telecom function (F ) by the second control unit (RC ). This returns the address (ADR ) of the telecom function to the first control unit (CC ) which sends the function address (ADR ) and the network address (ADR ) of the connection to the third control unit (BC ). This interconnects the corresponding switch function (CP ) and the telecom function (F ) after conversion to the common signal format (COM ) in the signal format converter (CP ). The first control unit (CC ) thereafter requests connection to the next node from the third control unit (BC ), which establishes and indicates the connection (C ) to the first control unit (CC ). This requests setting up of a corresponding switch function (CP ) by the third control unit (BC ), which connects together the switch function with the telecom function (F ) after reconversion of the signal format. The functions (F -F ;CP -CP ) are hardware or software. They can easily be supplemented for new network types or new telecom services.

Method and a device in telecommunication systems

An asynchronous transfer mode (ATM) switch ( ) has plural switch ports ( ) connected by respective bidirectional links ( ) to a switch core ( ). Connected to each switch port is a corresponding row column unit ( ), each row column unit managing the writing of service cells to one row of cross point units ( ) and the reading of service cells from one column of cross point units. The bidirectional links between each switch port and its corresponding row column unit of the switch core carry both service cells and control cells. An interactive exchange of control cells is implemented to sequence operation of the switch core. The operations particularly dependent upon control cell generation include transmission of service cells from the switch core; transmission of pollstate control cells from the switch core; retrieval of contents of certain control registers maintained by the switch core; and synchronization procedures. Pollstate information, indicative of &ldquo;occupied&rdquo;/&ldquo;free&rdquo; status of selected ones of the cross point units, is transmitted in pollstate control cells. The pollstate control cells are generated and transmitted either (1) in response to a particular control cell evocative of the pollstate information, or (2) upon a change of absence/presence (e.g., free/occupied status) of a predetermined number of the affected cross point units.

Asynchronous transfer mode switch providing pollstate status information

A queuing system ( ) stores a package ( ) derived from an ATM cell, the package including an internal interface header (IIH) and either an ATM cell payload or an AAL packet. The queuing system comprises a queue ( ) for storing the package, as well as a processor which executes plural functions. A time stamping function applies a time stamp upon storage of the package in the queue. The time stamping function can apply the time stamp to a package as replacement of the internal interface header. A time stamp checking function uses the time stamp to make a determination whether the tenure of the package in the queue is longer than permissible. The time stamp checking function can make the tenure determination in conjunction with a potential readout of the package from the queue. Alternatively, time stamp checking function can make the tenure determination when invoked by a queue monitoring function which monitors a fill level of the queue (e.g., when a queue fill level exceeds a threshold). A discard function is provided for discarding the package if the tenure of the package in the queue is longer than permissible.

ATM time stamped queuing

The invention relates to a method of changing the size of mini cells belonging to an individual connection during an ongoing connection. A control mini cell is used for this purpose. The control mini cell is transported either in a separate connection or in the same individual connection the mini cell size of which it shall change. Depending on system design the control mini cell is handled either at the control plane by the operation and maintenance system of the telecommunication network or is it handled at the traffic plane by transmission equipments.

Method of indicating mini cell size

An ATM switching node has an ATM switch ( ) to which at least one inter-node physical link ( ) is connected. In addition, a cell handling unit ( ) connected to the ATM switch has a centralized queuing resource ( ) which queues ATM cells which are to be routed through the ATM switch for transmission from the node on the physical link. ATM cells destined for the physical link from the queuing resource are discharged from the queuing resource in accordance with a parameter of the physical link. The parameter is preferably the capacity (e.g., transmission rate) of the physical link. In the illustrated embodiment, the node is one of the following nodes of a cellular telecommunications network: a base station ( ); a base station controller ( ); a mobile switching center ( ).

Coordinated cell discharge from ATM queue

A method of multiplexing a plurality of virtual channel connections into a single channel is disclosed. Each of the virtual channel connections is made up of a plurality of minicells within an AAL protocol. The user to user indication field of the minicell is used in addition to the connection identifier to identify each of the virtual channel connections. A method is also disclosed for demultiplexing virtual channel connections from a single channel into AAL minicells.

Extended AAL2 connection identifier

A distributed voice mail system in a network includes a server in a control layer of the network and one or more media gateways in a connectivity layer of the network, wherein the server controls resources in the media gateways to provide distributed voice mail services.

