Abstract:
A method and apparatus for assigning an IP address, in a modular network system, to at least one client premise equipment device coupled by a communications link to a router, wherein the last octet of said IP address may be one of at least three different values.

Description:
BACKGROUND OF INVENTION 
   1. Field of Invention 
   The present invention relates to the assigning of IP addresses to internal components of a modular network system. 
   2. The Background Art 
   The widespread use and acceptance of the Internet has generated much excitement, particularly among Competitive Local Exchange Carriers (“CLECs”), among others, who see advantages in networking their voice and data communications. A CLEC is a term coined for the deregulated, competitive telecommunications environment, envisioned by the Telecommunications Act of 1996. CLECs compete on a selective basis for local exchange service, as well as long distance, Internet access, and entertainment. They typically lease local loops from the incumbent Local Exchange Carriers (“LEC”) at wholesale rates and then resell to end users at a discounted price. CLECs often have customer premise equipment (CPE) on site. CPEs include, but are not limited to, devices such as CSU/DSUs, modems, Integrated Access Devices (IADs) and ISDN terminal adapters, required to provide an electromagnetic termination for wide-are network circuits before connecting to the router or access server. CPEs were historically provided by the telephone company, but are now typically provided by the customer (CLEC). 
   CPEs are often comprised of a manufacturer&#39;s proprietary system. Thus in order to connect, set up and maintain CPEs on a computer network, a computer network specialist trained and certified in the manufacturer&#39;s proprietary system was needed. Due to the nature and importance of keeping the computer network online and working properly, the computer network specialist was often a permanent employee of the business entity installing and maintaining the CPEs for the CLEC. 
   However many businesses simply do not desire a system so complex that a it requires having a computer network specialist on staff full time. Hence there is a need to be able to automatically configure CPEs with a minimum of human interaction. One aspect of such an automatic configuration is the assigning of IP addresses automatically to the CPEs after the CPEs power up. An IP address is usually a 32-bit address assigned to hosts using TCP/IP. An IP address belongs to one of five classes (A, B, C, D, or E) and is written as 4 octets separated by periods (dotted decimal format). Each address consists of a network number, an optional subnetwork number, and a host number. The network and subnetwork numbers together are used for routing, while the host number is used to address an individual host within the network or subnetwork. A subnet mask is used to extract network and subnetwork information from the IP address. 
   Referring to  FIG. 1  will aid in understanding a known method of assigning an IP address to a CPE. A device A  100  is shown with a serial connector  110 . A device B  120  is also shown with a serial connector  130 . Device A  100  may be a router. Device B may be a CPE. Upon powering up the system, device B  120 , may use an algorithm known as a Serial Line Address Resolution Protocol (SLARP) to assign itself an IP address. The SLARP protocol  140  is shown installed in device B. One example of the algorithm the SLARP protocol uses for assigning IP addresses is shown in  FIG. 2 . Referring to  FIG. 2 , device B powers up at act  210 . Device B requests A&#39;s IP address at act  220 . The algorithm determines whether the last octet in A&#39;s IP address is a one (1) at query  230 . If it is a one (1), the algorithm adds one (1) to the last octet of A&#39;s IP address and assigns that IP address to device B at act  240 . The algorithm ends at act  280 . If the algorithm determines that the last octet of A&#39;s IP address is not one (1), then the algorithm determines whether the last octet is two (2)  250 . If the last octet is two (2), then the algorithm subtracts 1 from the last octet, and assigns that IP address to device B at act  260 . The algorithm ends after that act  280 . If the last octet of A&#39;s IP address is neither a one (1) or a two (2), then the algorithm does not assign an IP address to device B shown at act  270 . 
   As can be seen, the algorithm described in  FIG. 2  can only work with an IP address where the last octet is either a one (1) or a two (2). For example, if the IP address for device A is 132.222.19.1, then the IP address assigned to device B is 132.222.19.2 pursuant to the algorithm shown on  FIG. 2 . If the IP address for device A is 132.222.19.2, then the IP address assigned to device B is 132.222.19.1. If the last octet of A&#39;s IP address is anything other than one (1) or two (2), then the algorithm cannot assign an IP address to B. 
   Thus, there is a need to be able to automatically configure CPEs. Part of that automatic configuration includes assigning IP addresses to the CPEs, however, assigning an IP address restricted by the last octet to either one (1) or two (2) is very limiting. Thus there is also a need to be able to automatically assign IP addresses to CPEs with a range in the last octet greater than one (1) or two (2). 
   SUMMARY OF THE INVENTION 
   The present invention is directed towards a method and apparatus for assigning an IP address, in a modular network system, to at least one client premise equipment device coupled by a communications link to a router wherein the last octet of said IP address may be one of at least three different values. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is described in greater detail by referencing the accompanying drawings. 
       FIG. 1  is a schematic of a prior art system. 
       FIG. 2  is a flowchart of a prior art method. 
       FIG. 3   a  is a schematic of one embodiment of the disclosed system. 
       FIG. 3   b  is a schematic of another embodiment of the disclosed system. 
       FIG. 4  is a flowchart of one embodiment of the disclosed method. 
