CS356 EXAM 2024/ NEWEST CS356 FINAL EXAM 2024
ALL 174 COMPLETE REAL EXAM QUESTIONS AND WELL
ELABORATED ANSWERS (VERIFIED ANSWERS) LATEST
UPDATES 2024 | ALREADY GRADED A+ (BRAND NEW!!)
What is Network Edge - ANSWER: hosts, access networks, physical media. Also
includes servers that often lie in data centers
What is network core - ANSWER: mesh of interconnected routers.
Packet switching happens here
What are some ways we measure performance - ANSWER: Loss, Delay, Throughput
What is the difference between hosts and end systems - ANSWER: No difference,
they are the same thing
What are some communication links - ANSWER: Fiber, copper, radio, satellite
What is a network - ANSWER: collection of devices, routers, links that are typically
managed by an organization
What is the internet - ANSWER: It is a network of interconnected networks
What are protocols - ANSWER: All communication activity in the internet is governed
by protocols
Protocols define the format, order of messages sent and received among network
entities, and actions taken on message transmission, receipt
What are 2 governing orgs of internet standards - ANSWER: RFC (Request for
Comment), IETF (Internet Engineering Task Force)
How are end systems connected to edge routers? - ANSWER: 1) residential access
nets
2) institutional access networks
3) mobile access networks (wifi, 4g,5g)
What wiring network does cable-based access use. - ANSWER: HFC (hybrid fiber
coax)
Is HFC symmetric in terms of upstream and downstream rates - ANSWER: No, it is
asymmetric (more down than up)
,Is cable-based access shared? - ANSWER: Yes homes share access network to cable
headend
How are multiple homes able to share access network in cable-based access? -
ANSWER: Through Frequency Division Multiplexing (FDM)
What is Frequency Division Multiplexing - ANSWER: A technique by which the total
bandwidth available in a communication medium is divided into a series of non-
overlapping frequency bands, each of which is used to carry a separate signal
How does DSL work? - ANSWER: Uses existing telephone lines to central office
DSLAM. Voice over the phone line goes to telephone net but data over the line goes
to internet
Do you share when you use DSL - ANSWER: No
What are the 2 types of wireless access networks - ANSWER: 1. Wireless LANs
(within a building - 100ft. - 802.11 b/g/n)
2. Wide-area Wireless Access (provided by cell operator - 10s of kms - 4G/5G)
What is the main responsibility of a host - ANSWER: Send packets of data
What is host sending function supposed to do - ANSWER: 1) Take app message
2) break message into small chunks called packets
3) transmit packet into acess network at transmission rate R ( link bandwidth)
What is a physical link - ANSWER: what lies between transmitter and receiver
What is guided media - ANSWER: signals propagate in solid media: copper, fiber,
coax
What is unguided media - ANSWER: signals propagate freely, e.g. radio
What is twisted pair - ANSWER: two insulated copper wires twisted together
What is coaxial cable - ANSWER: - Two concentric copper conductors
- Bidirectional
- Broadband:
- Multiple channels on cable
What is fiber optic cable - ANSWER: glass fiber carrying light pulses, each pulse a bit
high speed
low error rate
- repeaters spaced far apart
- immune to electromagnetic noise
, What is wireless radio and how does it work - ANSWER: Signal carried in various
"bands" in electromagnetic spectrum
No physical wire
susceptible to reflection, obstruction, interference
What is packet switching - ANSWER: hosts break application-layer messages into
packets
Network forwards packets from one router to the next, across links on path from
source to destination
What are 2 key network-core functions - ANSWER: Forwarding and Routing
What is Forwarding - ANSWER: Local action: move arriving packets from router's
input link to appropriate router output link
What is Routing - ANSWER: Global action: determine source to destination path
taken by packets
What is packet transmission delay - ANSWER: The time needed to transmit an L-bit
packet into the link at R bps is L/R seconds
What is store and forward - ANSWER: entire packet must arrive at router before it
can be transmitted on next link
When does queuing occur? - ANSWER: if arrival rate (in bps) to link exceeds
transmission rate (bps) of link for some period of time
When do packets get dropped - ANSWER: If packets are queuing but memory in
router fills up
What is the alternative to packet switching - ANSWER: circuit switching
What is circuit Switching - ANSWER: end-end resources allocated to, reserved for
"call" between source and destination
Dedicated resources: no sharing - guaranteed performance
What is FDM in circuit switching - ANSWER: Optical, electromagnetic frequencies
divided into (narrow) frequency bands
Each call is allocated its own band and can transmit at max rate of that narrow band
What is TDM in circuit switching - ANSWER: Time is divided into slots. Each call is
allocated periodic slots. During each slot, call can transmit at maximum rate of wider
frequency band
ALL 174 COMPLETE REAL EXAM QUESTIONS AND WELL
ELABORATED ANSWERS (VERIFIED ANSWERS) LATEST
UPDATES 2024 | ALREADY GRADED A+ (BRAND NEW!!)
