22 08, 2010
  • DSAM DOCSIS 3.0 Throughput Test

DOCSIS 3.0 Tutorial – Upstream Channel Bonding

2021-11-24T09:39:36-05:00August 22nd, 2010|

The focus of this article will be on the mechanics of upstream channel bonding and how it works more from a DOCSIS protocol perspective. Much more detailed information can be found in the DOCSIS 3.0 MULPIv3.0 document located in the Library, but this will provide a high level overview for the layman who is curious about the basics. First lets understand that it is the cable modem that is doing the channel bonding, remember in the upstream the cable modem transmits data to the CMTS. Per DOCSIS 3.0, the CM can bond from one to four channels in the upstream as coordinated by the CMTS. The CM is always under control by the CMTS.

18 07, 2010
  • oDownstream Channel Bonding

DOCSIS 3.0 Tutorial – Downstream Channel Bonding

2021-08-17T16:09:16-04:00July 18th, 2010|

Downstream Channel Bonding is perhaps the ball bearings of DOCSIS 3.0, enabling subscriber data speeds in excess of 160 Mbps (4 times that of previous DOCSIS versions). While conceptually simple, the principle of combining multiple downstream DOCSIS channels together to carry the same user data must have tight constraints in order to preserve the integrity of the data and have the data arrive at the correct subscriber's device and in sequence. This article will cover both the physical layer aspects and DOCSIS protocol aspects that enable channel bonding.

3 03, 2009
  • DOCSIS Station Maintenance

DOCSIS and Cable Modems – How it works :: Station Maintenance

2021-08-17T15:43:18-04:00March 3rd, 2009|

While the UCD provides the language of the DOCSIS network, the Station Maintenance messaging is the proverbial "heartbeat" of the DOCSIS network. A station maintenance session consists of a Range Request sent from a cable and a Range Response sent by the CMTS. The CMTS analyzes the signal quality of the Range Request message and sends back any necessary RF adjustments in the Range Response message. This "handshake" between every cable modem and the CMTS must occur once every 30 seconds as dictated by the DOCSIS specification.

22 02, 2009
  • DOCSIS cable modem data burst defined

DOCSIS and Cable Modems – How it works :: Anatomy of a Burst

2021-08-17T22:35:57-04:00February 22nd, 2009|

DOCSIS Cable Modem Data Burst Defined Previously I have discussed that cable modems share the upstream channel by using Time Division Multiple Access (TDMA).  This means that when a cable modem is not transmitting data its RF transmitter is turned off.  In order to transmit data it must transmit a burst of data which contains a REQUEST to the CMTS.  The REQUEST relays the cable modem's Service IDentifier and the number of bytes of information the modem has to transmit in its buffer.  The CMTS prioritizes all incoming

9 02, 2009
  • DOCSIS cable modem registration

DOCSIS and Cable Modems – How it works :: Cable Modem Registration

2021-08-17T09:54:53-04:00February 9th, 2009|

Through DOCSIS tutorial seminars, I have found the most effective way to bring someone up to speed on DOCSIS communications is by teaching the cable modem registration process. During the registration process, we will cover the RF physical layer, theDOCSIS Media Access Layer (MAC) and the Internet Protocol (IP) layer. Yes, the cable modem exercises the first three layers of the Open Systems Interconnection Reference Model (OSI Reference Model or OSI Model)...

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