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………………….. are connected together by a network of communication links and packet switches. a. Routers b. End systems c. Hosts d. b and c.
When one end system has data to send to another end system, the sending end system segments the data and adds ………… bytes to each segment. a. Header b. Sequence Number c. Packet d. All of the above.
When one end system has data to send to another end system, the sending end system segments the data into packages of information called ……………….. a. Packets b. Bits c. Links d. All of the above.
………………….. takes a packet arriving on one of its incoming communication links and forwards that packet on one of its outgoing communication links. Such as ………….. and ……………… a. Packet switches, router, host. b. Packet witches, link-layer switches, routers. c. Packet switches, link-layer switches, end systems. d. Routers, link-layer switches, routers.
………………….. are typically used in access networks, while …………… are typically used in the network core. a. Link-layer switches, routers b. Routers, link-layer switches c. Routers, hosts. d. Link-layer switches, hosts.
ISPs provide a variety of types of network access to the end systems, including ……….. a. residential broadband access such as cable modem or DSL b. high-speed local area network access c. mobile wireless access. d. All of the above.
End systems, packet switches, and other pieces of the Internet run …………… that control the sending and receiving of information within the Internet. a. Protocols b. Software c. Web services d. All of the above.
End systems connected to the Internet provide a …………………. that specifies how a program running on one end system asks the Internet infrastructure to deliver data to a specific destination program running on another end system. a. Socket interface b. TCP c. IP d. TCP/IP.
………………….. is a set of rules that the sending program must follow so that the Internet can deliver the data to the destination program. a. Protocol b. TCP c. IP d. TCP/IP.
………………….. is a set of rules that defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event. a. A Protocol b. Software c. A Web service d. All of the above.
The home’s DSL modem takes digital data and translates it to high- frequency tones for transmission over telephone wires to the CO (i.e. convert digital signal to analog signal) a. True b. False.
At the DSLAM , the analog signals from many such houses are translated back into digital format. a. True b. False.
In the cable internet access, Because both fiber and coaxial cable are employed in this system, it is often referred to as…………... a. hybrid fiber coax (HFC) b. twisted copper wire. c. Coaxial d. All of the above.
The cable modem takes digital data and translates it to high- frequency tones for transmission over telephone wires to the CO (i.e. convert digital signal to analog signal) a. True b. False.
At the CMTS , the digital signals from many such houses are translated back into analog format. a. True b. False.
…………...... concept is to provide an optical fiber path from the CO directly to the home. a. The fiber to the home (FTTH) b. DSL c. HFC d. Cable.
.................... is a mesh of packet switches and links that interconnects the Internet’s end systems. a. The network core. b. The network edge. c. The network access. d. Both a and b.
To send a message from a source end system to a destination end system, the source breaks long messages into smaller chunks of data known as ................. a. Packets b. Bits c. Links d. All of the above.
.............. also referred to as access or branch routers, are specialized routers that act as gateways at the network edge. a. Edge routers b. Network core. c. Network edge d. All of the above.
........................ refers to the area where a device or local network interfaces with the internet.
a. The network edge. b. the network core c. The edge router. d. All of the above.
The sequence of communication links and packet switches traversed by a packet from the sending end system to the receiving end system is known as a ........ through the network.
a. Route b. Path c. a or b d. non of the above.
...................... means that the packet switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link. a. Store-and-forward transmission b. Direct transmission c. Indirect transmission d. Not of the above.
A source is connected to a destination through one router. What is the total delay of transmitting the packet if the packet length is 1000 bits and the transmission rate is 1000 bps? Ignore the propagation delay.
𝑑= 𝑁*(𝐿/𝑅) a. 1 s b. 2 s c. 3 s d. 6 s.
A source is connected to a destination through one router. What is the total delay of transmitting 3 packets if the packet length is 1000 bits and the transmission rate is 1000 bps? Ignore the propagation delay.
𝑑= 𝑁*(𝐿/𝑅) a. 1 s b. 2 s c. 3 s d. 6 s.
A source is connected to a destination through two router. What is the total delay of transmitting the packet if the packet length is 1000 bits and the transmission rate is 1000 bps? Ignore the propagation delay.
𝑡𝑟𝑛𝑠𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝑑𝑒𝑙𝑎𝑦 𝑓𝑜𝑟 𝑚 𝑟𝑜𝑢𝑡𝑒𝑟𝑠 𝑎𝑛𝑑 𝑛 𝑝𝑎𝑐𝑘𝑒𝑡𝑠=𝑚 𝑡+(𝑛−1) 𝑡
𝑡 =𝐿/𝑅
a. 1 s b. 2 s c. 3 s d. 6 s.
A source is connected
to a destination through two router. What is the total delay of transmitting 3 packets if the packet length is 1000 bits and the transmission rate is 1000 bps? Ignore the propagation delay.
𝑝𝑟𝑜𝑝𝑎𝑔𝑎𝑡𝑖𝑜𝑛 𝑑𝑒𝑙𝑎𝑦 =𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒(𝑚) / 𝑠𝑝𝑒𝑒𝑑 (𝑚/𝑠) a. 1 s b. 3 s c. 5 s d. 4 s.
A source is connected to a destination
through two router. What is the total delay of transmitting 3 packets if the packet length is 1000 bits and the transmission rate is 1000 bps?.
Include the propagation delay, if the distance between each host and router is 500 m and the distance between the routers is 2500 km, if a propagation speed 2.5 x 108 m/s, a. 1.4 s b. 3.9 s c. 6.5 s d. 4010 ms.
For each attached link, the packet switch has an................, which stores packets that the router is about to send into that link.
a. Output buffer. b. Output queue. c. Both a and b. d. None of the above.
In .............................. , the resources needed along a path (buffers, link transmission rate) to provide for communication between the end systems are reserved for the duration of the communication session between the end systems. a. circuit-switched networks. b. Packet-switched networks. c. Both a and b d. None of the above.
In .............................. , the resources needed along a path (buffers, link transmission rate) to provide for communication between the end systems are not reserved for the duration of the communication session between the end systems.
a. circuit-switched networks. b. Packet-switched networks. c. Both a and b d. None of the above.
In Packet Switching:
a. All packets must follow the same path, thus packets are transmitted in order b. A path is reserved for the whole duration of the communication session
c. Store-and-forward transmission is used within the network routers d. Admission control is deployed by default, thus QoS guarantees can be easily forced.
In circuit Switching:
a. All packets must follow the same path, thus packets are transmitted in order b. A path is reserved for the whole duration of the communication session c. Store-and-forward transmission is used within the network routers d. Admission control is deployed by default, thus QoS guarantees can be easily forced.
The time required to examine the packet’s header and determine where to direct the packet is part of the ............
a. Processing delay b. Queuing delay c. Propagation delay d. Transmission delay.
.................... the time that a packet waits to be processed in the buffer of a switch.
a. Processing delay b. Queuing delay c. Propagation delay
d. Transmission delay.
