CN1474978A - Method and apparatus for selecting a download software image for a cable modem - Google Patents

Abstract

A data over cable modem requires initialization at each power-up. The initialization process includes downloading (88) a configuration file that includes the file name of an operating software table file. The cable modem compares (86) the operating software table file name with the version currently stored within the cable modem. If the two versions do not match, the cable modem downloads the new operating software table file. The operating software table file (90) lists cable modems according to class (based on the manufacturer and/or model number) and identifies the latest version of the operating software for each cable modem class. The cable modem determines the latest operating software version for its class and if this version differs from the version currently in use, the cable modem downloads (96) the latest operating software version.

Description

Method and apparatus for selecting a download software image for a cable modem

technical field

The present invention relates generally to cable modems, and more particularly to methods and apparatus for providing modem configuration information for a plurality of different cable modem hardware platforms in a single configuration file.

Background technique

Today it is possible to access the Internet via a telephone modem at speeds up to 56Kbps. A telephone-based modem modulates and demodulates data signals for transmission over a voice-based bandwidth telephone network. A cable modem provides access to the Internet through a cable television system, which has higher bandwidth and therefore can operate at higher data rates than the telephone system. A cable modem provides the connection between the user's computer and the headend of the cable system, at which point the cable operator provides access to the Internet via, say, a T1 line. In a cable network, the data sent from the network headend to the computer user is called downstream; the data sent from the user to the network headend is called upstream.

FIG. 1 is a block diagram of a cable system 10 including a cable modem 20 in communication with a cable system headend, not shown in FIG. Provides connectivity to the Internet or other external networks. Upon user permission, a 1 to 2 splitter 14 splits the incoming signal. The television program signal is displayed on the television 18 under the control of the set-top box 16 .

A second output of the 1 to 2 splitter 14 provides a connection to a cable modem 20 . The downstream signal stream from the headend is provided to an RF (Radio Frequency) tuner 22, which tunes the signal to the frequency band assigned to the cable modem 20 during the modem start-up phase. Usually, the downstream signal stream uses QAM (Quadrature Amplitude Modulation), so demodulation is performed in the QAM demodulator 24 . The demodulated signal is input into the media access controller 26 . The baseband data signals are input to a data and control logic unit 28 which controls the overall operation of the cable modem 20 and further provides data control functions. The computer 30 is connected to the data and control logic unit 28 for receiving data sent in the downstream direction and sending data in the upstream direction. The data flowing from the computer 30 or other data communication equipment passes through the data and control logic unit 28, the media access controller 26, and is finally modulated by a QPSK (Quadrature Phase Shift Keying)/QAM modulator. The choice of QPSK or QAM is set forth in the configuration information provided to each cable modem 20 . The upstream data stream then passes through the 1 to 2 splitter 14 to be sent to the headend of the cable system and finally to the external network.

In one embodiment, the downstream signal flow uses 64/256QAM signaling capable of delivering up to 30 to 40 Mbps of data over a 6MHz cable channel. The upstream data stream uses QPSK or 16QAM signaling available at data rates from 320Kbps to 10Mbps. Both uplink and downlink data flow rates can be flexibly configured to suit user data rate needs. For example, cable modem 20 used by business customers may be programmed to receive and transmit at relatively high data rates in both directions. On the other hand, the residential customer's cable modem 20 can be configured to have wider bandwidth access (and thus higher data rates) in the downstream direction to download from the Internet; It is limited at a lower rate.

At cable system headend 45 shown in FIG. 2 , cable system 52 demodulates and processes upstream data streams from customers 50 sent over cable network 51 where it routes data from a number of customers 50 to the illustrated Transform data when connected to the Internet, the World Wide Web, or another external network. Similarly, the cable modem termination system 52 receives data from the external network and provides the necessary data conversion to route the received downstream data stream to the appropriate subscriber 50 via the data forwarding transmitter 54 . Data repeater transmitter 54 also receives program signals (via satellite downlink, terrestrial microwave or terrestrial cable) for broadcast to subscribers 50 . User data is carried over 6MHz channels, which is the spectrum allocated to cable TV channels for broadcasting of program signals. At the subscriber's location, the program signal is received by the set top box 16 while the downstream data stream is received by the cable modem 20 alone. The RF tuner 22 tunes out the program signal from the cable modem 20, and the set top box 16 tunes out the data signal. The upstream and downstream channels in a given cable modem terminal are designed based on the service area, number of subscribers, data rate committed to each subscriber, and available spectrum.

