Background of the invention Conventional conferencing systems comprise a number of end- points communicating real-time video, audio and/or data streams over and between various networks such as WAN, LAN and circuit switched networks.

A number of conference systems residing at different sites may participate in the same conference, most often, through one or more MCU's (Multipoint Control Unit) performing i. a. switching functions to allow the audiovisual terminals to intercommunicate properly.

As videoconferencing involves various recourses and equipment simultaneously interoperating at different localizations and capabilities, there is a need for the possibility to manage the resources involved both for scheduled and ad hoc videoconferences. The wording schedule or scheduler shall also be understood as including setting up ad-hoc meetings or calls-insuring that all required resources are available for the call.

Conferencing systems are therefore often provided with a management tool. The management tool may i. a. include a resource scheduler. The resource scheduler is a module that is used to schedule or book resources at any given point in time. The resource scheduler will allow a user to request resource usage at a given time, and either allow or disallow the usage at that time. Resource schedulers are often used for scheduling the use of meeting rooms, network resources, video systems etc. The resource scheduler must

be connected to a database containing updated information regarding all accessible resources like MCU's, gateways, routers, end-points etc.

A resource scheduler may e. g. provide system and resource overview, allowing the user to create, edit, and delete reservations, reserve resources for dial-in participants and specify bandwidth and network settings. The resource scheduler may also support automatic call routing- automatic selecting use of a point-to-point connection, or including one or more MCU's. The resource scheduler normally operates with an intuitive web interface requiring no additional installation on the user terminal other than a conventional web browser.

The patent application NO 2003 2859 discloses a presence/Instant Messaging system connected to scheduling and accomplishment of a conference. Presence and IM applications are known as applications indicating whether someone or something is present or not. A so-called"buddy list"on a user terminal shows the presence of the people or systems (buddies) that have been added to the list. The list indicates if the"buddy"is present or not (logged on the computer, working, available, idle, or another status).

The presence functionality creates a feeling of presence also with people or objects that are located in other buildings, towns, or countries.

By connecting a presence application to the resource scheduler, a first user will be able to see when a second user is present (not busy with something else), and at the same time, an idle conferencing system may be selected according to the priority list of the second user. This will provide a new ad-hoc possibility to common resources, as unnecessary calls (due to ignorance of presence information) will be avoided and manual negotiations through alternative communication prior to the call will not be required. A double click on a"buddy"in a"buddy

list"may e. g. execute an immediate initiation of a call to the"buddy"using the most preferred idle system associated with the"buddy".

However, in NO 2003 2859, a call can only be made to users already defined in the"buddy-list". The invention also assumes that a presence/IM application is installed in the user terminal.

Another problem is that it may be hard to locate and find people, and even if a person is located, required information for initiating a call (e. g. dial out prefix, gateway to use-or if required at all-MCU used as gateway, etc. ) may still be missing.

Still another problem is that direct ad hoc dialling in prior art requires that the same protocol is being used on both originating and terminating side. As an example, SIP URLs are used for ad hoc calls between SIP-end-points, but this is not possible for calls between SIP and H. 323 end- points or SIP and H. 320 end-points. A call between end- points operating at different protocols requires one or more intermediate Gateways whose resources have to be booked, and no solutions providing resource scheduling in connection with one-click dialling is known in prior art.

Summary of the invention It is an object of the present invention to provide a method and system avoiding the above described problems.

The features defined in the independent claims enclosed characterise this method and system.

In particular, the present invention discloses a method for routing and establishing a call or a conference from an originating user to one or more terminating users each associated with one or more respective end-points, whereby

when an URL (Universal Resource Locators) with a unique dial prefix is activated, requesting a management tool to determine an available route of resources between a preferred one of the one or more end-points associated with the originating user and a respective preferred one of the one or more end-points respectively associated with the one or more terminating users, determining, by means of a routing module included in said management tool, a number of routes between said preferred one of the one or more end-points associated with the originating user and said respective preferred one of the one or more end-points respectively associated with the one or more terminating users based on capability and connection data stored in a database for the respective end-points and said resources, and assigning a cost value to each of said number of routes representing delay, bandwidth and/or reliability, determining, by means of a scheduling module included in said management tool, which of said number of routes whose resources currently and/or in near future are being idle, based on status data of said resources stored in said database, and selecting a route among which, having the lowest cost value, as said available route, and establishing the call or conference from said preferred one of the one or more end-points associated with the originating user to said respective preferred one of the one or more end-points respectively associated with the one or more terminating users through said determined available route.

The invention also discloses a corresponding system performing the above-described method.

Brief description of the drawings In order to make the invention more readily understandable, the discussion that follows will be supported by the accompanying drawings,

Figure 1 is a block diagram showing the different elements involved in an example embodiment of the present invention, Figure 2 is a flow sheet illustrating the steps of a method according to one aspect of the present invention, Best mode of carrying out the invention In the following, the present invention will be discussed by describing a preferred embodiment, and supported by the accompanying drawings. However, people skilled in the art will realize other applications and modifications within the scope of the invention as defined in the enclosed independent claims.

