WO2007010454A1

WO2007010454A1 - Method and device for discovery in a network

Info

Publication number: WO2007010454A1
Application number: PCT/IB2006/052376
Authority: WO
Inventors: Jozef P. Van Gassel; Eric H. J. Persoon
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-07-19
Filing date: 2006-07-12
Publication date: 2007-01-25
Also published as: CN101223736A; JP2009502079A

Abstract

A segmented network having a wireless part (17) includes a mobile, wireless device (10), an access point and a network device. The mobile has a wireless communication unit (11), a plug and play unit (12) for managing services with respect to the network according to a plug and play protocol, and a discovery unit (13) for managing a device status with respect to the network. The access point (20) has a wireless communication unit (21), a network communication unit (22) for communicating to a network device in the network. For improved handling of discovery, the access point has a plug and play unit (23) and an access point control unit (24). The access point detects a status modification of communication between the wireless communication units, generates, in dependence on the status modification, a protocol message according to the plug and play protocol, and transfers the protocol message to the network.

Description

Method and device for discovery in a network

The invention relates to a network having a wireless part, the network comprising at least one wireless device comprising a first wireless communication unit for communicating according to a wireless communication format, a first plug and play unit for managing services with respect to the network according to a plug and play protocol, and a discovery unit, coupled to the wireless communication unit and the plug and play unit, for managing a device status with respect to the network, and at least one access point.

The invention further relates to an access point comprising a second wireless communication unit for communicating according to the wireless communication format, and a network communication unit for communicating to a further part of the network according to a network communication format.

The invention further relates to a wireless device for use in the network having a wireless part, the mobile device comprising a first wireless communication unit for communicating according to a wireless communication format, a first plug and play unit for managing services with respect to the network according to a plug and play protocol, and a discovery unit, coupled to the wireless communication unit and the plug and play unit, for managing a device status with respect to the network.

The invention further relates to a method for managing services in the network.

The invention relates to the field of network communication in a segmented network. The network includes at least a wireless part and a further, usually wired, part. A device called access point in the network constitutes a bridge between the parts, communicates with wireless devices, and transfers messages to the wired part and vice versa. Devices in the network may provide and request services in the network, which services may include a representation of (virtual) devices, functions and/or services embedded in the device. Such services are managed based on a plug and play protocol, which defines the way such services may be made available, requested and communicated via protocol messages. The document WO 2004/107681 describes a wireless network comprising at least two wireless terminals which each contain a UPnP (Universal Plug and Play) module and a UPnP controller software component. Such a network may use the Bluetooth technology for the wireless communication and the UPnP protocol to set up a functional relationship with terminals for example over short distances. The wireless network may be operated for example in accordance with the Bluetooth standard or the standard "Wireless IEEE 802.11 (Wireless LAN)". Basically the UPnP module manages the embedded (or required) services and devices for the terminal according to a plug and play protocol, for example the UPnP standard. Such standards are well-known, and also further explained in the document.

In order to discover terminals wishing to integrate into an existing network, a software component has been provided in the wireless terminal which forwards messages to the respective UPnP module. A terminal that is to be newly integrated in the network, e.g. when coming into range of wireless communication of a further terminal, starts a so-called discovery phase in order to discover other terminals present in the network. The terminals which are already in the network are quiet until they receive a message during the discovery phase from the terminal that is to be integrated. According to the document, the UPnP controller software component of a terminal forwards specific messages from the associated UPnP module to subordinate software components only following a change in the network topology.

A problem not acknowledged in the document arises when wireless devices are communicating via access points, e.g. to a further wired or wireless part of the network. In such a network, devices called plug and play control points (CPs) manage available plug and play services. The normal UPnP discovery mechanism relies on sending so-called advertisements from new UPnP devices via multicasting to UPnP Control Points (CPs) in the network. Via this mechanism, interested CPs can discover new UPnP devices and services. The UPnP Device Architecture specification suggests a minimum time of 1800 seconds in between such advertisements. This mechanism however was never designed with wireless networks in mind. For very dynamic environments where mobile devices move in and out of the network constantly, an average (minimum) discovery time of 15 minutes is not acceptable. This would lead to a very disappointing user experience. A further problem is that decreasing this duration is not only prohibited by the standard but might also increase (unnecessary) network traffic. It is an object of the invention to provide a network solution to reduce the discovery time drastically without increasing the network load.

