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 method of routing digital information packets, the method comprising:
separating incoming packets into packets requiring digital signal processing from packets not requiring digital signal processing;
separating payload information from header information for the packets requiring digital signal processing;
transferring the payload information of the packets requiring digital signal processing from a CPU to at least one digital signal processor (DSP) via a hardware path;
performing digital signal processing on the payload information of the packets requiring digital signal processing to provide processed signal information; and
transmitting the processed signal information on a network.
2. The method of claim 1 , wherein separating incoming packets requiring digital signal processing from packets not requiring digital signal processing comprises separating the packets requiring digital signal processing into at least one separate buffer pool.
3. The method of claim 1 , wherein separating incoming packets requiring digital signal processing from packets not requiring digital signal processing comprises separating packets associated with real time communication services from packets associated with data services and packets associated with network control.
4. The method of claim 3 , wherein separating packets associated with real time communication services from packets associated with data services and packets associated with network control comprises separating packets associated with voice over packet services from protocol data unit (PDU) packets and media access control (MAC) packets.
5. The method of claim 1 , wherein separating payload information from header information for the packets requiring digital signal processing comprises stripping real time protocol (RTP) information from the packets requiring digital signal processing.
6. The method of claim 1 , wherein separating incoming packets requiring digital signal processing from packets not requiring digital signal processing is performed in a central processing unit (CPU) of a network node.
7. The method of claim 6 , wherein separating payload information from header information is performed by hardware without running software on the CPU.
8. The method of claim 1 , wherein transferring the payload information of the packets requiring digital signal processing to at least one DSP via a hardware path comprises transferring the payload information on a dedicated hardware bus.
9. The method of claim 8 , where the dedicated hardware bus uses serial transmission.
10. The method of claim 8 , where the dedicated hardware bus uses a transmission protocol supported by the CPU and by the DSP.
11. The method of claim 1 , wherein:
performing digital signal processing comprises performing digital to analog conversion of the payload information to provide an analog signal; and
transmitting the processed signal information on a network comprises transmitting the analog signal on the network.
12. A method of routing digital information packets, the method comprising:
receiving incoming payload information from a network;
performing digital signal processing on the payload information to provide processed payload information;
adding header information to the processed payload information to provide real time service packets;
putting the real time service packets into a buffer accessible by a central processing unit (CPU), the buffer being separate from buffers used for packets associated with data services and packets associated with network control; and
scheduling the real time service packets for transmission on the network, giving preference to the real time service packets over packets associated with data services and packets associated with network control.
13. The method of claim 12 , wherein the incoming payload information comprises a voice signal.
14. The method of claim 12 , wherein the packets associated with data services comprise protocol data unit (PDU) packets and the packets associated with network control comprise media access control (MAC) packets.
15. The method of claim 12 , wherein adding header information to the processed payload information comprises adding real time protocol (RTP) information.
16. The method of claim 12 , wherein separating incoming packets requiring digital signal processing from packets not requiring digital signal processing is performed in a central processing unit (CPU) of a network node.
17. The method of claim 16 , wherein adding header information to the processed payload information is performed by hardware without running software on the CPU.
18. The method of claim 12 , wherein putting the real time service packets into a buffer accessible by the (CPU) comprises transferring the real time service packets into the buffer without running software on the CPU.
19. The method of claim 18 , wherein transferring the real time service packets into the buffer without running software on the CPU comprises transferring the real time service packets on a dedicated hardware bus.
20. The method of claim 12 , wherein performing digital signal processing comprises performing analog to digital conversion of the payload information to provide a digital signal.