CNIT 344 FINALS 2026 EXAM QUESTIONS AND
ANSWERS RATED A+
✔✔What is the application layer of the OSI model responsible for? - ✔✔It provides the
interface between user applications and network's services (usually through network-
capable APIs).
This does NOT include actual user applications.
✔✔What are some application protocols that exist at the application layer? - ✔✔HTTP,
SIP, Telnet/SSH, SMTP, and Routing Protocols.
✔✔Where is the application layer of the OSI model defined? - ✔✔X.207
✔✔What is logical adjacency? - ✔✔The apparent capability of peer-layer protocols to
communicate directly. It is made possible through encapsulation and decapsulation.
✔✔What is the ideal correlation between layers for logical adjacency? - ✔✔1-1
✔✔Which layer has "true" adjacency? - ✔✔Physical layer
✔✔What is the equation for analog bandwidth? - ✔✔𝑓_𝑚𝑎𝑥 - 𝑓_𝑚𝑖𝑛
✔✔What transmission mode transmits one bit at a time? - ✔✔Serial
✔✔What transmission mode transmits multiple bits at a time? - ✔✔Parallel
✔✔What transmission mode transmits time-based (clock-based) with no gaps between
data items? - ✔✔Synchronous
✔✔What transmission mode transmits time-based (clock-based) but with a fixed gap
between the transmission of data items? - ✔✔Isochronous
✔✔What transmission mode transmits signal-based? - ✔✔Asynchronous
✔✔Describe a serial connection. - ✔✔Able to send data over long distances.
Nearly all LAN/WAN technologies utilize serial communications.
✔✔What are common implementations of a serial transmission mode? - ✔✔Telco/ISP
Links, Ethernet, SATA
✔✔Describe a parallel connection. - ✔✔Able to send data over short distances.
, Limited by electrical signal interference and degradation by EMI.
✔✔What are common implementations of a parallel transmission mode? - ✔✔PCI,
memory bus, many HDD interfaces, older printers, and some scanners.
✔✔Describe a synchronous transmission mode. - ✔✔It is time-based. An internal or
external clock provides the synchronization to handle this communication. Timing is
maintained regardless of presence of data.
✔✔Describe an asynchronous transmission mode. - ✔✔There is no timing source to
control when data is sent. It utilizes start and stop bits to indicate the beginning and end
of communication (it may have 1, 1.5, or 2 stop bits for simple RS systems). The
synchronization must be re-established for every communication cycle.
✔✔Examples of serial and synchronous - ✔✔T-Carrier system, SONET, frame relay,
xDSL, ISDN, USB, Firewire
✔✔Examples of serial and asynchronous - ✔✔Most "terminal" applications, keyboard,
mice, ATM, Firewire
✔✔Examples of parallel and synchronous - ✔✔Internal buses, printers and scanners
✔✔Examples of parallel and asynchronous - ✔✔Not many communications protocols
and standards, reviewed for HPC
✔✔Simplex - ✔✔Only unidirectional communication. One device can only transmit and
one device can only receive.
✔✔Example of simplex - ✔✔Keyboard can only input, monitor can only output.
✔✔Half-duplex - ✔✔Can transmit and receive, but not at the same time. It is used for
when there is no need to communicate in both directions at the same time.
✔✔Example of half-duplex - ✔✔A walkie-talkie sends one message at a time in both
directions.
✔✔Full duplex - ✔✔Can transmit and receive simultaneously. It is used when
communication in both directions is required all the time. The capacity of the channel
must be divided in two directions, however.
✔✔Example of full duplex - ✔✔Telephone network in which communication is occurring
between two persons who can talk and listen at the same time.
ANSWERS RATED A+
✔✔What is the application layer of the OSI model responsible for? - ✔✔It provides the
interface between user applications and network's services (usually through network-
capable APIs).
This does NOT include actual user applications.
✔✔What are some application protocols that exist at the application layer? - ✔✔HTTP,
SIP, Telnet/SSH, SMTP, and Routing Protocols.
✔✔Where is the application layer of the OSI model defined? - ✔✔X.207
✔✔What is logical adjacency? - ✔✔The apparent capability of peer-layer protocols to
communicate directly. It is made possible through encapsulation and decapsulation.
✔✔What is the ideal correlation between layers for logical adjacency? - ✔✔1-1
✔✔Which layer has "true" adjacency? - ✔✔Physical layer
✔✔What is the equation for analog bandwidth? - ✔✔𝑓_𝑚𝑎𝑥 - 𝑓_𝑚𝑖𝑛
✔✔What transmission mode transmits one bit at a time? - ✔✔Serial
✔✔What transmission mode transmits multiple bits at a time? - ✔✔Parallel
✔✔What transmission mode transmits time-based (clock-based) with no gaps between
data items? - ✔✔Synchronous
✔✔What transmission mode transmits time-based (clock-based) but with a fixed gap
between the transmission of data items? - ✔✔Isochronous
✔✔What transmission mode transmits signal-based? - ✔✔Asynchronous
✔✔Describe a serial connection. - ✔✔Able to send data over long distances.
Nearly all LAN/WAN technologies utilize serial communications.
✔✔What are common implementations of a serial transmission mode? - ✔✔Telco/ISP
Links, Ethernet, SATA
✔✔Describe a parallel connection. - ✔✔Able to send data over short distances.
, Limited by electrical signal interference and degradation by EMI.
✔✔What are common implementations of a parallel transmission mode? - ✔✔PCI,
memory bus, many HDD interfaces, older printers, and some scanners.
✔✔Describe a synchronous transmission mode. - ✔✔It is time-based. An internal or
external clock provides the synchronization to handle this communication. Timing is
maintained regardless of presence of data.
✔✔Describe an asynchronous transmission mode. - ✔✔There is no timing source to
control when data is sent. It utilizes start and stop bits to indicate the beginning and end
of communication (it may have 1, 1.5, or 2 stop bits for simple RS systems). The
synchronization must be re-established for every communication cycle.
✔✔Examples of serial and synchronous - ✔✔T-Carrier system, SONET, frame relay,
xDSL, ISDN, USB, Firewire
✔✔Examples of serial and asynchronous - ✔✔Most "terminal" applications, keyboard,
mice, ATM, Firewire
✔✔Examples of parallel and synchronous - ✔✔Internal buses, printers and scanners
✔✔Examples of parallel and asynchronous - ✔✔Not many communications protocols
and standards, reviewed for HPC
✔✔Simplex - ✔✔Only unidirectional communication. One device can only transmit and
one device can only receive.
✔✔Example of simplex - ✔✔Keyboard can only input, monitor can only output.
✔✔Half-duplex - ✔✔Can transmit and receive, but not at the same time. It is used for
when there is no need to communicate in both directions at the same time.
✔✔Example of half-duplex - ✔✔A walkie-talkie sends one message at a time in both
directions.
✔✔Full duplex - ✔✔Can transmit and receive simultaneously. It is used when
communication in both directions is required all the time. The capacity of the channel
must be divided in two directions, however.
✔✔Example of full duplex - ✔✔Telephone network in which communication is occurring
between two persons who can talk and listen at the same time.
