Telephonic communications – Plural exchange network or interconnection
Reexamination Certificate
2000-02-03
2001-09-11
Matar, Ahmad (Department: 2642)
Telephonic communications
Plural exchange network or interconnection
C379S220010, C379S229000
Reexamination Certificate
active
06289093
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for cascading V5 interfaces.
V5 interface standards ETS 300 324 and ETS 300 347 describe an interface between a local exchange and an access network and the functionality in each network element. The access network is the part of a local area network that contains the subscriber's lines. Thus, subscribers and subscriber's lines can be connected to the exchange either directly (direct subscribers) or via various multiplexers and/or concentrators. V5 interfaces enable subscribers belonging to a physically separate access network to be connected to a local exchange using a standard interface.
A dynamic concentrator interface (V5.2) as defined in the ETS 300 347 standard series consists of one or more (1-16) PCM (Pulse Code Modulation) lines. One PCM line comprises 32 channels, each of which with a transfer rate of 64 kbit/s, i.e. 2048 kbit/s altogether. The V5.2 interface supports analogue telephones as used in the public telephone network, digital, such as ISDN (Integrated Services Digital Network) basic and system subscriber lines as well as other analogue or digital terminal equipment based on semi-fixed connections.
A static V5.1 multiplexer interface consists of one 2048 kbit/s PCM line. The V5.1 interface supports the same subscriber types as the V5.2 interface except ISDN system lines.
Terminal equipment can be connected to the subscriber ports of the access node. One access node may have one or more V5 interfaces connected to it. Subscriber ports are created in the V5.1 interface by associating an unambiguous address of each subscriber port with a given address in the V5.1 interface. In the local exchange, this address is created as a V5 subscriber. In other words, each subscriber port has an unambiguous address which is coupled with a V5.1 interface address and which uses a certain time slot (analogue subscribers) or certain time slots (ISDN subscribers) for communication with the local exchange. In the V5.2 interface, too, each subscriber port has an unambiguous address, but the signalling to the local exchange is implemented using a dynamically allocated time slot/dynamically allocated time slots. This means that the BCC (Bearer Channel Control) protocol consistent with the V5 standard allocates the time slots to be used separately for each call.
V5 standardisation aims at creating an open interface for use between a local exchange and an access network. However, no interface for use between the access node and the subscribers within the access network has been defined. Therefore, problems are encountered in connecting subscribers to the access node e.g. via a static concentrator interface. A further problem is that, especially in an environment with multiple suppliers, the solutions of different suppliers for concentrating subscribers in an access network differ significantly from each other, which means that operators do not necessarily have enough choice options regarding suppliers of equipment.
SUMMARY OF THE INVENTION
The object of the present invention is to eliminate the problems described above.
A specific object of the present invention is to disclose a new type of procedure in a data communication system using known and supported standard solutions for cascading V5 interfaces as defined in the above-mentioned standards and for connecting subscribers to an access node. A further object of the invention is to eliminate supplier-specific solutions between subscriber and access node.
As for the features characteristic of the invention, reference is made to the claims.
The procedure of the invention for connecting a subscriber to a telephone network can be implemented e.g. in a data communication system comprising a telephone exchange and a number of subscribers defined in it. Further, the data communication system comprises an access network connected to the telephone exchange via a first V5 interface and comprising a first access node and a second access node. The V5 interface is preferably either a V5.1 or a V5.2 interface consistent with the above-mentioned standards. The second access node is preferably a switching stage through which a number of interconnecting feeders or subscriber lines carrying a relatively light traffic can be connected to a few lines carrying larger amounts of traffic. Using a subscriber terminal connected to the local exchange via the access network and/or directly via the second access node, connections are set up to other subscriber terminals or network elements.
According to the invention, the second access node is connected to the first access node via a second V5 interface, the connection between the subscriber or subscriber terminal and the telephone exchange being thus set up by cascading two V5 interfaces. In a preferred case, the first V5 interface is a standard V5.2 interface and the second V5 interface is a standard V5.1 interface.
As compared with prior art, the invention has the advantage that it makes it possible to create access networks using network components manufactured by any manufacturer. In particular, a V5 interface can be used both between the second access node and the first access node and between the first access node and the local exchange.
A further advantage of the invention is that, since according to the V5 definitions the first access node can be connected to two or more local exchanges e.g. via a V5.2 interface, the invention significantly facilitates the hand-over of subscribers from one local exchange to another local exchange.
Moreover, the invention allows the second access node to be easily connected to the local exchange using a V5 interface either via a first access node supporting the V5 interface or directly via a V5.1 interface.
The protocols common to the first and second V5 interfaces are controlled in the first access node either by a common Control and PSTN protocol object or by separate Control and PSTN protocol objects of each interface. In a preferred case, the protocols to be used in the first V5 interface, such as BCC, Link Control and Protection protocol, are determined in the first access node.
In an embodiment of the present invention, in conjunction with the creation of the second V5 interface, interface parameters are defined for it, said parameters comprising an interface identifier, interface type, identifier of the physical connection to be used, i.e. the number or equivalent of the PCM line, and the voice time slots to be used in the interface. In addition, the Control protocol of the V5 definitions is assigned to time slot
16
. The first and second V5 interfaces are preferably activated independently in accordance with the V5 definitions.
In a preferred embodiment of the present invention, the PSTN signalling between the first and second V5 interfaces is signalled without L3-layer processing consistent with the V5 definitions. This provides the advantage that the first access node will have no need to know anything about national PSTN settings (PSTN mapping), so the implementation becomes considerably simpler.
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9/94, ETS 300 347-1 Signalling Protocols and Switching (SPS); V interfaces at the digital Local Exchange (LE) V5.2 interface for the support of Access Network (AN) Part 1: V5.2 interface specification.
2/94, ETS 300 324-1 Signalling Protocols and Switching (SPS); V interfaces at the digital Local Exchange (LE) V5.1 interface for the support of Access Network (AN) Part 1: V5.1 interface specification.
2/99, International Search Report for PCT/FI98/00619.
1994, “V5 Interfaces between Digital Local Exchanges and Access Networks” Khakzar, pp. 44-50.
Haukilahti Jarmo
Liinamaa Olli
Vehmer Seppo
Altera Law Group LLC
Bui Bing
Matar Ahmad
Nokia Networks Oy
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