EP1295488A1

EP1295488A1 - A method and system for managing communication traffic

Info

Publication number: EP1295488A1
Application number: EP01937076A
Authority: EP
Inventors: Lars-Olof Haster
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2000-05-31
Filing date: 2001-05-28
Publication date: 2003-03-26
Also published as: AU2001262843A1; CN1432257A; SE0002027D0; WO2001093605A1; CN1193625C

Abstract

A method and a system for setting up a connection over a dedicated connection interface between a user (202) connected to an access network (200), and an access resource (212), also connected to the access network (200). The impact on signalling messages, being defined for a V5.2 interface between the access network (200) and a service node (204) for setting up the connection, is minimised by using an existing standardised V5.2 identity field for uniquely identifying the access resource (212). A free V5.2 address identity, which is not used for links of the V5.2 interface (208), is used for identifying the access resource (212).

Description

A method and system for managing communication traffic TECHNICAL FIELD

The present invention relates to a method and a system for managing communication traffic. In particular, the invention deals with the handling of call requests from users being connected to an access network.

BACKGROUND OF THE INVENTION AND PRIOR ART

Telecommunication end-users are typically connected to an access network (AN) for communicating with other end- users or service providers. The access network is thus capable of routing calls from the end-users within the access network as well as to other networks, such as a public telephony- network (PSTN) and the Internet, for connecting the end-users with other users or service providers . The end-users are thereby able to make a variety of different calls, such as voice calls, video calls, web surfing and media streaming. The end-users may be equipped with one or more terminals, such as telephone sets, mobile phones, PCs, TVs, with some kind of communication unit which is connected to the access network. The connection may be either fixed or wireless . In the following text, any^' end-user and/or terminal will be referred to simply as "user" .

Fig. 1 is a schematic view of an exemplary prior art telecommunication system including an access network 100. having a plurality of users 102 connected thereto. The access network 100 is connected to a service node 104-, acting as a gateway to a PSTN 106, via a standardised communication interface 108. The service node 104 may be a local exchange or the like. The PSTN 106 comprises further service nodes 110, 112, acting as gateways to other networks 114, 116, e.g., private networks, the Internet, Local Area Networks (LANs) etc .

The European Telecommunications Standard Institute (ETSI) has defined standards relating to interfaces between different telecommunication networks, such as the interface 108 between the access network 100 and the service node 104. Such interface standards specifies a communication protocol comprising predefined messages and data fields, such as address fields . One such standard used between access networks and public networks is the V5.2 standard (EN 300 347-1), which is used in concentrating interfaces having a limited number of channels, being fewer than the number of users 102 connected to the access network 100. The V5.2 interface may therefore become congested with calls during peak hours .

The V5.2 interface was originally designed for ordinary voice calls. However, there has been a shift towards data traffic in recent years where many users accesses the Internet via the V5.2 interface and the PSTN. Data traffic, e.g., over the Internet, is different from ordinary voice traffic since actual transmissions of data are relatively short-lived and bursty, although the connection is usually established during a relatively long time. For example, when a homepage has been downloaded to a PC or a mobile phone, the user wants to study the homepage before the next action is taken. This behaviour will cause conventional traffic models based on voice calls, which where used for dimensioning the V5.2 interface, to be less valid.

In the International patent application WO 98/58502, which is incorporated herein by reference, a telecommunication system is disclosed addressing this problem. In the system described in WO 98/58502, a user (TE) , being connected to an Access Network (AN) , sends a request for Internet traffic, which is detected by a Local Exchange (LE) being connected to the AN via a V5.2 interface. An Internet connection is then routed from the TE to an access server (R-AS) in the AN, which is directly connected to an Internet Service Provider (ISP) via a dedicated connection interface which is more suitable for long time data connections than the V5.2 interface. Thereby, a function is provided in the AN and the LE enabling long time connections between a user and the Internet to take place via the access device over the separate interface, rather than over the V5.2 interface between the AN and the LE . Thus, when the LE detects an Internet call request from a TE, the LE sends a BCC (ALLOCATION) message back to the AN for setting up a connection between the TE and the R-AS. However, it is not described in WO 98/58502 how the R-AS is identified in the BCC (ALLOCATION) message.

