WO2006120590A1

WO2006120590A1 - A tunnel device to be used in networks for etablishing a connection therebetween

Info

Publication number: WO2006120590A1
Application number: PCT/IB2006/051322
Authority: WO
Inventors: Boris Cobelens
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-05-09
Filing date: 2006-04-28
Publication date: 2006-11-16

Abstract

The present invention relates to a tunnel device (111) to be used in a network (101) for establishing a connection between a network and devices in an external network(113) so that the devices (117, 119, 121) may be advertised in the network and remotely controlled. This is done by monitoring the availability of the tunnel connection (125) between the network and the external network. Once the monitoring shows that the tunnel connection is available a multicast query is sent to the external network, wherein the external network is adapted to respond to it by sending responses back to the receiver. These responses are then translated into advertisements and multicast in the network.

Description

A TUNNEL DEVICE TO BE USED IN NETWORKS FOR ETABLISHING A CONNECTION THEREBETWEEN

The present invention relates to a method and a tunnel device for managing a connection between a network and an external network comprising devices so that said devices may be advertised in said network and remotely controlled. The present invention further relates to a system comprising a first and a second tunnel device to be used in a first and a second network for establishing a connection between said first network and devices in said second network so that said devices may be advertised in said first network and remotely controlled.

In the home environment, broadband Internet connections are becoming very commonplace and with the upcoming UMTS and public WiFi penetration that will also happen for Body Area Networks (BANs). This leads to a new trend, which is connectivity between Home Networks (HNs) and BANs through the Internet. As an example, a user may want to have access to his own HN while he is at a friend's place, or he may just grant his friend access to this HN anytime. A similar situation exists when a user is on the move with his BAN (for instance mobile phone and a PDA) and wants to use his HN functionality remotely.

An example of such a HN is a UPnP-based home network, where networking- enabled mobile devices like PDAs, MP3 players, digital cameras, etc. can be a part of an infrastructure of connected consumer electronics inside the home. A problem with UPnP networks is however that they are targeted at small local networks.

In US 2003/0063608 a method is disclosed for bridging a plurality of multicast domains, such as UPnP HNs, where a multicast message originating in a specific domain, e.g. an HN, is sent to other HNs to discover devices and their services present in these other HNs.

A problem with this method is that once a tunnel connection between two networks is available, it can take a considerable time before the multicast message is actually sent to the other network. This timeout value, i.e. the time interval from where the tunnel connection is available until the multicast message is actually sent, can cause a delay up to several minutes. Furthermore, the tunnel connection can appear and disappear any time, which can easily enhance this delay further. Also, when a tunnel connection breaks it can take a considerable time before the disappeared remote services time out.

It is an object of the present invention to solve the above-mentioned problems by means of managing a tunnel connection between two or more networks so that the waiting time for discovering remote devices and their services is minimized.

According to one aspect, the present invention relates to a method for managing a connection between a network and an external network comprising devices so that said devices may be advertised in said network and remotely controlled, said method comprising the steps of: monitoring the availability of the tunnel connection between said network and said external network, - generating and sending a multicast query for discovering said devices in said external network, wherein said external network is adapted to respond to said multicast query by sending responses to said multicast query back to said network, wherein said responses are translated into advertisements and multicast in said network, wherein said multicast query is sent once the monitoring shows that a connection has been established between said networks.

In that way any time delays from where the connection has been established until the multicast query is actually send will be eliminated, since the multicast query is sent immediately when said connection has been established. The time needed until receiving advertisements from remote devices and their services is therefore minimized. In an embodiment, once said monitoring shows a disconnection between said networks a sign-off message is issued on behalf of said devices. Thereby, the tunnel device plays an active role in the process of informing devices in said network about the status of said tunnel connection as soon as the tunnel connection disappears. An example of a sign-off message is a SSDP BYEBYE message defined for UPnP. In one embodiment, establishing said connection is triggered by a user. It is therefore the user who determines when to establish a connection with said external network. This could e.g. be done by using a UPnP Control Point where by pressing a "connection" button said tunnel connection is established. In another embodiment, establishing said connection is triggered autonomously, such as by the tunnel device in said network. In that way, if a user e.g. frequently accesses his home network from an external network, the managing can comprise maintaining an on-line connection between said networks.

In an embodiment, the disconnection between said networks is triggered by a user. The user who initially triggered the connection can therefore in the same way disconnect the tunnel connection by pressing a "disconnection" button on the Control Point.

In an embodiment, said multicast query comprises a request relating to at least the type of said devices and their services. Thereby, the necessary information for remotely controlling said devices is obtained.

