Motorola SURFboard DOCSIS 3.0 Cable Modem

Motorola SURFboard DOCSIS is a cable modem with the DOCSIS 3.0 specification, Cable Internet providers can take advantage of the extra capacity provided by channel-bonding technology in order to offer ultra-fast broadband services. Channel bonding allows parallel data pipes to act as a single broadband conduit. With each channel capable of providing around 40 Mbps of data. Currently, Cable Internet providers max out at around 50 Mbps of downstream data throughput, but Motorola SURFboard 3.0 with DOCSIS 3.0 will enable Cable Internet providers to continue to improve the speed of their networks. The Motorola SURFboard DOCSIS 3.0 Cable Modem's four downstream channels can provide a theoretical maximum of 160 Mbps of throughput.

What Is DOCSIS 3.0?

DOCSIS References: http://en.wikipedia.org/wiki/DOCSIS | Data Over Cable Service Interface Specification - DOCSIS is an international telecommunications standard that permits the addition of high-speed data transfer to an existing CATV system. It is employed by many cable television operators to provide Internet access over their existing HFC infrastructure.

DOCSIS provides great variety in options available at OSI layers 1 and 2, the physical and data link layers.

Physical layer

• Channel width: All versions of DOCSIS utilize either 6 MHz channels or 8 MHz channels for downstream transmission. In the upstream, DOCSIS 1.0/1.1 specifies channel widths between 200 kHz and 3.2 MHz. DOCSIS 2.0 also specifies 6.4 MHz, but can use the earlier, narrower channel widths for backward compatibility.
• Modulation: All versions of DOCSIS specify that 64-QAM or 256-QAM be used for modulation of downstream data, utilizing the ITU-T J.83-AnnexB standard for 6 MHz channel operation, and the DVB-C modulation standard for 8 MHz operation. Upstream data uses QPSK or 16-QAM for DOCSIS 1.x, and it uses QPSK, 8-QAM, 16-QAM, 32-QAM, 64-QAM for DOCSIS 2.0 & 3.0. DOCSIS 2.0 & 3.0 also support 128-QAM with trellis coded modulation in S-CDMA mode.

Data link layer

• DOCSIS employs a mixture of deterministic access methods for upstream transmissions, specifically TDMA for DOCSIS 1.0/1.1 and both TDMA and S-CDMA for DOCSIS 2.0 and 3.0, with a limited use of contention for bandwidth requests. In contrast to the pure contention-based MAC CSMA/CD employed in older Ethernet systems, DOCSIS systems experience few collisions.
• For DOCSIS 1.1 and above the MAC layer also includes extensive QoS features that help to efficiently support applications that have specific traffic requirements such as low latency.
• DOCSIS 3.0 features channel bonding, which enables multiple downstream and upstream channels to be used together at the same time by a single subscriber.

Throughput

• All of these features combined enable a total upstream throughput of 30.72 Mbit/s per 6.4 MHz channel, or 10.24 Mbit/s per 3.2 MHz channel. All three versions of the DOCSIS standard support a downstream throughput with 256-QAM of up to 42.88 Mbit/s per 6 MHz channel, or 55.62 Mbit/s per 8 MHz channel for EuroDOCSIS.

Network layer

• DOCSIS modems are managed via an IP address.
• DOCSIS 3.0 adds management over IPv6.
• The 'DOCSIS 2.0 + IPv6' specification also allows support for IPv6 on DOCSIS 2.0 cable modems.

Motorola SURFboard DOCSIS 3.0 Cable Modem Product Summary

Motorola SB6121 SURFboard DOCSIS 3.0 Cable Modem is a new Motorola SURFboard DOCSIS 3.0 Product and improved version of the world's most widely deployed DOCSIS 3.0 Cable Modem. For the residential cable subscriber who wants a powerful modem capable of delivering a high-speed data service at blazing fast speeds.