Abstract:
A Network Address Translating (“NAT”) Router, particularly designed for mobile use, and for managing one or more local area networks, having private internet protocol (“IP”) address ranges, along with multiple “upstream” networks, and for efficiently routing communications traffic to and from the upstream networks, is disclosed. The inventive router allocates multiple network connections of varying quality, to automatically optimize the effective connection speed in a mobile client network with optional personal “hotspot” sub-networks. The inventive NAT router is also capable of managing IP address allocation on local networks to substantially avoid conflicts with other networks encountered in normal use.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/663,910, filed on Jun. 25, 2012, the contents of which are incorporated by reference herein, in their entirety and for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of computer networks and routers, and in more particularity, relates to a network address translating (“NAT”) router for mobile use and managing at least one local area network having private internet protocol (“IP”) address ranges, along with a plurality of upstream networks. The inventive NAT router efficiently routes communications traffic with the upstream networks, and optimizes connection speed in a mobile client network along with optional personal “hotspot” sub-networks. The inventive NAT router is also capable of managing IP address allocation on local networks to substantially avoid conflicts with other networks encountered in normal use. 
       TECHNICAL BACKGROUND OF THE INVENTION 
       [0003]    Computers are able to communicate with other computers and systems only when such devices are “connected” together as part of a communications network. The Internet is one such communications network. A primary advantage of the Internet is that is a world-wide, and widely used network, and therefor can connect computers together that may be located anywhere in the world. Other types of communications networks include local area networks (“LAN”), which are private networks, often created to connect a limited number of trusted computers, usually in an office or home setting. Another type of network is a wide area network (“WAN”) that typically provides communication access to the Internet using a wireless radio protocol. 
         [0004]    There are many different reasons for wanting to connect one or more remote computers to a LAN. By way of example, a LAN is often secure, and it may contain important corporate resources at the office, or contain one&#39;s personal media files in a home environment. Usually in conjunction with a private LAN, a device known as a Network Address Translating (“NAT”) Router will manage the network connections between (a) multiple devices (logical or physical) on the LAN and (b) an “upstream” connection to another network that typically leads eventually to the Internet. 
         [0005]      FIG. 1A  illustrates a typical prior art Network Address Translating Router  100 .  FIG. 1A  shows the general physical architecture of such a system. In this configuration, the Network Address Translator/Router  102  is connected to a series of client devices  104  through a local area network  106 . The NAT  112  is connected to the local area network via a local adapter  108 . The NAT views all traffic on the LAN, and any traffic it deems routable will be accepted into the NAT  112  for address translation. This translation involves taking the network address of the LAN  106  and creating a socket-for-socket translation that is native to the “upstream” network  114 . The network  114  is also accessed via a local adapter  108 , which may be of the same type as used for the local network  106 . The upstream network will generally connect to one or more servers  116 . 
         [0006]    From the point of view of each server  116 , the client LAN  106  appears to be one or more clients on a directly accessible network  114 . However, traffic from server network  114  is only passed back to the specific client  104  based upon the stored translations of addresses maintained in the NAT  112 . In other words, if an address is not known to the NAT  112 , it will not be granted access to the local network  106 . 
         [0007]      FIG. 1B  illustrates another example of a prior art network configuration. In this example, the network architecture is looking at the IP addresses rather than physical connections, and may focus on a single client  104  making connections to the upstream network. As shown in  FIG. 1B , the client  104  is connected to a LAN  106  shared with the NAT Router  102 . As an alternative, the NAT Router  102  may also communicate with other clients similar to client  104 , through LAN  106 . Traffic from the LAN  106  handled by the NAT router  102  is mapped or translated to a range of addresses appropriate to or recognized by the server&#39;s network. If such mapping were on the internet, such mapping could entail an extremely large range of legal addresses. 
         [0008]    In at least one mode, the NAT router described above, can be used to support the inventive architecture relying on a class of NAT known as a “symmetric NAT.” More particularly, as shown in  FIG. 1B , a client network connection  132 , which has a specific address and port, is given a unique translation address  136  for accessing the particular server  116  in question. A new and unique address and port  136  is assigned for each new address and port on the LAN  106 . In this configuration, the address and port  136  is sent to a specific address and port  140  on the corresponding server  116 . Given this mapping, only a return from the address and port  140  on the upstream network  138  will ever be mapped back to the original address and port on the client  106 . While this is one example of a prior art configuration, the application and scope of the inventive router is not limited to symmetric NATs, but is one type of configuration supported by the inventive router. 
