Abstract:
A roaming local area network (LAN) includes a first Internet Protocol (IP) sharing device for sharing connection to a first dynamic IP address, a first group of network devices connected to the first IP sharing device, a second IP sharing device for sharing connection to a second dynamic IP address, and a second group of network devices connected to the second IP sharing device, wherein each network device in the first and second groups of network devices has a unique virtual IP address. A host is connected to the Internet through a static IP address, and the host controls data traffic between the first group of network devices and the second group of network devices.

Description:
BACKGROUND OF INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     he present invention relates to a local area network (LAN), and more specifically, to a roaming LAN created across the Internet by using dynamic Internet Protocol (IP) addresses.  
         [0003]     2. Description of the Prior Art  
         [0004]     bk popularity and affordability of computers and networking equipment has led to a tremendous growth of local area networks (LANs). A LAN can be easily created in a small local environment such as a home or an office. The LAN allows all computers to access other computers or network devices within the LAN. A LAN can provide a high degree of privacy and security from outside threats, especially when used in conjunction with a firewall.  
         [0005]     On the other hand, when a private network is required between two geographically separated networks, a virtual private network (VPN) may be used. A VPN is a network utilizing the encrypting technology of the Internet Protocol (IP) to establish a virtual tunnel through the Internet in order to form a structure similar to a private network.  
         [0006]     Please refer to  FIG. 1 .  FIG. 1  is a functional block diagram of a VPN  10  according to the prior art. The VPN  10  connects a first LAN  26  to a second LAN  30 . Both the first LAN  26  and the second LAN  30  contain a plurality of computers  28  and other network devices. Each of the first and second LANs  26  and  30  is connected to each other through an Internet connection  20 , such as an xDSL connection or another suitable broadband Internet connection. The Internet connection  20  provides a static IP address to each of the first and second LANs  26  and  30 . A VPN server  22  handles all data received from and transmitted to the Internet connection  20 . The VPN server  22  transmits all downstream data to a hub  24  (or a switch) for distributing network data to the appropriate computer  28  in the first LAN  26  or second LAN  30 .  
         [0007]     Unfortunately, the VPN  10  requires each of the first and second LANs  26  to be connected to the Internet  12  through a static IP address. Not only are static IP addresses more expensive than dynamic IP addresses, but also neither of the first and second LANs  26  can be easily moved since the static IP address service would have to be moved to another location as well.  
       SUMMARY OF INVENTION  
       [0008]     It is therefore an objective of the claimed invention to provide a roaming local area network that can be expanded through dynamic IP addresses in order to solve the above-mentioned problems.  
         [0009]     According to the claimed invention, a roaming local area network (LAN) includes a first Internet Protocol (IP) sharing device for sharing connection to a first dynamic IP address, a first group of network devices connected to the first IP sharing device, a second IP sharing device for sharing connection to a second dynamic IP address, and a second group of network devices connected to the second IP sharing device, wherein each network device in the first and second groups of network devices has a unique virtual IP address. A host is connected to the Internet through a static IP address, and the host controls data traffic between the first group of network devices and the second group of network devices.  
         [0010]     It is an advantage of the claimed invention that computers can easily be added to the roaming LAN through a connection to the Internet using a dynamic IP address. Thus, computers can be added to the roaming LAN at any time, and without additional cost involved to register a static IP address. Moreover, the roaming LAN only requires a single host, and does not require a server at each geographical location of the roaming LAN.  
         [0011]     These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0012]      FIG. 1  is a functional block diagram of a VPN according to the prior art.  
         [0013]      FIG. 2  is a diagram of a roaming local area network (LAN) according to a first embodiment of the present invention.  
         [0014]      FIG. 3  is a detailed diagram of a telephone shown in  FIG. 2 .  
         [0015]      FIG. 4  is a diagram of a roaming LAN according to a second embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]     Please refer to  FIG. 2 .  FIG. 2  is a diagram of a roaming local area network (LAN)  50  according to a first embodiment of the present invention. Unlike the VPN  10  of the prior art, a network device only needs an Internet connection  60  providing a dynamic IP address in order to be added to the roaming LAN  50 . Therefore, without the restriction of needing a static IP address, network devices can quickly and easily be added to the roaming LAN  50  from anywhere in the world. All network devices will be able to communicate with network devices at other geographic locations through the Internet  52 .  
         [0017]     Each network device is connected to the roaming LAN  50  through an Internet connection  60 , such as an xDSL connection or another suitable broadband Internet connection. An IP sharing device  62  containing a hub or switch is used to share the Internet connection  60  with each network device connected to the IP sharing device  62 . As shown in  FIG. 2 , two pairs of Internet connections  60  and IP sharing devices  62  are used to connect several network devices to the roaming LAN  50  via the Internet  52 . Referring to  FIG. 2 , a topmost IP sharing device  62  shares the Internet connection  60  with two telephones  64 . Each telephone  64  is capable of placing a phone call over the Internet  52 . A hub  63  is connected to one of the telephones  64  for sharing the Internet connection  60  with both a computer  66  and a network printer  68 . The other telephone  64  is connected to another computer  66 . A bottommost IP sharing device  62  in  FIG. 2  shares the Internet connection  60  with two telephones  64  and an information technology (IT) device  70  connected directly to one of the telephones  64 . The IT device  70  is a general name for any computer, network printer, network appliance, etc.  