The invention further relates to a computer-readable medium having stored thereon instructions for causing a processing unit to execute said method.

According to another aspect, the present invention relates to a tunnel device to be used in a network for managing a connection between said network and an external network comprising devices so that said devices may be advertised in said network and remotely controlled, comprising: - a receiver, a tunnel verification mechanism for monitoring availability of the tunnel connection between said network and said external network, a transmitter interconnected to said tunnel verification mechanism for generating and sending a multicast query from said network to said external network for discovering said devices, wherein said external network is adapted to respond to said multicast query by sending responses to said multicast query back to said receiver, wherein said responses are translated into advertisements and multicast in said network. wherein said transmitter sends the multicast query once the tunnel verification mechanism shows that a connection has been established between said networks. Thereby, it is ensured that the multicast query is sent immediately when the tunnel verification mechanism monitors that the tunnel connection has been established. The multicast query can be sent on behalf of a control point by the tunnel device, or be triggered by a user.

In an embodiment, the tunnel device further comprises means for issuing a sign-off message towards said network on behalf of said devices in said external network when the tunnel verification mechanism detects a disappearance of said tunnel connection.

According to a further aspect, the present invention relates to a system comprising a first and a second tunnel device to be used in a first and a second network for establishing a connection between said first network and the devices in said second network so that said devices may be advertised in said first network and remotely controlled, comprising: at the first network side: a first receiver, - a tunnel verification mechanism for monitoring the availability of the tunnel connection between said first network and said second network, a first transmitter interconnected to said tunnel verification mechanism for generating and sending a multicast query to said second network for discovering said devices in said second network, wherein said multicast query is sent once the tunnel verification mechanism shows that a connection has been established between said networks, and at the second network side: a second receiver for receiving said multicast query forwarded from said first transmitter, and a second transmitter for forwarding said multicast query to the devices in said second network, wherein said devices respond to said multicast query by sending responses to said multicast query back to said second receiver, wherein said responses are forwarded by said second transmitter back to said first receiver, wherein said responses are translated into advertisements and multicast in said first network. Thereby, a system is provided where the time until devices in one network and their services are discovered by another network is greatly reduced. This makes it much easier and faster to access a network and remotely control the devices in said network. Also, the functionality of the tunnel devices requires no standardization. The SSDP (Simple Service Discovery Protocol) remains the same, so compatibility with all e.g. UPnP devices and UPnP control points is guaranteed. Also, the system does not depend on the iunctionality in the remote tunnel device. Therefore, the interoperability between tunneled UPnP networks is maintained.

In an embodiment, said first and second networks are Universal Plug and Play (UPnP) networks and said devices are UPnP devices. The responsiveness of UPnP control points in a local network is therefore more optimal. Further, frequent topology changes in dynamic networks, leading to UPnP tunnel connections appearing and disappearing, will be handled more effectively. Because of this, the transparency to a user of such networks increases. In the following, the present invention, and in particular preferred embodiments thereof, will be described in more detail in connection with accompanying drawings in which: Fig. 1 shows a tunnel device according to the present invention,

Fig. 2 illustrates one embodiment of the present invention, showing two networks, network A and network B, being connected using an Internet Protocol (IP) tunnel connection with two tunnel connection endpoints,

Fig. 3 illustrates where a control point (CPl-A) in network A sends a multicast query to detect UPnP devices in network B,

Fig. 4 illustrates where the multicast query has been picked up by the tunnel device (TS A) in network A and is forwarded to the tunnel device (TS B) in network B using a unicast communication tunnel,

Fig. 5 illustrates where the multicast query is sent from the tunnel device (TS B) to all the devices in network B,

Fig. 6 shows where the devices in network B send a response to the multicast query to the tunnel device (TS B) in network B,

Fig. 7 illustrates where the responses as shown in Fig. 6 are transmitted back to network A, and Fig. 8 shows where the responses are forwarded to the control point (CPl-A) which initiated the request.