         [0009]    Although not specifically illustrated, another task of the NAT router is to create a safe IP address range for any of the client LANs  106  that are managed by the router. For some router setups, the NAT address range will be manually configured by the IT personnel. In other configurations, the router will use an IP address range from a number of legal “private network” ranges (e.g., ranges guaranteed to not be on the internet, and reserved only for private networks). 
         [0010]    To improve the technology of NAT routers, a number of additional features have been designed for use with a NAT router system. Particularly when used in a mobile context, it would be advantageous to use multiple upstream connections where possible. This also allows for intelligent routing over different connections as their quality changes either through, by way of example simple usage, or through mobility of the router. Making the router more “connection-aware” allows these decisions to be made efficiently and effectively. For use in personal networks, the NAT router should be more intelligent in the selection and assignment of IP address ranges, given that the router will typically not always by connected to the internet, and may have to contend with other NAT routers. The selection and assignment process for IP address ranges needs to occur automatically and without professional personnel or human intervention. Moreover, such selection and assignment needs to be able to change dynamically, without re-starting or rebooting the personal network. 
       SUMMARY OF THE INVENTION 
       [0011]    The basic elements and attributes of the inventive NAT Router are to manage a LAN or LANs having private IP address ranges while co-existing with multiple “upstream” networks, and to automatically and efficiently route traffic to and from the upstream networks as needed. In an exemplary embodiment, the inventive router may embed the NAT in a personal computer or other similar mobile devices such as smartphones, tablets, or other similar devices. A primary aspect of the inventive router is to be able to access multiple, independent networks, where such networks are typically accessed by application-processing equipment such as personal computers. By way of one preferred example, the inventive router may be installed within a small computer dedicated as stand-alone router, so long as the router is capable of communicating with multiple simultaneous networks. 
         [0012]    The inventive NAT router is capable of (a) monitoring bandwidth across multiple network interfaces, (b) appropriately selecting LAN address ranges that do not conflict with upstream networks currently in use or likely to be used in the same session, and (c) communicating network communications information to the system user. The address selection process reduces the potential that any of the managed personal area networks (“PANs”) will need to reset address ranges (which detrimentally breaks all connections) as the device is moved from location to location and between different upstream opportunities. 
         [0013]    More particularly, the present invention overcomes the disadvantages of the prior art and fulfills the needs described above by providing, in a preferred embodiment, a computer hosted network address translating router, comprising (a) a network address translating router; (b) a host computer communicatively connected to said network address translating router; (c) a plurality of local network adapters, each said local network adapter communicatively connected to said network address translating router; (d) a plurality of client devices, each said client device communicatively connected to a first subset of said local network adapters; (e) at least one remote network, each said remote network communicatively connected to a second subset of said local network adapters; and (f) at least one remote server, each said remote server communicatively connected to said at least one remote network; wherein said network address translating router manages network traffic to and from said at least one remote network and said at least one remote server by reassigning network connections, without restarting the networking connections, if said network connections fail, become unavailable, or degrade in performance. 
         [0014]    Another embodiment of the present invention is a method for a computer hosted network address translating router to select internet protocol (“IP”) address ranges, said method comprising the steps of (a) determining the last used IP address; (b) comparing said last used IP address against a listing of IP addresses not to be used; (c) comparing said last used IP address against a listing of historically used upstream IP addresses; (d) if said last used IP address is not on said listing of IP addresses not to be used or said listing of historically used upstream IP addresses, then said network address translating router uses said last used IP address; (e) if either said last used IP address is on said listing of IP addresses not to be used or said listing of historically used upstream IP addresses, then randomly selecting a new IP address; and (f) comparing said randomly selected new IP address against said listing of IP addresses not to be used; (g) comparing said randomly selected new IP address against a listing of historically used upstream IP addresses; (h) if said randomly selected new IP address is not on said listing of IP addresses not to be used or said listing of historically used upstream IP addresses, then said network address translating router uses said new IP address; and (i) if either said randomly selected new IP address is on said listing of IP addresses not to be used or said listing of historically used upstream IP addresses, then returning to step (d) and again random selecting a new IP address. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In the drawings, which form a part of this specification, include the following: 
           [0016]      FIG. 1A  shows an example prior art network address translator/router configuration; 
           [0017]      FIG. 1B  shows another example prior art network address translator/router configuration; 
           [0018]      FIG. 2  illustrates an exemplary embodiment of the physical architecture of the inventive NAT Router; 
           [0019]      FIG. 3  illustrates an exemplary embodiment of the logical architecture of the inventive NAT Router; and 
           [0020]      FIG. 4  illustrates an exemplary embodiment of the process used by the inventive NAT Router for providing IP Address allocation. 
