WO2002028115A2 - Method and system for effective utilizing the switching capacity of local exchanges - Google Patents
Method and system for effective utilizing the switching capacity of local exchanges Download PDFInfo
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- WO2002028115A2 WO2002028115A2 PCT/IL2001/000890 IL0100890W WO0228115A2 WO 2002028115 A2 WO2002028115 A2 WO 2002028115A2 IL 0100890 W IL0100890 W IL 0100890W WO 0228115 A2 WO0228115 A2 WO 0228115A2
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- Prior art keywords
- traffic
- local exchange
- voice
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q3/00—Selecting arrangements
- H04Q3/0016—Arrangements providing connection between exchanges
- H04Q3/0062—Provisions for network management
- H04Q3/0091—Congestion or overload control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q3/00—Selecting arrangements
- H04Q3/58—Arrangements providing connection between main exchange and sub-exchange or satellite
- H04Q3/60—Arrangements providing connection between main exchange and sub-exchange or satellite for connecting to satellites or concentrators which connect one or more exchange lines with a group of local lines
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13039—Asymmetrical two-way transmission, e.g. ADSL, HDSL
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13164—Traffic (registration, measurement,...)
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13166—Fault prevention
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13176—Common channel signaling, CCS7
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13196—Connection circuit/link/trunk/junction, bridge, router, gateway
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/1329—Asynchronous transfer mode, ATM
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13292—Time division multiplexing, TDM
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13298—Local loop systems, access network
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13344—Overflow
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13349—Network management
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13381—Pair-gain system, digital loop carriers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13383—Hierarchy of switches, main and subexchange, e.g. satellite exchange
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13389—LAN, internet
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13395—Permanent channel, leased line
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13399—Virtual channel/circuits
Definitions
- the present invention relates to telecommunication systems and more particularly, to a method and system for sharing switching capacity of switched telephone networks for utilizing their shared resources.
- bypass networks permit all forms of traffic on a telephone system, including various forms of data traffic, to be handled without resulting in significant degradation in service to customers while facilitating the controlled growth of the telephone system to handle rapidly increasing classes and levels of traffic.
- This is accomplished by providing one or more bypass networks in the system, with at least one class of traffic being diverted through such bypass network so as to utilize shared resources of the system.
- the idea of bypassing is described and illustrated with respect to the data traffic constituting the source of congestion in the system, while for the voice traffic of a particular local switch subscribers the basic route via the local loop and the local switch is preserved.
- the above object can be achieved by providing a method for supporting a changing volume of a voice-grade traffic in an access network having a local exchange with a limited capacity ! the method comprising steps of: providing two or more access networks, each having its subscribers and its associated local exchange with a limited capacity; each of the access networks being capable of dividing traffic, outgoing from its subscribers, into the voice-grade traffic portion and data traffic portion, and capable of directing the data traffic portion to a packet network while directing the voice-grade traffic portion to a PSTN network via said associated local exchange; wherein the PSTN network and the packet network are respectively common for said two or more access networks, defining an overload condition of a local exchange as a condition when traffic there-through equals to a predetermined threshold forming at least a portion of the local exchange capacity, defining a normal load condition of the local exchange as a condition when traffic there-through is below said predetermined threshold, detecting the overload condition on one of said local exchanges, the overload local exchange being indicated
- the overload condition definition may be performed based on a particular predetermined daytime schedule. For example, during working hours, one local exchange serving subscribers of an industrial zone is considered overloaded, while another local exchange serving a residence area is considered to be in the normal condition. After the working hours, the residential local exchange may easily become overloaded, while the industrial local exchange will definitely be under-loaded.
- the beginning/termination of the peak hours might be determined based on a preliminarily defined value of the threshold load of the local exchange or based on dynamically monitoring the local exchange by the control plane in the network. In the most simple case (predefined management schedule), after the load fluctuation profile is studied and an appropriate schedule is composed, the latter may become a tool for the load sharing.
- the two local exchanges may form shared resources of the converged network and assist one another during the alternating peak hours.
- the overload condition may be detected during monitoring the local exchange and/or equipment of the access network associated with the local exchange, and this condition is stated when the predetermined threshold is determined.