Fig. 1 shows a tunnel device 111, according to the present invention comprising a tunnel verification mechanism (T V M) 131 for monitoring availability of the tunnel connection between a network A lOl and an external network B 113 as shown in Fig. 2, a transmitter (T) 129 interconnected to said tunnel verification mechanism (T V M) 131 for generating and sending, as soon as the tunnel verification mechanism (T V M) 131 monitors that a tunnel connection has been established, a multicast query 133 for discovering devices 117, 119, 121 of external network B 113 (see Fig. 2) from said network A 101 to said external network B 113. Also comprised in the tunnel device 111 is a receiver (R) 127 for receiving multicast queries within network A 101 and for receiving responses from the external network B 113 to said multicast query 133. In one preferred embodiment the tunnel device 111 further comprises means (M) 135 for issuing sign-off messages towards the network A 101 on behalf of the devices 117, 119, 121 (see Fig. 2) once the tunnel verification mechanism (T V M) 131 detects that the tunnel connection 125 between networks A and B is terminated. Fig. 2 illustrates one embodiment of the present invention, showing said two networks, network A lOl and network B 113 being connected using an Internet Protocol (IP) tunnel connection 125 with two tunnel connection endpoints, and wherein the tunnel connection is managed by tunnel devices (TS A, TS B) 111, 115 at said endpoints. The tunnel 125 is adapted to transport unicast IP traffic only. In this embodiment it is furthermore assumed that the networks are UPnP networks, and that the devices 105, 107, 109, 117, 119, 121 in the two UPnP networks 101, 113 are UPnP devices, which are controlled by two UPnP control points 103, 123 arranged in these networks. In order to enable a user in network A 101 to access network B 113 the control point (CPl-A) 103 in network A must discover the devices 117, 119, 121 in network B 113, i.e. what type of devices these are and what kind of service they provide. This is done by sending said multicast query 133, or an M- Search to the external network B 113. In the following the term multicast query 133 will be used instead of M-Search. Preferably, the tunnel devices (TS A, TS B) 111, 115 listen to the SSDP (Simple Service Discover Protocol) multicast port, so that SSDP queries and advertisements may be forwarded between said networks 101, 113 using unicast communication through the tunnel 125.

In Fig. 3 the control point (CPl-A) 103 in network A 101 sends said multicast query 133 to discover the UPnP devices 117, 119, 121 in network B. This multicast query is received by said receiver 127 in the tunnel device (TS A) 111, and said transmitter 129 in said tunnel device transmits the multicast query 133 as soon as there is a tunnel connection between the two networks, which is monitored by said tunnel verification mechanism 131. Accordingly, it is not until after connecting to the external network B, and preferably immediately after the connection has been established, that the multicast query is sent, whereby establishing said connection can be done by a user when using said control point (CPl-A) 103, e.g. by pressing a "connection" button on the control point. In another embodiment, the process of establishing said connection can be triggered autonomously, such as by the tunnel device in said network.

Instead of the control point (CPl-A) 103 in network A 101 sending said multicast query 133 to discover the UPnP devices 117, 119, 121 in network B, it may also be the tunnel device (TS A) 111 itself that generates the multicast query in response to a connection to the external network B being established. Thereby, the availability of UPnP devices 117, 119, 121 in network B is advertised in network A 101, to e.g. control point (CPl-A) 103, automatically.

In one embodiment, monitoring the availability of the tunnel connection between said networks 101, 113 is done by sending a probe signal, generally called a "ping", and obtaining a reply from the other party. If no reply arrives within x seconds, there is a timeout. After a timeout the connection is considered to be broken. However, once the detection mechanism detects that the tunnel connection between the networks is available, the multicast query is sent to network B. In this way, the control point (CPl-A) 103 is not aware when the multicast query request is forwarded to network B 113.

In one embodiment, the multicast query has a lifetime, specified by a so-called "MX field". Therefore, the control point (CPl-A) 103 waits for a reply to the multicast query sent by the tunnel device (TS A) 111 once it has forwarded the multicast query. This time corresponds to the number of seconds specified by MX. So for example, if the control point (CPl-A) 103 sends a multicast query with MX=IO, it waits for 10 seconds for a reply. If there is no reply, the control point (CPl-A) 103 sends again the multicast query. This is repeated until the control point receives a reply from the tunnel device (TS A) 111 that the multicast query has been sent. Accordingly, the control point (CPl-A) 103 is aware that the multicast message has been sent once it has received said reply. In Fig. 4 the multicast query has been picked up by the tunnel device (TS A)

111 and is forwarded to the tunnel device (TS B) 115 in network B 113 using said unicast communication tunnel 125.

In an embodiment the multicast query could also be sent to other networks (not shown) using unicast tunnels. In this way a user located in network A lOl can enter more than one external network at the same time.

In Fig. 5 the multicast query is sent from the tunnel device (TS B) 115 to all the UPnP devices 117, 119, 121 in network B 113, which are adapted to respond to the query by sending the necessary information, e.g. the type of the device and their services back to the tunnel device (TS B) 115 as shown in Fig. 6. In one embodiment the devices 117, 119, 121 are preprogrammed so that they do not respond simultaneously to the multicast query, but with a predefined time interval to prevent an overload at the tunnel device (TS B) 115. From the tunnel device (TS B) 115 the response is sent back to the tunnel device (TS A) 111 as illustrated in Fig. 7, where the response is translated into advertisements which are sent as a multicast in network A 101, i.e. to the control point (CPl-A) 103 which initiated the request (see Fig. 8). Since the control point is now aware of the type and the services provided by said devices 117, 119, 121 , these devices can be remotely controlled from network A lOl.