What is Network Edge - ANSWER: hosts, access networks, physical media. Also
includes servers that often lie in data centers
What is network core - ANSWER: mesh of interconnected routers.
Packet switching happens here
What are some ways we measure performance - ANSWER: Loss, Delay, Throughput
What is the difference between hosts and end systems - ANSWER: No difference,
they are the same thing
What are some communication links - ANSWER: Fiber, copper, radio, satellite
What is a network - ANSWER: collection of devices, routers, links that are typically
managed by an organization
What is the internet - ANSWER: It is a network of interconnected networks
What are protocols - ANSWER: All communication activity in the internet is governed
by protocols
Protocols define the format, order of messages sent and received among network
entities, and actions taken on message transmission, receipt
What are 2 governing orgs of internet standards - ANSWER: RFC (Request for
Comment), IETF (Internet Engineering Task Force)
How are end systems connected to edge routers? - ANSWER: 1) residential access
nets
2) institutional access networks
3) mobile access networks (wifi, 4g,5g)
What wiring network does cable-based access use. - ANSWER: HFC (hybrid fiber
coax)
Is HFC symmetric in terms of upstream and downstream rates - ANSWER: No, it is
asymmetric (more down than up)
,Is cable-based access shared? - ANSWER: Yes homes share access network to cable
headend
How are multiple homes able to share access network in cable-based access? -
ANSWER: Through Frequency Division Multiplexing (FDM)
What is Frequency Division Multiplexing - ANSWER: A technique by which the total
bandwidth available in a communication medium is divided into a series of non-
overlapping frequency bands, each of which is used to carry a separate signal
How does DSL work? - ANSWER: Uses existing telephone lines to central office
DSLAM. Voice over the phone line goes to telephone net but data over the line goes
to internet
Do you share when you use DSL - ANSWER: No
What are the 2 types of wireless access networks - ANSWER: 1. Wireless LANs
(within a building - 100ft. - 802.11 b/g/n)
2. Wide-area Wireless Access (provided by cell operator - 10s of kms - 4G/5G)
What is the main responsibility of a host - ANSWER: Send packets of data
What is host sending function supposed to do - ANSWER: 1) Take app message
2) break message into small chunks called packets
3) transmit packet into acess network at transmission rate R ( link bandwidth)
What is a physical link - ANSWER: what lies between transmitter and receiver
What is guided media - ANSWER: signals propagate in solid media: copper, fiber,
coax
What is unguided media - ANSWER: signals propagate freely, e.g. radio
What is twisted pair - ANSWER: two insulated copper wires twisted together
What is coaxial cable - ANSWER: - Two concentric copper conductors
- Bidirectional
- Broadband:
- Multiple channels on cable
What is fiber optic cable - ANSWER: glass fiber carrying light pulses, each pulse a bit
high speed
low error rate
- repeaters spaced far apart
- immune to electromagnetic noise
, What is wireless radio and how does it work - ANSWER: Signal carried in various
"bands" in electromagnetic spectrum
No physical wire
susceptible to reflection, obstruction, interference
What is packet switching - ANSWER: hosts break application-layer messages into
packets
Network forwards packets from one router to the next, across links on path from
source to destination
What are 2 key network-core functions - ANSWER: Forwarding and Routing
What is Forwarding - ANSWER: Local action: move arriving packets from router's
input link to appropriate router output link
What is Routing - ANSWER: Global action: determine source to destination path
taken by packets
What is packet transmission delay - ANSWER: The time needed to transmit an L-bit
packet into the link at R bps is L/R seconds
What is store and forward - ANSWER: entire packet must arrive at router before it
can be transmitted on next link
When does queuing occur? - ANSWER: if arrival rate (in bps) to link exceeds
transmission rate (bps) of link for some period of time
When do packets get dropped - ANSWER: If packets are queuing but memory in
router fills up
What is the alternative to packet switching - ANSWER: circuit switching
What is circuit Switching - ANSWER: end-end resources allocated to, reserved for
"call" between source and destination
Dedicated resources: no sharing - guaranteed performance
What is FDM in circuit switching - ANSWER: Optical, electromagnetic frequencies
divided into (narrow) frequency bands
Each call is allocated its own band and can transmit at max rate of that narrow band
What is TDM in circuit switching - ANSWER: Time is divided into slots. Each call is
allocated periodic slots. During each slot, call can transmit at maximum rate of wider
frequency band