For this purpose, according to a first aspect of the invention the access point, in the network, as described in the opening paragraph comprises a second plug and play unit for accommodating the plug and play protocol, and an access point control unit for detecting, from the second wireless communication unit, a status modification of communication between the first and second wireless communication units, generating, via the second plug and play unit and in dependence on the status modification, at least one protocol message according to the plug and play protocol, and transferring the protocol message to the network via the network communication unit.

For this purpose, according to a second aspect of the invention, the wireless communication device, in the network, as described in the opening paragraph comprises the discovery unit is arranged for detecting, from the first wireless communication unit, a status modification of communication between the first and second wireless communication units, and controlling the first plug and play unit for managing the services in accordance with said protocol message.

The measures in the access point have the effect that the access point control unit is enabled to detect any changes in the wireless communication status, e.g. a new wireless device entering the network, or a wireless device that is integrated in the network but is loosing wireless communication. Subsequently, due to the plug and play unit included in the access point, the access point control unit is enabled to accommodate protocol messages to be transferred to the further part of the network regarding the (non-)availability of plug and play services of the wireless device. Accordingly, in the wireless device, the discovery unit is arranged for exchanging plug and play messages with the access point taking into account the extended function of the access point. The measures have the advantage, that the plug and play functionality is accommodated for network devices in the segmented network across various parts, e.g. further wireless and/or wired parts. The plug and play services that are actually available are managed without delay and with a limited amount of messages when the wireless communication status changes.

In an embodiment of the access point, the access point control unit is arranged for requesting services from the wireless device according to the plug and play protocol, and storing said services in a service memory based on a unique device identifier. This has the advantage that the access point is enabled to generate said protocol message applying the contents of the service memory regarding said device.

In an embodiment of the access point, the access point control unit is arranged for, when the status modification indicates that the wireless device has joined the wireless part, requesting services from the wireless device according to the plug and play protocol, and generating the protocol message in dependence on received services. It is noted that said requesting of services may be based on sending a plug and play message from the access point to the device for acquiring information regarding the services, and/or receiving a plug and play message from the new device by the access point for advertising information regarding the services. This has the advantage that such exchange of information regarding the services is effected without delay after the wireless communication has been established. In an embodiment of the access point, the access point control unit is arranged for, when the status modification indicates that the wireless device has joined the wireless part, identifying the wireless device according to a unique device identifier, retrieving services of the wireless device from a service memory based on the unique device identifier, and generating the protocol message in dependence on retrieved services. This has the advantage that no plug and play messages need to be exchanged via the wireless communication format, because information is retrievable from the service memory based on the unique device identifier. In an embodiment of the access point, the access point control unit is arranged for, when the status modification indicates that the wireless device has left the wireless part by sending a wireless message, generating the protocol message indicative of services no longer available. This has the advantage that the access point communicates with devices in the further part of the network, e.g. control points, to make sure that they are aware of the fact that the wireless device is no longer available. In particular this may occur when a control point is not immediately available for said communication, and requires finalization of the communication after the wireless device is actually out of the network.

In an embodiment of the access point, the access point control unit is arranged for, when the status modification indicates that the wireless device has left the wireless part without sending a wireless message, identifying the wireless device according to a unique device identifier, retrieving services no longer available from a service memory based on the unique device identifier, and generating the protocol message indicative of the services no longer available. This has the advantage that the access point communicates with devices in the further part of the network, e.g. control points, to make sure that they are aware of the fact that the wireless device is no longer available, which would otherwise be undetected due to the lack of a protocol message from the wireless device.