With .................. , the frequency spectrum of a link is divided up among the connections established across the link.
a. FDM (frequency-division multiplexing). b. TDM (time-division multiplexing). c. Both a and b. d. None of the above.
.................... is the time that it takes for a bit to reach from one end of a link to the other.
a. Processing delay b. Queuing delay c. Propagation delay d. Transmission delay.
................... the time it takes to transmit a data packet onto the outgoing link.
a. Processing delay b. Queuing delay c. Propagation delay d. Transmission delay.
For a ................ link, time is divided into frames of fixed duration, and each frame is divided into a fixed number of time slots.
a. FDM (frequency-division multiplexing). b. TDM (time-division multiplexing). c. Both a and b. d. None of the above.
Guided media:
a. fiber-optic cable, b. a twisted-pair copper wire, c. a coaxial cable d. all of the above.
Unguided media:
a. wireless LAN b. cellular satellite c. digital satellite d. all of the above.
the law of the end-to-end delay is
a. 𝑑𝑒𝑛𝑑−𝑒𝑛𝑑 = 𝑁 (𝑑𝑝𝑟𝑜𝑐 + 𝑑𝑡𝑟𝑎𝑛𝑠+ 𝑑𝑝𝑟𝑜𝑝) b. 𝑑𝑒𝑛𝑑−𝑒𝑛𝑑 = 𝑁 (𝑑𝑝𝑟𝑜𝑐 + 𝑑𝑡𝑟𝑎𝑛𝑠) c. 𝑑𝑒𝑛𝑑−𝑒𝑛𝑑 = 𝑁 (𝑑𝑝𝑟𝑜𝑐 + 𝑑𝑝𝑟𝑜𝑝) d. 𝑑𝑒𝑛𝑑−𝑒𝑛𝑑 = 𝑁 ( 𝑑𝑡𝑟𝑎𝑛𝑠 + 𝑑𝑝𝑟𝑜𝑝).
The protocols of the layer ...................... can be implemented in software in the end system only.
a. Application layer b. Transport layer c. Network layer d. Both a and b.
The protocols of the layer ...................... can be implemented in a network interface card.
a. Application layer b. Data-link layer c. physical layer d. Both b and c.
The protocols of the layer ...................... is often a mixed implementation of hardware and software.
a. Application layer
b. Data-link layer c. Network layer d. Both b and c.
In the protocols that found in the application layer are:
a. HTTP b. FTP c. DNS d. SMTP e. All of the above.
In the protocols that found in the network layer are:
a. HTTP b. FTP c. IP d. All of the above.
In the protocols that found in the transport layer are:
a. TCP b. UDP c. Both and b d. None of the above.
The naming of the packets in the application layer, transport layer, network layer, data-link layer respectively is, .............., ....................., ......................., .................... a. Message, datagram, segment, frame b. Frame, message, datagram, segment c. Message, segment, datagram, frame. d. Datagram, message, frame, segment.
TCP protocol is connectionless:
a. True b. False.
UDP protocol is connection-oriented
a. True b. False.
.............. protocol offer flow control and congestion control:
a. TCP b. UDP c. Both a and b d. None of the above.
................... protocol offers error detection.
a. TCP b. UDP c. Both a and b d. None of the above.
The following is kind of addressing in the application layer:
a. Email address b. Domain c. Both a and b d. None of the above.
The following is kind of addressing in the transport layer:
a. Port number b. IP address
c. MAC address
d. All of the above.
he following is kind of addressing in the data-link layer:
a. Port number b. IP address c. MAC address d. All of the above.
In the OSI model, .......................provide services that allow communicating applications to interpret the meaning of data exchanged.
a. The presentation layer b. The session layer c. Both a and b d. None of the above.
In the OSI model, the services that provided by the presentation layer includes:
a. data compression b. data encryption c. data description d. All of the above.
................................ provides for delimiting and synchronization of data exchange, including the means to build a check pointing and recovery scheme.
a. The presentation layer b. The session layer c. Both a and b d. None of the above.
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In a ............................. there is an always-on host, called the server, which services requests from many other hosts, called clients.
a. client-server architecture b. layered architecture c. P2P architecture d. None of the above.
The architecture that is use to make two applications (called peers) establish direct communications between themselves, is .............
a. client-server architecture b. layered architecture c. P2P architecture d. None of the above.
Internet telephony and video conference (Skype) are examples of using ………………..
a. client-server architecture b. layered architecture c. P2P architecture d. None of the above.
HTTP, FTP, Telnet, and e-mail
a. client-server architecture b. layered architecture c. P2P architecture d. None of the above.
…………………..is called program that is running (at execution).
a. Architecture b. process. c. Both a and b. d. None of the above.
6) A networking process sends messages into, and receives messages from, the network .........
a. Socket b. IP c. Port. d. None of the above.
To identify a receiving process, two addresses are needed:
a. IP b. The port number. c. both a and b. d. none of the above.
With the Web, a browser is a ........... process and a ............is a server process.
a. Client, Web server b. Client, router, c. Web server, client d. Router, host.
With P2P file sharing, the peer that is downloading the file is labeled as the ......... , and the peer that is uploading the file is labeled as the ...................
a. Client, Web server b. Client, router, c. Web server, client d. Router, host.
In the context of a communication session between a pair of processes, the process that initiates the communication (that is, initially contacts the other process at the beginning of the session) is labeled as the ................. . The process that waits to be contacted to begin the session is the ..........................
a. Client, Web server b. Client, router, c. Web server, client d. Router, host.
............... is the interface between the application layer and the transport layer within a host. It is also referred to as the ...................... between the application and the network.
a. Socket, API (Application programming interface) b. IP, API c. Socket, ABI. d. None of the above.
The (HTTP), the Web’s application-layer protocol, is implemented in two programs:
a. Client only. b. Server only. c. Client and server. d. None of the above.
HTTP save connection states (i.e. storing any state information about the client).
a. True b. False.
HTTP is stateless because HTTP server does not maintain any information about clients..
a. True b. False.
In ........................ each request/response pair between the client and the server is sent over a separate TCP connection.
a. Non-persistent connections b. Persistent connections. c. TCP connection d. None of the above.
In ........................ all of the requests and their corresponding responses between the client and the server are sent over the same TCP connection.
a. Non-persistent connections b. Persistent connections. c. TCP connection d. None of the above.
In HTTP non-persistent connections
a. each request/response pair between the client and the server is sent over a separate TCP connection b. all of the requests and their corresponding responses between the client and the server are sent over the same TCP connection c. Server leaves the TCP connection open after sending a response and subsequent requests and responses between the same client and server can be sent over the same connection d. an efficient data transmission can be achieved especially when responding to multiple client requests.