       FIG. 5  is a flowchart of another embodiment of the disclosed method. 
   

   DETAILED DESCRIPTION 
   Those of ordinary skill in the art will realize that the following description of the present invention is illustrative only and not in any way limiting. Other embodiments of the invention will readily suggest themselves to such skilled persons. 
   In the prior art, a known method of automatically assigning an IP address to a CPE was by using the SLARP protocol. However, a draw-back to using only the SLARP protocol was that if device A (referring to  FIG. 1 ) had an IP address in which the last octet was neither a one (1) or a two (2), the SLARP protocol would not be able to assign an IP address to device B (referring to  FIG. 1 ). Further, SLARP would only assign an IP address with the last octet being either a one (1) or a two (2). 
   The present disclosed system will automatically assign an IP address to a CPE that is coupled to a device which has IP address with a last octet of one (1), two (2) and at least one other octet value. 
   Referring to  FIG. 3   a , a disclosed modular system is shown. Device A  300  may be a router. Device B  320  may be a CPE. Device A  300  may have a serial connector  310 . Device B  320 , may also have its own serial connector  330 . Device B is shown with a disclosed method for automatically assigning IP address to device B as  335 . In this application the term “simplex IP address” refers to an IP address in which the last octet of the IP address is one (1). Likewise, the term “duplex IP address” shall refer to an IP address in which the last octet of the IP address is two (2). Device A and device B may be coupled by a communications link via the following non-limiting list of protocols: SLARP, ATM INARP, PPP/IPCP and Frame Relay protocols over Serial, T1 and DSL connections. The communications link may be any link suitable for transmitting IP Protocol information. 
   Referring to  FIG. 3   b , the modular system of  1   a  is shown with devices B 1  through B n    320 ,  360  and  380  shown coupled to device A. When coupling more than one device to device A, each serial connector of device A  310 ,  340  and  350  may have its own IP address. Each serial connector of device A  310 ,  340  and  350  are coupled to the respective serial connectors of devices B 1  through B n    330 ,  370  and  390 . If the last octet for the IP addresses for serial connectors  310 ,  340  and  350  are anything other than one (1) or two (2), then the known SLARP algorithm will not be able to assign an IP address to devices B 1  through B n    320 ,  360  and  380 . The disclosed method is shown installed in devices B 1  through B n  as  335 . 
     FIG. 4  shows an embodiment of the disclosed method. This embodiment allows for assigning of IP addresses with a last octet ranging from 1 through 254, inclusive. Referring to  FIG. 4 , device B powers up at act  404 . Device B requests A&#39;s IP address at act  408 . The algorithm determines whether the last octet in A&#39;s IP address is a one (1) at query  412 . If it is a one (1), the algorithm adds one (1) to the last octet of A&#39;s IP address and assigns that IP address to device B at act  416 . The algorithm ends at act  440 . If the algorithm determines that the last octet of A&#39;s IP address is not one (1), then the algorithm determines whether the last octet is two (2) at query  420 . If the last octet is two (2), then the algorithm subtracts 1 from the last octet, and assigns that IP address to device B at act  424 . The algorithm ends after that at act  440 . If the last octet of A&#39;s IP address is neither a one (1) or a two (2), then the algorithm proceeds to determine whether the last octet in A&#39;s IP address is less than 254 at query  428 . If the last octet is less than 254, the algorithm adds 1 to the last octet of A&#39;s IP address and assigns that IP address to device B at act  432 . This IP address may be referred to as an “added IP address”. If the last octet of A&#39;s IP address is greater than or equal to 254, the algorithm subtracts 1 from A&#39;s IP address and assigns that IP address to device B at act  436 . This IP address may be referred to as a “subtracted IP address”. 
   In one embodiment of the disclosed system, the disclosed algorithm may be stored on each CPE device. 
   Referring back to  FIG. 3   a , if the IP address of device A is 21.244.119.254, then the disclosed algorithm would assign an IP address of 21.244.119.253. 
   Similarly, the disclosed system will work in a modular system shown in  FIG. 3   b . For instance, assuming that serial connector  310  has an IP address of 235.17.198.2, serial connector  340  has an IP address of 235.17.198.234, and serial connector  350  has an IP address of 235.17.198.99, then, pursuant to the disclosed system, the algorithm will assign the following IP addresses: B 1  will have an IP address of 235.17.198.1, B 2  will have an IP address of 235.17.198.233, and B n  will have an IP address of 235.17.198.100. 
     FIG. 5 , shows another embodiment of the disclosed system. Device B powers up at act  504 . The algorithm requests device A&#39;s IP address at act  508 . The algorithm determines whether the last octet in A&#39;s IP address is less than 254 at query  512 . If the last octet is less than 254, then at act  510 , the algorithm adds 1 to the last octet of A&#39;s IP address and assigns that address to device B. After act  510 , the algorithm ends at act  520 . If the last octet of A&#39;s IP address is greater than or equal to 254, then the algorithm subtracts 1 from the last octet of A&#39;s IP address and assigns that IP address to device B at act  524 . The algorithm then ends at act  520 . 
   While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications than mentioned above are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the appended claims.