WO1998059470A2 - Method and apparatus to enable a first subscriber in a larger network to retrieve the address of a second subscriber in a virtual private network - Google Patents

Abstract

The present invention relates to an apparatus and a method for use in a virtual private network, VPN, (7, 7'), or a network domain forming part of a larger network, such as the Internet, to enable a first subscriber (1; 1') in the larger network to retrieve the address of a second subscriber (3; 3') in the VPN. The address may be returned to the first subscriber (1; 1') or a connection means (11) may set up the connection between the subscribers (1, 3; 1', 3') automatically.

Description

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METHOD AND APPARATUS TO ENABLE A FIRST SUBSCRIBER IN A LARGER NETWORK TO RETRIEVE THE ADDRESS OF A SECOND SUBSCRIBER IN A VIRTUAL PRIVATE NETWORK

Technical Field

The present invention relates to the communication between teirninals connected to data or multimedia networks, such as the Internet.

Background

Internet Protocol (IP) type networks are used to an increasing degree for data, video and audio communication. It is a problem for subscribers in such networks to find the physical addresses, or IP addresses, of subscribers in other networks or subnetworks.

Summary of the Invention

It is an object of the present invention to enable a subscriber in any part of an IP based network to locate other subscribers in the same or other parts of the IP based network.

It is another object of the invention to enable subscribers in any part of an IP based network to connect to other subscribers in the same or other parts of the IP based network, for any kind of communication according to any known protocol.

It is yet another object of the invention to enable a subscriber to move between different locations in the network and still be reached.

The objects are achieved in a network by using a name server means according to the invention for each Virtual Private Network (VPN) connected to the network, the name server means being adapted to

- resolve a logical address in the VPN to the real IP address of hosts and user terminals for a specific service, such as e-mail or communication according to the H.323 protocol, - function as a look-up table between the logical E.164 addresses in the NPN and the real IP addresses of the hosts and users

- cooperate with connection means for call set-up.

The solution according to the invention offers the following advantages:

As it is based on known solutions, it may be implemented at a relatively low cost.

It involves the separation of an internal and an external number plan, thus increasing the flexibility in the network.

It enables the connection between an H.323 domain and an Internet domain.

Brief Description of the Drawings

Figure 1 is a schematic drawing of a connection between two user terminals set up according to a first embodiment of the invention. Figure 2 is a flow chart of the actions performed when a connection between two user terminals is set up according to the first embodiment.

Figure 3 is a schematic drawing of a connection between two subscribers set up according to a second embodiment of the invention.

Figure 4 is a flow chart of the actions performed when a connection between two user terminals is set up according to the second embodiment.

Detailed Description of Embodiments

The dotted line in Figure 1 shows a connection between a first 1 and a second 3 user teirninal. The teπninals 1, 3 may be any kind of ten-ninals which may be used for communication, for example personal computers (PCs) or telephones. The first user terminal 1 is connected to a data or telecommunications network 5 via a leased line, a modem a corporate network, or in any other way. The network 5 may be any network allowing communication between two end points on a logical connection, which may be packet switched or circuit switched. A common network today, in which the teachings of the invention may become particularly useful, is the Internet. In the following discussion, therefore, the network 5 will be referred to as the Internet.

The second user teπriinal is found in a Virtual Private Network (VPN) 7, which functions as an Internet domain. A name server 9 in the VPN 7 is connected to the Internet 5 and to a connection unit 11. In TCP/IP networks the name server 9 might be a Domain Name Server (DNS) well known in the art. If the H.323 protocol for data, audio and video communication is used, the connection unit 11 might be a gatekeeper, of a kind well known in the art. The connection unit 11 is connected to the second user terminal 3 with a semi-permanent connection.

The name server 9 is a database comprising, in addition to the information found in prior art name servers, an MX record 13 for each user teπninal in the VPN 7. The MX record comprises information about the IP addresses of all user terminals in the VPN 7 for different types of communication, for example, e-mail, H.323, or telnet connections.

Figure 2 shows the actions taken when the first user 1 in the first embodiment wishes to establish a connection to the second subscriber 3.

Step S 11 : The first user 1 connects to the name server 9 and requests the gate number for H.323 and enters the known address of the second user 3.