In HTTP persistent connections
a. Multiple Web pages residing on the same server can be sent from the server to the same client over a single persistent TCP connection b. all of the requests and their corresponding responses between the client and the server are sent over the same TCP connection
c. Server leaves the TCP connection open after sending a response and subsequent requests and responses between the same client and server can be sent over the same connection.
d. The HTTP server closes a connection when it isn’t used for a certain time e. All the above.
If the client needs to fetch HTML page including 10 images and one video with HTTP non-persistent connection, how many TCP connections the clients will request:
a. 1 b. 10 c. 12 d. 11.
If the client needs to fetch HTML page including 10 images and one video with HTTP persistent connection, how many TCP connections the clients will request:
a. 1 b. 10 c. 12 d. 11.
The amount of time that elapses from when a client requests the base HTML file until the entire file is received by the client, is called...........
a. Round trip time (RTT) b. Response time c. Transmission time. d. None of the above.
................................ is the time it takes for a small packet to travel from client to server and then back to the client.
a. Round trip time (RTT) b. Response time c. Transmission time. d. None of the above.
The RTT includes ....................
a. packet-propagation delays. b. packet- queuing delays c. packet-processing delays. d. All of the above.
If the client needs to fetch HTML page including 11 images and one video with HTTP non-persistent connection, what is the total delays in RTTs?
𝑑𝑒𝑙𝑎𝑦 (𝑅𝑇𝑇)−𝑵𝑶𝑵−𝑝𝑒𝑟𝑠𝑖𝑠𝑡𝑒𝑛𝑡=2 𝑛 𝑜𝑏𝑗𝑒𝑐𝑡𝑠 a. 14 b. 23 c. 25 d. 26.
If the client needs to fetch HTML page including 11 images and one video with HTTP persistent connection, what is the total delays in RTTs?
𝑑𝑒𝑙𝑎𝑦 (𝑅𝑇𝑇)−𝑝𝑒𝑟𝑠𝑖𝑠𝑡𝑒𝑛𝑡=𝑛 𝑜𝑏𝑗𝑒𝑐𝑡𝑠+1 a. 14 b. 23 c. 25 d. 26.
The disadvantages of HTTP non-persistent connection includes:
a. A new connection must be established and maintained for each requested object. b. Each object suffers a delivery delay of two RTTs. c. Each object suffers a delivery delay of one RTTs. d. Both a and b.
The disadvantages of HTTP persistent connection includes:
a. A new connection must be established and maintained for each requested object. b. Each object suffers a delivery delay of two RTTs. c. Both a and b d. None of the above.
............................ is the first line of an HTTP request message.
a. Request line. b. Header line. c. Both a and b. d. None of the above.
The following are the fields of the request line of the HTTP request message ...................
a. The method field b. The URL field c. HTTP version field d. All of the above.
In the HTTP request message, the header line includes ...................
a. The header line Host b. Connection: close c. User-agent d. Accept-language e. All of the above.
The Host header line is needed if the client has already established a connection with the server to used by the web proxy caches.
a. True b. False.
With GET message, the entity body of the HTTP request message is empty.
a. True b. False.
With POST message, the entity body of the HTTP request message is empty.
a. True b. False.
The data entered by the user in the web form is stored in the entity body of the HTTP request message with the ..................
a. POST message b. GET message c. HEAD message d. PUT message.
The data entered by the user in the web form is stored in the URL field of the HTTP request message with the ..................
a. POST message b. GET message c. HEAD message d. PUT message.
The server responds with an HTTP message but it leaves out the requested object, if the HTTP request method is
a. POST b. GET c. HEAD d. PUT.
The ............. HTTP method allows a user to upload an object to a specific path (directory) on a specific Web server.
a. POST b. GET c. HEAD d. PUT.
The ............. HTTP method allows a user, or an application, to delete an object on a Web server.
a. POST b. GET c. HEAD d. DELETE.
the HTTP response message includes
a. an initial status line, b. six header lines, c. the entity body d. all of the above.
In the HTTP response message, the status line includes
a. The protocol version field, b. A status code, c. Status message d. all of the above.
In the HTTP response message, the header line includes ...................
a. Connection: close b. Date c. Server d. Last-Modified e. Content-Length f. Content-Type g. All of the above.
In the HTTP response message, the .............................. is the status code that means that the Request succeeded and the information is returned in the response.
a. 200. b. 301. c. 404. d. 505.
n the HTTP response message, the .............................. is the status code that means that Requested object has been permanently moved.
a. 200. b. 301. c. 404. d. 505.
In the HTTP response message, the .............................. is the status code that means that the request could not be understood by the server.
a. 200. b. 301. c. 400 Bad request. d. 505.
In the HTTP response message, the .............................. is the status code that means that the requested document does not exist on this server.
a. 200. b. 301. c. 404. d. 505.
In the HTTP response message, the .............................. is the status code that means that The requested HTTP protocol version is not supported by the server.
a. 200. b. 301. c. 404. d. 505.
cookie technology has the following components:
a. a cookie header line in the HTTP response message; b. a cookie header line in the HTTP request message; c. a cookie file kept on the user’s end system and managed by the user’s browser; d. a back-end database at the Web site. e. All of the above.
The HTTP protocol is stateless but we use ........... to store the state of the connection (i.e. the information about the client)
a. Cookies b. Cache c. Both a and b d. None of the above.
............................... is a network entity that satisfies HTTP requests on the behalf of an origin Web server.
a. Web cache b. Proxy cache c. Both a and b d. None of the above.
The advantages of the Web cache is
a. reduce the response time for a client request. b. reduce Web traffic. c. Both a and b d. None of the above.
The major components of the electronic mail in the internet are .........
a. user agent b. mail server c. simple mail transfer protocol (SMTP) d. all of the above.
............... is the principal application-layer protocol for Internet electronic mail.
a. SMTP. b. DNS. c. FTP. d. HTTP.
The SMTP of the application layer uses the ............... protocol of the transport layer
a. UDP b. TCP c. HTTP d. DNS.
...................... translate user-supplied hostnames (domain name) to IP addresses.
a. SMTP b. DNS. c. FTP. d. HTTP.
The DNS protocol runs over ................. and uses port 53.
a. UDP b. TCP c. HTTP d. DNS.
............................. provide the IP addresses of the TLD servers.
a. Root name servers b. TLD c. Authoritative DNS servers d. None of the above.
............................. provide the IP addresses for authoritative DNS servers.
a. Root name servers b. TLD (top-level-domain servers) c. Authoritative DNS servers
d. None of the above.
In the ...................... DNS query, the local DNS server connects directly with each DNS server involved in the lookup.
a. Iterative. b. Recursive. c. Both a and b d. None of the above.
In the ...................... DNS query, the local DNS server connects only with the root DNS server involved in the lookup.
a. Iterative. b. Recursive. c. Both a and b d. None of the above.
In ..........................., server must send a copy of the file to each of the peers.
a. Client-server file distribution b. P2P file distribution c. Both a and b d. None of the above.
In ................................, each peer redistributes portions of the file it has received to other peers:
a. Client-server file distribution b. P2P file distribution c. Both a and b d. None of the above.
