Upstream contention measurement reporting and mitigation in DOCSIS remote PHY network environments

• US 9,692,563 B2
• Filed: 04/07/2015
• Issued: 06/27/2017
• Est. Priority Date: 04/14/2014
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Jin, Hang, Liu, Tong
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): Lee, Andrew C
• Application Number:
  US14/680,873
• Publication Number:
  US 20150295838A1
• Time in Patent Office: 812 Days
• CPC Class Codes: H04B 3/542 the information being in digital form
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04J 3/0673 using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 27/2697 in combination with other modulation techniques
• CPC Class Codes: H04L 27/3405 Modifications of the signal space to increase the efficiency of transmission, e.g. reduction of the bit error rate, bandwidth, or average power
• CPC Class Codes: H04L 27/345 Modifications of the signal space to allow the transmission of additional information
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling

Abstract

An example method for upstream contention measurement and reporting in Data Over Cable Service Interface Specification (DOCSIS) remote physical layer (R-PHY) network environments is provided and includes receiving, at a Converged Cable Access Platform (CCAP) core from a R-PHY node over a converged interconnect network (CIN) in the DOCSIS R-PHY network environment, an indication of a collision level in an upstream network between the R-PHY node and a plurality of cable modems (CMs), calculating a congestion level in the upstream network based on the collision level indicated by the R-PHY node, adjusting back-off window parameters for cable modem retransmissions based on the calculated congestion level, and adjusting a contention transmission opportunity density in a downstream Media Access Protocol (MAP) message based on the adjusted back-off window parameters.

Claims

1. A method comprising:

receiving, at a Converged Cable Access Platform (CCAP) core from a remote physical layer (R-PHY) node over a converged interconnect network (CIN) in a Data Over Cable Service Interface Specification (DOCSIS) R-PHY network environment, an indication of a collision level in an upstream network between the R-PHY node and a plurality of cable modems (CMs);

calculating a congestion level in the upstream network based on the collision level indicated by the R-PHY node;

adjusting back-off window parameters for cable modem retransmissions based on the calculated congestion level; and

adjusting a contention transmission opportunity density in a downstream Media Access Protocol (MAP) message based on the adjusted back-off window parameters, wherein the adjusting the contention transmission opportunity density comprises calculating a maximum number of contention transmission opportunities in a specific back-off window bounded by the adjusted back-off window parameters, and changing a value of the contention transmission opportunity density on a specific channel for a specific contention type to ensure the maximum number of contention transmission opportunities within a maximum acceptable access delay.

2. The method of claim 1, further comprising transmitting by the CCAP core to the R-PHY node, the downstream MAP message having the contention transmission opportunity density and including the adjusted back-off window parameters in an Upstream External Physical Interface (UEPI) MAP pseudowire (PW), wherein the contention transmission opportunity density bounds a transmission back-off delay at the CMs.

3. The method of claim 1, wherein the congestion level is calculated as a ratio of a number of collisions to a number of successful requests, wherein the collision level comprises a ratio of the number of collisions to a number of transmission opportunities indicated in at least one previously sent MAP message during a preconfigured calculation window.

4. The method of claim 1, wherein the back-off window parameters are adjusted if the calculated congestion level falls outside a preconfigured congestion window.

5. The method of claim 1, wherein the contention transmission opportunity density is adjusted to achieve the maximum acceptable access delay.

6. The method of claim 1, wherein the indication from the R-PHY node is received at the CCAP core in a UEPI PW.

7. The method of claim 1, wherein the R-PHY node detects collisions between initial ranging requests from the plurality of cable modems, wherein the detected initial ranging request collisions are indicated in a trailing segment of a UEPI ranging (RNG) request (REQ) PW.

8. The method of claim 7, wherein the R-PHY node detects the initial ranging request collisions using at least a cyclic redundancy check (CRC) and power level threshold.

