Video Part1
https://www.youtube.com/watch?v=NmdOcoagZMc
1.1 Which of the following are “internet applications” ?
(a) Switches
(b) Facebook
(c) Internet protocol (IP protocol)
(d) On-line games
(e) Dropbox
1.2 Which of the following are NOT “internet applications” ?
(a) Transmission Control Protocol (TCP)
(b) YouTube
(c) Gmail
(d) Skype
(e) Routers
Video Part2
https://www.youtube.com/watch?v=yhJD3OrDlh8
1.3 Which of the following statements are correct for “links” of a network?
(a) A “point-to-point” link is a link to connect two devices or hosts.
(b) A “multiple access” link is a link to connect many devices or hosts.
(c) A “point-to-point” link is a link to connect more than two devices or hosts.
(d) A “multiple access” link is a link to connect only two devices or hosts.
(e) The IEEE 802.11 wireless LAN (WiFi) is a multiple access link.
1.4 Which of the following are “nodes” of a network?
(a) Switches
(b) IEEE 802.3 Ethernet protocol
(c) IEEE 802.11 wireless LAN (WiFi) protocol
(d) Wireless Access points (APs)
(e) Routers
1.5 Which of the following statements are correct for “store-and-forward” concept ?
(a) It’s a way for a network device to handle an incoming packet by storing the packet first and then forwarding the packet according to some switching/routing policy.
(b) A router usually stores an incoming packet in the memory first and then lookups the routing table to determine which port to forward the packet.
(c) A switch usually stores an incoming frame in the memory first and then lookups the MAC address table to determine which port to forward the frame.
(d) The store-and-forward technology is usually used in a circuit switched network.
(e) The store-and-forward technology is usually used in a packet switched network.
1.6 Which of the following are correct for a “switched network” ?
(a) A switched network is a network connected by switches and routers.
(b) A switched network is a network connected by switches.
(c) The “topology” of a switched network is limited to be a “spanning tree”.
(d) The “topology” of a switched network is not limited, but the frames (packets) are delivered along the “spanning tree” of the switched network.
(e) The frames (packets) are delivered along the “shortest path” of the switched network.
1.7 Which of the following statements are correct for an “interconnected network” ?
(a) An interconnected network is a network that several networks are connected by switches.
(b) An interconnected network is a network that several networks are connected by routers.
(c) The “topology” of an interconnected network is limited to be a “spanning tree”.
(d) The “topology” of an interconnected network is not limited, but the packets are delivered along the “spanning tree” of the connected networks.
(e) The packets are delivered along the routing path determined by the routing protocols.
1.8 Which of the following statements are correct for “unicast/broadcast/multicast” ?
(a) For unicast, a packet is delivered to only a destination station.
(b) For broadcast, a packet is delivered to multiple but not all the stations.
(c) For multicast, a packet is delivered to all stations of the network.
(d) In a switched network, a broadcast frame will be received by all the stations in the switched network.
(e) In an interconnected network, a broadcast frame will be received by all the stations in the interconnected network.
Video Part3
https://www.youtube.com/watch?v=4slUtL5qMhI
1.9 Which of the following statements are correct for delivering packets (datagrams) over the Internet ?
(a) All packets destined to the same destination will be forwarded along the same routing path.
(b) The routing path of a packet is determined first before the packet is sending into the Internet.
(c) The Internet is reliable so that all packets will be received by the destination correctly.
(d) A packet may be partitioned into several fragments by routers.
(e) All fragments of a packet will be forwarded along the same path to the destination.
Video Part4
https://www.youtube.com/watch?v=azfaJ5JSe3g
1.10 Which of the following statements are correct for “multiplexing” ?
(a) Multiplexing is method usually used by a switch to transmitting multiple logical flows over a single physical link.
(b) In TDM (Time-Division-Multiplexing), data are transmitted in predetermined frequency.
(c) In FDM (Frequency-Division-Multiplexing), data are transmitted in predetermined time slots.
(d) One of the drawbacks of TDM is that a flow can use only the time slots allocated to it.
(e) The link utilization for TDM and FDM may not good when some flows are overloaded and some are lightly loaded.
1.11 Which of the following statements are correct for “statistical multiplexing” ?
(a) Data are transmitted based on demand of each flow.
(b) Data are transmitted based on the arrival time of each flow.
(c) The bandwidth used by different flows may be different.
(d) The statistical multiplexing is fair due to the bandwidth used by different flows are the same.
