Wideband cable downstream protocol

• US 8,149,833 B2
• Filed: 05/24/2005
• Issued: 04/03/2012
• Est. Priority Date: 05/25/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Fox, David B., Chapman, John T., Bernstein, Alon S., Slane, Albert A.
• Primary Examiner(s): BLANTON, JOHN D
• Application Number:
  US11/137,606
• Publication Number:
  US 20050265392A1
• Time in Patent Office: 2,506 Days
• Field of Search: 370/392
• US Class Current: 370/392
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A network device has a communications port to provide communication with a data network and a cable port to provide communication with a cable network across multiple channels. The network device also has a processor to receive data from the data network, format the data into packets for transmission across the multiple channels and provide an identifier to allow the packets to be reconstructed.

Claims

1. A method of packet bonding, the method comprising:

receiving data traffic over a first network at a Cable Modem Termination System (CMTS);

extracting a plurality of physical layer packets from the data traffic using the CMTS, the physical layer packets to be transmitted to a same cable modem in a second cable network, wherein the physical layer packets are part of a same bonded channel feeding data to a same physical destination address;

attaching multilink headers to the physical layer packets;

assigning a first one of the physical layer packets for transport over a first available Quadrature Amplitude Modulation (QAM) channel in the second cable network and a second one of the physical layer packets for transport over a second available QAM channel in the second cable network, wherein the physical layer packets are assigned to be distributed intact over different available QAM channels using the CMTS;

wherein assigning the first physical layer packet for transport over the first available QAM channel further includes;

selecting an initial packet/QAM association for the first physical layer packet using a Hierarchical Queuing Function (HQF) component of the CMTS; and

selecting a final packet/QAM association using a Shortest Queue Function (SQF) component of the CMTS and the initial packet/QAM association, wherein said assigning the first physical layer packet is based on the final packet/QAM association; and

transmitting the first physical layer packet over the first available QAM channel and the second physical layer packet over the second available QAM channel using the CMTS, wherein the first physical layer packet is transmitted according to the final packet/QAM association.

2. The method of claim 1, further comprising sending from the CMTS to the cable modem a control packet that corresponds to at least one of the physical layer packets, wherein a control header of the control packet includes a type field used to indicate whether the corresponding physical layer packet is an upstream communication or a downstream communication.

3. The method of claim 2, wherein the control header includes a length field used to indicate whether the corresponding physical layer packet is a multilink type or a transport stream type.

4. The method of claim 3, wherein if the length field indicates the multilink type, then the corresponding physical layer packet includes an entire representation of a packet communication received over the first network.

5. The method of claim 2, wherein the control header includes a length field set to indicate whether sequence numbers of the corresponding physical layer packet were locally or remotely inserted.

6. The method of claim 1, further comprising:

identifying QAM channels usable for sending wideband communications;

identifying a subset of the QAM channels according to a customer identification associated with the received data traffic; and

selecting the first and second available QAM channels from the subset when the first and second available QAM channels each have a shorter queue than remaining QAM channels within the subset.

7. The method of claim 1, further comprising sending from the CMTS to the cable modem a control packet to correspond to at least one of the physical layer packets, wherein the control packet includes a control header comprising:

a type subfield to store a first bit value if the corresponding physical layer packet is a downstream transmission and a second different bit value if the corresponding physical layer packet is an upstream transmission;

a length subfield to indicate, according to the number of bits stored in the length subfield, whether the corresponding physical packet contains sequence numbers; and

a value subfield.

8. The method of claim 1, wherein the multilink headers have a sequence number field and a downstream identifier field, and wherein a first one of the multilink headers has a sequence number value N and a second one of the multilink headers has a sequence number value N+1, and wherein the downstream identifier fields of the multilink headers have identical values;

wherein the CMTS is located remotely with respect to an origination endpoint that originally encoded the physical layer packets and transmitted the same over the first network, and wherein the sequence numbers and the downstream identifiers are midpoint-inserted by the remotely located CMTS some time after transmission from the encoding origination endpoint; and

wherein the sequence number values N and N+1 are repeated by multilink headers for other physical layer packets of another bonded channel that utilizes at least one of the QAM channels of the bonded channel, and wherein the overlapping bonded channels carry different downstream identifier field values to allow a cable modem monitoring the QAM channels to distinguish independent sequencing contexts on a per flow basis for each bonded channel.

9. The method of claim 8, further comprising using the cable modem to order the received first and second physical layer packets independently of an order of arrival, wherein the cable modem identifies a common sequencing context for the first and second physical layer packets separate from a different sequencing context of other received physical layer packets having a same Media Access Control (MAC) address as the first and second physical layer packets by analyzing the downstream identifier fields of such packets and then orders the received first and second physical layer packets according to the sequence number values N and N+1.