An element management system (not shown) is another element of cable system 10 located at cable headend 45 for configuring and managing multiple cable modem termination systems 52 . Operation of the element management system includes provisioning of the system, day-to-day management of the system, monitoring, activation of alarms and testing of the various elements of the cable modem termination system 52. Typically, a single element management system is located at the cable system network operations center and is capable of supporting many cable modem termination systems 52 over a wide geographic area.

When cable modem 20 is powered on, a connection is made to cable modem terminal 52 via cable network 51 . This connection is made using the Internet Protocol (IP) format so that data received by the cable termination system 52 from the Internet and the World Wide Web can be sent in the downstream direction via the cable network 51 to the cable modem 20 of the subscriber 50.

During a typical cable modem initialization (ie, power-up) phase, cable modem 20 contacts a Dynamic Host Configuration Protocol server using Dynamic Host Configuration Protocol (DHCP). Many such DHCP servers are available on the network, and cable modem 20 simply broadcasts to all of them. Any DHCP server can answer broadcast requests. Cable modem 20 obtains an IP address, other IP related operating parameters, and the address of its configuration file from a DHCP server. This configuration file is then downloaded from a Trivial File Transfer Protocol (TFTP) server by using the configuration file address provided by the DHCP server. As is well known to those skilled in the art, TFTP is a simple protocol used to transfer files, and under this protocol, any error that occurs during the file transfer usually results in the termination of the file transfer process. TFTP provides limited error correction capabilities. TFTP files consist of a number of contiguous 512-byte blocks. The receiver processes blocks of 512 bytes until a block of less than 512 bytes or zero bytes is received. At this point, the receiving device recognizes that the TFTP file transfer is complete. The configuration file downloaded from the TFTP server includes various modem configuration settings such as access control information, downstream and upstream channel assignments, security configuration information, and the TFTP server address. Since the DHCP server provides only one configuration file address, all cable modems on the cable system 10 are configured from this file.

Given that many different makes and models of cable modems are available, a single common configuration file is not appropriate. The filename and location of the software that the cable modem runs as is also included in the configuration file. Therefore, all cable modems on the system will have to use the same operating software. The content of the configuration file is governed by a cable modem industry standard called DOCSIS (Data Over Cable Service Interface Standard). According to this standard, only a single runtime software file name can be included in the configuration file. The disadvantage is that using the same operating software for various makes and models of cable modems prevents the unique operating features that a certain cable modem may offer. However, supporting multiple makes and models of cable modems requires each modem to have a unique configuration file on the TFTP server from which its unique operating software can be derived. Further, the DHCP server will then need to maintain a list of configuration files for each type of modem. It is not considered practical to use multiple configuration files in the cable system 10 . Further, modifying a DHCP server to accommodate multiple configuration file names conflicts with the spirit of the DHCP standard, and is also expensive due to the need to modify a large number of DHCP servers in an existing wired system.

Brief description of the drawings

The invention and its further advantages will be more readily understood, and its use more apparent, upon consideration of the description of the preferred embodiment and the following drawings.

Fig. 1 is the component block diagram of the prior art at user's site;

Fig. 2 is the wired system block diagram of prior art;

Figure 3 is a flow diagram for downloading recent software configuration information for a cable modem in accordance with the teachings of the present invention; and

Figure 4 shows the different fields for the name of the running software.

Detailed ways

Before describing in detail the particular method and apparatus for downloading a unique configuration file (and its latest version) for a cable modem in accordance with the present invention, it should be noted that the invention pertains primarily to a combination of steps and apparatus. Accordingly, conventional elements of hardware and method steps are depicted in the drawings, only specific details pertaining to the present invention are shown in order not to obscure the disclosure of the present invention without structural details, which have been described herein. The structural details of the advantages will be readily apparent to those of ordinary skill in the art.

As noted above, there exists a need for a method and apparatus that would allow a cable modem manufacturer, ie, a cable modem operator, to provide the cable modem hardware The platform uses one configuration file, while at the same time providing unique operating software for different makes and models of cable modems. In particular, the DOCSIS standard (Data Over Cable Services Interface Specification) describes a mechanism by which configuration information and operating software version information are provided to a cable modem, such as cable modem 20 of FIG. 1 . Accordingly, the present invention operates within the constraints of those standards.

