`
`
`
`
`
`
`
`
`
`
`Exhibit 101 9
`
`Exhibit 1019
`
`
`

`

`US007047313B1
`
`(12)
`
`United States Patent
`Broerman
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,047,313 B1
`May 16, 2006
`
`(54) METHOD FOR REDIRECTING
`PACKETIZED DATA ASSOCIATED WITH A
`DESTINATION ADDRESS IN A
`COMMUNICATION PROTOCOL LAYER TO
`A DIFFERENT DESTINATION ADDRESS IN
`A DIFFERENT PROTOCOL LAYER
`1. IN
`(75) I
`: Keith Robert B
`C
`nventor: Keith Robert Broerman, Carmel,
`(US)
`(73) Assignee: Thomas Licensing,
`Boulogne-Billancourt (FR)
`
`FOREIGN PATENT DOCUMENTS
`
`WO
`
`10/1998
`WO98/47310
`(Continued)
`
`OTHER PUBLICATIONS
`“The Convergence of Layer 2 and Layer 3 in Today's LAN”.
`Foundry Networks, Gigabit Info Center, Improving Perfor
`mance; http://www.foundrynet.com/wpwols.html, Jul. 27,
`2000, pp. 1-13.
`, pp
`
`(Continued)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 529 days.
`
`- -
`-
`Primary Examiner—David Y. Eng
`(74) Attorney, Agent, or Firm—Joseph S. Tripoli; Ronald H.
`Kurdyla; Joel M. Fogelson
`
`(21) Appl. No.: 09/644,337
`
`(22) Filed:
`
`Aug. 23, 2000
`
`Related U.S. Application Data
`-
`-
`. -
`-
`(60) º application No. 60/174,565, filed on Jan.
`s
`-
`(51) Int. Cl
`e vº._2 - e.
`G{}6F H 5/16
`
`(2006.01)
`
`(52) U.S. CI - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 709/238
`
`(58) Field of Classification Search ................ 709/238,
`709/218, 230, 245
`See application file for complete search history.
`e
`References Cited
`
`(56)
`
`|U.S. PATENT DOCUMENTS
`
`5,355,365 A 10/1994 Bhat et al. ............... 370/85, 13
`5,666,487 A
`9/1997 Goodman et al. ....... 395/200.7
`
`(57)
`
`ABSTRACT
`
`A system enables a bi-directional communication device
`such as a modem to facilitate local communication between
`the modem and an attached PC as well as to enable the PC
`to conduct concurrent Internet and local communication. A
`bi-directional communication system employs a method for
`seamlessly communicating packetized data between differ
`ent networks using hierarchical layers of communication
`protocols (e.g. including Internet Protocol (IP) and Media
`Access Control (MAC) layers). The method involves com
`paring a received IP packet destination address in a first
`if there is an address match. Upon such an address match, a
`payload of the received IP packet is redirected from an
`Internet network to a local network (e.g. an Ethernet, HPNA
`or USB network) by substituting a second protocol layer
`address for a received second protocol layer address (e.g. a
`MAC address). In another feature, a second Application (e.g.
`eripheral control) is initiated to operate concurrently with
`perip
`p
`y
`a first Application (e.g. web surfing) in response to receiving
`the redirected payload data.
`
`protocol layer with &l predetermined IP address to determine
`
`19 Claims, 7 Drawing Sheets
`
`|N A HIERARCHICAL PACKETIZED COMMUNICATION PROTOCOL COMPRISED OF
`MULTIPLE HERARCHICAL PROTOCOLLAYERS, COMPAREA RECEIVED IP
`PACKET DESTINATION ADDRESS RECEIVED ON A FIRST PROTOCOLLAYER
`WITH APREDETERMINED IP ADDRESS TO DETERMINE IF THERE ISA MATCH.
`
`
`
`{F THERE IS AN ADDRESS MATCH.
`ONA PACKET BY PACKET BASIS, REDIRECT APAYLOAD OF THE RECEIVED
`IP PACKET FROMAN INTERNET NETWORK TO A LOCAL NETWORK BY
`SUBSTITUTING ASECOND PROTOCOLLAYER ADDRESS FOR THE RECEIVED
`SECOND PROTOCOLLAYER ADDRESS ASSOCATED WITH THE RECEIVED P PACKE
`
`
`
`INITIATE AN APPLICATION PROGRAM SUCH AS DIAGNOSTICS, HOME CONTROL,
`PERIPHERAL CONTROL, COMMUNICATION, INTRANET OR OTHER APPLICATION
`PROGRAM IN RESPONSE TO RECEIVING THE REDIRECTED PAYLOAD.
`CONCURRENTLY OPERATE ANOTHERAPPLICATION PROGRAM SUCH ASA WEB
`SURFING, EMAIL, OR OTHER COMMUNICATION APPLICATION.
`
`
`
`410
`
`415
`
`