SUMMARY

It. is an object of this invention to provide a simple way of routing data traffic over a dedicated connection interface with a minimum impact on the existing standardised signalling messages over the V5.2 interface between an access network and a service node for setting up the connection. This object and others are achieved by providing a method and a system for setting up a connection between a user connected to an access network and an access resource, also connected to the access network, using the standardised V5.2 identity field for uniquely identifying the access resource. When a connection request from a user to a specific service provider or dedicated network is received at a service node, the service node determines that a connection should be established between the user and a corresponding access resource. An allocation message is then transmitted, comprising an identity uniquely identifying the access resource, from the service node to the access network. In response to the allocation message, the access network sets up a connection between a user port of the user and the access resource.

It is not obvious how to uniquely identify the target access resource in the allocation message over the V5.2 interface to the access network. There is a problem to - introduce a new address field for accommodating identities of specific access resources and their interfaces, since protocol modifications of the V5.2 interface would then be necessary with respect to messages and information elements. This would thus require that both sides are updated properly, which can be complicated in global networks with many players. According to the invention, the problem is solved by using the V5.2 identity field, which is an existing already defined protocol element in the V5.2 interface standard, for uniquely identifying the access resource. The need for introducing a new address field is thereby eliminated. It is possible to use the existing V5.2 identity field since there are typically a number of free address identities available which are not used for the links of the V5.2 interface. In this way, new access resources can be established and identified with a minimum impact on the V5.2 interface standard . BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail and with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of an exemplary telecommunication system according to prior art .

Fig. 2 is a schematic view of a telecommunication system according to the invention.

Fig. 3 is a signalling scheme illustrating different steps carried out in the system shown in Fig. 2 when setting up a connection between a user and an access resource.

DESCRIPTION OF PREFERRED EMBODIMENTS

In Fig. 2, a telecommunication network according to the invention is shown, comprising a plurality of users 202 being connected to an access network 200. The access network 200 is further connected to a service node 204, acting as a gateway to a public telephony network (PSTN) 206, via a V5.2 interface 208 comprising a limited number of communication links 208a.

The V5.2 standard defines an 8-bit address field in signalling messages, whereby it is possible to uniquely identify 256 different addresses. However, a typical V5.2 interface 208 comprises a much lower number of links or channels 208a, e.g. 16 links, each capable of carrying 2048 kbit/s. There are hence a number of free addresses or link identities which are never used in the V5.2 interface 208. According to the present invention, these free addresses are used for addressing other functions and resources than those of the V5.2 interface 208, which will be explained later.

In Fig. 2., the access network 200 is also connected to a plurality of access resources 212, of which three are shown, 212a-c. The term "access resource" is used in this context to generally denote a device, server or node providing access to and communication with at least one specific service provider or dedicated network. In this example, the access resource 212a is connected to an Internet service provider 214 for communication over the Internet 216.

210 denotes a collection of various interfaces or links 210a from the access network 200 towards the access resources 212, each interface or link 210a preferably using a communication protocol suitable for the characteristics of the service being provided. The interfaces or links 210a towards the access resources 212 are separate from the V5.2 interface 208 towards the service node 204. The access resources 212 may be physically implemented in any of: the access network 200, each respective service provider, and separate nodes located therebetween .

When a user 202 sends a request for a connection with a specific service provider and/or dedicated network, such as the Internet, the request is forwarded by the access network 200 to the service node 204. The request includes an indication of the corresponding access resource 212, which is detected by the service node 204, e.g., by reading a B-number in the request. The service node 204 then orders the access network 200 in an allocation message to set up a traffic connection directly between a port of the user 202 and the identified access resource 212 over the corresponding interface 210a. In this way, the traffic connection will not take place over the limited V5.2 interface 208. Only a control signalling connection may be maintained over the V5.2 interface 208 during the traffic connection, using a control channel shared with other users .

It is not obvious how to uniquely identify the target access resource 212 in the allocation message over the V5.2 interface 208 to the access network 200. If a new address field for accommodating identities of specific access resources 212 and their interfaces is introduced, protocol modifications are necessary of the V5.2 interface with respect to messages and information elements. However, this is a cumbersome process requiring that both sides are updated properly, which can be quite complicated in global networks with many players .