The process of configuring the cable modem is shown in the flowchart of Figure 3 and must be performed at each power cycle. The process of FIG. 3 begins at step 70 when cable modem 20 is powered on. Cable modem 20 then associates with cable modem termination system 52 at step 72 to receive channel assignments (see step 74 ) for sending data through cable system 10 in both the upstream and downstream directions. At step 76, cable modem 20 issues a request to the DHCP server for an IP address and a configuration file name containing cable modem configuration parameters. IP address requests are broadcast to all available DHCP servers. Cable modem 20 simply selects an IP address and profile name from the first DHCP server in response to the broadcast request. The IP address will be used during the interactive session to allow the cable modem 20 to reach and communicate with sites on the Internet or other external network. IP addresses are "leased" to cable modems for a period of configuration. When the "lease" period expires, the cable modem requests an updated IP address from the DHCP server. Typically, update requests are granted. At step 78, the DHCP server sends the cable modem 20 the name and address of the configuration file (ie, the TFTP server address).

In the prior art, each DHCP server contains the same configuration file name. Thus, each cable modem in cable system 10 receives this same configuration file name in response to its request. In the prior art, according to the DOCSIS standard, a configuration file refers to the name of a single running software. Thus, the operation of each cable modem is controlled by the same operating software. According to the teachings of the present invention, the contents of the configuration file are used to indicate to the cable modem its unique operating software files, based on the cable modem brand and model number, or assigned cable modem class designator.

At step 80 , the cable modem 20 uploads the configuration file from the TFFP server using the name provided at step 78 . As known to those skilled in the art, TFTP sends data in consecutive 512-byte blocks. Byte blocks are processed at the receiving end until a byte block containing less than 512 bytes or a byte block containing zero bytes is received. Either of these two conditions indicates that the TFTP session has ended.

As is known to those skilled in the art, in addition to the cable modem operating software file names that are the subject of the present invention, configuration files include a number of configuration settings that include standard configurations common to the entire cable system and manufacturer-specified configurations for specific cable modem hardware platform. The content of the configuration file is in binary (.bin) type/length/value format. The type field is a single byte identifier that defines configuration parameters listed in the value field. The length field is also a one-byte field that determines the length of the value field that follows. The value field ranges from 1 to 254 bytes and contains the specific value used by the configuration parameter.

In accordance with the teachings of the present invention, regardless of the cable modem's make or model, the configuration file download at step 80 allows the cable system operator to configure all configurations of its cable modem to operate with the specific desired operating software for the cable modem . In accordance with the present invention, instead of operating software file names as taught in the prior art, the configuration file includes the names of a list of operating software for the cable modem. Also, embedded in the list file name is the list's most recent version number. The list itself contains modem hardware identifiers (eg, class designators) and the running software filename (including the most recent version number) for each modem hardware identifier.

At step 82, the configuration file is validated. If the configuration file is valid, at step 84 the running software field of the configuration file is read. In the prior art, this field included the filename of the associated cable modem. The disadvantage is that this single filename and associated single operating software cannot accommodate the wide variety of cable modems used on the cable system, including cable modems from different manufacturers as well as different models from a single manufacturer. For example, when a cable modem manufacturer releases a new cable modem model with a different central processing unit than the previous model, the software must be upgraded to use the additional features of the new processor. If all modems on the cable system were restricted to running software using the lowest common denominator, certain features and functions incorporated into the hardware components would not be available. Therefore, it is clearly advantageous to identify the unique and best running software for each cable modem.

At step 86, the running software list filename read at step 84 is compared to the software list filename now stored in the cable modem 20 that was downloaded during the previous power-up process. If the version numbers do not match, then the process moves to step 88 where the latest version of the running software list file is downloaded from the TFTP file server. At step 78, the slave DHCP server provides the cable modem 20 with that TFTP file server address to invoke.

Note that because the runtime software list filenames include version information, whenever a runtime software file referenced in the list is changed, the filename must also be changed. Such operational software changes may be made, for example, due to major software releases adding new features, minor releases that patch software vulnerabilities, or patch releases in which only a few lines of code have been modified. It should be further noted that before downloading the new version at step 88, the cable modem 20 first stores an earlier version of the running software list file. In the event that the download process corrupts the file or renders the file unreadable for any reason, the cable modem 20 can continue to use the old file version until the new version is successfully downloaded.