- the predetermined threshold can be a value reflecting proportion of busy lines in the local exchange, busy channels in the interface between the local exchange and its access node(s), proportion of calls rejected by the local exchange, etc.
- the step of finding the non-overload local exchange can be performed in different ways. For example, the search may be performed in a sequential manner, using messages sent from the overloaded local exchange to other ones in the converged network according to a predetermined list (a decentralized manner). Another way is by applying to a central management entity, which collects the load status information from all local exchanges of the system and is thereby capable of determining a non-overload one for sharing the voice-grade traffic with the overloaded one (a centralized manner).
- Each of said access networks extends between its local subscribers and the local exchange originally predestined to connect the subscribers to the PSTN network.
- the term of voice-grade traffic covers both a part of a digital format traffic flow outgoing from the subscribers' side to the side of a local exchange, and a traffic flow incoming the access network (and its local exchange) from the PSTN network and addressed to the subscribers of said local exchange.
- the step of partially diverting the voice-grade traffic via the overload local exchange can be performed by at least one of the following two ways:
- a system for supporting a changing volume of a voice-grade traffic in an access network having a local exchange with a limited capacity wherein said access network forms part of a converged network comprising a PSTN network, a packet network and at least one additional access network, each of the access networks having its subscribers and its associated local exchange with a limited capacity and each being capable of dividing traffic, outgoing from its subscribers, into the voice-grade traffic stream and data traffic stream, and capable of directing the data traffic stream to the packet network while directing the voice-grade traffic stream to the PSTN network via said associated local exchange;
- the system comprising: control means capable of distinguishing between an overload condition and a normal condition of the local exchanges, and operative to cause at least partial diversion of the voice-grade traffic, previously intended for handling by the overload local exchange, and passing said diverted traffic via said packet network and a local exchange being in the normal load condition, wherein the overload condition of a local exchange is a condition when traffic there-through equals to
- said control means comprise a plurality of control blocks respectively situated at said local exchanges and equipment associated therewith, wherein each of the control blocks is capable of monitoring a particular local exchange and its associated equipment, determining its load condition, and of applying to another local exchange to initiate said diversion if the overload condition is determined in said particular local exchange.
- the control blocks may use proprietary or standard protocols for communication there-between.
- control means may constitute a central Network
- Control Management unit capable of collecting load status information from the local exchanges and the associated equipment and controlling said diversion accordingly.
- the NCM can be preprogrammed to consider any of the exchanges as overloaded during a particular period (hours, days, etc) according to a predetermined time schedule, and to consider it in the normal load condition when the time period terminates. It is understood that the time schedule always reflects fluctuations of the traffic load.
- the NCM may provide continuous monitoring of the local exchanges' load condition.
- the system may comprise one or more load condition monitoring means (LCM) capable of continuously checking current load of respective said local exchanges, detecting the overload condition whenever it appears and informing the NCM accordingly.
- LCM load condition monitoring means
- the LCM function may be performed using the local exchange data base, or by other data bases e.g., of an access node or a gateway associated with the local exchange.
- the LCM functions might be performed by the control blocks situated at the local exchanges and the associated equipment.
- the converged network suitable for the invention comprises two or more access networks.
- Each of the access networks is typically provided with an access node comprising multiplexer/demultiplexer means.
- the access node constitutes a
- DSL Access Multiplexer - DSLAM being capable of receiving a digital format traffic flow received from the corresponding subscribers (e.g., in the form of one or more xDSL lines) and sorting said flow into a data traffic stream and the voice-grade traffic stream (i.e., telephone traffic including both voice and fax traffic), transmitted as follows: the data traffic stream via said packet network to its addressee, and the voice traffic stream - via a gateway to its associated local exchange (LE) and further to the PSTN network.
- the gateway may be integrated with the appropriate DSLAM, but may be configured separately, co-located with the local exchange.
- the system is characterized in that the access node (DSLAM), while sorting the digital format traffic flow received from the subscribers into the data traffic and the voice traffic streams, is capable of controllably changing (reducing and then increasing up to a particular limit) the proportion of the voice traffic stream extracted from said flow for diverting at least a portion of the "potential" voice traffic.
- the diverted traffic can controllably be transmitted from the DSLAM- 1 of the overloaded local exchange LEI, via the packet network: either to the DSLAM-2 of another (non-overloaded) local exchange LE2, then via the corresponding gateway to its non-overloaded local exchange, or directly to the gateway of the non-overloaded local exchange LE2.
