Patent Application
20080005345
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph.
Much of the inventive functionality and many of the inventive principles are best implemented with or in software programs or instructions and integrated circuits (ICs) such as application specific ICs. It is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. Therefore, in the interest of brevity and minimization of any risk of obscuring the principles and concepts in accordance to the present invention, further discussion of such software and ICs, if any, will be limited to the essentials with respect to the principles and concepts of the preferred embodiments.
As above, gateway device 202 may request, or be assigned, an IP address by the ISP 204. The network address may be an IP address, in this case, 210.187.110.101. Computer 210, using the DHCP protocol to dynamically assign an address or using static IP addressing may be assigned an IP address of 192.168.100.3. However, in one embodiment, when the second gateway device 212 requests an address and receives an IP address in the range of 192.168.x.x, the second gateway device 212 may determine that it is not connected to an ISP, but rather to an upstream gateway device, such as gateway device 202. The second gateway device 212 may then disable its own DHCP server and network address translation functionality and instead provide layer 2 bridging between all interfaces, which may include passing through IP address requests, e.g. DHCP registration requests) from downstream devices and pass traffic bi-directionally without network address translation.
For example, when printer 216 and computer 218 request IP addresses, the request will not be serviced by the second gateway device 212 but the requests will instead be passed to gateway device 202. Gateway device 202 will assign IP addresses using its current methodology, in this case, sequentially. Printer 216 and computer 218 may be assigned IP addresses 192.168.100.4 and 192.168.100.5 respectively. Because only one gateway device 202 is assigning addresses, duplicate addressing is avoided, as are routing problems associated with the second gateway device 212 having the same address on both upstream and downstream sides.
A network address translation circuit 314 or function may assign addresses to downstream devices and perform address translation that is required when a single upstream connection 306 supports one or more downstream connections 320322, each having different IP addresses from that at the upstream port. The bridging circuit 316 may perform routing between the single upstream connection 306 (via the address translation circuit 314, when active, and the one or more downstream connections 320322 supported by a corresponding number of downstream ports represented by block 318. A manager 324 may monitor traffic on the upstream port 308 via connection 326. The manager 324 may determine when the traffic on the upstream connection 306 is from an ISP 302, or, as shown in dotted lines, when the upstream port 308 is coupled to another gateway device 330. This determination may be made, as discussed above, by watching the address assigned to the gateway device 304. When the address is in the range 192.168.x x, the manager 324 may assume that the gateway device 304 may be in an alternate configuration downstream of another gateway device 330. In this case, the manager 324 may disable the address management circuit 314 via connection 328 so that the DHCP assignment of addresses (if active) and network address translation are disabled and the gateway device 304 only performs bridging. Such operation is typical of an IPv4 gateway device.
Alternately, the manager 324 may receive a signal from an upstream gateway device, such as gateway device 330, that network address translation is being performed elsewhere and that gateway device 304 should not perform network address translation.
In an alternate network configuration, a system manager, such as system manager 220 of
When the manager 324 determines that the upstream port 308 is connected to an ISP 302 or other Internet connection, not only may the address management circuit 314 be enabled, but the manager 324 may cause a signal or other message to be broadcast from the downstream port 318 indicating that network address translation is being performed by gateway device 304 and that any downstream gateway devices (not depicted) should not perform network address translation. In Internet Protocol version 6 (IPv4, IPv6) gateway device embodiments, the conditions may be slightly different, but the function is-similar. IPv6 supports longer addresses that are expected to allow every device wishing a public address to have one available. The address management circuit 314 may include using Dynamic Host Configuration Protocol version 6 (DHCPv6) Prefix Delegation for acquiring one or more prefixes for the downstream ports. When the manager 324 determines that the gateway device 304 is behind a security boundary (such as 304) and should only perform a bridging function, it may likewise disable routing and DHCPv6 Prefix Delegation and only perform a bridging function for IPv6 traffic. It is typical for gateways performing a bridging function to do so independent of the type of traffic (whether IPv4 or IPv6 or otherwise).
The system memory 430 may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 431 and random access memory (RAM) 432. A basic input/output system 433 (BIOS), containing the basic routines that help to transfer information between elements within gateway device 410, such as during start-up, is typically stored in ROM 431. RAM 432 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 420. By way of example, and not limitation,
The drives and their associated computer storage media discussed above and drives illustrated in
The gateway device 410 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example, the gateway device 410 may include a removable non-volatile memory interface 450 that may read from or write to a removable, nonvolatile magnetic disk drive 451 with removable magnetic media 452, and an optical disk drive 455 that reads from or writes to a removable, nonvolatile optical disk 456 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive interface 440 and the removable non-volatile memory interface 450 are typically connected to the system bus 421. Note that some gateway devices may not have rotating media drives or removable media.
The gateway device 410 may typically include a variety of computer readable media. Computer readable media can be any available media that can be accessed by gateway device 410 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by gateway device 410. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency, infrared and other wireless media. Combinations of the any of the above should also be included within the scope of computer readable media.
The gateway device 410 typically operates in a networked environment using logical connections to an upstream device, such as the Internet 474 over wide area network connection 473 via network interface 472. The network interface 472 may be connected to system bus 421. Another network interface 470 may couple one or more downstream computers 480 or other devices (not depicted) through local area network connection 471 that may also be connected to the system bus.
The remote computer 480 may be a personal computer, a server, a router, a network PC, a peer device or other common network node. The logical connections depicted in
Although the forgoing text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possibly embodiment of the invention because describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
Thus, many modifications and variations may be made in the techniques and structures described and illustrated herein without departing from the spirit and scope of the present invention. Accordingly, it should be understood that the methods and apparatus described herein are illustrative only and are not limiting upon the scope of the invention.