If the existing version file stored on the cable modem 20 is actually the latest version of the file, or once the latest version has been downloaded at step 88, the process proceeds to step 90 where the modem classification or other hardware identifier is used as Enter the list's index to see the version list file.

An example running software list file is shown in the table below:

Modem Classification Running Software File Name

32 mot020000t51p5g2.bin

33 mot020000t51p5g2.bin

34 mot030000t51p5g2.bin

35 mot030100t51p5g2.bin

36 mot030001t51p5g2.bin

The left column identifies each modem on the cable system 10 by its modem class number. The right column identifies by filename the running software for each modem classification. FIG. 4 is an example runtime software file name, wherein the meaning of different components of the file name is identified. Column 110 indicates the cable modem manufacturer. Columns 112, 114 and 116 represent the major version number, minor version number and patch version number, respectively. The two columns indicated by reference character 118 are used by modem manufacturers to internally track the stages of a new software version release. Reference character 120 shows the software generation for the modem. Finally, the file extension 122 shows that the contents of the file are in binary format.

Implementation of the present invention requires that each cable modem include a hardware identifier (which, in one embodiment, is stored in non-volatile memory during manufacture) so that the running software list can be used to identify the most recent running software version. Assuming the modem class is identified by class number 34, the file name for the available cable modem operating software is mot030000t51p5g2.bin. Note that each revision of the runtime software files is reflected as a change in the file name. Therefore, at step 92, the cable modem 20 compares the runtime software filename from the list with the runtime software stored in the cable modem memory, and finally for the cable modem 20. A match between these two filenames indicates that the cable modem 20 is already using the most recent operating software. Therefore, it can be concluded that the new version list file name must have been changed by another operating software file name change, not the operating software file name change for this modem. In step 94, the cable modem 20 stores the running software list file name so that on the next power-up this stored value can be compared with the value in the running software field of the configuration file (as set forth in steps 84 and 86) to determine Whether any changes have occurred in the list.

If it is indicated at determination step 92 that the cable modem 20 is not using the latest version of the cable modem operating software, then the process proceeds to step 96 where the cable modem downloads the latest operating software version from the TFTP server using the TFTP protocol, the TFTP server address being at step 76 Obtained from the DHCP server. In one embodiment of the invention, the most recent version of the running software is always downloaded even if the filename reflects only a minor version or patch change to the most recent version. Before the download step 96 is executed, the cable modem 20 first copies and stores the old software version in another memory location, so that when the new download overwrites the old version in memory, the new running software is damaged or damaged during the download process. In case it cannot be read for some reason, the old version can still be used. After downloading at step 96, the listing filename is stored at step 94. The modem then begins its operational state, as shown in step 98 .

In accordance with the present invention, whenever the operating software for a particular cable modem is revised, the operating software name must be changed to reflect the revision. Then, the operating software list file is updated with the revised operating software file name based on the modem identifier. Finally, the listing filename must also be revised to reflect the revision of the running software.

In another embodiment of the present invention, the DHCP server queries the cable modem 20 to determine the cable modem brand and model number, ie, the modem class. Based on this information, the DHCP server identifies the available cable modem runtime software filenames as shown in the list below. The DHCP server then sends this file to the cable modem 20 for comparison with the existing operating software version stored in the cable modem. If the two software versions are the same, the cable modem can transition to its operational state. If the two versions are different, the modem 20 must download a new version of the operating software as shown at step 96 in FIG. 3 .

In yet another embodiment of the present invention, (see list above) may simply display the version number representing the most recent version of the operating software for the associated cable modem class, rather than displaying the version number set forth in the operating software list file. file name. In this embodiment, when the runtime software list is retrieved and read, the cable modem determines the version number for the runtime software currently in use and compares this value to the version number listed in the list. If the version numbers do not match, the cable modem is not using the most recent version of the software it was running and should be downloaded before proceeding to ensure that all features contained within the cable modem are available during operation. In yet another embodiment of the present invention, the version checking process shown in steps 86 and 92 of FIG. 3 may be deleted, and in its place, the file may be downloaded each time the process of FIG. 3 is executed. Thus, in this embodiment, the running software list and running software files are downloaded during each power up process, as compared to the process of FIG. 3 which downloads these files only when the version number changes from the most recent download.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, the teachings of the present invention may be modified to suit a particular application without departing from the essential scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that it will include all embodiments falling within the scope of the appended claims.