`

`US 7,047,313 B1
`Page 2
`
`|U.S. PATENT DOCUMENTS
`5,790,548 A
`8/1998 Sistanizadeh et al. ....... 370/401
`5,884,024 A
`3/1999 Lim et al. ................... 395/187
`5,961,604 A 10/1999 Anderson et al. ........... 709/229
`6,006,265 A 12/1999 Rangan et al. .............. 709/226
`6,012,088 A
`1/2000 Li et al. ..................... 709/219
`6,049,826 A
`4/2000 Beser ......................... 709/222
`6,061,796 A
`5/2000 Chen et al. ................. 713/201
`6,377,990 B1 * 4/2002 Slemmer et al. ............ 709/225
`6,640,251 B1 * 10/2003 Wiget et al. ................ 709/238
`
`
`
`FOREIGN PATENT DOCUMENTS
`
`WO
`
`WO99/30449
`
`6/1999
`
`OTHER PUBLICATIONS
`“DOCSIS Cable Device MIB-Cable Device Management
`Information Base for DOCSIS Compliant Cable Modems
`and Cable Modem Termination Systems, ’’ Network Working
`Group, RFC: 2669, Category: Proposed Standard, Aug.
`1999.
`IETF RFC 2663, P. Srisuresh, M. Holdrege, “IP Network
`Address Translator (NAT) Terminology & Considerations”,
`Aug. 1999
`-
`-
`(EPO Communication Pursuant to Article 96(2) dated May
`18, 2004 attached).
`* cited by examiner
`
`

`

`U.S. Patent
`
`May 16, 2006
`
`Sheet 1 of 7
`
`US 7,047,313 B1
`
`TOETE ? | | | | | | | | | |
`
`
`
`
`
`
`
`
`
`| | | | | | | |
`
`

`

`U.S. Patent
`
`May 16, 2006
`
`Sheet 2 of 7
`
`US 7,047,313 B1
`
`FLF
`
`//
`
`H010ENN00
`
`FLF
`
`8010ENN00
`
`0/
`
`99
`
`09
`
`06
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`
`08
`
`9/
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`ETEWO
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`ENIT
`
`
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`
`
`
`
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`
`

`

`U.S. Patent
`
`May 16, 2006
`
`Sheet 3 of 7
`
`US 7,047,313 B1
`
`FGURE3
`
`|NA|H|ERARCHICAL PACKETIZED COMMUNICATION PROTOCOL COMPRISED OF
`MULTIPLE HERARCHICAL PROTOCOLLAYERS, COMPAREA RECEIVED IP
`PACKET DESTINATION ADDRESS RECEIVED ON A FIRST PROTOCOLLAYER
`WITH APREDETERMINED IP ADDRESS TO DETERMINE IF THERE IS A MATCH.
`
`|F THERE IS AN ADDRESS MATCH:
`ONAPACKET BY PACKETBASIS, REDIRECT APAYLOAD OF THE RECEIVED
`|P PACKET FROMAN INTERNET NETWORK TO A LOCAL NETWORK BY
`SUBSTITUTING ASECOND PROTOCOLLAYER ADDRESS FOR THE RECEIVED
`SECOND PROTOCOLLAYERADDRESS ASSOCIATED WITH THE RECEIVED IP PACKE
`
`
`
`
`
`
`
`INITIATE AN APPLICATION PROGRAM SUCH AS DIAGNOSTICS, HOME CONTROL,
`PERIPHERAL CONTROL, COMMUNICATION, INTRANET OR OTHER APPLICATION
`PROGRAM IN RESPONSE TO RECEIVING THE REDIRECTED PAYLOAD.
`CONCURRENTLY OFERATE ANOTHERAPPLICATION PROGRAM SUCH ASA WEB
`SURFING, EMAIL, OR OTHER COMMUNICATION APPLICATION.
`
`410
`
`415
`
`