- the system may be provided with switching means (such as a Tandem Switch), to controllably divert part of the voice-grade traffic incoming an overloaded local exchange (LEI) from the PSTN network, to another local exchange (LE2).
- switching means such as a Tandem Switch
- control means should be capable of instructing at least one of the following two groups of equipment to partially divert the voice-grade traffic incoming the overloaded local exchange:
- Instruct DSLAM-1 of the overloaded local exchange LEI to reduce the volume of voice traffic "extractable" from the total digital format data flow and transmit the "non-extracted” voice portion of the traffic flow" via the packet network in the digital format, together with the original data traffic stream.
- This non-extracted at least a portion of the voice traffic which is not transferred to its associated local exchange (LEI) is thereby diverted via the packet network to another local exchange (LE2) interconnected with the PSTN.
- L2 gateway To divert the voice traffic in the digital format from the packet network to the LE2, it should be passed through the LE2 gateway either directly, or via another multiplexer/demultiplexer (DSLAM-2) of the system.
- a group of subscribers are connected to their local exchange via an access node (such as DSLAM) which communicates with the local exchange using an interface, such as a standard interface V5.2.
- an access node such as DSLAM
- an interface such as a standard interface V5.2.
- AN access node
- L1 local exchange
- capacity of the interface there-between can be considered equal both to the local exchange capacity (actually, such a capacity is defined by the number of channels available in the interface; some channels not belonging to the interface may exist but can be neglected), and to the access node capacity.
- the local exchange may be provided with more than one access nodes to serve more than one groups of subscribers, and communicate with the access nodes via their respective interfaces.
- the local exchange capacity in this case will be defined by the total capacity of these interfaces (or total capacity of its access nodes).
- the proposed diversion of the voice-grade traffic is usually performed by means of re-routing such a traffic from one access node to another via a common packet network.
- a method for supporting a changing volume of a voice-grade traffic in an access node connected to a local exchange via an interface having a limited capacity comprising steps of: providing two or more of said access nodes, each having its subscribers and its associated local exchange; each of said access nodes being capable of dividing traffic, outgoing from its subscribers, into the voice-grade traffic portion and data traffic portion, and capable of directing the data traffic portion to a packet network while directing the voice-grade traffic portion to a PSTN network via its associated local exchange; wherein the PSTN network and the packet network are respectively common for said two or more access nodes, defining an overload condition of an access node as a condition when traffic there-through equals to a predetermined threshold forming at least a portion of capacity of the interface between the access node and its associated local exchange, defining a normal load condition of the access node as a condition when traffic there-through is below said predetermined threshold, detecting the overload condition on one of said access nodes, the
- the AN1 and AN2 may belong to different local exchanges, though there is an option that both AN1 and AN2 are associated with one and the same local exchange.
- the access nodes belonging to one local exchange use one another as shared resources.
- each local exchange LE is associated with one access node AN
- capacity of a local exchange is understood as capacity of interface between the local exchange and its associated access node.
- the overload/normal load condition of a particular local exchange we will mean the overload/normal load condition of a particular local exchange.
- the local exchanges serve shared resources to one another.
- a system for supporting a changing volume of a voice-grade traffic in an access node communicating with a local exchange via an interface having a limited capacity wherein said access node forms part of a converged network comprising a PSTN network, a packet network and at least one additional access node; each of the access nodes having its subscribers and its associated local exchange communicating with the access node via a limited capacity interface, and each being capable of dividing traffic, outgoing from its subscribers, into the voice-grade traffic stream and data traffic stream, and capable of directing the data traffic stream to the packet network while directing the voice-grade traffic stream to the PSTN network via said associated local exchange; the system comprising: control means capable of distinguishing between an overload condition and a normal condition of the access nodes, and operative to cause at least partial diversion of the voice-grade traffic, previously intended for handling by an overload access node, and passing said diverted traffic via said packet network and another access node being in the normal load condition, wherein the
- said control means may constitute a plurality of logical circuits respectively inco ⁇ orated in the access nodes; each of the logical circuits being capable of monitoring a particular access node, determining its load condition, and of applying to another access node to initiate said diversion of voice-grade traffic if the overload condition of the particular access node is determined.