Distributed voice mail system

An ATM switching node has a queuing resource ( ) connected to an ATM switch core ( ). The queuing resource provides centralized queuing for ATM cells destined for routing through the ATM switch core to plural output links. The ATM switch core routes an ATM cell destined for any output link requiring queuing to the centralized queuing resource. ATM cells for output links not requiring queuing are not directed to the queuing resource. The queuing resource has a link multiplexer ( ) for each output link which is handled by the queuing resource. Each link multiplexer has both a first stage ( ) and a second stage ( ). The second stage comprises plural queues ( ) for storing ATM packets and a second stage multiplexer ( ) for selecting the ATM packets stored in the plural queues of the second stage for transmission to the first stage. The first stage comprises plural queues ( ) for storing ATM cells and a first stage multiplexer ( ) for selection of ATM cells including ATM cells formed of multiplexed ATM packets of the second stage for discharge from the queuing resource. The centralized and selective queuing resource obviates the necessity for queuing at each terminal board connected to the ATM switch core.

Centralized queuing for ATM node

An asynchronous transfer mode (ATM) switch ( ) has plural switch ports ( ) connected by respective bidirectional links ( ) to a switch core ( ). Connected to each switch port is a corresponding row column unit ( ), each row column unit managing the writing of service cells to one row of cross point units ( ) and the reading of service cells from one column of cross point units. The bidirectional links between each switch port and its corresponding row column unit of the switch core carry both service cells and control cells. Cells of differing sizes are carried on the bidirectional links between the switch core and the switch ports. Service cells have a differing cell size than the control cells, and the cell size of the service cells need not necessarily be uniform. Differing types of control cells&mdash;link connection control (LCC) cells and link synchronization control (LSC) cells are provided. The link connection control cells (LCC) are used e.g., to read and write control data into and from control registers of the switch core. The link connection control cells (LCC) include cells of two formats&mdash;a bitmapped format (for reading/writing with respect to bitmapped control registers) and a &ldquo;coded&rdquo; format (used for input/output operations for some bitmapped as well as non-bitmapped registers).

Asynchronous transfer mode switch

Within an ATM node, a cell handling unit (CHU) receives incoming ATM cells from an ATM switch and provides outgoing ATM cells back to the ATM switch. The cell handling unit consults a combined or consolidated table to obtain ATM parameters (e.g., VCI) for use in headers of outgoing ATM cells. The combined table can be utilized both for ATM cells with AAL2 protocol and ATM cells of a second type AAL protocol. The second type AAL protocol is preferably AAL2 prime, which requires that AAL2 packets carried in the ATM cell payload be whole packets and that the ATM payload not have an AAL2-type start field. The combined table is structured to have plural intervals, including a first interval for AAL2 protocol connections and plural other intervals for the second type AAL protocol connections. Each row for the AAL2 protocol interval associates (1) a unique incoming VCI value; (2) an output link value; (3) an outgoing VCI value; and (4) an offset value. The offset value points to the one of the plural intervals for the second AAL protocol connection. Each of the rows for the table intervals for the second AAL protocol connections associates (1) an incoming VCI value; (2) a channel identifier (CID); (3) an output link value; and (4) an ATM parameter for use in an ATM header of an outgoing ATM cell.

Combined header parameter table for ATM node

A multi-stage ATM node ( ) comprises plural ATM switches ( ) connected together in cascading fashion. A tagging unit (BP/TU) appends a tag ( ) to a cell which is to be routed through the ATM node. The tag comprises, e.g., a transfer list ( ) of destination addresses for switching of the cell through the ATM node. For monitoring purposes, a node performance monitoring manager ( ) defines one or more segments of monitored cell travel through the plural ATM switches of the ATM node, and then selectively starts and stops monitoring with respect to the defined segment. A terminating monitoring unit at a terminating end of the segment uses the tag of a received cell to determine whether the received cell is subject to performance monitoring, and also prepares a termination unit report. The node performance monitoring manager further causes generation of monitoring management cells which also bear a tag, including a monitoring activation cell; a response cell; and a monitoring result cell. The monitoring result cell includes monitoring data. Selective starting and stopping of monitoring over a defined segment is facilitated by additional monitoring management cells which have either a start code or a stop code included in their tags.

Segmented performance monitoring of multi-stage ATM node

A method of indicating the length of a mini cells in a mobile telephony network. Non linear coding of a short fixed length field in the header of the mini cell is described. Either an extension bit method or an extension code method is used to extend the length field so as to increase the number of length values available for coding of the mini cell sizes. The length of a mini cell is indicated in the individual mini cell or is indicated indirectly using a CID/length mapping table. Mini cell sizes are changed during a connection and methods are described for doing this. Cell header reading devices for extracting user information of individual mini cells are described. A mobile telephone network using the cell header reading devices is described.

Growing community of inventors

Tumba, Sweden

Lars-Göran Petersen

Growing community of inventors

Tumba, Sweden

Lars-G&ouml;ran Petersen

Lars-Göran Petersen