`

`U.S. Patent
`
`May 16, 2006
`
`Sheet 4 of 7
`
`US 7,047,313 B1
`
`
`
`
`
`?|
`
`~, NECONHIAVO
`
`

`

`U.S. Patent
`
`May 16, 2006
`
`Sheet 5 of 7
`
`US 7,047,313 B1
`
`
`
`NYEBOOI
`
`9|9
`
`

`

`U.S. Patent
`U.S. Patent
`
`7
`
`US 7,047,313 B1
`US 7,047,313 B1
`
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`

`U.S. Patent
`U.S. Patent
`
`May 16, 2006
`May 16, 2006
`
`Sheet 7 of 7
`Sheet 7 of 7
`
`US 7,047,313 B1
`US 7,047,313 B1
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`

`1
`METHOD FOR REDIRECTING
`PACKETIZED DATA ASSOCIATED WITH A
`DESTINATION ADDRESS IN A
`COMMUNICATION PROTOCOL LAYER TO
`A DIFFERENT DESTINATION ADDRESS IN
`A DIFFERENT PROTOCOL LAYER
`
`5
`
`This is a non-provisional application of provisional appli
`cation Ser. No. 60/174,565 by K. Broerman, filed Jan. 5,
`2000.
`
`10
`
`FIELD OF THE INVENTION
`
`This invention concerns a bi-directional Internet compat
`ible communication system for re-routing packetized data
`associated with a destination address to Applications in a
`cable modem, computer, TV, VCR, or an associated periph
`eral device.
`
`BACKGROUND OF THE INVENTION
`
`15
`
`20
`
`25
`
`30
`
`Home entertainment systems increasingly include both
`Personal Computer and television functions (PC/TV func
`tions) involving multiple source and multiple destination
`communication. Such a system may receive data from
`satellite or terrestrial sources comprising High Definition
`Television (HDTV) broadcasts, Microwave Multi-point Dis
`tribution System (MMDS) broadcasts and Digital Video
`Broadcasts (DVB). Such a system may also provide high
`speed Internet access through a broadcast link or a coaxial
`link (e.g. cable TV lines) using a cable modem or via a
`telephone line link using an ADSL or ISDN (Asynchronous
`Digital Subscriber Line or Integrated Services Digital Net
`work) compatible modem, for example. A home entertain
`ment system may also communicate with local devices using
`different communication networks. Such local devices
`include Digital Video Disk (DVD), CDROM, VHS, and
`Digital VHS (DVHSTM) type players, PCs, set top boxes and
`many other types of devices.
`It is desirable for home entertainment systems, supporting
`Internet compatible bi-directional communication using
`cable and other types of modems, to be able to seamlessly
`communicate with networked devices on different networks.
`For example, such a home entertainment system may com
`45
`municate on Ethernet, Home Phoneline Networking Alli
`ance (HPNA) or Universal Serial Bus (USB) local networks.
`These requirements and associated problems are addressed
`by a system according to the present invention.
`
`35
`
`40
`
`SUMMARY OF THE INVENTION
`
`50
`
`A bi-directional communication system employs a
`method for seamlessly communicating packetized data
`between different networks using hierarchical layers of
`55
`communication protocols (e.g. including Internet Protocol
`(IP) and Media Access Control (MAC) layers). The method
`involves comparing a received IP packet destination address
`in a first protocol layer with a predetermined IP address to
`determine if there is an address match. Upon such an address
`match, a payload of the received IP packet is redirected from
`an Internet network to a local network by substituting a
`second protocol layer address for a received second protocol
`layer address (e.g. a MAC address). In another feature, a
`second Application (e.g. peripheral control) is initiated to