In a preferred embodiment, once a tunnel connection disappears, this is detected by the tunnel device 111, which responds by sending a sign-off message, e.g. a UPnP SSDP "BYEBYE" message on behalf of the remote devices 117, 119, 121 and their services that got lost. In that way, a user will notice when the tunnel connection is no longer available. In an embodiment, devices or services for which e.g. control point 103 is to receive said message, are identified by their UPnP UUID. This means that a list of UUIDs of remote devices or services is made, and used to send BYEBYE messages containing those UUIDs when the tunnel connection is terminated.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other elements or steps than those listed in a claim. The invention can be implemented by means of hardware comprising several distinct elements and by means of a suitably programmed computer. In a device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different, dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

CLAIMS:

1. A method for managing a connection between a network (101) and an external network (113) comprising devices (117, 119, 121) so that said devices (117, 119, 121) may be advertised in said network (101) and remotely controlled, said method comprising the steps of: - monitoring the availability of the tunnel connection (125) between said network (101) and said external network (113), generating and sending a multicast query for discovering said devices (117, 119, 121) in said external network (113), wherein said external network (113) is adapted to respond to said multicast query by sending responses to said multicast query back to said network (101), wherein said responses are translated into advertisements and multicast in said network, wherein said multicast query is sent once the monitoring shows that a connection has been established between said networks (101, 113).

2. A method according to claim 1, wherein once said monitoring shows a disconnection between said networks (101, 113) a sign-off message is issued on behalf of said devices (117, 119, 121).

3. A method according to claim 1, wherein establishing said connection is triggered by a user.

4. A method according to claim 1, wherein establishing said connection is triggered autonomously.

5. A method according to claim 2, wherein the disconnection between said networks (101, 113) is triggered by a user.

6. A method according to claim 1, wherein said multicast query comprises a request relating to at least the type of said devices (117, 119, 121) and their services.

7. A computer-readable medium having stored thereon instructions for causing a processing unit to execute a method according to claim 1-6.

8. A tunnel device ( 111 ) to be used in a network ( 101 ) for managing a connection between said network (101) and an external (113) network comprising devices (117, 119, 121) so that said devices (117, 119, 121) may be advertised in said network (101) and remotely controlled, comprising: a receiver (127), - a tunnel verification mechanism (131) for monitoring availability of the tunnel connection (125) between said network (101) and said external network (113), a transmitter (129) interconnected to said tunnel verification mechanism (131) for generating and sending a multicast query from said network to said external network (113) for discovering said devices (117, 119, 121), wherein said external network (113) is adapted to respond to said multicast query by sending responses to said multicast query back to said receiver, wherein said responses are translated into advertisements and multicast in said network (101), wherein said transmitter (127) sends the multicast query once the tunnel verification mechanism (131) shows that a connection has been established between said networks (101, 113).

9. A tunnel device (111) according to claim 8, further comprising means (135) for issuing a sign-off message on behalf of said devices (117, 119, 121) once the tunnel verification mechanism detects a disappearance of said tunnel connection (125).

10. A system comprising a first (111) and a second (115) tunnel device to be used in a first (101) and a second (113) network for establishing a connection between said network (101) and devices (117, 119, 121) in said second network (113) so that said devices (117, 119, 121) may be advertised in said first network (101) and remotely controlled, comprising: at the first network side (101): a first receiver (127), a tunnel verification mechanism (131) for monitoring the availability of the tunnel connection (125) between said first network (101) and said second network (113), a first transmitter (129) interconnected to said tunnel verification mechanism (131) for generating and sending a multicast query to said second network (113) for discovering said devices (117, 119, 121) in said second network (113), wherein said multicast query is sent once the tunnel verification mechanism shows that a connection has been established between said networks (101, 113), and at the second network side (113): a second receiver for receiving said multicast query forwarded from said first transmitter, and a second transmitter for forwarding said multicast query to the devices (117, 119, 121) in said second network (113), wherein said devices (117, 119, 121) respond to said multicast query by sending responses to said multicast query back to said second receiver, wherein said responses are forwarded by said second transmitter back to said first receiver, wherein said responses are translated into advertisements and multicast in said first network (101).

11. A system according to claim 10, wherein said first and second networks are

Universal Plug and Play (UPnP) networks and said devices are UPnP devices.