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Transport-layer protocols are implemented in network routers but not in the end systems.
a. True b. False.
................................ protocol provides logical communication between application processes
a. Application layer b. Transport layer c. Network layer d. Data-link layer.
................................ protocol provides Logical communication between hosts.
a. Application layer b. Transport layer c. Network layer d. Data-link layer.
................................ provides a process-to-process communication.
a. Application layer b. Transport layer c. Network layer d. Data-link layer.
................................ provides a host-to-host communication.
a. Application layer b. Transport layer c. Network layer d. Data-link layer.
.................... protocol provides an unreliable, connectionless service.
a. TCP. b. UDP. c. HTTP. d. FTP.
.................... provides a reliable, connection-oriented service.
a. TCP. b. UDP. c. HTTP.
d. FTP.
we refer to the transport-layer packet as a segment. But often refers to the packet for UDP as a ....................
a. datagram b. segment c. frame d. message.
In user datagram protocol (UDP),
a. Flow control is enforced b. Error control is enforced c. Best effort service is provided d. End-to-end delay limits are guaranteed.
................................ protocol provides logical communication between application processes
b. UDP a. TCP c. IP d. Both a and b.
................................ protocol provides Logical communication between hosts.
a. TCP b. UDP c. IP d. Both a and b.
Extend host-to-host delivery service provided by the network layer to a process-to-process delivery service for applications running on the hosts is called.
a. Multiplexing. b. Demultiplexing c. Multiplexing and demultiplexing d. None of the above.
At the sending host, the transport layer receives messages from the application layer processes and sends these messages to the network layer
a. Multiplexing. b. Demultiplexing c. Multiplexing and demultiplexing d. None of the above.
At the receiving host, the transport layer receives messages from the network layer and sends them to the appropriate application layer processes
a. Multiplexing. b. Demultiplexing c. Multiplexing and demultiplexing d. None of the above.
Transport layer multiplexing/demultiplexing requires:
a. sockets have unique identifiers b. each segment have special fields that indicate the socket to which the segment is to be delivered (source port number and destination port number) c. both a and b d. none of the above.
TCP ensures that data is delivered from sending process to receiving process, correctly and in order using:
a. Using flow control, b. sequence numbers, c. acknowledgments, and timers. d. All of the above.
This job of delivering the data in a transport-layer segment to the correct socket is called .....................
a. Multiplexing. b. Demultiplexing c. Multiplexing and demultiplexing d. None of the above.
The job of gathering data chunks at the source host from different sockets, encapsulating each data chunk with header information to create segments, and passing the segments to the network layer is called ...........................
a. Multiplexing. b. Demultiplexing c. Multiplexing and demultiplexing d. None of the above.
With .................... protocol there is no handshaking between sending and receiving transport-layer entities before sending a segment.
a. TCP. b. UDP. c. HTTP. d. FTP.
With .................... protocol there is handshaking between sending and receiving transport-layer entities before sending a segment. a. TCP. b. UDP. c. HTTP. d. FTP.
Connectionless means ...............
a. no connection established, b. no flow control c. no congestion control d. no quality-of-service guarantee. e. All of the above.
UDP guarantee of the quality of the serve:
a. True b. false.
TCP guarantee of the quality of the serve:
a. True b. false.
Advantages of UDP:
a. Finer application-level control over what data is sent, and when
b. No connection establishment.
c. No connection state.
d. Small packet header overhead e. All of the above.
The fields of the UDP header includes .....................
a. Source port number
b. Destination port number c. Checksum d. Header length e. All of the above.
Reliable data connection means .............
a. guarantees that packet is delivered and delivered correctly, b. do flow control, c. congestion control.
d. All of the above.
In the TCP connection, If the destination is not found, then the sender will be notified:
a. True b. false.
In the UDP header, the checksum is used for:
a. Error detection b. Error correction c. Flow control d. Congestion control.
................................. a mechanism is needed to allow the receiver to detect when bit errors have occurred and notify the sender a. Error detection b. Error correction c. Flow control d. Congestion control.
The IP protocol provides unreliable connection but with the TCP protocol it provides reliable connection ..........
a. True b. false.
.................................. is the acknowledgement of the receiver after receiving a packet.
a. Receiver feedback b. Error correction c. Flow control d. Congestion control.
......................... signal is sent to reject a previously received message or to indicate some kind of error.
a. Negative acknowledgement (NACK) b. Positive acknowledgement (ACK) c. Both a and b d. None of the above.
In case of ......................... the receiver explicitly notifies the sender which packets, messages, or segments were received correctly.
a. Negative acknowledgement (NACK) b. Positive acknowledgement (ACK) c. Both a and b d. None of the above.
............................. is used to account for the possibility of corruption of the ACK or NAK during transmission from receiver to sender?
a. Sequence number b. Retransmission
c. Error detection
d. Error correction.
In the reliable data transfer in noisy channel, the sender can retransmit the packet if, .....
a. If an ACK is not received before the timer ends. b. The ACK is lost. c. There is a large delay in the packet delivery. d. All of the above.
The destination host may receive a duplicate of a packet, if ..............
a. The ACK is lost. b. The timer is prematurely timed out. c. Both a and b d. None of the above.
In the stop-and-wait protocol, the sender can’t send a new packet if it doesn’t receive the ACK of the previous packet.
a. True b. false.
In the ............................., the sender is allowed to transmit multiple packets (when available) without waiting for an acknowledgment but is constrained to have no more than some maximum allowable number, N, of unacknowledged packets in the pipeline.
a. stop-and-wait protocol. b. Go-back-N protocol. c. Selective repeat d. Both b and c.
A transmitter has already transmitted 12 frames. There was one error in frame number 8 (frames are numbered starting from 0 to 11). How many frames the transmitted retransmits using a Go back N ARQ error control?
a. 1 b. 4 c. 8 d. 12.
A transmitter has already transmitted 12 frames. There was one error in frame number 8 (frames are numbered starting from 0 to 11). How many frames the transmitted retransmits using a the selective repeat ARQ error control?
a. 1 b. 4 c. 8 d. 12.
The TCP segment includes:
a. Source and destination port numbers b. Checksum field c. Header. d. data e. all of the above.
TCP segment header includes
a. 32-bit sequence number field and the 32-bit acknowledgment number field b. 16-bit receive window
c. 4-bit header length field
d. options field e. flag field f. all of the above.
CS509 MCQ - Chapter four check here.
The Network Layer provides:
a. Host-to-host communication b. Process-to-process communication c. Both a and b d. None of the above.
The Network Layer can be decomposed into two interacting parts:
a. Data plane
b. Control plane
c. Both a and b d. None of the above.
............... is per-router functions that determine how a datagram (a network layer packet) arriving on one of a router’s input links is forwarded to one of that router’s output links
a. Data plane b. Forwarding c. Both a and b d. None of the above.