Further preferred embodiments of devices according to the invention are given in the appended claims, disclosure of which is incorporated herein by reference.

These and other aspects of the invention will be apparent from and elucidated further with reference to the embodiments described by way of example in the following description and with reference to the accompanying drawings, in which Fig. 1 shows a network having a wireless part,

Fig. 2 shows a functional diagram of managing services when a device is joining a network,

Fig. 3 shows a functional diagram of managing services when a device is leaving a network in an uncontrolled way, Fig. 4 shows a functional diagram of managing services when a device is joining a network using an access point, and

Fig. 5 shows a functional diagram of managing services when a device is leaving a network in an uncontrolled way using the access point.

Corresponding elements in different Figures have identical reference numerals.

Figure 1 shows a network having a wireless part. In the network a wireless device 10 (shortly WD) and an access point 20 (shortly AP) are shown in communication via antennas 14,26 to a wireless part 17 of the network. For example the wireless device is a mobile device like a laptop or a mobile phone, or a consumer device provided with wireless communication like an audio-video device or a refrigerator. A network device 30, for example a control point (shortly CP), is shown in communication with the access point via a further part 18 of the network, e.g. a wired part such as a company or home LAN, or the Internet. The access point, for example, may be a dedicated device coupled to the wired network for accommodating local wireless communication.

The wireless device 10 has a WD wireless communication unit 11 for communicating according to a wireless communication format, e.g. WiFi standard (IEEE 802.11) as mentioned in the introduction. It should be noted that the invention is not limited to WiFi networking but might equally apply to new and emerging wireless standards like for instance Bluetooth, UltraWide Band (UWB), Near Field Communications and others. The wireless device 10 further has a WD plug and play unit 12 for managing services with respect to the network according to a plug and play protocol, e.g. UPnP as mentioned in the introduction. The wireless device 10 further has a discovery unit 13, coupled to the WD wireless communication unit 11 and the WD plug and play unit 12, for managing a device status with respect to the network.

The access point 20 has an AP wireless communication unit 21 for communicating according to the wireless communication format, a AP network communication unit 22 for communicating to network devices in the network according to a network communication format, and an AP plug and play unit 23 for accommodating the plug and play protocol.

It is noted that the Figure shows the parts of the network as physically separate parts. Alternatively, the further part 18 that provides communication with the network device 30 according to the invention may be the same part as the wireless part 17. Hence in that case the communication from the wireless device 10 to the network device 30 is accommodated on a logical level via the access point 20 according to the invention, but is using the same physical wireless connection format. Subsequently the AP communication unit 22 communicates to the network device via the wireless part 17 of the network. The network device 30, for example a computer containing the functionality of a control point (CP), has a CP network communication unit 31 for communicating to the network according to the network communication format, and an CP plug and play unit 32 for accommodating the plug and play protocol.

In addition, the access point 20 has an access point control unit 24, coupled to the AP wireless communication unit 21, the AP network communication unit 22 and the AP plug and play unit 23. The access point control unit is arranged for executing a process of managing services according to the invention as explained in detail below. The process comprises at least the following functions. A first function is detecting, from the AP wireless communication unit 21, a status modification of communication between the first and second wireless communication units. A second function is generating, via the AP plug and play unit 23 at least one protocol message according to the plug and play protocol. The protocol message is generated in dependence on the status modification of the wireless communication, e.g. when a new wireless device enters into radio communication range of the access point. Finally, a third function is transferring the protocol message to devices in the network via the network communication unit 22, for example to the network device 30.

In an embodiment the access point 20 is provided with a memory 25. The access point control unit 24 is arranged for requesting information regarding plug and play services from the wireless device according to the plug and play protocol, and storing said services in the memory. A service memory based on a unique device identifier is provided as follows. The data on said services is stored using an identifier coupled to the respective wireless device, e.g. a unique name or number.

