BDS DOCSIS Standards and Protocols

Question 1

What does DOCSIS stand for?

Accepted Answer

Data Over Cable Service Interface Specification

Answer

DOCSIS stands for Data Over Cable Service Interface Specification, the standard that enables broadband internet over hybrid fiber-coaxial cable systems.

Question 2

What is the role of the CMTS in a DOCSIS network?

Accepted Answer

It terminates cable modem connections and bridges them to the IP network

Answer

The Cable Modem Termination System (CMTS) communicates with cable modems, manages upstream/downstream channels, and connects the HFC plant to the IP backbone.

Question 3

How many downstream and upstream channels can DOCSIS 3.0 bond?

Accepted Answer

Up to 32 downstream / 8 upstream

Answer

DOCSIS 3.0 supports channel bonding of up to 32 downstream SC-QAM channels and 8 upstream SC-QAM channels to increase aggregate throughput.

Question 4

What modulation technology does DOCSIS 3.1 introduce for the downstream?

Accepted Answer

OFDM (Orthogonal Frequency Division Multiplexing)

Answer

DOCSIS 3.1 introduced OFDM for the downstream, enabling up to 4096-QAM and supporting channel widths up to 192 MHz for dramatically higher throughput.

Question 5

What is the purpose of the DOCSIS ranging process during modem initialization?

Accepted Answer

To adjust the modem's transmit power and timing so its upstream signals arrive correctly at the CMTS

Answer

Ranging synchronizes the cable modem's upstream timing offset and transmit power level so that multiple modems sharing a channel arrive at the CMTS without collision.

BDS - Broadband Distribution Specialist Practice Test

BDS - Broadband Distribution Specialist Practice Test

BDS DOCSIS Standards and Protocols