The present invention suggests using special type URLs in a conventional web browser to initiate an ad hoc conference call from a user terminal. URLs (Universal Resource Locators) are being used for identifying resources in a network (typically the internet). URLs exist for among others ftp and http locations. As an example, when clicking on http://www. tandberg. net/, the web browser will request the site with the address www. tandberg. net to download the content of which to the web browser's terminal using the HTTP protocol, and the content will after downloading show up on the screen. Conventionally, when clicking on a link in a web browser, a content handler is requested to analyze the URL to determine the characteristics of the link, and initiate further actions according to the content. Thus, it is also allowable with URLs that do not go directly to locations, but initialize a certain service or application on the local system. Such URLs include prefixes indicating the service to be used. Examples are mailto-links that start creating an e-mail message to a specific person. A mailto-link is in html-code typically represented by the anchor tag <a> with a hyperlink attribute (href) that includes the prefix"mailto", followed by a colon and a mail-address, e. g. <a href="mailto: name@domain">text</a>.

When clicking at a mailto-link, the phrase"mailto" executes start-up of a default mail application associated with the web-browser for handing mailto-link (if the mail application is not already running), and creates a new empty e-mail with the given mail-address inserted in the address field of the e-mail. In this way, the user does not have to bother about the mail-address of the receiver of the e-mail, or what kind of e-mail application the web- browser or terminal is using.

According to the present invention, a special conference prefix is used in the URL to initiate an ad-hoc conference call from a web browser. In addition to indicate the link type, the prefix should preferably also include information of what kind of conference call to be initiated. Examples of call links are could be: dial-h323: 0012121212012@gatekeeper dial-h320: +1 (555) 1231234 dial-sip: user@company. com Referring to the first link, "Dial"indicates that a dialling service is about to be initiated,"h323"indicates that the subsequent address is an H. 323 address, and "0012121212012@gatekeeper"is the address of the end-point to be called, associated with the given gatekeeper. If the user or the web browser's terminal (e. g. a PC, PDA or mobile phone) has predefined a preferred conferencing end- point, a click on a dial-link will define one originating and one terminating end-point. In case of having predefined more than one preferred end-point, the most preferred currently idle end-point will be selected as the originating end-point.

The minimum available information that is required to initiate a call or conference between to end-points. is unique identification of the terminating system to be called. However, in connection with conferencing,

identification of end-points are not always sufficient to set up a call, and in some cases, i. a. due to IP limitations and firewall/NAT obstacles, a unique identification is neither possible. Intermediate resources like Gateways, MCUs, which bandwidth to use, end-point capabilities etc. have to be considered in order to provide a stable connection with an adequate quality, or even to for being able to establish a connection at all.

Conventionally, this may be provided manually through a user interface of the management tool. An administrator then has to determine in advance the required resources for a scheduled call or conference, based on his knowledge of the participating end-points and of the available resources. However, in the case of ad hoc conferences, the routing and scheduling of resources has to be carried out automatically.

According to the present invention, the content handler therefore also sends a request to a management tool for providing automatic routing and resource scheduling for the call between the parties when identifying a dial-prefix in an activated URL. The routing and resource scheduling could also be carried through by other applications like stand- alone modules e. g. accessible through a presence/IM application installed on the user terminal, but for simplicity, the term management tool will be used in the following.

When the management tool receives the request from the content handler, the first step is to collect registered data about the end-points involved from a database storing the capabilities of end-points and other resources like Gateways and MCUs. The capabilities of the end-points will then determine the required resources for establishing the call. As an example, if the originating end-point is a H. 320 end-point, and the terminating end-point is a H. 323 end-point, an intermediate Gateway will be required.

Further, if the call is a conference call between multiple

end-points, then an MCU will be required. The management tool will then generate a list of possible routes between the participating end-points based on capability and connection data captured from the database. The routes include the intermediate nodes between the end-points and connection types (IP, ISDN) between them. The list is preferably arranged in a prioritized order, depending on a cost associated with each route. The cost may be deduced from a set of network parameters representing e. g. delay, bandwidth, reliability etc.

This list does not take into account whether the resources currently are available or not. The scheduling feature of the management tool is capable of determining this. A scheduler module is always updated on the present and future status of its associated conferencing resources.

This information is also stored in a database either separated from, or integrated in, the above-mentioned database storing capabilities. The uppermost route in the prioritized list having all the included resources available now and in a predefined period of time will then be selected. The scheduling module will also book the resources for a default duration of e. g. 10 minutes to make sure that the call has access to the resources in a minimum of time. The scheduled time is preferably extended consecutively as the conference call proceeds.

The final step for the management tool will be to actually initiate a call using the selected route. The set-up procedure is carried out by issuing commands to the originating end-point and the other selected resources in a similar way as for any other conference scheduled by a management tool.

Note that even if the example embodiment above describes a one-to-one connection, the invention is also applicable for ad-hoc multi-site conferencing initiated by one user. The dial-link may then include a group of originating end-

points, or the user may click on a multiple dial-links, all-participating in the same conference. The invention is neither limited to conventional videoconferencing. One or more of the participants could be web participants using a PC or other personal computer devices as the conference end-point. If the originating user is a web participant, the originating end-point is the web browser's terminal itself, and there is no need to predefine preferred end- points.

For a user, the present invention will appear easy and intuitive. As a dial-URL implicitly will include all required information for routing a call, one single click on a link in a web browser will be sufficient for establishing a call to a second party, or to a group of parties. Dial-links will be suitable to insert in e. g. contact information on an enterprise or a personal web site, or in e-mails.