According to the invention, the existing V5.2 identity field is used for uniquely identifying the access resource 212a. This is possible, since there are typically a number of free address identities available which are not used for the links of the V5.2 interface 208, as mentioned above. Thus, when a connection request from the user 202 to the Internet service provider 214 is received at the service node 204, logic in the service node 204 determines from the received connection request that a connection should be established between the user 202 and the access resource 212a. An ALLOCATION message is then transmitted, comprising a V5.2 identity field uniquely identifying the access resource 212a, from the service node 204 to the access network 200. The V5.2 identity field is an existing protocol element in the V5.2 interface standard. In response to said ALLOCATION message, the access network 200 sets up a connection between a user port of the user 202 and the access resource 212a. By using the already existing V5.2 identity field for identifying the access resource 212a, modifications to the V5.2 interface 208 protocol are avoided for the connection set-up.

In Fig.3, an exemplary signalling scheme is shown, comprising different signalling steps carried out over the V5.2 interface between the access network 200 and the service node 204 when setting up a traffic connection between a user 202 and the Internet service provider 214 via the access resource 212a. In this example, standard messages for setting up a PSTN connection are used. However, it is also possible to apply the same or corresponding method to other standards, such as for ISDN (Integrated Services Digital Network) connections. The messages transmitted will then be other corresponding messages, such as a SETUP message instead of an ESTABLISH message, etc.

Thus, the following signalling steps are carried out when the user 202 initiates a connection, as indicated by the arrow 300, with the access network 200. First, an ESTABLISH message 302 is transmitted to the service node 204 identifying a user port (UP) of the user 202, in this example, UP=73. The service node 204 then allocates a connection link of the V5.2 interface 208, in this example, V5.2ID=5, and returns an ALLOCATION message 304. Upon reception of the ALLOCATION message 304, the access network 200 replies with an ALLOCATION COMPLETE message 306, and the service node 204 in turn returns an ESTABLISH ACKNOWLEDGE message 308. The user 202 now gets a dial tone and can send a connection request, as indicated with the arrow 310, over the allocated connection link, using a B- number or the like indicating that a data connection is to be set up to the Internet service provider 214.

When the service node 204 has received the complete B-number from the user 202, logic in the service node 204 determines that a traffic connection is to be set up between the user port of the user 202 and the access resource 212a, based on the received B-number. The service node 204 then transmits a new ALLOCATION message 312 to the access network 200 over the V5.2 interface comprising a V5.2 identification of the access resource 212a, V5.2ID=240 in this ₍example, and the number of the user port, UP=73. The access network 200 returns an ALLOCATION COMPLETE message 314 to the service node 204 in response to the ALLOCATION message 312.

The V5.2 identifications of the access resources 212 comprises predetermined V5.2 identities not used for the V5.2 interface. If 16 links are used in the V5.2 interface, V5.2ID=1-16 may be used for identifying those links, leaving V5.2ID=17-256 available for identifying the access resources 212. Thus, V5.2ID=240 is used for uniquely identifying the access resource 212a in this example.

Returning to Fig. 3, when the access network 200 receives the new ALLOCATION message 312 having V5.2ID=240, this is interpreted by the access network 200 as an instruction to disconnect the traffic connection link V5.2ID=5 established over the V5.2 interface. Instead, the access network 200 sets up a new traffic connection, as dictated by UP=73 and V5.2ID=240, between the user 202 and the access resource 212a for communication with the Internet service provider 214. Furthermore, when the service node 204 receives the ALLOCATION COMPLETE message 314 from the access network 200, ' the service node 204 releases the V5.2ID=5 link used for transmitting the dial tone or receiving DTMF (Dual Tone Multi- Frequency) signals from the access network 200. A control signalling link between the user port 73 and the service node 204 may be maintained over the V5.2 interface for supervising the traffic connection between the user 202 and the access resource 212a. Typically, one of the channels in the V5.2 interface is used for such control signalling of several users. After the ALLOCATION COMPLETE message 314, transmission may thus begin, as indicated in Fig. 3.