- said control means may comprise a central network control and management entity capable of performing a centralized control based on information on the load status collected from the access nodes.
- the proposed concept of sharing the voice-grade traffic load allows not only to handle voice calls safely in any peak conditions, but more important - to expand the number of subscribers of the mentioned central office without expanding the central office's capacity, which is very often the requirement in practice.
- By dynamically diverting a portion of the overflow voice calls in the form of data to another shared resource of the network the problem is resolved by the traffic load sharing and more effective utilizing of the shared resources' capacity in the combined network.
- PSTN network should be understood not only as a Public Service Telephone Network, but also as a conventional telephone switched network, which is not obligatory public.
- packet network covers a plurality of modern data-oriented networks comprising networks ATM, Frame Relay, IP and the like.
- Fig. 1 (prior art) is a schematic pictorial representation of the widely known PSTN architecture with a conventional access network.
- Fig. 2 (prior art) is a pictorial representation of a modern converged network where the PSTN network and the packet network are accessed via an access network utilizing xDSL lines and DSLAM/Gateway architecture.
- Fig. 3 is a pictorial representation of one embodiment of the proposed novel architecture where a number of access networks interact with the converged network via shared resources.
- Fig. 4a and 4b are schematic message flow representations of the control process taking place in the converged network when the proposed method is performed, for different call directions.
- Fig. 1 is a schematic illustration of a classic architecture of a public switching service telephone network (PSTN) 10 with one access network (schematically marked 12) enabling subscribers 14 to be connected to any destination via the PSTN network.
- the subscribers 14 are schematically shown as telephone terminal devices, but usually include telephones, fax machines, PBXs and computers via modems.
- the terminal devices are connected via a Digital Loop Concentrator Device 16 to a Local Exchange or Central Office (LE or LE) 18.
- the digital loop carrier system derives multiple channels, typically 64-Kbps voice channels, from a single four-wire distribution cable running from the central office (LE) to a remote site.
- the DLC 16 and LE 18 usually communicate via a standard interface like V5.2 or GR.303.
- V5.2 or GR.303 In the architecture shown in Fig.
- Fig. 2 illustrates a modern access network 22 converged with a packet network 20 (ATM-network in this particular embodiment) offering a technical solution for faster transmission of new types of services.
- Packet networks (ATM, Frame relay, IP network, etc.) are adapted for transmitting packets of digital information.
- DSL Digital Subscriber Lines
- IAD Integrated Access Devices
- DSL Digital Subscriber Lines
- SLAM access node
- DSLAM 30 is responsible for splitting the incoming xDSL traffic flow into two streams: a data traffic stream to be directed via the packed switched network 20, and a voice/fax traffic stream intended to be fed to a Gateway 32, which can either be integrated with the DSLAM, or form a separate unit.
- the Gateway converts the voice traffic stream, obtained in the digital format, into the form understood by a local exchange (LE) 34 to which subscribers of the access network 22 belong.
- L local exchange
- DSLAM can be understood as interconnected with the local exchange LE via a standard interface such as V5.2.
- the local exchange 34 communicates with a conventional PSTN network 36 for transmitting the voice calls.
- Fig. 3 illustrates one embodiment of the newly proposed configuration 40 of the converged network enabling the purpose of the invention to be achieved.
- the configuration comprises at least two so-called local areas: local area A and local area B.
- Each of the local areas may be considered a separate access network of the PSTN.
- Each of the local areas comprises components similar to those illustrated in Fig. 2 i.e., multiple subscribers connected via xDSL lines to its local access node AN (DSLAM in this case) connected to its associated local exchange (LE) via a local Gateway.
- DSLAM local access node
- LE local exchange
- DSLAM supports voice traffic between its subscribers and the PSTN network.
- DSLAMs DSLAM-A and DSLAM-B
- Packet network say, ATM network
- LE-A and LE-B servicing the areas A and B respectively are both located in the common PSTN network marked 44.
- the local exchanges LE-A and LE-B are both connected to one or more controllable Tandem Switches (only one switch is shown and marked 46).
- the control means responsible for sharing the traffic load are shown as a central Network Control and Management unit (NCM) 48 performing centralized control of the system.