It is noted that the above described units may be constructed using dedicated hardware circuits, for example specially designed ICs, but usually the functions are at least partly performed using a processing unit and software. Such software may be embedded in read-only memory devices, but may also be accommodated on, and retrieved from, other sources, like storage media or on a server device connected to the network. In particular the functions described for the access point control unit 24, and/or the AP plug and play unit 23, may be provided as a software program product to be downloaded to a programmable part of an access point device.

The process of managing services according to the invention in practice, applying WiFi as the wireless communication format, involves exploiting the information that is present at the WiFi module to detect going in and out of WiFi networks. Normally when mobile WiFi devices come in the range of a wireless network they go through the steps of scanning, joining, authentication and association. After that, for connecting to the further part of the network, some TCP/IP related initializing might take place, for example network protocol addressing issues using DHCP, link- local and ARP messages. In the access point control unit, this sequence of actions also triggers the UPnP advertisement / byebye protocol mechanism. This could also be implemented in the mobile devices. The function of the Access Points (APs), and the wireless device, is as follows.

In the access point the following functions are executed. As soon the access point detects a new mobile device it will generate a protocol message for advertising the device and its services on behalf of the mobile device. This could be achieved by caching information on the plug and play services of the mobile device in the AP, or by sending a search to the mobile device to obtain this information beforehand. The caching may be done in an initialization phase before actual use, or by downloading or retrieving the capabilities of mobile devices via a network, or directly from the device. When the access point discovers that a mobile device is no longer associated to the network (i.e. the respective wireless part of the network), it could send a byebye message on behalf of the mobile device even though the actual device is already out of range of the wireless network as explained in detail below. It is noted that the additional actions assure that control points (CP in the network) will discover the devices as soon as they become part of the wireless network (i.e. without generating additional traffic). The AP that sends byebye 's on behalf of the mobile device assures that all UPnP Control Points are aware of the fact that the device is no longer available. Some Access Points also implement a further plug and play gateway function, called the UPnP Internet Gateway Device (IGD). By combining the novel plug and play unit with such gateway iunction, so the UPnP Software Stacks can be shared for both purposes. In the wireless devices, usually mobile devices like phones and audio video (AV) players, the following functions are included in the discovery unit 13. As soon as the device is associated with the WiFi network and the addressing has taken place, an UPnP Advertisement is sent to advertise the UPnP device and its services to UPnP Control Points in the network. However, when the wireless device communicates with the access point provided with the additional functions as defined above, the wireless device will communicate data regarding its services to the AP for caching. Actually, the wireless device may also request the AP to provide the UPnP advertisement on behalf of the wireless device based on a unique device identifier included in a message to the AP.

When the device de-associates (for some reason) from the WiFi network a byebye message is sent to indicate to UPnP Control Points that the device is no longer available. The byebye message may be processed in the AP to update the service memory. The AP will send a byebye message to the network for the de-associated device. In the case the mobile wireless device detects going out of range of the wireless network unintentionally, there is no opportunity to send a byebye message to the network anymore. Hence the discovery unit 13 may block the byebye message from the plug and play unit. Also in this situation, i.e. when the AP detects that the communication status has changed due to said going out of range, the AP will generate and transfer the byebye message on behalf of the wireless device.

Note that both the Mobile Device message when a new device associates, and the Access Point byebye message, can be implemented. On the other hand only implementing one of both already improves the discovery performance of wireless devices with respect to plug and play services drastically. For detecting the modification of the wireless communication status the access point, and/or the wireless device, can use transmission signal parameters from the wireless communication units. In an embodiment, a mobile device could use parameters like signal strength to send a byebye message before going out of range. This would make the UPnP Discovery mechanism more robust against the dynamics of such mobile devices, especially in case the AP is not implemented to send byebye 's on behalf of the mobile device as discussed above.

