Packet handler for high-speed data networks
View Patent ↗An improved packet handler for VoIP cable modems and other high-speed digital devices includes a direct communication link via hardware among internal processing components. Incoming and outgoing digital information packets are filtered into MAC packets, voice PDU packets, and non-voice PDU packets, such that priority can be given to relaying voice packets and minimizing potential voice delay within the cable network. Hardware components, including specialized logic circuitry, modify voice packets to an appropriate signal form for subsequent signal processing or signal transmission. Proprietary bus communication protocols can also be provided to facilitate relay of packets between a central processing unit (CPU) and a digital signal processor (DSP) within a VoIP cable modem. Line cards including subscriber line interface circuit (SLIC) and subscriber line audio processing circuit (SLAC) components provide analog-to-digital (A/D) and digital-to-analog (D/A) conversion functionality.
1. A cable modem for use with Voice over Internet Protocol (VoIP) applications, comprising:
a central processing unit (CPU) for:
receiving a plurality of digital information packets including management packets, non-voice data packets and voice packets; and
sorting the management packets, the non-voice data packets, and the voice packets into a corresponding management packets buffer pool, a non-voice data packets buffer pool, and a voice packets buffer pool, the management packets buffer pool, the non-voice data packets buffer pool, and the voice packets buffer pool being separate from each other;
a logic circuit, the logic circuit receiving the voice packets from the voice packets buffer pool and modifying only the voice packets to include stripping off protocol information; and
a digital signal processor (DSP) interfaced with said CPU via a communications bus, the DSP processing the modified voice packets received by the CPU prior to processing management packets and non-voice data packets;
the logic circuit relaying the modified voice packets directly from the CPU to the DSP via the communications bus.
2. A cable modem as in claim 1 , wherein said logic circuit comprises an application specific integrated circuit (ASIC) that strips off the protocol information, including real-time protocol (RTP) information, from the voice packets before relaying the voice packet to said DSP.
3. A cable modem as in claim 1 , further comprising bus communication protocol modules at said CPU and said DSP, said protocol modules transforming the voice packets into an appropriate signal form for relaying the voice packets over the communications bus.
4. A cable modem as in claim 1 , further comprising a line card connected to said DSP, said line card converting digital voice packets processed by said DSP into analog voice signals.
5. A cable modem as in claim 4 , wherein said line card comprises a subscriber line interface circuit (SLIC) and a subscriber line audio processing interface (SLAC).
6. A cable modem as in claim 1 , wherein said cable modem is configured within a data network such that said cable modem transmits and receives digital voice signals from a cable modem termination system and analog voice signals from audio modules at various end locations.
7. A cable modem as in claim 6 , wherein said logic circuit comprises an application specific integrated circuit (ASIC) that strips off the protocol information, including Real Time Protocol (RTP) information, from the voice packets before relaying the voice packets to said DSP.
8. A cable modem as in claim 6 , further comprising bus communication protocol modules at said CPU and said DSP, said bus communication protocol modules transforming the voice packets into an appropriate signal form for relaying the voice packets over the communications bus.
9. A cable modem as in claim 6 , further comprising a line card connected to said DSP, said line card converting digital voice packets processed by said DSP into analog voice signals.
10. A cable modem as in claim 9 , wherein said line card comprises a Subscriber Line Interface Circuit (SLIC) and a Subscriber Line Audio proCessing interface (SLAC).
11. A packet handler for digital data applications, said packet handler comprising:
sorting means for identifying a plurality of digital information packets received from a digital signal transmission medium as one of management packets, non-voice data packets, and voice packets and for sorting the management packets, the non-voice data packets, and the voice packets into a corresponding management packets buffer pool, a non-voice data packets buffer pool and a voice packets buffer pool, the management packets buffer pool, the non-voice data packets buffer pool and the voice packets buffer pool being separate from each other;
hardware means for receiving the voice packets from the voice packets buffer pool and modifying only the voice packets to include stripping off protocol information for further transmission and processing; and
processing means interfaced with said hardware means for processing the modified voice packets from said hardware means prior to processing the management packets and the non-voice data packets, and for converting the modified voice packets into analog signal format.
12. A packet handler as in claim 11 , wherein said hardware means comprises circuitry for stripping the protocol information, including Real Time Protocol (RTP) information, from the voice packets received from the voice packets buffer pool.
13. A packet handler as in claim 12 , wherein said processing means for converting modified voice packets into analog signal format comprises a Subscriber Line Interface Circuit (SLIC) and a Subscriber Line Audio proCessing interface (SLAC).
14. A method for routing digital information packets, said method comprising:
receiving a plurality of information packets from a digital signal transmission medium, wherein the plurality of information packets are provided in accordance with a real time protocol (RTP) configuration, the plurality of information packets including management packets, non-voice data packets and voice packets;
sorting the management packets, the non-voice data packets, and the voice packets into a corresponding management packets buffer pool, a non-voice data packets buffer pool, and a voice packets buffer pool, the management packets buffer pool, the non-voice data packets buffer pool and the voice packets buffer pool being separate from each other;
modifying only the voice packets to include stripping off protocol information; and
routing the voice packets directly from a central processing unit to a digital signal processor within a cable modem prior to relaying management packets and non-voice data packets.
15. A method for routing digital information packets as in claim 14 , further comprising the step of converting between digital information communicated over the digital signal transmission medium and analog information relayed to and from an end location audio module.
16. A method for routing digital information packets as in claim 14 , wherein stripping off protocol information includes removing real time protocol (RTP) information from voice packets before step routing the voice packets.
17. A method for routing digital information packets, said method comprising the following steps:
utilizing logic circuitry to determine a presence of management packets, non-voice data packets and voice packets;
sending an interrupt signal from a digital signal processor to a central processing unit upon detecting the voice packets;
modifying the voice packets to include real time protocol (RTP) information;
transmitting only the voice packets directly from the digital signal processor to the central processing unit
an initial step of converting the voice packets from analog information provided by an end location audio module to digital information for communication over the digital data network; and
providing communications protocols within both the central processing unit and the digital signal processor and providing a communications bus for relaying digital information packets between the central processing unit and the digital signal processor.