- NCM Network Control and Management unit
- the object of the invention is achieved by providing the following traffic load sharing mechanism between the local exchanges LE-A and LE-B.
- voice traffic in the LE-A of the Local Area A may increase during specific peak hours.
- LE-B of the local area B might handle relatively low traffic since this time period is not a peak time at the area B.
- outgoing calls e.g., the calls entering LE-A from the side of subscribers of the area A
- the following actions can be performed by the proposed system:
- this signaling information may be produced, for example, from detecting that a predetermined threshold number of the LE-A lines are busy
- NCM 48 will issue instructions to DSLAM-A and DSLAM-B to prepare reserve or semi-permanent virtual paths VP (or virtual circuits VC) 50 there-between for transferring an extra traffic via the packet switching network 42;
- DSLAM-A will limit a portion of voice traffic stream to be directed to Gateway-A; Say, it may be accomplished by diverting any new voice calls, entering DSLAM-A from xDSL, to DSLAM-B via the VP or VC 50, while marking this diverted calls as an extra-outgoing traffic (the marking can be provided either in-band or out-of-band);
- the NCM 48 receives indication that LE-A is overloaded; - NCM 48 simultaneously confirms that LE-B is not in the overload condition and instructs LE-B that it is going to receive stranger calls which should not be rejected; - NCM 48 instructs DSLAMs to create there-between reserve VC (VT) 50 for extra traffic, (these steps are the same with the first three steps above, and they are already done if the operations of traffic sharing is performed simultaneously in both directions)
- VT reserve VC
- NCM 48 instructs the Tandem Switch 46 to divert new incoming calls intended for subscribers of area A, to LE-B and mark them respectively as an extra incoming traffic intended to be routed via VC 50; - According to instructions of NCM 48, the extra-incoming voice traffic arriving to DSLAM-B is not transferred to xDSL lines, but routed via the VC 50;
- the virtual circuits 50 comprise separate flows of traffic in both directions, forming, for example V5.2 tunnel "voice circuits". It should be noted that in the particular configuration shown in Fig. 3, where the Gateways do not form integral part of the DSLAMs, the virtual circuits 50 for diverting the voice-grade traffic may be formed not between DSLAMs of the cooperating access networks, but directly between DSLAM of the overloaded access network and Gateway of the assisting one. This option is actual both for incoming and outgoing voice-grade traffic.
- NCM 48 could be implemented either by proprietary protocols between the various components of the network, or by utilizing the existing signaling protocols like SS7 and V5.2 (or GR-303).
- Fig. 4a schematically illustrates how the signaling information flows between elements of the system according to the invention, when the control means are decentralized and comprise control logical blocks
- the control logical block of an access node comprises a data bases for monitoring a) status of ports connecting the access node to the subscribers' local loops, b) status of channels available in the interface between the local exchange and the access node, and is operative to initiate forming virtual paths via the packet network when, based on the status information, the interface is considered overloaded.
- the virtual path can be built, for example, by initiating an additional signaling port for emulating a signaling channel via the packet network and by further emulating a plurality of voice-grade traffic circuits via the packet network.
- the logical block of the receiving access node & central office preferably comprises a copy of the data base of the overloaded access node & data base with the map of its local ports. Providing such mutual copies of data bases in the converged network is only a matter of software and some additional memory, and is therefore much more economical than deploying new physical facilities for extending local exchanges.
- Fig. 4a presents management of the traffic load sharing performed for the outgoing calls. The drawing is divided into three horizontal sections by two dotted lines.
- the upper section of the drawing comprises a simplified diagram of a converged network comprising an ATM or IP network 42, a PSTN-like network 44, where two access nodes are marked AN-A and AN-B, respective local exchanges are marked LE-A and LE-B, interfaces there-between are V5.2 interfaces in this example, subscribers of AN-A are marked S, and TE (which constitutes a Tandem Exchange or Switch) plays part of a destination point.
- TE which constitutes a Tandem Exchange or Switch
- the middle section of the drawing presents conventional signaling messages accepted in SS7 networks, which run between a subscriber S, its assigned local exchange LE-A and the tandem switch TE when the local exchange LE-A is not overloaded.
