NCTI -HSD FINAL-DOJ 2.
The first version of the Data Over Cable Service Interface Specification (DOCSIS) was approved as an
international standard by what organization?
The International Telecommunication Union (ITU).
What criteria does the Data Over Cable Service Interface Specification (DOCSIS) certification process
ensure?
Compliance with the DOCSIS standard and interoperability between suppliers.
What layers of the Open Systems Interconnection (OSI) reference model are applied between Data
Over Cable Service Interface Specification (DOCSIS) modems and the cable modem termination system
(CMTS)?
Layers 1 through 4 (Physical layer, Data Link Layer, Network Layer, and Transport Layer) are applied
between the DOCSIS modem and CMTS.
What access technology does the first version of the Data Over Cable Service Interface Specification
(DOCSIS 1.0) use to send data upstream over the network's RF return path?
Time division multiple access (TDMA).
What was added to the first Data Over Cable Service Interface Specification (DOCSIS) that enabled
broadband cable operators to provide telephone service with quality and reliability that rivaled the
products of the traditional telephone companies?
Quality of service (QoS) controls, enhanced security, and adaptive equalization in the upstream path.
What features were introduced with the 3.1 version of the Data Over Cable Service Interface
Specification (DOCSIS 3.1) to increase the downstream and upstream data throughput?
Orthogonal frequency division multiplexing (OFDM) and low-density parity-check (LDPC).
Which Data Over Cable Service Interface Specification (DOCSIS) version was the first to provide an
option for raising the top frequency of the upstream spectrum to 85 MHz in order to create enough
bandwidth for upstream carriers from modems running on previous DOCSIS versions?
DOCSIS 3.0.
Why are the data throughput rates for both downstream and upstream in Data Over Cable Service
Interface Specification (DOCSIS) networks asymmetrical?
Because the narrower bandwidths and lower orders of modulation for the return path carriers cause the
DOCSIS downstream and upstream data rates to be unequal or asymmetrical.
Which Open Systems Interconnection (OSI) reference model layers does the MAC Layer in the Data
Over Cable Service Interface Specification (DOCSIS) overlap?
The Physical and Data Link Layers.
, From where do Data Over Cable Service Interface Specification (DOCSIS) modems receive their
configuration files, billing system messages, and access control messages?
From the cable modem termination system (CMTS) acting as a "proxy" or messenger that transfers
messages and files between the modems and the respective servers.
What messages must a cable modem receive from the downstream signal in order to begin a
transmitting relationship with the cable modem termination system (CMTS)?
An upstream channel descriptor (UCD) message, a symbol timing message (SYNC), and a bandwidth
allocation message (MAP).
What instructions might a cable modem termination system (CMTS) send in a RNG-RSP message to
modify the modem's transmission parameters?
An adjustment to the modem's timing interval, transmit frequency, or power level
Why would a cable operator consider activating device class identification (DCI) as part of a DOCSIS
modem's initialization?
To enable the cable operator to define special modem classes or service levels that can be prioritized for
ranging after a massive outage.
What does a DOCSIS 3.1 seek first when synchronizing with the cable modem termination system
(CMTS) in order to receive operational information?
An orthogonal frequency division multiplexing (OFDM) channel that contains a set of contiguous
subcarriers called the PHY link channel (PLC).
What information does a DOCSIS 3.1 modem provide in its Bonded Initial Ranging Request (B-INIT-
RNG-REQ) message to the cable modem termination system (CMTS)?
The modem's downstream service group (DS-SG) if determined.
What Internet protocol (IP) connectivity modes are supported in DOCSIS 3.0 and 3.1?
IPv4 only, IPv6 only, alternate provisioning mode (APM), and dual-stack provisioning mode (DPM).
What happens if a DOCSIS modem is unable to acquire the current time and date from one or more
time-of-day (ToD) servers during registration with the cable modem termination system (CMTS)?
The modem proceeds to an operational state and issues at least one ToD request per 5-minute period for
each server specified until local time is established.
What is the last step in a cable modem's registration?
When the cable modem termination system (CMTS) receives a registration acknowledge (REG-ACK)
message confirming the modem's registration.
What type of security does the baseline privacy interface (BPI) protocol provide?
It prevents a cloned modem from full, illegal, access to the network.