10. The method of claim 8, further comprising using the cable modem to order the received first and second physical layer packets independently of an order of arrival, wherein the cable modem identifies a common sequencing context for the first and second physical layer packets without analyzing MAC address fields included in the first and second physical layer packets.

11. The method of claim 8, wherein the downstream identifier field is separate from an MPEG PID field in the multilink headers.

12. The method of claim 8, wherein the sequence numbers vary per packet in a pre-negotiated pattern according to packet transmission order.

13. The method of claim 12, wherein the pre-negotiated pattern is monotonically ascending or descending.

14. The method of claim 1, wherein the combination of the initial selection using the HQF component and the final selection using the SQF component results in the first physical layer packet being rate shaped, queued, and allocated to a particular subset of QAMs of the CMTS, and then allocated to a specific QAM of the subset having the shortest queue being selected from that subset.

15. An article of manufacture including a memory device having instructions stored thereon that, in response to execution by a computing device, cause the computing device to perform operations comprising:

extracting a plurality of physical layer packets from received data traffic, the physical layer packets to be transmitted to a same cable modem in a cable network, wherein the physical layer packets are part of a same bonded channel feeding data to a same physical destination address;

assigning a first one of the physical layer packets for transport over a first available Quadrature Amplitude Modulation (QAM) channel in the cable network and a second one of the physical layer packets for transport over a second available QAM channel in the cable network, wherein the physical layer packets are assigned to be distributed intact over different available QAM channels;

wherein assigning the first one of the physical layer packets for transport over the first available QAM channel further includes;

selecting an initial packet/QAM association for the first one of the physical layer packets using a Hierarchical Queuing Function (HQF) component; and

selecting a final packet/QAM association using a Shortest Queue Function (SQF) component and the initial packet/QAM association, wherein said assigning the first one of the physical layer packets is based on the final packet/QAM association;

attaching multilink headers to the first and second ones of the physical layer packets; and

transmitting the first one of the physical layer packets over the first available QAM channel and the second one of the physical layer packets over the second available QAM channel, wherein the first one of the physical layer packets is transmitted according to the final packet/QAM association.

16. The article of manufacture of claim 15, wherein the combination of the initial selection using the HQF component and the final selection using the SQF component result in the first physical layer packet being rate shaped, queued, and allocated to a particular subset of QAMs of the CMTS, and then allocated to a specific QAM of the subset having the shortest queue being selected from that subset.

17. The article of manufacture of claim 15, wherein the multilink headers have a sequence number field and a downstream identifier field, and wherein a first multilink header has a first particular sequence number value and a second multilink header has a second different particular sequence number value, and wherein the downstream identifier fields of the multilink headers have identical values;

wherein the sequence numbers and the downstream identifiers are midpoint-inserted some time after transmission from an origination source that originally encoded the physical layer packets; and

wherein the first and second particular sequence number values are repeated by multilink headers for other physical layer packets of another bonded channel that utilizes at least one of the QAM channels of the bonded channel, and wherein the overlapping bonded channels carry different downstream identifier field values to allow a cable modem monitoring the QAM channels to distinguish independent sequencing contexts on a per flow basis for each bonded channel despite the repeated sequence number values.

18. The article of manufacture of claim 15, wherein the operations further comprise sending from a Cable Modem Termination System (CMTS) to the cable modem a control packet that corresponds to at least one of the physical layer packets, wherein a control header of the control packet includes a type field used to indicate whether the corresponding physical layer packet is an upstream communication or a downstream communication.

19. The article of manufacture of claim 18, wherein the control header includes a length field used to indicate whether the corresponding physical layer packet is a multilink type or a transport stream type.

20. The article of manufacture of claim 19, wherein if the length field indicates the multilink type, then the corresponding physical layer packet includes an entire representation of a packet communication received over the first network.

21. The article of manufacture of claim 18, wherein the control header includes a length field set to indicate whether sequence numbers of the corresponding physical layer packet were locally or remotely inserted.

22. The article of manufacture of claim 15, wherein the operations further comprise:

identifying QAM channels usable for sending wideband communications;

identifying a subset of the QAM channels according to a customer identification associated with the received data traffic; and

selecting the first and second available QAM channels from the subset when the first and second available QAM channels each have a shorter queue than remaining QAM channels within the subset.

23. The article of manufacture of claim 15, wherein the operations further comprise sending from a Cable Modem Termination System (CMTS) to the cable modem a control packet to correspond to at least one of the physical layer packets, wherein the control packet includes a control header comprising:

a type subfield to store a first bit value if the corresponding physical layer packet is a downstream transmission and a second different bit value if the corresponding physical layer packet is an upstream transmission;

a length subfield to indicate, according to the number of bits stored in the length subfield, whether the corresponding physical packet contains sequence numbers; and

a value subfield.