The following Figures and description provide examples of the process of managing plug and play services (UPnP) in the network having a wireless part according to WiFi, the network communication format being the well known TCP/IP format. The examples occur when a (mobile) device leaves or joins the (wireless) UPnP network. The first two cases focus on improved discovery efficiency by measures in the mobile device while the last two illustrate which measures are relevant in the access point. Steps in the diagrams are indicated by numbered arrows. Figure 2 shows a functional diagram of managing services when a device is joining a network. The functions are indicated to be performed in a mobile, wireless device 210, an access point 220 and a network device 230, e.g. a control point. It is noted that, in fact, the control point may be embedded in a further device coupled to the network, e.g. a computer, but may be embedded also in further wireless devices, that are actually coupled to the network via the wireless part. In the current examples the network device 230 is assumed to be in stable contact with the network, whereas the mobile device 210 is assumed to cause changes in the network communication status.

In the mobile device 210 a wireless communication function 211 is accommodating wireless communication, e.g. according to IEEE 802.11 Physical and MAC (Media Access Control).

A TCP/IP stack 215 accommodates network communication according to the network protocol, and an UPnP stack 212 provides the plug and play functions. The process of managing communication and plug and play services is controlled by a discovery unit 213, whereas an application 216 may require (or provide) said services from (or to) the communication units.

The access point 220 accommodates network communication according to the TCP/IP network protocol, and has a wireless communication unit 221 to accommodate the wireless communication, and a plug and play control unit 223 that provides the additional plug and play functions as described earlier with Figure 1. The network device also includes a TCP/IP stack 231, an UPnP stack 232 and an application 236 that may require (or provide) said services from (or to) the communication units.

The process of managing communication and plug and play services has the following numbered steps when the mobile device 210 joins the WiFi based UPnP network.

1. Mobile Device 210 goes through the steps of scanning, joining, authentication and association with the Access Point 220.

2. The WiFi driver unit 211 sends a "Authenticated" message to the Discovery Unit 213. 3. The Discovery Unit 213 instructs the TCP/IP stack 215 to go through the process of addressing.

4. The TCP/IP stack 215 is where obtaining an IP address using Auto IP, DHCP or local link addressing takes place. This only needs to be done if the interface has not been assigned a valid address before. 5. TCP/IP stack 215 notifies Discovery Unit 213 that addressing was successful.

6. Discovery Unit 213 instructs the UPnP stack 212 to advertise the (embedded) devices and services of mobile device 210 to the network.

7. The UPnP stack 212 sends the multicast UPnP advertisements to the other UPnP devices in the network via the access point 220. It is to be noted that in the access point, the plug and play control unit 223 receives the UPnP advertisements for processing, such as local storage in the access point memory, or further transmittal on behalf of the mobile device 210. Finally, the application 236, in the network device, may access (or provide) services in (or to) the mobile device. Figure 3 shows a functional diagram of managing services when a device is leaving a network in an uncontrolled way. The functions are indicated to be performed in the mobile, wireless device 210, the access point 220 and the network device 230, having similar constituting elements as described with Figure 2.

The process of managing communication and plug and play services has the following numbered steps when mobile device 210 leaves the network in an "uncontrolled" way, i.e. the application 216 does not initiate sending a byebye message.

1. The WiFi driver unit 211 has received request to de-associate mobile device 210, and it sends a notification to the Discovery Unit 213 and waits for further instructions.

2. The Discovery Unit 213 instructs the UPnP stack 212 to send the byebye messages now the network still exists. 3. The UPnP sends the actual multicast byebye messages to the control points in the UPnP network via the access point 220.

4. After byebye messages have been sent, the Discovery Unit 213 instructs the WiFi driver unit 211 to start with the de-association process. 5. The WiFi driver unit 211 de-associates from the WiFi network.

It is to be noted that in the access point, the plug and play control unit 223 receives the UPnP byebye message for processing, such as local storage in the access point memory, updating the available services, or further transmittal on behalf of the mobile device 210. Figure 4 shows a functional diagram of managing services when a device is joining a network using an access point. The functions are indicated to be performed in the mobile, wireless device 210, the access point 220 and the network device 230, having similar constituting elements as described with Figure 2. The access point 220 is provided with a TCP/IP stack 222 for accommodating network communication. The process of managing communication and plug and play services has the following numbered steps when mobile device 210 joins the network and communicates with the access point 220 for caching or retrieving plug and play information in a memory in the access point.