- Signaling message "off-hook” indicates to the equipment of access network AN-A that subscriber S lifted the telephone receiver; a message “establish” indicates that the equipment of AN-A requests establishing a channel in the interface for an outgoing call via the local exchange LE-A.
- LE-A works in a normal condition, it sends back to AN-A a message "establish acknowledged” to confirm recognition of the access node, and a message “allocate” for connecting a free channel in the interface to a particular port number in the access node (which port is associated with the subscribers' local loop).
- the access network AN-A returns to the LE-A a message "allocation complete” signifying that the channel is allocated, after which the LE-A sends to the subscriber a dial tone which gives him an indication that he received a line.
- the subscriber dials a number he needs, and DTMF tones (coded digits of the number) are forwarded to the LE-A via the allocated channel. If the call was not local, i.e.
- LE-A sends via the PSTN network 44 a so-called IAM (initial address message) to establish connection with the destination point.
- IAM initial address message
- the IAM message transmits address and other information relating to the routing and handling of a call.
- the tandem switch TE upon receiving the IAM signal, forwards it to a local exchange (not shown) serving the dialed number.
- the lower section of the drawing comprises a modified set of messages which are performed when the local exchange AN-A is overloaded.
- the fact of overload results in the rejection of a new call outgoing from AN-A, so that the AN-A receives a message "establish Not acknowledged” or "Disconnect” from the LE-A.
- the logical block of the equipment of AN-A in the situation of the interface overload, will send another "establish” message to equipment of the second access node AN-B, which forwards the message to its LE-B.
- the acknowledgement from the LE-B is forwarded by the AN-B to the AN-A, then the allocation messages exchange is performed between the AN-A and LE-B via the AN-B, and the dial tone is sent to the subscriber from the LE-B using the virtual voice channels 50 in the ATM network 42. (It should take less than one second to receive the dial tone after the off-hook.)
- the DTMF digits dialed by the subscriber reach the LE-B via the same voice channels 50, and if the call was not directed to a number belonging to the LE-B, LE-B sends to the switch TE the IAM message for establishing the connection.
- the message is forwarded to its real destination. Fig.
- FIG. 4b illustrates succession of management messages taking place in the converged network in the direction of incoming traffic i.e., the traffic directed from PSTN to subscribes of a particular LE.
- Elements of the pictorial representation are marked identically to the respective ones shown in Fig. 4a.
- the three-section structure of the drawing is also similar to that of Fig. 4a.
- the message flow and routing in this case utilize a rerouting mechanism of protocol ISUP of SS7.
- ISUP Integrated
- Services digital networks User Part is the call control part of the SS7 protocol.
- IAM Message
- LE-A Message
- ACM Address Complete Message
- the local exchange LE-A sends a signal "establish” to the AN-A, and AN-A causes the subscriber's telephone set to ring.
- the AN-A then returns to the LE-A the signal "establish acknowledged" which indicates to the calling party that the telephone rings at the destination.
- the call is established via the PSTN network 44, as usual.
- the lower section of the drawing illustrates how the signaling messages circulate to establish connection with the subscriber S, when the LE-A is overloaded.
- the Tandem Exchange TE
- REL release message
- the TE confirms the end of its correspondence with LE-A by sending a message RLC which means "release complete”.
- the TE uses the ISUP part of the SS7 protocol to send another (rerouted) message IAM to a local exchange which is presently below the predefined load threshold (e.g., LE-B).
- the LE-B sends a standard message "allocate" to its access node AN-B which, in a regular case, cannot confirm the message since the subscriber S cannot be allocated in
- the message "allocate" will be forwarded to the access network equipment AN-A. Due to the declared rerouting, the confirmation "allocation complete” is sent by the AN-A to the assisting local exchange LE-B (and not to its own local exchange LE-A), via the access node AN-B. Upon receipt of the "allocate complete", LE-B confirms to the TE (by message ACM) that address details of the called party are received. Meanwhile, the signal message (“establish ring”) is sent from LE-B to AN-B but, due to the rerouting regime, this connection signal is rerouted to AN-A via the virtual circuits 50 in the ATM network.
- the access node AN-A Upon receipt of the connection signal, the access node AN-A initiates the subscriber's phone ring and sends acknowledgement of the established ring to the access node AN-B which reports it to the local exchange LE-B.