.............. is the function performed when a packet arrives at a router’s input link, the router must move the packet to the appropriate output link.
a. Routing. b. Forwarding c. Both a and b d. None of the above.
............... is the network-wide logic that controls how a datagram is routed among routers along an end-to-end path from source host to destination host using routing protocols, such as OSPF and BGP
a. Control plane b. Routing c. Both a and b d. None of the above.
........................ is one function implemented in the data plane.
a. Routing. b. Forwarding c. Both a and b d. None of the above.
.............. is the function in which the network layer must determine the route or path taken by packets as they flow from a sender to a receiver.
a. Routing. b. Forwarding
c. Both a and b
d. None of the above.
The algorithms that calculate paths taken by the packet are referred to as ...........
a. Routing algorithms. b. Forwarding algorithms c. Both a and b d. None of the above.
................ is implemented in the control plane of the network layer.
. a. Routing. b. Forwarding c. Both a and b d. None of the above.
Routing is often implemented in ..................
a. Software b. Hardware c. Both a and b d. None of the above.
Forwarding is often implemented in ..................
a. Software b. Hardware c. Both a and b d. None of the above.
.............................. is responsible for creating the forwarding table
a. Control plane b. Data plane c. Both a and b d. None of the above.
Traditionally, .............................. determines the contents of the routers’ forwarding tables, in the control plane.
a. Routing algorithms. b. Forwarding algorithms c. SDN (software-defined networking). d. None of the above.
....................... approach is a physically separate (from the routers), remote controller computes and distributes the forwarding tables to be used by each and every router.
a. SDN b. Traditional c. Both a and b d. None of the above.
In ....................... approach, the routing algorithms determines the contents of the routers’ forwarding tables.
a. SDN b. Traditional c. Both a and b d. None of the above.
The data plane components are the same in both the traditional and SDN approaches.
a. True b. False.
.............................. defines the characteristics of end-to-end delivery of packets between sending and receiving hosts.
a. Network service model b. Access service model c. Both a and b d. None of the above.
........................... is a network service that guarantees that a packet sent by a source host will eventually arrive at the destination host.
a. Guaranteed delivery
b. Guaranteed delivery with bounded delay c. In-order packet delivery d. Guaranteed minimal bandwidth.
........................... is a network service that not only guarantees delivery of the packet, but delivery within a specified host-to-host delay bound.
a. Guaranteed delivery b. Guaranteed delivery with bounded delay c. In-order packet delivery
d. Guaranteed minimal bandwidth.
........................... is a network service that guarantees that packets arrive at the destination in the order that they were sent..
a. Guaranteed delivery b. Guaranteed delivery with bounded delay c. In-order packet delivery
d. Guaranteed minimal bandwidth.
........................... is a network service that emulates the behavior of a transmission link of a specified bit rate (for example, 1 Mbps) between sending and receiving hosts.
a. Guaranteed delivery
b. Guaranteed delivery with bounded delay c. In-order packet delivery d. Guaranteed minimal bandwidth.
........................... is a network service that could encrypt all datagrams at the source and decrypt them at the destination to provide confidentiality to all transport-layer segments.
a. Guaranteed delivery b. Guaranteed delivery with bounded delay c. In-order packet delivery d. Security.
The Internet’s network layer provides a single service, known as..............................
a. best-effort service. b. DSL service
c. Both a and b
d. None of the above.
24) The functions that are performed by the input link of the router includes:
a. physical layer functions
b. link-layer functions
c. lookup function d. all of the above.
............................. connects the router’s input ports to its output ports.
a. Switching fabric b. Input link c. Output link d. Routing processor.
............................. stores packets received from the switching fabric and transmits these packets on the outgoing link by performing the necessary link-layer and physical-layer functions.
a. Switching fabric b. Input link c. Output link d. Routing processor.
............................. performs control-plane functions.
a. Switching fabric b. Input link c. Output link d. Routing processor.
In traditional routers, ................ executes the routing protocols, maintains routing tables and attached link state information, and computes the forwarding table for the router.
a. Switching fabric b. Input link c. Output link d. Routing processor.
In SDN routers, ........................... is responsible for communicating with the remote controller in order to (among other activities) receive forwarding table entries computed by the remote controller and install these entries in the router’s input ports
a. Switching fabric b. Input link c. Output link d. Routing processor.
Using the following forwarding table, determine the link interface for the packet containing the following address, 11001000 00010111 00010110 10100001 a. 0 b. 1 c. 2 d. 3.
Using the following forwarding table, determine the link interface for the packet containing the following address, 11001000 00010111 00011000 10101010 a. 0 b. 1 c. 2 d. 3.
In the switching via ............... , An input port with an arriving packet first signaled the routing processor via an interrupt.
a. Memory b. Bus
c. Crossbar
d. None of the above.
In the switching via ............... , the lookup function is performed by routing processing.
a. Memory b. Bus c. Crossbar d. None of the above.
In the switching via ............... , an input port transfers a packet directly to the output port over a shared bus, without intervention by the routing processor..
a. Memory
b. Bus c. Crossbar
d. None of the above.
In the switching via Memory , the lookup function is performed by ....................
a. Switching fabric b. Input link c. Output link d. Routing processor.
In the switching via ............... , the lookup function is performed by input link.
a. Memory b. Bus c. Crossbar d. None of the above.
In the switching via bus , the lookup function is performed by ....................
a. Switching fabric
b. Input link c. Output link d. Routing processor.
........................ scheduling discipline selects packets for link transmission in the same order in which they arrived at the output link queue
a. FIFO b. Priority Queuing c. Round Robin and d. None the above.
.......................... packets arriving at the output link are classified into priority classes upon arrival at the queue
a. FIFO b. Priority Queuing c. Round Robin and Weighted Fair Queuing (WFQ) d. None the above.
........................... in which if the output link is processing a lowest priority packet and a highest priority one arrives, then the processing of the lowest priority stopped to process the highest priority packet first.
a. FIFO b. Preemptive priority queuing c. None-Preemptive priority queuing d. Round Robin and Weighted Fair Queuing (WFQ).
In the .................discipline, the transmission of a packet is not interrupted once it has begun.
a. FIFO b. Preemptive priority queuing c. None-Preemptive priority queuing d. Round Robin and Weighted Fair Queuing (WFQ).
............................. will serve classes in a circular manner— first serving class 1, then serving class 2, then serving class 3, and then
a. FIFO b. Preemptive priority queuing c. None-Preemptive priority queuing d. Round Robin and Weighted Fair Queuing (WFQ).
The 223.1.2.0/28 subnet thus consists of the two host interfaces (223.1.2.1 and 223.1.2.2) and one router interface (223.1.2.6). The maximum number of hosts within this subnet = ................ hosts.
a. 15 b. 14 c. 16 d. 12.
CS509 Questions Bank Sample #1 check here.
Each application uses the transport layer services must have a unique ISP number
a.True b.False.