Step S12: The name server 9 determines what type of connection is wanted and forwards the request to the connection unit 11, together with the address of the first user 1.

Step S 13: The connection unit 11 retrieves the appropriate IP address of the second user 3 for the type of connection, in this case, the H.323 address. The type of connection may be determined, for example, by the port of the name server at which the connection is made. Step S 14: The connection unit 11 establishes the connection between the users 1,

->.

Figure 3 shows a second embodiment of the invention. In this embodiment a first user terminal 1' is connected to a second user terminal 3 ' as shown by the dotted line. The second user terminal is found in a VPN 7', which also comprises a name server 9', identical to the name server 9 in Figure 1. A user directory 11 ' is connected to the name server 9'. The user directory 9' comprises information about the physical addresses of the user terminals 3 ' in the VPN 7'. In a TCP/IP network, the name server will be a Domain Name Server (DNS) and the user directory will be a Lightweight Directory Access Protocol (LAPD) server of the kinds known in the art.

Figure 4 shows the actions taken when the first user 1 ' in the second embodiment wishes to establish a connection to the second subscriber 3 ' .

Step S21: The first user 1' connects to the name server 9' and transmits the known, logical address of the second user 3 ' to the name server 9'.

Step S22: The name server 9' determines what type of connection is wanted and forwards the logical address of the second user 3 ' to the user directory l l' ofthe VPN 7\

Step S23 : The user directory 11 ' retrieves the physical address corresponding to the logical address entered.

Step S24: The user directory 11' returns the physical address of the second user 3' to the first user 1 ' via the name server 9' . Step S25: The first user 1' initiates the connection to the second user 3' in a - conventional manner.

If the first user 1' knows the address to the user directory 11', he can go directly to the user directory 11 ' instead of connecting via the name server 9'.

Claims

Claims

1. A name server means (9; 9') for use in a virtual private network (7; 7'), or a network domain, forming part of a compound network, said means (9; 9') being characterized by means ( 13 ; 13 ') for receiving a request for the physical address of a user terminal (3; 3') from another user terminal (1; 1') and forwarding said request to a connection means (11; 11 ') in the virtual private network (7; 7') or network domain.

2. A name server means according to claim 1, characterized in that the logical addresses comprise IP addresses, addresses according to the E.164 protocol and/or other logical identities according to the appropriate numbering plan.

3. A name server means according to claim 1 or 2, characterized by means (11, 11 ') for initiating the connection between two subscribers (1, 3).

4. A connection means (11; 11 ') for use in a virtual private network (7; 7') or a network domain, forming part of a compound network, said connection means being characterized in that it is adapted to return, upon a request comprising a logical address of a user (3 ;3 ') in the virtual private network (7; 7'), a physical address of said user (3; 3').

5. A connection means (11; 11') according to claim 4, characterized in that it is adapted, upon a request originating from a user (1; 1 ') in said compound network, said request comprising a logical address of a user (3; 3') in the virtual private network (7; 7'), to establish a connection between said users (1, 3; 1 ' 3').

6. A telecommunications or data communications network, forming part of a compound network, characterized by at least one connection means, according to . claim 4 or 5.

7. A network according to claim 6, characterized by at least one name server means according to any one of claims 1-3.

8. A method for enabling a user (1; 1') in compound network to retrieve the IP address of a second user (3; 3') in a virtual private network (7; 7') or a network domain, forming part of said compound network, characterized by the following steps:

- transnήtting a request for a physical address, the request comprising a logical address of the second user (3; 3')

- forwarding the logical address of the second user (3; 3') to a connection means

(i i);

- returning the logical address to the first user (1; 1') or automatically establishing a connection between the first (1; 1') and the second (3; 3 ') user.

9. A method according to claim 8, characterized by

- automatically establishing a connection between the first (1) user and the second user (3).

10. A method according to claim 8, characterized by

- returning the address of the second user (3') to the first user (T).

11. A method according to any one of claims 8-10, characterized by determining the type of address to be used in dependence of the port of the name server (9; 9') on which the request was received.

12. A method according to any one of claims 6-11, characterized in that the physical address may be an e-mail-address, and/or an E.164 address.