(e) It provides better link utilization than TDM (Time-Division-Multiplexing) and FDM (Frequency-Division-Multiplexing).
1.12 Which of the following scheduling policies are usually used in “statistical multiplexing” to select flows for transmitting ?
(a) TDM
(b) Round-Robin
(c) Priority-based (based on flow priority)
(d) FIFO (first-in-first-out)
(e) FDM
Video Part5
https://www.youtube.com/watch?v=xp_PQCBA4ww
1.13 Which of the following statements are correct to describe the “network reliability” of Internet ?
(a) Packets may be lost due to network congestion.
(b) Lost packets will be retransmitted by the routers.
(c) Packets may be delayed for different delay time before reaching the destination.
(d) Packets may be out-of-order due to different routing paths.
(e) Packets will be delivered to the destination based on “first-in-first-out” order.
Video Part6
https://www.youtube.com/watch?v=WMFZVtVHIow
1.14 Which of the following statements are correct to describe the “protocols” ?
(a) Protocols are the building blocks of a network architecture.
(b) The “service interface” of a protocol describes the messages exchanged with other peer.
(c) The “peer-to-peer interface” of a protocol describes the operations on this protocol.
(d) The Internet Protocol (IP) provides a “reliable transmission service” to upper level protocols, such as TCP and UDP.
(e) The “peer-to-peer interface” of the IP protocol describes the “IP header” of the IP packet.
1.15 Which of the following schemes are usually used to describe the “protocol specification” ?
(a) Pseudo-code
(b) State-machine diagram
(c) Message format
(d) Network topology
(e) Network architecture
Video Part7
https://www.youtube.com/watch?v=w4LeQtquN2A
1.16 Which of the following statements are correct to describe the “protocols” ?
(a) For sending node, the data from application level will be encapsulated larger and larger until to the physical level.
(b) For receiving node, the data from physical level will be decapsulated smaller and smaller until to the application level.
(c) The TCP segment is encapsulated into the IP datagram. That’s the IP protocol treats the TCP segment as data.
(d) The IP datagram is encapsulated into the underlying MAC frame. That’s the MAC protocol treats the IP datagram as a data.
(e) For a router, it first uses encapsulation scheme to get an IP datagram from the receiving port, and then uses decapsulation scheme to transmit the IP datagram.
Video Part8
https://www.youtube.com/watch?v=4osiWNPehu4
Video Part9
https://www.youtube.com/watch?v=e7q3ZCt5Gzo
1.17 In the OSI (Open Systems Interconnection) 7-layer model, which of the following layers are usually included in a “router” ?
(a) Transport layer
(b) Network layer
(c) Presentation layer
(d) Data link layer
(e) Physical layer
1.18 In the OSI (Open Systems Interconnection) 7-layer model, which of the following layers are usually included in a “switch” ?
(a) Transport layer
(b) Network layer
(c) Data link layer
(d) Session layer
(e) Physical layer
1.19 In the OSI (Open Systems Interconnection) 7-layer model, which of the following layers are usually included in a wireless “Access Point (AP)” ?
(a) Application layer
(b) Transport layer
(c) Network layer
(d) Data link layer
(e) Physical layer
Video Part10
https://www.youtube.com/watch?v=Z-jr6pIvNyY
1.20 Which of the following statements are correct for the “physical layer” in the OSI 7-layer model ?
(a) It handles the transmission of “raw bits” over a communication link.
(b) It handles the transmission of “frames” over a communication link.
(c) To overcome noise or interference, different signal coding schemes may be used.
(d) The physical layer must be a “wired link”
(e) The physical layer can be a “wireless link”
1.21 Which of the following links belong to the “physical layer” ?
(a) Coaxial cable
(b) Twisted pair cable
(c) Optical Fiber
(d) Air space
(e) Power line
Video Part11
https://www.youtube.com/watch?v=iFVupG3fU7o
1.22 Which of the following statements are correct for the “data link layer” in the OSI 7-layer model ?
(a) It handles the transmission of “raw bits” over a communication link.
(b) It handles the transmission of “frames” to a directly connected device or host.
(c) Different medium access control (MAC) protocols are used for different medium links.
(d) The CSMA/CD is the MAC protocol used by IEEE 802.11 wireless LAN network
(e) The CSMA/CA is the MAC protocol used by IEEE 802.3 Ethernet LAN network”
1.23 We say that a device is a “layer 2” device if it implements only data link layer protocol and physical layer protocol. Which of the following devices are usually layer 2 devices ?