The coaxial cable, twisted pair and optical fiber belong to the unguided media a.True b.False.
The bandwidth-sensitive applications can make use of as much, or as little, throughput as happens to be available. a.True b.False.
HTTP server is stateless. a.True b.False.
In persistent HTTP, at most one object sent over a TCP connection and then the connection is closed, so downloading multiple objects require multiple connections a.True b.False.
End-point authentication is the best defense mechanism against DoS attacks. a.True b.False.
The seawater could be considered as unguided transmission medium. a.True b.False.
Multimedia applications can tolerate some amount of data loss. a.True b.False.
The IP datagram is created by appending an IP header to an application packet
a.True b.False.
Average throughput is the rate at which bits transferred between sender and receiver at any instant of time. a.True b.False.
In P2P architecture, there is no always-on server in data center. a.True b.False.
Transmission control protocol (TCP) guarantees message delivery and prevents duplication a.True b.False.
The processing delay is the waiting time of a packet to be transmitted over the output link of a router in its path across the network. a.True b.False.
Worm is self-replicating malware requires some form of user interaction to infect the user’s device. a.True b.False.
Self-scalability is an important property of P2P network application architecture. a.True b.False.
In HTTP, post method uploads inputs in the URL field of the message request line. a.True b.False.
Both TCP and UDP provide minimum delay, throughput and security guarantees. a.True b.False.
Network layer of TCP/IP protocol stack is found in every host and router. a.True b.False.
The ………… guarantees delivery and prevents duplication. a. UDP b. TCP c. POP.
The …………. means the host that generates data to be transmitted. a. source b. transmitter c. (a) or (b).
.......... layer provides messages routing between hosts attached to different networks. a. Physical b. Application c. Internet.
The telephone network switching technology is ……………-switching. a. packet b. circuit c. (a) or (b).
.......... is a malware can record keystrokes, visited web sites, social security numbers, or passwords and upload that info to collection site. a. Virus b. Worm c. Spyware.
Every host on the network needs to have a unique ………. address. a. IP b. ISP c. SAP.
In ……… transmission, two host can exchange data simultaneously. a. simplex b. half-duplex c. full-duplex.
………. control is a mechanism assures that a sending entity does not overwhelm a receiving entity with huge data. a. Error b. Congestion c. Flow.
………. is a better-known P2P application. a. Telnet b. DNS c. Bit-Torrent.
The socket number of HTTP process on TCP is ……….. a. 80 b. 25 c. 21.
The application layer protocol of ………. is intentionally not available in the public domain because it is not specified in RFCs. a. skype b. email c. web.
The ……… delay is the time taken by a bit to travel across a link between two nodes.
a. processing b. transmission c. propagation.
Cryptography is best defense against ………. attack.
a. denial of service b. packet sniffing c. IP spoofing.
CS509 Questions Bank Sample #2 check here.
Network layer protocols is implemented in every host and router. a.True b.False.
IP address is conventionally expressed in hexadecimal notation. a.True b.False.
IPv4 uses four bytes to specify host address while IPv6 uses six bytes. a.True b.False.
IPv6 increases the number of assigned bits to host address without any other advantage over IPv4. a.True b.False.
ICMP messages are carried in IP datagrams as TCP & UDP segments. a.True b.False.
DNS and SNMP use TCP as underlying transport protocol. a.True b.False.
The IP datagram is created by appending an IP header to an application packet. a.True b.False.
Transmission control protocol guarantees message delivery and prevents duplication. a.True b.False.
Both TCP and UDP provide minimum delay, throughput and security guarantees a.True b.False.
DHCP allows a host to dynamically obtain an IP address from a network server when this host joins this network. a.True b.False.
.......... layer provides messages routing between hosts attached to different networks. a. Application b. Transport c. Network.
IPv6 uses ……… bits for specifying host address. a. 32 b. 48 c. 128.
Inside router, switching via ……… forwards multiple packets in parallel. a. memory b. bus c. crossbar.
The application layer protocol of ………. is intentionally not available in the public domain because it is not specified in RFCs. a. skype b. email c. web.
UDP checksum treats segment contents as sequence of ………-byte integers. a. 2 b. 3 c. 4.
Hosts and mail servers communicate over UDP using port ……… a. 25 b. 53 c. 80.
DHCP server returns to host ……… main pieces of information. a. two b. three c. four.
Final June 2022(CS509) check here.
Routing algorithm determines local forwarding at a router a.True b.False.
Network layer protocols is implemented in every host and router. a.True b.False.
Cookies maintain the state between mail agent and mail server. a.True b.False.
In router, the switching via bus causes two bus crossings per datagram. a.True b.False.
The IMAP is used only to pull emails from mail servers. a.True b.False.
In persistent HTTP, at most, one object is sent over a TCP connection and then the connection is closed, so downloading multiple objects require multiple connections. a.True b.False.
IPv4 allows datagram fragmentation and variable length of datagram header. a.True b.False.
In tunneling, IPv6 datagram is carried as payload in IPv4 datagram among IPv4 routers. a.True b.False.
Chrome, Skype and WhatsApp are examples of application layer protocols. a.True b.False.
In P2P architecture, there is no always-on server in data center. a.True b.False.
User datagram protocol guarantees message delivery and prevents errors. a.True b.False.
Link frame is created by appending the link layer header to transport segment. a.True b.False.
Switching datagrams from input port(s) to output port(s) inside router is performed in decentralized form without interruptions of router processor. a.True b.False.
IPv4 uses four bytes to specify host address while IPv6 uses six bytes. a.True b.False.
TCP provides minimum delay, throughput and security guarantees. a.True b.False.
Twisted pair, coaxial cable and optical fiber belong to guided transmission media. a.True b.False.
Multimedia applications can tolerate some amount of data loss. a.True b.False.
Each process uses transport layer services must have a unique port number. a.True b.False.
Self-scalability is an important property of P2P network application architecture.. a.True b.False.
DNS iterative query puts heavy load at the upper levels of DNS servers hierarchy. a.True b.False.
___ are remote controllers computes, which install forwarding tables in routers. (A) RDN (B) CDN (C) FDN (D) SDN.
TCP applies ___ approach to control congestion and reduce segments loss (A) MIAD (B) AIMD (C) MDAI (D) ADMI.
Human communication needs ___-way handshake procedure to establish a connection. (A) five (B) four (C) three (D) two.
TCP segment retransmission is triggered by the occurrence of at least one of ___ actions.
(A) five (B) four (C) three (D) two.
The number of DHCP messages is ___
(A) five (B) four (C) three (D) two.
A protocol must define ___ aspects for communication.
(A) five (B) four (C) three (D) two.
ICANN allocates IP addresses, through ___ regional registries who may then reallocate to local registries.
(A) five (B) four (C) three (D) two.
28. Types of DNS resource record are ___.
(A) five (B) four (C) three (D) two.