9. The method of claim 1, wherein the R-PHY node detects collisions between bandwidth requests from the plurality of cable modems, wherein the detected bandwidth request collisions are indicated in a request block of a UEPI REQ PW.

10. The method of claim 9, wherein the R-PHY node detects the bandwidth request collisions using at least a packet header check sum (HCS) and power level threshold.

11. A non-transitory tangible computer readable medium embedded with instructions, which when executed by a processor, performs method steps comprising:

receiving, at a Converged Cable Access Platform (CCAP) core from a remote physical layer (R-PHY) node over a converged interconnect network (CIN) in a Data Over Cable Service Interface Specification (DOCSIS) R-PHY network environment, an indication of a collision level in an upstream network between the R-PHY node and a plurality of cable modems (CMs);

calculating a congestion level in the upstream network based on the collision level indicated by the R-PHY node;

adjusting back-off window parameters for cable modem retransmissions based on the calculated congestion level; and

adjusting a contention transmission opportunity density in a downstream MAP message based on the adjusted back-off window parameters, wherein the adjusting the contention transmission opportunity density comprises calculating a maximum number of contention transmission opportunities in a specific back-off window bounded by the adjusted back-off window parameters, and changing a value of the contention transmission opportunity density on a specific channel for a specific contention type to ensure the maximum number of contention transmission opportunities within a maximum acceptable access delay.

12. The non-transitory tangible computer-readable medium of claim 11, wherein the operations further comprise transmitting by the CCAP core to the R-PHY node, the downstream MAP message having the contention transmission opportunity density and including the adjusted back-off window parameters in a UEPI MAP PW, wherein the contention transmission opportunity density bounds a transmission back-off delay at the CMs.

13. The non-transitory tangible computer-readable medium of claim 11, wherein the back-off window parameters are adjusted if the calculated congestion level falls outside a preconfigured congestion window.

14. The non-transitory tangible computer-readable medium of claim 11, wherein the contention transmission opportunity density is adjusted to achieve the maximum acceptable access delay.

15. The non-transitory tangible computer-readable medium of claim 11, wherein the indication from the R-PHY node is received at the CCAP core in a UEPI PW.

16. An apparatus, comprising:

a Converged Cable Access Platform (CCAP) core;

a memory element for storing data; and

a processor, wherein the processor executes instructions associated with the data, wherein the processor and the memory element cooperate, such that the apparatus is configured for;

receiving, at the CCAP core from a remote physical layer (R-PHY) node over a converged interconnect network (CIN) in a Data Over Cable Service Interface Specification (DOCSIS) R-PHY network environment, an indication of a collision level in an upstream network between the R-PHY node and a plurality of cable modems (CMs);

calculating a congestion level in the upstream network based on the collision level indicated by the R-PHY node;

adjusting back-off window parameters for cable modem retransmissions based on the calculated congestion level; and

adjusting a contention transmission opportunity density in a downstream Media Access Protocol (MAP) message based on the adjusted back-off window parameters, wherein the adjusting the contention transmission opportunity density comprises calculating a maximum number of contention transmission opportunities in a specific back-off window bounded by the adjusted back-off window parameters, and changing a value of the contention transmission opportunity density on a specific channel for a specific contention type to ensure the maximum number of contention transmission opportunities within a maximum acceptable access delay.

17. The apparatus of claim 16, further configured for transmitting by the CCAP core to the R-PHY node, the downstream MAP message having the contention transmission opportunity density and including the adjusted back-off window parameters in a UEPI MAP PW, wherein the contention transmission opportunity density bounds a transmission back-off delay at the CMs.

18. The apparatus of claim 16, wherein the back-off window parameters are adjusted if the calculated congestion level falls outside a preconfigured congestion window.

19. The apparatus of claim 16, wherein the contention transmission opportunity density is adjusted to achieve the maximum acceptable access delay.

20. The apparatus of claim 16, wherein the indication from the R-PHY node is received at the CCAP core in a UEPI PW.