`operate concurrently with a first Application (e.g. web
`surfing) in response to receiving the redirected payload data.
`
`65
`
`60
`
`US 7,047,313 B1
`
`2
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the drawing:
`FIG. 1 provides a simplified overview of a packet
`switched network consisting of remotely-located cable com
`pany head-end equipment, a customer owned or leased cable
`modem, and its attached Customer Premise Equipment
`(CPEs.), according to the invention.
`FIG. 2 shows a cable modem system, according to the
`invention.
`FIG. 3 shows a flowchart of a method for use in a
`bi-directional communication system for seamlessly com
`municating data between an Internet network and a local
`network, according to the invention.
`FIG. 4 shows an exemplary cable modem providing
`bi-directional network bridging communication between
`Radio Frequency (RF) and Customer Premises Equipment
`(CPE) interfaces, according to the invention.
`FIG. 5 shows the cable modem of FIG. 4 including a filter
`for performing parsing and packet classification and for
`editing Media Access Control (MAC) data link layer pack
`ets, according to the invention.
`FIG. 6 shows MAC layer encapsulation of IP layer
`packets received on one interface and forwarded to another
`interface, according to the invention.
`FIG. 7 shows the hierarchically layered communication
`protocols used in a bi-directional communication system,
`according to the invention.
`
`DETAILED DESCRIPTION OF THE DRAWINGS
`
`A bi-directional communication system (e.g. a cable
`modem) supports seamless communication of packetized
`data between different networks using hierarchically orga
`nized communication protocols. A packet classifier and
`MAC frame header editing function (a network filter) is
`advantageously incorporated in the cable modem system to
`support the operation of local applications by Customer
`Premise Equipment (CPE) such as a PC that is attached to
`the modem. Such Applications may include, for example, (a)
`home appliance control, e.g., heating control, (b) peripheral
`control, e.g., TV or VCR or DVD control, (c) a communi
`cation function, e.g., between different appliances in a home,
`(d) a diagnostic function, e.g., for a cable modem diagnos
`tics function and (e) secure private internet or intranet
`communication functions, e.g., Email between different
`home PCs. The use of the network filter in a cable modem
`enables CPE devices on local networks (e.g. Ethernet, USB
`or HPNA networks), to directly exchange data through the
`modem using a hierarchically organized communication
`protocol comprised of multiple protocol layers. These layers
`may include Internet Protocol (IP) and Media Access Con
`trol (MAC) layers, for example.
`The use of the network filter in the modem also advan
`tageously eliminates a manual configuration operation
`within an attached PC, and enables concurrent communica
`tion, (a) between the PC and the Internet and (b) between the
`PC and the cable modem. The communication between the
`PC and modem is used to support local Applications such as
`a diagnostics Application as may be described by reference
`to the system of FIG. 1. The system of FIG. 1 comprises a
`packet-switched network consisting of remotely-located
`MSO (Multiple System Operator) cable company head-end
`equipment 90, a customer owned or leased cable modem 12,
`and its attached Customer Premise Equipment (CPE) 95. As
`an illustration, in the system of FIG. 1, one of the CPE
`
`