Claims (19)

1. In a network comprising a plurality of network devices, a class is assigned to each network device based on characteristics of the device, a method for providing software files to a network device, the method comprising: (a) downloading a list to the network device, wherein the list includes a list of software filenames, where each software filename is associated with a network device class; (b) determine the category of network equipment; (c) use the network device category as an index into the list to determine the software files available for the network device; and (d) downloading the software file identified in step (c). 2. The method of claim 1, wherein said network device is a cable modem operable in a network in which data is transmitted over a cable. 3. The method of claim 1, wherein the network device class is determined by at least one of a network device manufacturer and a network device model. 4. The method of claim 3, wherein the network device class is stored in a network device. 5. The method of claim 1, wherein the downloaded software file provides some operational information for the network device. 6. The method of claim 1, wherein said downloaded software file comprises network device operating software. 7. The method according to claim 1, wherein said step (c) further comprises: (c1) using the network device as an index into said list, determining software files available to the network device; and (c2) comparing the version of the software file determined in step (c1) with the version in the software file used by the network device, wherein if the result of step (c2) shows that there is a difference between the compared versions, then perform step ( d). 8. The method of claim 7, wherein the version number of the software file is included in the software file name. 9. The method of claim 1, wherein the list is contained in a configuration file for the network device. 10. The method of claim 9, wherein the list filename is contained in a running software field of the configuration file, wherein the list filename is used to download the list. 11. In a network comprising a plurality of network devices, each network device being assigned a class based on characteristics of the device, a method for providing each network device with operable software, the method comprising: (a) downloading the configuration file to the network device, wherein the configuration file includes the file name of the software list; (b) determine the version of the software list; (c) comparing the version of the software list with the version stored in the network device; (d) if the result of step (c) shows that the compared versions are different, download the software list determined in step (b), wherein the software list includes a list of executable software filenames, wherein each filename Associated with network device classes. (e) determine network equipment categories; (f) Use the category of network equipment as an index into the software list to determine the operating software that can be used for network equipment; (g) comparing the version of the operable software determined in step (f) to the version of the operating software used by the network device; and (h) If the result of step (g) shows that the compared versions are identical, download the running software determined in step (f). 12. The method of claim 11, wherein the network device is a cable modem operable in a network in which data is transmitted over a cable. 13. The method of claim 11, wherein the network device class is determined by at least one of a network device manufacturer and a network device model, wherein the network device class is stored in the network device. 14. The method according to claim 11, wherein the version number of the operating software is included in the operating software file name, wherein said operating software file name is determined in step (f), and step (g) further comprises: f) The location determines the file name of the running software and compares it with the file name of the running software used by the network device. 15. The method according to claim 11, wherein the version number of the software list is included in the software list file name, wherein the running software file name is determined in step (b), and wherein step (c) Further comprising: comparing the software list filename determined at step (b) with the software list filename used by the network device. 16. The method of claim 11, further comprising: prior to step (a) downloading the configuration file, determining the validity of the configuration file. 17. In a network comprising a plurality of network devices, wherein each network device is assigned a class based on characteristics of one or more devices, a method for providing each network device with operable software, said method include: (a) downloading the configuration to the network device, wherein the configuration file includes a list of software; (b) determine the version of the software list; (c) comparing the version of the software list with the version stored in the network device; (d) if the result of step (c) shows that the compared versions are different, download the software list determined in step (b), wherein the software list includes executable software file names, each of which can be executed Software filenames are relative to network device classes. (e) determine network equipment categories; (f) Use the network device category as an index into the software list to determine the executable software that can be used for the network device; (g) comparing the version of the executable software file determined in step (f) with the version of the executable software used by the network device; and (h) downloading the executable software file determined in step (f) if the result of step (g) shows that the compared versions are identical. 18. A product comprising: A computer-usable medium having machine-readable program code embedded therein for providing initialization files to a network device, comprising: (a) computer readable program code configured to cause a computer to download a list to a network device, wherein the list includes a list of filenames, where each filename is associated with a network device category. (b) configure the computer-readable program code to determine the category of network equipment; (c) for computer-readable program code configurations that use the network device category as an index into the list to allow the computer to determine the filenames available for the network device; (d) computer readable program code configured to cause the computer to compare the version of the file determined in step (c) with the version of the file used by the network device; and (e) configuring the computer-readable program code to cause the computer to download the file determined in step (c) if the result of step (d) shows that the compared versions are different. 19. The product of claim 18, wherein the computer readable code is embedded in a network device.

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