Later, the call will end when the user initiates a release of the call using a conventional release procedure defined for PSTN. If the connection is a ISDN connection a corresponding procedure is initiated. Thus, when a release message is received by the service node 204, the connection is released in a conventional way, not shown. Also, the connection with the access resource 212a is released by sending a DE-ALLOCATE message 316 from the service node 204 to the access network 200, which replies with a DE-ALLOCATE COMPLETE message 318.

Finally, if a fault occurs in the access resource 212a, a fault will be indicated to the manager of the access resource 212a, which in turn will generate an AN-FAULT message ■ to the access network 200. This function is useful, since the service node^' 204 may mistakenly specify an address identity in the ALLOCATION message 312 which is not defined' in the access network 200.

Claims

1. A method of setting up a connection in a telecommunication network between a user (202) being connected to an access network (200) , and an access resource (212) being connected to the access network (200) , wherein the access network (200) is connected to a service node (204) over a V5.2 interface (208), characterised by the steps of : - receiving a connection request from the user (202) , setting up a connection link (208a) for the user (202) over the V5.2 interface (208) from the access network (200) to the service node (204) , transmitting an allocation message, comprising a V5.2 identity field uniquely identifying the access resource (212) , from the service node (204) to the access network (200) if logic in the service node (204) determines from the received connection request that a connection should be established between the user (202) and the access resource (212), wherein the V5.2 field is an existing protocol element in the V5.2 interface standard, and setting up a connection by the access network (200) between a user port of the user (202) and the access resource (212) in response to said allocation message.

2. A method according to claim 1, characterised in that the received connection request includes an indication of the access resource (212) .

3. A method according to claim 1 or 2 , characterised in that the access network (200) disconnects the connection link (208a) over the V5.2 interface (208) in response to receiving the allocation message.

4. A method according to any of claims 1 - 3, characterised by the further step of returning an ALLOCATION COMPLETE message from the access network (200) to the service node (204) in response to receiving the allocation message.

5. A method according to claim 3 , characterised in that a control signalling link is maintained between the user port of the user (202) and the service node (204) over the V5.2 interface (208) for controlling the connection between the user (202) and the access resource (212) .

6. A method according to any of claims 1 - 5, characterised in that received connection request is a request for connection to the Internet (216) , and that the access resource (212) is further connected to an Internet service provider (214) .

7. A telecommunication system comprising an access network (200) , an access resource (212) connected to the access network (200) , and a service node (204) also connected to the access network (200) over a V5.2 interface (208), characterised by that the system further comprises: - means for receiving a connection request from a user (202) being connected to the access network (200) , - means for setting up a connection link (208a) for the user

(202) over the V5.2 interface (208) from the access network (200) to the service node (204) ,

- means in the service node (204) for determining if a connection should be established between the user (202) and the access resource (212) , based on the received connection request,

- means for transmitting an allocation message, comprising a V5.2 identity field uniquely identifying the access resource (212) , from the service node (204) to the access network (200), wherein the V5.2 field is an existing protocol element in the V5.2 interface standard, and

- means in the access network (200) for setting up a connection between a user port of the user (202) and the access resource (212) in response to said allocation message.

8. A telecommunication system according to claim 7, characterised in that the connection request includes an indication of the access resource (212) .

9. A telecommunication system according to claim 7 or 8, characterised in that the system further comprises means in the access network (200) for disconnecting the connection link (208a) over the V5.2 interface (208) in response to receiving the allocation message.

10. A telecommunication system according to any of claims 7 - 9, characterised in that the system further comprises means for returning an ALLOCATION COMPLETE message from the access network (200) to the service node (204) in response to the allocation message.

11. A telecommunication system according to claim 9, characterised in that the system further comprises means for maintaining a control signalling link between the user port of the user (202) and the service node (204) over the V5.2 interface (208) for controlling the connection between the user (202) and the access resource (212) .

12. A telecommunication system according to any of claims 7 -

11, characterised in that the connection request is a request for connection to the Internet (216) , and that the access resource (212) is further connected to an Internet service provider (214) .

13. A telecommunication system according to any of claims 7 -

12, wherein a plurality of access resources (212) are connected to the access network (200) , characterised in that each access resource (212) is identified by a V5.2 identity.