`

`US 7,047,313 B1
`
`10
`
`15
`
`25
`
`30
`
`45
`
`20
`
`3
`devices 95 communicates to the Internet via cable modem
`12 and head-end equipment 90 and also concurrently down
`loads diagnostics information from modem 12. The head
`end 90 typically provides Internet Service Provider (ISP)
`functionality such that CPE devices 95 may connect to the
`Internet, browse the World Wide Web, perform FTP file
`transfers and exchange email, etc.
`The cable modem of system 12 implements applications
`involving local communication such as multiple diagnostic
`Applications, for example. The diagnostic Applications
`communicate with CPE equipment 95 using a network IP
`address that is constrained to a particular fixed value (dif
`ferent from the IP address assigned to system 12) by the
`multiple system operator (MSO) of head end 90. Further,
`CPE 95 typically resides on a different logical network or
`subnetwork than the diagnostics Application. As a result
`there are problems involved in, (a) configuring CPE network
`parameters to support local communication between modem
`system 12 and CPE 95, and in (b) maintaining Internet
`communication between CPE 95 and a remote source
`accessed via head end 90 (e.g., for web surfing), whilst
`concurrently maintaining communication between system
`12 and CPE 95 for local (e.g., diagnostic) applications.
`Specifically, in order to enable CPE 95 to access diagnostics
`information in system 12, it is necessary to configure CPE
`95 to reside on the same logical network as that used by the
`system 12 diagnostics application. One way to address this
`problem is to temporarily reconfigure the CPE 95 network
`address such that the CPE device resides on the same
`network as the modem diagnostic Applications. This ensures
`that CPE 95 and system 12 are directly connected from a
`network protocol perspective. However, such a configura
`tion operation is a non-trivial and error-prone task requiring
`a User to determine a valid network address and subnet mask
`as well as requiring a User to follow a detailed procedure to
`35
`enter configuration values and activate them in a CPE
`device. In order to set a fixed network address on a Microsoft
`Windows PC requires that a User enters its Network Setup
`control menu, changes existing options, enters the correct
`parameters, and reboots the PC. This operation requires
`40
`capabilities likely to be beyond the majority of the PC
`literate population. Moreover, once the CPE network
`address has been fixed for this purpose, the CPE device no
`longer resides on the same logical network as the head-end
`and the CPE device (e.g., a PC) is unable to concurrently
`browse the Internet or exchange email.
`The exemplary embodiment of system 12 of FIG. 2
`addresses these problems by advantageously incorporating a
`packet classifier and MAC frame header editing function (a
`network filter). This eliminates the need to manually fix the
`network address of a CPE device in order to perform a local
`network function such as exchanging diagnostics data with
`the cable modem 12, for example. It also permits the CPE
`device to simultaneously browse the Web while exchanging
`modem diagnostics data. System 12 of FIG. 2 supports cable
`modem bridging communication between the Internet
`(through the CATV head end) and local area network (LAN)
`devices (including PCs). Further, the bi-directional commu
`nications between system 12 and the CATV head-end are in
`a multi-layered protocol format illustrated in FIG. 7.
`The multi-layered protocol format illustrated in FIG. 7
`involves a QAM (Quadrature Amplitude Modulation) or
`QPSK (Quadrature Phase Shift Keying Modulation) physi
`cal layer 629 for upstream communication between system
`12 and the head end (via line 10 of FIG. 2). This physical