         [0018]     A network private branch exchange (PBX) host  74  is connected to the Internet  52  through another Internet connection  72 , which provides a static IP address. The network PBX host  74  provides telephone service to each of the telephones  64 . Two telephones  64  are connected to the network PBX host  74 , and the network PBX host  74  is also used to coordinate all data transmitted and received in the roaming LAN  50 . This functions just like anEan EthernetC-base Switch HUB or an IP-base Switch, and a server  76  (may be a Windows® 2000server) is connected directly to one of the telephones  64 . All the other IT devices can directly access this server and other IT-devices through a “network neighborhood” (the VPN is only an IP-base switch tunnel). In addition, another hub  63  is connected to the other telephone for sharing the Internet connection  72  with another computer  66  and another IT device  70 .  
         [0019]     Please refer to  FIG. 3 .  FIG. 3  is a detailed diagram of the telephone  64  shown in  FIG. 2 . The telephone  64  contains a controller  80  for controlling operation of the telephone  64 . The controller  80  has a two-way converting function, in which the controller  80  is able to convert voice signals to the form of voice packets, and is able to restore the voice packets to the voice signals. The telephone  64  also contains a handset  82  similar to handsets of other phones. The handset  82  is used to receive voice signals from a user and then transmit the voice signals to the controller  80 , or to broadcast voice signals output from the controller  80 .  
         [0020]     The telephone  64  connects to the roaming LAN  50  through a first wired network interface  84 . The first wired network interface  84  preferably has an RJ12 female connector, although other connectors may be used as well. The first wired network interface  84  communicates with the roaming LAN  50  using the IEEE 802.3 protocol. The telephone  64  also contains a second wired network interface  86  for connecting a network device such as the computer  66 , the IT device  70 , or the network printer  68  to the roaming LAN  50 . The second wired network interface  86  preferably has an RJ45 female connector, although other connectors can also be used. The second wired network interface  86  also communicates with the roaming LAN  50  using the IEEE 802.3 protocol. In this way, the telephone  64  acts as an intermediary node that allows a network device to communicate with the roaming LAN  50  via the telephone  64 .  
         [0021]     The network PBX host  74  and the telephones  64  form an inner IP-based network through the first wired network interfaces  84  of the telephones  64 . All network devices connected to the telephones  64  through the second wired network interfaces  86  form what is being referred to as a roaming LAN. The roaming LAN is said to be roaming because each of the telephones  64  can be connected to the Internet  52  anywhere that a dynamic IP address is present. A static IP address can also be used, but is not necessary when using the present invention. In addition to LAN data packets being transmitted within the roaming LAN  50 , audio, voice, and control packets can also be transmitted. Audio packets can be given higher priority to ensure that the audio performance of the telephones is of sufficient quality for telephone conversations.  
         [0022]     Instead of using the first wired network interface  84  to communicate with the roaming LAN  50 , the telephone  64  can also use a wireless network interface  88  to wirelessly communicate with the roaming LAN  50  using any one of the IEEE 802.11x protocols. The wireless network interface  88  is preferably a PCMCIA slot for receiving a PCMCIA 802.11x card, but other slots or connectors may also be used such as a USB connector, a CardBus slot, a mini-PCI slot, a PCI slot, etc. Thus, the telephone  64  can be connected to the roaming LAN  50  with a wire using the first wired network interface  84  or wireless network interface  88  using the wireless network interface  88 .  
         [0023]     The telephone  64  also has a keypad  90  used for dialing the telephone  64  and utilizing the functions of the telephone  64 . A display  92  is connected to the controller  80  for displaying any messages of the telephone  64 . Each telephone  64  further includes a bridge  94  linked between the first wired network interface  84 , the second wired network interface  86 , and the wireless network interface  88  to perform transmission flow control for data sent to and received from the roaming LAN  50 .  
         [0024]     Please note that in  FIG. 2 , all connections between network devices are wired connections, and utilize the IEEE 802.3 protocol. Please refer to  FIG. 4 .  FIG. 4  is a diagram of a roaming LAN  100  according to a second embodiment of the present invention. The roaming LAN  100  is similar to the roaming LAN  50  shown in  FIG. 2 , and the same reference numbers will be used to refer to the same parts. Instead of using wired connections to connect network devices, the roaming LAN  100  utilizes access points  102  to wirelessly connect with the network devices in the roaming LAN  100 . As shown, the telephones  64 , the computer  66 , and the network printer  68  can all communicate with the access point  102  using at least one of the many IEEE 802.11x protocols. As before, devices connecting directly to the telephones  64  still connect to the roaming LAN  100  through a wired connection to the second wired network interface  86  of the telephones  64 .  
         [0025]     In contrast to the prior art, the present invention roaming LAN utilizes dynamic IP addresses to connect all network devices to the roaming LAN. Only the host device requires a static IP address so that the other network devices have a stable address in which to communicate with the host. Thus, computers can be added to the roaming LAN at any time, and without additional cost involved to register a static IP address. Moreover, the roaming LAN only requires a single host, and does not require a server at each geographical location of the roaming LAN.  
         [0026]     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.