       
    
    
       [0021]    Other features and advantages of the present invention are provided in the following detailed description of the invention, which refers to the accompanying drawings. 
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0022]    The present invention discloses and teaches preferred embodiments of methods and systems for a Network Address Translating (“NAT”) Router that is design to effectively and efficiently handle the demands of mobile personal LANs. Within this design capability, the inventive NAT Router is capable of (a) managing network traffic across multiple upstream LAN connections, (b) handling connections that fail or that may become unreliable, and (c) managing LAN connections that may become available, and then become unavailable, all without the need to restart the LAN. 
         [0023]    A diagram of an exemplary embodiment of the inventive NAT router  200  is shown in  FIG. 2 . Similar to the connections shown in  FIGS. 1A and 1B , the inventive router consists of a plurality of local network adapters  108 , which can share a LAN  106  with multiple client devices  104 . Since the inventive router  200  is running on a computer, it necessarily will have a virtual port  110  for the host computer  210 . Network traffic from the host computer  210  is also routed through the NAT router  200 , thus allowing local PC traffic to see the same load balancing advantages. 
         [0024]    The inventive system typically will include one or more personal area networks (“PAN”)  204 , although such PANs are not required as part of the inventive systems and routers. All PANs are networks that can be directly managed by the inventive router. As designed the inventive router provides a virtual switch (as needed by the network type), a dynamic host configuration protocol (“DHCP”), and other services independently to each PAN. The inventive router also routes each PAN though the NAT for upstream access. A PAN may be an Ethernet, 802.11, Bluetooth, IEEE1394, or any other network  106  based upon the physical media local adapter  108  running the IP network protocol. 
         [0025]    Similar to the prior architectures described, there is also an upstream LAN connection, but the inventive router is designed to be able to access any number of local adapters  108  for multiple parallel upstream connections. Each local adapter  108  is connected to a separate remote network  114 . While these networks  114  may ultimately connect or communicate with the internet or some other common network, the route-ability of a particular connection to a selected server  116  establishes the use or disuse of a particular adapter  108 . The PAN  204  is a network managed by the inventive router, while the Remote Network  206  communicates with the inventive router such that the inventive router is a normal client. The same kind of adapter  108  may be used for either type of network. 
         [0026]    Another element and aspect of the inventive router, as shown in  FIG. 2 , is the system performance monitor and load balancing  208 . The inventive system is knowledgeable of the expected performance of each upstream interface. As compared to the expected performance levels, there are the actual performance levels of the upstream interfaces, which may vary as a function of signal conditions, network traffic, interference, and other similar metrics. The performance monitor and load balancing element  208  collects the actual performance data from each interface, and maintains an average of each interface&#39;s performance. 
         [0027]    In one exemplary embodiment, the performance and load balancing element  208  may determine and maintain a running average of performance. This performance monitoring data is used by the router  112 , and is also supplied to the user via a User Interface  214 . By way of one example, the User Interface  214  offers various performance data in different simplified formats, including performance graphs over time for each interface, and a simple indicator of when the system throughput exceeds that of any single interface. 
         [0028]    Another diagram of an exemplary embodiment of the inventive router  300  is illustrated in  FIG. 3 . Similar to the processing used in a prior art NAT  102 , packets not bound for the LAN are accepted by the router and translated to the IP space of the targeted network, which may be the host computer  210 , any device on any of a plurality of PANs  204 , or potentially a remote network  206  accessible via the upstream networks  138 . Similarly, traffic from the host computer  210  is routed and translated to any PAN  204  or is routed to one or more of the remote networks  206  via the upstream connections  138 . 
         [0029]    PANs  204  may connect to and use the inventive router to provide certain management services  301 . Such management services may include DHCP or other network address allocation protocols, and may also include virtual switch/routing for any traffic remaining on each specific PAN, which does not need the NAT layer of routing. When packets that originate from a device on the PAN  204  address resources off the PAN, the NAT router  134  will normally route this traffic to other PANs, to the host computer  210 , or via the scheduler and load balancer  302 , to one or more upstream networks  138  and then onto the final Remote Network  206 . 