29. Computers communication model involves ___ key elements.
(A) five (B) four (C) three (D) two.
UDP checksum treats segment contents as sequence of ___-byte integers.
(A) 5 (B) 4 (C) 3 (D) 2.
Bit-Torrent divides distributed file into ___ chunks.
(A) 256Kb (B) 256KB (C)256Mb (D) 256MB.
The application layer protocol of ___ is intentionally not available in the public domain because it is not specified in RFCs.
(A) Skype (B) Web (C) Email (D) P2P.
___ uses UDP as its underlying transport protocol.
(A) HTTP 1.0 (B) HTTP 1.1 (C) HTTP 2.0 (D) HTTP 3.0.
___ is a wireless medium used for transmission in short distances with limited rates.
(A) Satellite (B) Microwave (C) Bluetooth (D) Radio.
___ scheduling policy of queued datagrams in output port buffer inside router guarantees minimum bandwidth per traffic-class.
(A) FCFS (B) RR (C) WFQ (D) Priority.
___ is a malware can record keystrokes, visited web sites, social security numbers, or passwords and upload that info to collection site.
(A) Spyware (B) Virus (C) Worm (D) Trojan.
___control is a mechanism assures that a sending entity does not overwhelm a receiving entity with huge data.
(A) Error (B) Congestion (C) flow (D) Alarm.
38. ___ DNS servers are responsible for popular domains such as com, org, net, and all country level domains, e.g.: uk, fr, ca, jp.
(A) Root (B) TLD (C) Authoritative (D) Local.
Presenting an address to ___ memory in router retrieves the stored address with longest prefix matching in one clock cycle, regardless of forward table size.
(A) TCAM (B) SCAM (C) DCAM (D) RCAM.
___ delay of a packet is the time elapsed to push out the full packet onto a link.
(A) Queuing (B) Switching (C) Transmission (D) Processing.
Final January 2023 check here.
TCP provides minimum delay, throughput and security guarantees. True False.
IPv4 uses four bytes to specify host address while IPv6 uses six bytes. True False.
Link frame is created by appending the link layer header to transport segment. True False.
Seawater itself is unguided transmission medium. True False.
IP address is conventionally expressed in hexadecimal notation. True False.
User datagram protocol guarantees message delivery and prevents errors. True False.
Twisted pair, coaxial cable and optical fiber belong to guided transmission media. True False.
Self-scalability is an important property of P2P network application architecture. True False.
The forward table of router is stored in the memory of its input port. True False.
Each process uses transport layer services must have a unique port number. True False.
Multimedia applications can tolerate some amount of data loss. True False.
DNS iterative query puts heavy load at the upper levels of DNS servers hierarchy. True False.
Cookies maintain the state between mail agent and mail server. True False.
In NAT, just one IP address needed from provider ISP for all host in local network. True False.
Routing algorithm determines local forwarding at a router. True False.
Human communications needs 2-way handshake procedure to setup a connection. True False.
In tunneling, IPv6 datagram is carried as payload in IPv4 datagram among IPv4 routers. True False.
HTTP protocol is implemented in host and router. True False.
End-point authentication is the best defense mechanism against DoS attacks. True False.
In CIDR, x means the number of bits in subnet portion of address format: a.b.c.d/x. True False.
Connectionless service must first setup connection between two involved hosts. True False.
The IMAP is used only to pull emails from mail servers. True False.
The Discover and Offer broadcast messages of DHCP are mandatory. True False.
In P2P, any host can be client and server at the same time. True False.
HTTP protocol is stateless. True False.
Chrome, Skype and WhatsApp are examples of application layer protocols. True False.
IPv4 allows datagram fragmentation and variable length of datagram header. True False.
Transport segment is created by appending a transport header to an application packet. True False.
In persistent HTTP, at most, one object is sent over a TCP connection and then the connection is closed, so downloading multiple objects require multiple connections True False.
Switching datagrams from input port(s) to output port(s) inside router is performed in decentralized form without interruptions of router processor. True False.
Presenting an address to ___ memory in router retrieves the stored address with longest prefix matching in one clock cycle, regardless of forward table size.
(A) TCAM (B) SCAM (C) DCAM (D) RCAM.
___control is a mechanism assures that a sending entity does not overwhelm a receiving entity with huge data.
(A) Flow (B) Exception (C) Error (D) Congestion.
33. ___ delay of a packet is the time elapsed to push out that full packet onto a link.
(A) Processing (B) Switching (C) Queuing (D) Transmission.
In router, the switching via memory causes ___ bus crossings per datagram.
(A) two (B) three (C) four (D) five.
___ is a malware can record keystrokes, visited web sites, social security numbers, or passwords and upload that info to collection site.
(A) Virus (B) Trojan (C) Worm (D) Spyware.
___ DNS servers are responsible for popular domains such as com, org, net, and all country level domains, e.g.: uk, fr, ca, jp.
(A) Root (B) Authoritative (C) TLD (D) Local.
Bit-Torrent divides distributed file into ___ chunks.
(A) 256MB (B) 256Mb (C) 256KB (D) 256Kb.
___ is a wireless medium used for transmission in short distances with limited rates.
(A) Microwave (B) Satellite (C) Radio (D) Bluetooth.
The standard Open System Interconnection model consists of ___ layers.
(A) seven (B) six (C) five (D) four.
___ uses UDP as its underlying transport protocol.
(A) HTTP 1.0 (B) HTTP 2.0 (C) HTTP 3.0 (D) HTTP 4.0.
The application layer protocol of ___ is intentionally not available in the public domain because it is not specified in RFCs.
(A) Web (B) Email (C) P2P (D) Skype.
UDP checksum treats segment contents as sequence of ___-byte integers.
(A) 2 (B) 4 (C) 6 (D) 16.
___ are remote controllers computes, which install forwarding tables in routers.
(A) FDN (B) SDN (C) RDN (D) CDN.
ICANN allocates IP addresses, through ___ regional registries who may then reallocate to local registries.
(A) two (B) three (C) four (D) five.
TCP applies ___ approach to control congestion and reduce segments loss.
(A) MDAI (B) ADMI (C) AIMD (D) MIAD.
DNS resource record have ___ types.
(A) five (B) three (C) four (D) two.
In HTTP, the ___ method sends user inputs in the URL field of the message request line.
(A) POST (B) HEAD (C) GET (D) PUT.
Computers communication model involves ___ key elements.
(A) two (B) three (C) four (D) five.
Hosts and DNS servers communicate over UDP using port ___.
(A) 53 (B) 80 (C) 20 (D) 25.
Protocol must define ___ aspects for communication.
(A) five (B) four (C) three (D) two.
___ is the incentive mechanism for file distribution in Bit-Torrent.
(A) Step-By-Step (B) Tit-For-Tat (C) One-After-One (D) Back-To-Back.
The occurrence of at least one of ___ actions triggers TCP segment retransmission.
(D) five (C) four (B) three (A) two .