`layer conveys MPEG2 (Moving Pictures Expert Group)
`transport protocol data conveying DOCSIS MAC (Media
`
`50
`
`55
`
`60
`
`65
`
`4
`Access Control) data frames 631. The MAC data conveys
`Ethernet-II/802.3 logical link control data frames 633 or
`MAC management data and the Ethernet data in turn con
`veys IP layer data. The cable modem also maintains a return
`communication path to the CATV head-end employing the
`hierarchically ordered 633, 631 and 629 protocol layers for
`Time Division Multiplexed communication of return data in
`Ethernet protocol.
`The encompassing physical layer data transmitted from
`the CATV head-end to the cable modem is processed for
`Ethernet communication in 802.3 Ethernet data frames by
`Ethernet transparent link layer bridge 617 or is converted to
`USB or HPNA format by USB/MAC layer 623. In commu
`nicating via port 72 (FIG. 2) in Ethernet format, the Ether
`net-II/802.3 data 619 provided by bridge 617 is encapsulated
`as MAC layer data 623 for communication in Ethernet-II/
`802.3 physical layer format 626 to attached LAN devices on
`port 72. Similarly, in communicating via ports 82 and 77
`(FIG. 2) in USB and HPNA format respectively, the Ether
`net-II/802.3 data 619 provided by bridge 617 is encapsulated
`in USB MAC layer or HPNA MAC layer data frames 623
`for communication in USB or HPNA physical layer format
`626 to attached LAN devices on ports 82 and 77.
`The cable modem maintains bi-directional communica
`tion with the LAN devices and also receives data from the
`devices in corresponding Ethernet, USB or HPNA protocol.
`In other embodiments, system 12 may maintain bi-direc
`tional communication with LAN devices via other methods
`including 802.11 and ‘Bluetooth’ data links.
`The data received from both the CATV head-end and
`attached CPE devices may be bridged (forwarded) to the
`opposite interface or passed to TCP/IP stack 615 (FIG. 7).
`TCP/IP stack 615 provides protocol layering and delayering
`of data in communicating between link layer bridge 617 and
`a socket Application Programming Interface (API) used by
`internal software Applications. The internal software Appli
`cations include SNMP (System Network Management Pro
`tocol) application 605, DHCP (Dynamic Host Configuration
`Protocol) application 607, HTTP server 609, Diagnostic
`Application 611 and ATE (Automatic Test Equipment)
`server 613.
`The cable modem described herein employs an MPEG
`compatible protocol conforming to the MPEG2 image
`encoding standard, termed the “MPEG standard”. This stan
`dard is comprised of a system encoding section (ISO/IEC
`13818-1, Jun. 10, 1994) and a video encoding section
`(ISO/IEC 13818- Jan. 20, 1995). The Internet TCP/IP
`(Transmission Control Protocol/Internet Protocol) and Eth
`ernet compatible protocols described herein provide com
`patibility with the Multimedia Cable Networks Systems
`(MCNS) preliminary requirements and DOCSIS 1.0 (Data
`Over Cable Service Interface Specification 1.0) require
`ments ratified by the International Telecommunications
`Union (ITU) March 1998 and as specified in RFC 2669
`(Request For Comment Document 2669). The RFC docu
`ments are available via the Internet and are prepared by
`Internet standards working groups.
`The principles of the invention may be applied to any
`bi-directional communication system and are not restricted
`to cable, ADSL, ISDN or conventional type modems. Fur
`ther, the disclosed system processes Internet Protocol (IP)
`data from a variety of Internet sources including streamed
`video or audio data, telephone messages, computer pro
`grams, Emails or other packetized data and communications,
`for example.
`The cable modem (system 12) of FIG. 2 communicates
`with a CATV head-end over a bi-directional broadband high
`
`