         [0030]    For any upstream access, each address/port socket  132  is scheduled on one of the multiple physical network interfaces  306 . This scheduling is used to balance the load for increased performance across all active interfaces, and also to dynamically move traffic away from connections that are not performing or have failed. As part of the translation function, the interface scheduler and load balancer  302 , work with the mapping function to determine and report the performance of every interface in use. The performance monitor  308  reports the running load on each interface back to the scheduler, and to advise the translator/scheduler  134 / 302  of the next “best” interface to use. 
         [0031]    The NAT router  134  used in the inventive system also provides performance data to the performance monitor  308 . By way of example, new socket connections can occur quite rapidly in a busy system, but it may take time for traffic to actually appear on any completed connection. To avoid problems with scheduling based on this slow start phenomenon, an estimated load is immediately added to the interface load score for any new connection. Over time, the real traffic will replace the estimated traffic in the performance monitor  308  calculations for that connection. 
         [0032]    While the primary work of the performance monitor  308  is monitoring and determining actual traffic, the monitor  308  may also evaluate the relative expense of the particular interface. This evaluation allows the system to use a lower cost connection for the bulk of the network traffic when such a lower cost connection may be available, but also allows the system to alter the connection and use a more expensive interface if the lower cost connection becomes bogged down or faulty. 
         [0033]    Similar to the connection shown in  FIG. 2 , data from the performance monitor  308  is available to the user in user-friendly form through the user interface  214 . By way of example, such performance data may include per interface traffic graphing, or a simple indicator of performance exceeding that of any single interface. 
         [0034]    As described above, and shown in  FIG. 2 , the dispatch router  202  assigns IP address ranges to the necessary client devices  104 . In an exemplary embodiment of the present inventive router, the system manages both the local network  106  and the wireless network  204 . An advantageous aspect of the inventive router is the intelligent allocation of the IP address range handled by the DHCP and Range Analyst  304  element. By way of example, the host network and router may be operating on a mobile device, such as a laptop computer. As the laptop relocates or moves, there would normally be a need to change the IP address range to avoid upstream conflicts. Without the inventive router and intelligent allocation of IP address ranges (from the DHCP and Range Analyst  304 ), there would normally be a need to completely reboot the network, which could result in lost work, information, or resources. The inventive router addresses and solves that mobility problem by selecting the best range of private addresses to allocate. 
         [0035]      FIG. 4  illustrates an exemplary embodiment of this IP address range selection process  400 . The process typically commences with step  401  by checking for a last-used address  402 . If there is a last-used address range, this is then checked against a global blacklist  410  to determine if the address should not be used. The last-used address is the checked against a list of historically encountered upstream addresses  412 . If both checks pass (e.g., not on the blacklist and within the listing of previously encountered upstream addresses), the last-used address is selected, and the process ends  420 . 
         [0036]    If either the blacklist or previously encountered upstream address test fails, then a new address range is needed for the attached network. To determine a new address range, the starting address is randomized  404  using one out of  256 . This address is then iterated  406  over the private address ranges with, by way of example, 192.168.10 to 192.168.254, from the starting point, and again checking each number against the blacklist  410  and against a list of historically significant IP addresses  412 . 
         [0037]    As above, if the IP address selected passes both tests, the process succeeds  420 . If either of the tests fails, the process iterates sequentially  406  to the next address within the allowable range, and so on. If all addresses are selected and tested  408 , the process starts again  404  with another random start address  414  within the range, by way of example, 172.16 to 172.31.0. If that second address range also fails to yield a usable IP range, the process again  415  selects another random start  404  within the range, by way of example, 10.0.0 to 10.0.254. Similar to the above steps within the inventive process, if a usable address is found, it is stored  418  as the last-used address, and the process exits  420 . 
         [0038]    If the test again fails to identify a usable address range, the least recently seen addresses are dropped  416  from the history buffer, and the process re-starts  404 . This closed loop processing ensures that the best address is assigned when starting a network, based on the entire history of the mobile device&#39;s interaction with upstream networks on any interface in use. 
         [0039]    While certain exemplary embodiments have been disclosed and described, there are other system configurations that are equally possible with this hardware and system architecture, and it should be understood that the invention is not limited to those embodiments described. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional applications and embodiments, further modifications, and certain substitution of equivalents, all of which are understood to be within the scope of the claimed inventive router configurations and systems and methods. Accordingly, the invention is not to be considered as limited by the foregoing description.