The first version of the Data Over Cable Service Interface Specification (DOCSIS) was approved as an
international standard by what organization?
The International Telecommunication Union (ITU).
What criteria does the Data Over Cable Service Interface Specification (DOCSIS) certification process
ensure?
Compliance with the DOCSIS standard and interoperability between suppliers.
What layers of the Open Systems Interconnection (OSI) reference model are applied between Data
Over Cable Service Interface Specification (DOCSIS) modems and the cable modem termination system
(CMTS)?
Layers 1 through 4 (Physical layer, Data Link Layer, Network Layer, and Transport Layer) are applied
between the DOCSIS modem and CMTS.
What access technology does the first version of the Data Over Cable Service Interface Specification
(DOCSIS 1.0) use to send data upstream over the network's RF return path?
Time division multiple access (TDMA).
What was added to the first Data Over Cable Service Interface Specification (DOCSIS) that enabled
broadband cable operators to provide telephone service with quality and reliability that rivaled the
products of the traditional telephone companies?
Quality of service (QoS) controls, enhanced security, and adaptive equalization in the upstream path.
What features were introduced with the 3.1 version of the Data Over Cable Service Interface
Specification (DOCSIS 3.1) to increase the downstream and upstream data throughput?
Orthogonal frequency division multiplexing (OFDM) and low-density parity-check (LDPC).
Which Data Over Cable Service Interface Specification (DOCSIS) version was the first to provide an
option for raising the top frequency of the upstream spectrum to 85 MHz in order to create enough
bandwidth for upstream carriers from modems running on previous DOCSIS versions?
DOCSIS 3.0.
Why are the data throughput rates for both downstream and upstream in Data Over Cable Service
Interface Specification (DOCSIS) networks asymmetrical?
Because the narrower bandwidths and lower orders of modulation for the return path carriers cause the
DOCSIS downstream and upstream data rates to be unequal or asymmetrical.
Which Open Systems Interconnection (OSI) reference model layers does the MAC Layer in the Data
Over Cable Service Interface Specification (DOCSIS) overlap?
The Physical and Data Link Layers.
, From where do Data Over Cable Service Interface Specification (DOCSIS) modems receive their
configuration files, billing system messages, and access control messages?
From the cable modem termination system (CMTS) acting as a "proxy" or messenger that transfers
messages and files between the modems and the respective servers.
What messages must a cable modem receive from the downstream signal in order to begin a
transmitting relationship with the cable modem termination system (CMTS)?
An upstream channel descriptor (UCD) message, a symbol timing message (SYNC), and a bandwidth
allocation message (MAP).
What instructions might a cable modem termination system (CMTS) send in a RNG-RSP message to
modify the modem's transmission parameters?
An adjustment to the modem's timing interval, transmit frequency, or power level
Why would a cable operator consider activating device class identification (DCI) as part of a DOCSIS
modem's initialization?
To enable the cable operator to define special modem classes or service levels that can be prioritized for
ranging after a massive outage.
What does a DOCSIS 3.1 seek first when synchronizing with the cable modem termination system
(CMTS) in order to receive operational information?
An orthogonal frequency division multiplexing (OFDM) channel that contains a set of contiguous
subcarriers called the PHY link channel (PLC).
What information does a DOCSIS 3.1 modem provide in its Bonded Initial Ranging Request (B-INIT-
RNG-REQ) message to the cable modem termination system (CMTS)?
The modem's downstream service group (DS-SG) if determined.
What Internet protocol (IP) connectivity modes are supported in DOCSIS 3.0 and 3.1?
IPv4 only, IPv6 only, alternate provisioning mode (APM), and dual-stack provisioning mode (DPM).
What happens if a DOCSIS modem is unable to acquire the current time and date from one or more
time-of-day (ToD) servers during registration with the cable modem termination system (CMTS)?
The modem proceeds to an operational state and issues at least one ToD request per 5-minute period for
each server specified until local time is established.
What is the last step in a cable modem's registration?
When the cable modem termination system (CMTS) receives a registration acknowledge (REG-ACK)
message confirming the modem's registration.
What type of security does the baseline privacy interface (BPI) protocol provide?
It prevents a cloned modem from full, illegal, access to the network.