`

`US 7,047,313 B1
`
`10
`
`20
`
`5
`speed RF link on line 10 which typically consists of coaxial
`cable or hybrid fiber/coax (HFC). The modem system 12
`bi-directionally communicates with devices located at a
`User site over local area networks (LANs). Typical User
`side local area networks include Digital/Intel/Xerox Ether
`net compatible networks attached via connector 72. Other
`User-side devices communicate via a Universal Serial Bus
`(USB) or HPNA compatible networks attached via connec
`tors 82 and 77 respectively. User devices attached on the
`Ethernet, HPNA and USB networks may include equipment
`such as personal computers (PCs), network printers, video
`receivers, audio receivers, VCRs, DVDs, scanners, copiers,
`telephones, fax machines and home appliances, for example.
`In operation, diplexer 20 of cable modem system 12 of
`FIG. 2 separates upstream communications (sent from
`15
`modem 12 to a CATV head-end) from downstream com
`munications (sent from a CATV head-end to modem 12)
`conveyed via cable line 10. Diplexer 20 separates upstream
`data from downstream data based on the different frequency
`ranges that the upstream data (typically 5–42 MHz) and
`downstream data (typically 92–855 MHz) respectively
`employ. Controller 60 configures the elements of cable
`modem 12 of FIG. 2 to receive MPEG2 transport data from
`the CATV head-end on cable line 10 and to convert the data
`to Ethernet, USB or HPNA compatible format for output via
`ports 72, 82 and 77 respectively. Similarly, controller 60
`configures the elements of cable modem 12 of FIG. 2 to
`receive Ethernet, USB or HPNA compatible data from ports
`72, 82 and 77 and to convert and transmit MPEG2 transport
`protocol data to the CATV head-end on cable line 10.
`Controller 60 configures the elements of system 12 through
`the setting of control register values within these elements
`using a bi-directional data and control signal bus. Specifi
`cally, controller 60 configures tuner 15, saw filter 25, dif
`ferential amplifier 30 and MCNS (Multimedia Cable Net
`works Systems) interface device 35 to receive a DOCSIS
`formatted signal on a previously identified RF channel
`frequency. The DOCSIS formatted signal comprises an
`MPEG2 transport protocol format conveying Ethernet com
`patible data frames including IP data content.
`40
`Controller 60 employs an initialization process to deter
`mine the RF channel frequency that tuner 15 is to be
`configured to receive. The initialization process involves
`iteratively tuning to successive candidate RF channel fre
`quencies until a DOCSIS compliant signal is obtained.
`Controller 60 recognizes a DOCSIS compliant signal on a
`candidate channel through the successful decode by MCNS
`interface processor 35 of the received data and through a
`correspondingly acceptable error rate for the decoded data.
`In the initialization process, controller 60 in conjunction
`with MCNS interface 35, amplifier 85 and RF transformer
`87, also transmits data upstream to the CATV head-end for
`a variety of purposes including for adaptively and iteratively
`adjusting upstream and downstream communication param
`eters. These parameters include cable modem transmission
`power level and timing offset, for example.
`Following initialization and in normal operation, an RF
`carrier is modulated with MPEG2 transport protocol data
`using 64 or 256 QAM (Quadrature Amplitude Modulation).
`The MPEG2 transport data includes Ethernet formatted data
`which in turn includes IP data representing a User requested
`HTML (HyperText Mark-Up Language) web page, for
`example. The MPEG transport data is provided by diplexer
`20 to tuner 15. Tuner 15 down-converts the input signal from
`diplexer 20 to a lower frequency band which is filtered by
`saw filter 25 to enhance signal isolation from neighboring
`RF channels. The filtered signal from unit 25 is level shifted
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`6
`and buffered by differential amplifier 30 to provide a signal
`compatible with MCNS interface processor 35. The result
`ant down converted, level-shifted signal from amplifier 30 is
`demodulated by MCNS processor 35. This demodulated
`data is further trellis decoded, mapped into byte aligned data
`segments, deinterleaved and Reed–Solomon error corrected
`within processor 35. Trellis decoding, deinterleaving and
`Reed–Solomon error correction are known functions
`described, for example, in the reference text Digital Com
`munication, Lee and Messerschmidt (Kluwer Academic
`Press, Boston, Mass., USA, 1988). Processor 35 further
`converts the MPEG2 format data to Ethernet data frames
`that are provided to controller 60.
`Controller 60 parses and filters the Ethernet compatible
`data from unit 35 using filters configured from the CATV
`head-end. The filters implemented by controller 60 match
`data identifiers in incoming Ethernet frame packets provided
`by unit 35 with identifier values pre-loaded from the CATV
`head-end. The identifier values are pre-loaded during a
`previously performed initialization or configuration opera
`tion. By this means controller 60 implements a data admis
`sion control function forwarding selected data to local LAN
`devices and discarding other selected data content. This
`configurable filter system may be advantageously used to
`filter data based on metadata items in the incoming data for
`a variety of purposes including based on, (a) content rating
`for parental or other blocking control, (b) predetermined
`User preferences for targeting advertisements and “push
`content”, (c) firewall filtering, (d) identity of source, and (e)
`a data search function. The filtered Ethernet compatible
`serial data is communicated to a PC via Ethernet interface
`65, filter and isolation transformer 70 and port 72. Interface
`65 buffers and conditions the data from controller 60 for
`filtering and transforming by unit 70 for output to a PC via
`port 72.