2. One of the alternatives below will occur. a) The access point 220 will request the embedded and services from mobile device 210 by issuing a search request, and store said data in a service memory. b) The access point 220 will look up embedded devices and services of device 210 in internal table of a service memory in the access point based on a device identifier, called Unique Device Name (UDN).

3. The access point 220 advertises the services and embedded devices on behalf of the mobile device 210 to the UPnP network.

Usually option 2a will be performed when a mobile device joins for the first time, or for variable services. Option 2b will be applied when a known mobile device joins the network; when the UDN cannot be found in the service memory the access point will switch to option 2a.

Figure 5 shows a functional diagram of managing services when a device is leaving a network in an uncontrolled way using the access point. The functions are indicated to be performed in the mobile, wireless device 210, the access point 220 and the network device 230, having similar constituting elements as described with Figure 4. Mobile device 210 leaves the network in an "uncontrolled" way, i.e. the application 216 does not send a byebye message. Note that this scenario also includes the case where a mobile device goes out of range of the network, breaks down or the battery runs empty, which is not covered by the case described with Figure 3.

The process of managing communication and plug and play services via the access point has the following numbered steps when mobile device 210 leaves the network in an "uncontrolled" way. 1. The first step can be one of the following two starting points: a) The mobile device 210 de-associates from the network without sending a byebye message to the network; b) The mobile device 210 moves out of range of the network (or the battery runs empty) and it does not explicitly de-associate from the network. 2. As soon as the access point 210 discovers that the device is gone it looks up the device information in its internal table in the service memory using the Unique Device Name (UDN).

3. Finally the plug and play unit 223 of the access point sends the byebye messages for embedded devices and services on behalf of the mobile device to the control points in the network.

It is noted that in the mobile device, discovery unit 213 is arranged for taking into account the fact that the access unit generates and transmits protocol messages regarding UPnP on behalf of the wireless device. For example discovery unit 213 may notify the UPnP stack that the mobile device 210 is de-associated, but that the byebye message has already been taken care off by the access point. Hence the UPnP stack will not keep such a byebye message in its memory as a message still to be transmitted.

Although the invention has been explained mainly by embodiments based on WiFi networks and UPnP protocols, any similar network having a wireless part, and protocols for exchanging data on services, is suitable for implementing the invention. Further it is noted, that in this document the word 'comprising' does not exclude the presence of other elements or steps than those listed and the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements, that parts of a logically segmented network discussed in the above may coincide on a single physical level such as a wireless transmission medium, that any reference signs do not limit the scope of the claims, that the invention may be implemented by means of both hardware and software, and that several 'means' may be represented by the same item of hardware. Further, the scope of the invention is not limited to the embodiments, and the invention lies in each and every novel feature or combination of features described above.

Claims

CLAIMS:

1. A network having a wireless part (17), the network comprising: at least one wireless device (10) comprising: a first wireless communication unit (11) for communicating according to a wireless communication format, a first plug and play unit (12) for managing services with respect to the network according to a plug and play protocol, and a discovery unit (13), coupled to the wireless communication unit (11) and the plug and play unit (12), for managing a device status with respect to the network, and at least one access point (20) comprising: a second wireless communication unit (21) for communicating according to the wireless communication format, a network communication unit (22) for communicating to a network device (30) in the network according to a network communication format, a second plug and play unit (23) for accommodating the plug and play protocol, and an access point control unit (24) for detecting, from the second wireless communication unit (21), a status modification of communication between the first and second wireless communication units, generating, via the second plug and play unit (23) and in dependence on the status modification, at least one protocol message according to the plug and play protocol, and transferring the protocol message to the network via the network communication unit (22).