(a) Routers
(b) Bridges
(c) Switches
(d) Firewalls
(e) Load Balancers
Video Part12
https://www.youtube.com/watch?v=JGgosF5GFX4
1.24 Which of the following statements are correct for the “network layer” in the OSI 7-layer model ?
(a) It deals with the problem of how to transmit packets to a destination host via the Internet.
(b) The Internet Protocol (IP) is a network layer protocol.
(c) The User Datagram Protocol (UDP) is a network layer protocol.
(d) The routing protocols are used by routers to establish the routing table.
(e) The routing table is used by a router to determine where a received packet should be forwarded.
1.25 We say that a device is a “layer 3” device if it implements network layer protocol, data link layer protocol, and physical layer protocol. Which of the following devices are usually layer 3 devices ?
(a) Routers
(b) Bridges
(c) Switches
(d) Wireless Access Points
(e) Wireless routers
1.26 Which of the following protocols are routing protocols ?
(a) Internet Protocol (IP)
(b) Router Information Protocol (RIP)
(c) Open Shortest Path First (OSPF) protocol
(d) Boarder Gateway Protocol (BGP)
(e) Transmission Control Protocol (TCP)
Video Part13.14
https://www.youtube.com/watch?v=USECIlL-_IM
1.27 Which of the following statements are correct for the “transport layer” in the OSI 7-layer model ?
(a) It deals with the problem of how to transmit packets between a pair of processes in different hosts.
(b) The User Datagram Protocol (UDP) is a transport layer protocol that provides reliable transmission service.
(c) The Transmission Control Protocol (TCP) is a transport layer protocol that provides reliable transmission service.
(d) Routers usually not implement transport layer protocols.
(e) Transport layer protocols usually are only implemented in end hosts.
1.28 Which of the following are the main features of the Internet Architecture ?
(a) Strict layering. The layer N protocol is only allowed to use the services provided by layer N-1 protocol.
(b) Not strict layering. The layer N protocol is allowed to use the services provided by layer N-2 protocol or other underlying protocols directly.
(c) An hour-glass shape of protocols and IP serves as the focal point for the architecture
(d) An hour-glass shape of protocols and TCP/UDP serves as the focal point for the architecture.
(e) In order for a new protocol to be officially included in the architecture, there needs to be both a protocol specification and at least one representative implementations of the specification.
Video Part15
https://www.youtube.com/watch?v=4AS9DEU_3Ts
1.29 Which of the following factors are usually included to calculate the delay (latency) of transmitting a packet from a source device (such as switch) to a destination device ?
(a) Queuing time
(b) Transmission time
(c) Propagation time
(d) Receiving time of the destination device
(e) Table lookup time
1.30 The “transmission time” of a network interface (card) to transmit a packet is defined as packet size/bandwidth. For a 1Mbps Ethernet interface, what is the transmission time to transmit a packet of size 1Kbytes ?
(a) 1 ms
(b) 8 ms
(c) 10 ms
(d) 80 ms
(e) 800 us
1.31 The “propagation time” of a link to transmit a bit from one end to another end is defined as link distance/speed of light. For a link of 30Km, what is the propagation time of such a link ? Assume the speed of light is 3 x 108 m/second.
(a) 1 us
(b) 10 us
(c) 100 us
(d) 1 ms
(e) 10 ms
1.32 Which of the following statements are correct for “transmission time” and “propagation time” ?
(a) For short packet, the propagation time is more important as the packet will be complete transmitted quickly but needs a longer time to propagate to the other end of the link.
(b) For short packet, the transmission time (bandwidth) is more important as the packet will be complete transmitted quickly and only needs a shorter time to propagate to the other end of the link.
(c) For long packet, the propagation time is more important as the packet will be complete transmitted slowly but needs a longer time to propagate to the other end of the link.
(d) For long packet, the transmission time (bandwidth) is more important as the packet will be complete transmitted slowly but the first bit only needs a shorter time to propagate to the other end of the link.
(e) The transmission time and propagation time are equal important for both short packet and long packet.
Video Part16
https://www.youtube.com/watch?v=y86wh4tOTMU
1.33 The channel between a pair of processes can be viewed as a pipe. Delay x Bandwidth means how many data can be stored in the pipe. For a pipe with a delay of 80 ms and bandwidth of 1000 Mbps, how many data can be stored in the pipe ?
(a) 1 MB
(b) 8 MB
(c) 10 MB
(d) 80 MB
(e) 100 MB
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