- the local exchange LE-B informs the tandem switch TE, by the message ACM, that the called subscriber is allocated and being contacted.
- a computer program product comprising program code means stored in a computer readable medium for performing said method when the program is run on a computer.
- the computer program product forms part of the NCM, and can particularly be designed for use in conjunction with a system SS7 and the interface V5.2 between the local exchanges and the access nodes.
- the Inventor has resolved not only a problem of temporary overloads in local exchanges, but also the task of increasing a number of subscribers in an access network cooperating with a converged network, without upgrading the existing equipment of local exchanges though preserving the voice quality of service.
- the proposed way has become possible unexpectedly or as a bonus due to efforts invested in resolving the problem of data traffic congestion.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- General Physics & Mathematics (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
- Telephonic Communication Services (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2001294154A AU2001294154A1 (en) | 2000-09-28 | 2001-09-24 | Method and system for effective utilizing the switching capacity of local exchanges |
EP01974643A EP1320999A2 (en) | 2000-09-28 | 2001-09-24 | Method and system for effectively utilizing the switching capacity of local exchanges |
CA002423155A CA2423155A1 (en) | 2000-09-28 | 2001-09-24 | Method and system for effective utilizing the switching capacity of local exchanges |
US10/372,773 US7254228B2 (en) | 2000-09-28 | 2003-02-26 | Method and system for effective utilizing the switching capacity of local exchanges |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IL13876100A IL138761A (en) | 2000-09-28 | 2000-09-28 | Method and system for effectively utilizing the switching capacity of local exchanges |
IL138761 | 2000-09-28 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/372,773 Continuation US7254228B2 (en) | 2000-09-28 | 2003-02-26 | Method and system for effective utilizing the switching capacity of local exchanges |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2002028115A2 true WO2002028115A2 (en) | 2002-04-04 |
WO2002028115A3 WO2002028115A3 (en) | 2002-05-30 |
Family
ID=11074682
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IL2001/000890 WO2002028115A2 (en) | 2000-09-28 | 2001-09-24 | Method and system for effective utilizing the switching capacity of local exchanges |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1320999A2 (en) |
AU (1) | AU2001294154A1 (en) |
CA (1) | CA2423155A1 (en) |
IL (1) | IL138761A (en) |
WO (1) | WO2002028115A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10225913A1 (en) * | 2002-06-11 | 2004-01-15 | Siemens Ag | Method for protecting against overload e.g. in digital subscriber line access multiplexer (DSLAM), involves evaluating address information of messages via logic |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0708570A2 (en) * | 1994-10-18 | 1996-04-24 | AT&T Corp. | Completing telecommunications calls in a competitive environment |
-
2000
- 2000-09-28 IL IL13876100A patent/IL138761A/en not_active IP Right Cessation
-
2001
- 2001-09-24 WO PCT/IL2001/000890 patent/WO2002028115A2/en active Application Filing
- 2001-09-24 EP EP01974643A patent/EP1320999A2/en not_active Withdrawn
- 2001-09-24 CA CA002423155A patent/CA2423155A1/en not_active Abandoned
- 2001-09-24 AU AU2001294154A patent/AU2001294154A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0708570A2 (en) * | 1994-10-18 | 1996-04-24 | AT&T Corp. | Completing telecommunications calls in a competitive environment |
Non-Patent Citations (1)
Title |
---|
VERHOEYEN M: "DELIVERING VOICE SERVICES OVER DSL" ALCATEL TELECOMMUNICATIONS REVIEW, no. 4, 2000, pages 244-249, XP000976726 ISSN: 0013-4252 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10225913A1 (en) * | 2002-06-11 | 2004-01-15 | Siemens Ag | Method for protecting against overload e.g. in digital subscriber line access multiplexer (DSLAM), involves evaluating address information of messages via logic |
DE10225913B4 (en) * | 2002-06-11 | 2005-08-11 | Siemens Ag | Method for overload protection |
Also Published As
Publication number | Publication date |
---|---|
CA2423155A1 (en) | 2002-04-04 |
WO2002028115A3 (en) | 2002-05-30 |
EP1320999A2 (en) | 2003-06-25 |
IL138761A0 (en) | 2001-10-31 |
AU2001294154A1 (en) | 2002-04-08 |
IL138761A (en) | 2005-11-20 |
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