To reduce processing time at each hop, IPv6 removed ___ field that was in IPv4 header.
(A) hop limit (B) checksum (C) version (D) flow label.
The number of all DHCP messages is ___.
(A) five (B) four (C) three (D) two.
In communication model, the ___ means the host that generates data to be transmitted.
(A) source (B) destination (C) transmitter (D) receiver.
___ services are provided by DNS server to hosts.
(A) Two (B) Three (C) Four (D) Five.
___-scheduling policy of queued datagrams in output port buffer inside router guarantees minimum bandwidth per traffic-class.
(A) FCFS (B) WFQ (C) Priority (D) RR.
___ main pieces of information are returned by DHCP server to host.
(A) Five (B) Four (C) Three (D) Two.
To transmit at the wider frequency band, ___ allocates periodic time slot(s) for a call.
(A) FDM (B) SDM (C) TDM (D) WDM.
To schedule frames and mitigate HOL blocking, ___ divides objects to be sent into frames.
(A) HTTP 3.0 (B) HTTP 2.0 (C) HTTP 1.1 (D) HTTP 1.0.
IPv6 uses ___ bits for specifying host address.
(A) 32 (B) 48 (C) 64 (D) 128.
Police radios transmission is a ___ type of communication.
(A) simplex (B) duplex (C) half-duplex (D) full-duplex.
___ layer is directly responsible for transporting TCP segment between two connected hosts from source to destination.
(A) Transport (B) Network (C) Link (D) Physical.
HTTP 1.1 provides ___ method types in the request line of its request message.
(A) two (B) three (C) four (D) five.
Cryptography is the best defense against ___ attack.
(A) IP spoofing (B) denial of service (C) DNS tunneling (D) packet sniffing.
professors before dr ahmed questions check here.
1. A _______ link has a dedicated communication medium. a) point-to-point b) multipoint c) ring d) bus.
3. TV broadcast is an example of _______ communication. a) simplex b) half-duplex c) full-duplex d) semi-duplex.
2. A handheld transceiver (also known as walkie-talkie) is an example of _______. a) simplex b) half-duplex c) full-duplex d) semi-duplex.
4. A _______ is a communication network within a building or between nearby buildings. a) MAN b) LAN c) WAN d) BAN.
5. A star network topology with 5 computers has _______ full duplex links. a) 1 b) 5 c) 10 d) 20.
6. The number of network interfaces in a bus topology network with 5 computers is _______ for each computer. a) 1 b) 5 c) 10 d) 20.
7. A fully connected mesh network topology with 5 computers has _______ full-duplex links. a) 4 b) 5 c) 10 d) 20.
8. A ring network topology with 5 computers has _______ full-duplex links. a) 4 b) 5 c) 10 d) 20.
9. _______ is the network topology that is affected the least in case of a link failure. a) Star b) Bus c) Mesh d) Ring.
10. _______ is the network topology that has the highest cost.
a) Star b) Bus c) Mesh d) Ring.
11. The number of network interfaces in each device in a mesh network with 5 devices ______. a) 4 b) 5 c) 10 d) 20.
12. In the OSI model, the _______ layer is responsible for moving frames from one hop (node) to the next. a) physical b) data-link c) transport d) network.
13. _______ is responsible for delivery of messages from one process to another in the OSI model. a) The physical layer b) The transport layer c) The network layer d) The application layer.
14. In the TCP/IP protocol suite, a port number is the address used at the_______.
a) application layer
b) transport layer
c) network layer
d) physical layer
.
15. The application layer in the TCP/IP protocol suite is usually considered to be the combination of _______ layers in the OSI model. a) application, presentation, and session
b) application, transport, and network
c) application, data-link, and physical d) network, data-link, and physical.
16. A _______ is a set of rules that governs data communication. a) forum
b) protocol
c) standard
d) Request For Comment (RFC).
17. As the data packet moves from the upper to the lower layers, headers are _______. a) Added b) Removed c) Rearranged d) Modified.
18. Which of the following applications is the most sensitive to jitter? a) Sending an e-mail b) Having real time speech conversation with a friend c) Downloading a file d) Surfing the Internet.
19. The _______ layer changes bits into electromagnetic signals. a) physical b) data link
c) transport
d) session
.
20. When data are transmitted from device A to device B, the header from A's layer 4 is read by B's _______ layer. a) physical b) transport c) application d) application.
1. Suppose that an application-layer protocol is written such that it uses the services of TCP. However, for some reasons it is decided to use the services of UDP to support your protocol (instead of TCP). Answer the following two questions.
(1 point) What might be the reasons that require the change from TCP to UDP?
Answer:
The application may be delay sensitive such as audio calls.
.
b) (1 points) Do you need to do any changes for the application layer protocol to facilitate the transition from TCP to UDP? If no, explain your answer. If yes, propose what services must be added to the application layer protocol.
Answer:
Depending on the application requirements an error control and flow control modules may be needed.
2. (1 point) Explain briefly the reason why there are two layers of addressing: one at the physical layer (such as the MAC address) and one at the network layer (such as the IP address).
Answer:
For flexibility: The physical address can be changed without affecting the logical address, and vice versa, the logical address can be changed without affecting the physical address.
.
1 point) Suppose we want to connect two isolated hosts together to let each host communicate with the other. Do we need a network-layer router between the two? Explain.
Answer:
No, we do not network layer router in this case as traffics from one host destined the other do not need routing. .
4. (1 point) Assume that a private internet requires that the messages received from the application layer be encrypted and decrypted for security purposes. If you need to add some information about the encryption/decryption process (such as the algorithms used in the process and the encryption key lengths), what layer should be added to the TCP/IP protocol suite? Redraw the TCP/IP layers placing the new layer in its appropriate place within the protocol stack.
Answer:
Presentation layer.
- Application layer -
---------------------------
- Presentation layer -
---------------------------
- Transport layer -
---------------------------
- Network layer -
---------------------------
- Physical layer -
---------------------------
.
9. (2 points) What is the total delay (latency) for a frame of size 5 million bits that is being sent on a link with 10 routers each having a queuing time of 2 μs and a processing time of 1 μs. Assume that the overall length of the link is 2000 Km, speed of light inside the link is 2 × 108 m/s, and the link has bandwidth of 5 Mbps. Which component of the total delay is dominant?
Delay = Transmission delay + Propagation delay + Processing and queuing delay
Transmission delay = Message size / Bandwidth
Propagation delay = length of link / propagation speed
Answer:
Delay = Transmission delay + Propagation delay + Processing and queuing delay
Transmission delay = Message size / Bandwidth
Transmission delay = 5 * 10^6 / (5 * 10^6) = 1 second
Propagation delay = length of link / propagation speed
Propagation delay = 2000 (103) / (2 * 108) = 0.01 second
Processing and queuing delay = 10 * 3 * 10-6 = 20 micro second
Delay = 1 + 0.01 + 0.00002 = 1.01003 second.
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