`In similar fashion, controller 60 converts and filters data
`(conveyed in Ethernet MAC frames) from processor 35 for
`output in USB format via port 82 or in HPNA format via port
`77. The USB data is buffered by transceiver 75 and filtered
`by noise and interference suppression (EMI/ESD) filter 80
`prior to output to USB compatible LAN devices connected
`to port 82. Similarly, the HPNA data is conditioned by
`interface 62 and buffered by transceiver amplifier 67 prior to
`output to HPNA compatible LAN devices connected to port
`77.
`Modem system 12 also communicates data upstream from
`an attached PC, for example, to a CATV head-end. For this
`purpose, controller 60 of system 12 receives Ethernet com
`patible data from the attached PC via port 72, interface 65
`and filter/isolation transformer 70 and provides it to proces
`sor 35. Processor 35 modulates an RF carrier with the
`received Ethernet format data using 16 QAM or QPSK
`(Quadrature Phase Shift Keying Modulation). The resultant
`modulated data is time division multiplexed onto cable line
`10 for upstream communication via amplifier 85, trans
`former 87 and diplexer 20. Amplifier 85 outputs the data to
`the CATV head-end with an appropriate power level
`selected in the previously described initialization process.
`Transformer 87 provides a degree of fault and noise isolation
`in the event of a failure in the modem 12 or upon the
`occurrence of locally generated noise in the modem or in
`attached devices.
`In similar fashion, modem system 12 also communicates
`data upstream from devices attached via USB port 82 or via
`HPNA port 77. In an exemplary implementation, controller
`60 of system 12 receives Ethernet compatible data from
`transceiver 75 and provides it to processor 35 for upstream
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`US 7,047,313 B1
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`communication in the manner previously described. For this
`purpose, transceiver 75 receives Ethernet data encapsulated
`within USB frames from port 82 via filter 80 and removes
`the USB frame data to provide Ethernet format data to
`controller 60. Similarly, interface 62 receives data encapsu
`lated in HPNA format from port 77 via transceiver 67 and
`provides Ethernet format data to controller 60.
`Controller 60 is also responsive to on/off and reset switch
`90 and performs a variety of functions in addition to those
`already described. Controller 60 configures modem 12
`parameters using configuration information provided from a
`CATV head-end. Controller 60 also directs system 12 in
`synchronizing and multiplexing upstream communication
`onto cable line 10 and implements a rate limit in controlling
`upstream data traffic. Further, controller 60 bi-directionally
`filters received data and provides selected data to either the
`CATV head-end or LAN devices attached to ports 72, 77 and
`82. Controller 60 also supports data ranging communication
`with the CATV head-end. The ranging communication is
`initiated by the CATV head-end and comprises the continu
`ous but intermittent polling of individual modems to deter
`mine status and to identify modem or line failures.
`System 12 also uses a network filter operating under the
`direction of controller 60 to advantageously intercept pack
`ets (from a CPE device destined for the CATV head-end)
`and replace the destination MAC address with the diagnostic
`interface MAC address of modem system 12. This results in
`the packet being directed to TCP/IP stack (stack 615 of FIG.
`7) and not to the CATV head end, and makes modem system
`12 appears to reside on the same logical network as the
`attached CPE device. This interception mechanism and
`apparent direct connection addresses the previously
`described problems of (a) configuring network parameters
`to support local communication between modem system 12
`and attached CPE devices, and (b) concurrently maintaining
`Internet communication between a CPE device and the
`Internet via system 12, whilst concurrently maintaining
`communication between system 12 and the CPE device for
`local, e.g., diagnostic Applications.
`These problems arise because an IP address that may be
`allocated for local, e.g., diagnostic Applications, in system
`12 is constrained to be a fixed value. Such a constraint may
`occur, for example, because it is required by a proprietary
`equipment sourcing specification or because another body
`such as IANA (Internet Assigned Numbers Authority) has
`defined fixed values, or a fixed range of predetermined
`values, as addresses for specific tasks. The IP address range
`192.168.xxxx, has been defined by the IANA as one of a
`small number of local private networks that should not be
`assigned to a real public network, for example. Therefore, a
`gateway router filtering Internet data traffic received via the
`CATV head end discards traffic with 192.168.xxxx desti
`nation IP addresses. This is so unless the router has been
`specifically configured to route 192.168.xx.xx packets,
`which is unlikely.
`55
`A specific illustration of how a problem occurs because of
`the reservation of a fixed, non-public use IP address for
`particular applications follows. Firstly, it is assumed IP
`address 192.168.100.1 has been designated for use for cable
`modem diagnostic Applications. It is also assumed that an
`attached CPE device is assigned a dynamic IP address of
`172.10.2.65 from a head-end DHCP server. A User of the
`attached CPE device, desiring to browse modem diagnostic
`web pages (at 192.168.100.1), enters a corresponding URL
`of system 12, e.g., www.rca_modem.com, via a web browser
`65
`resident in the CPE device. An Internet Domain Name
`Resolution request generated by the browser is submitted by
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`the CPE device to system 12 for forwarding and translation
`of the Domain Name entered by the User into a correspond
`ing IP address of the source of the r