2. Access point for use in a network having a wireless part (17), the network comprising at least one wireless device (10) comprising: a first wireless communication unit (11) for communicating according to a wireless communication format, a first plug and play unit (12) for managing services with respect to the network according to a plug and play protocol, and a discovery unit (13), coupled to the wireless communication unit and the plug and play unit, for managing a device status with respect to the network, the access point (20) comprising: a second wireless communication unit (21) for communicating according to the wireless communication format, a network communication unit (22) for communicating to a network device (30) in the network according to a network communication format, a second plug and play unit (23) for accommodating the plug and play protocol, and an access point control unit (24) for detecting, from the second wireless communication unit (21), a status modification of communication between the first and second wireless communication units, generating, via the second plug and play unit (23) and in dependence on the status modification, at least one protocol message according to the plug and play protocol, and transferring the protocol message to the network via the network communication unit (22).

3. Access point as claimed in claim 2, wherein the access point control unit (24) is arranged for requesting services from the wireless device according to the plug and play protocol, and storing said services in a service memory (25) based on a unique device identifier.

4. Access point as claimed in claim 2, wherein the access point control unit (24) is arranged for, when the status modification indicates that the wireless device (10) has joined the wireless part (17), requesting services from the wireless device according to the plug and play protocol, and generating the protocol message in dependence on received services.

5. Access point as claimed in claim 2, wherein the access point control unit (24) is arranged for, when the status modification indicates that the wireless device (10) has joined the wireless part (17), identifying the wireless device according to a unique device identifier, retrieving services of the wireless device from a service memory (25) based on the unique device identifier, and generating the protocol message in dependence on retrieved services.

6. Access point as claimed in claim 2, wherein the access point control unit (24) is arranged for, when the status modification indicates that the wireless device (10) has left the wireless part by sending a wireless message, generating the protocol message indicative of services no longer available.

7. Access point as claimed in claim 2, wherein the access point control unit (24) is arranged for, when the status modification indicates that the wireless device (10) has left the wireless part without sending a wireless message, identifying the wireless device according to a unique device identifier, retrieving services no longer available from a service memory (25) based on the unique device identifier, and generating the protocol message indicative of the services no longer available.

8. Wireless device for use in a network having a wireless part (17), the wireless device comprising: a first wireless communication unit (11) for communicating according to a wireless communication format, a first plug and play unit (12) for managing services with respect to the network according to a plug and play protocol, and a discovery unit (13), coupled to the wireless communication unit (11) and the plug and play unit (12), for managing a device status with respect to the network, the network comprising at least one access point (20) comprising: a second wireless communication unit (21) for communicating according to the wireless communication format, a network communication unit (22) for communicating to a network device (30) in the network according to a network communication format, a second plug and play unit (23) for accommodating the plug and play protocol, and an access point control unit (24) for detecting, from the second wireless communication unit, a status modification of communication between the first and second wireless communication units, generating, via the second plug and play unit and in dependence on the status modification, at least one protocol message according to the plug and play protocol, and transferring the protocol message to the network via the network communication unit, wherein the discovery unit (13) is arranged for detecting, from the first wireless communication unit (11), a status modification of communication between the first and second wireless communication units, and controlling the first plug and play unit (12) for managing the services in accordance with said protocol message.

9. Method for managing services in a network, the network having a wireless part and comprising: at least one wireless device comprising: a first wireless communication unit for communicating according to a wireless communication format, a first plug and play unit for managing services with respect to the network according to a plug and play protocol, and a discovery unit, coupled to the wireless communication unit and the plug and play unit, for managing a device status with respect to the network, at least one access point comprising: a second wireless communication unit for communicating according to the wireless communication format, a network communication unit for communicating to a network device in the network according to a network communication format, and a second plug and play unit for accommodating the plug and play protocol, the method comprising the steps of: detecting, from the second wireless communication unit, a status modification of communication between the first and second wireless communication units, generating, via the second plug and play unit and in dependence on the status modification, at least one protocol message according to the plug and play protocol, and transferring the protocol message to the network via the network communication unit.