CPSC FAHY 353 Midterm

What are the required responsibilities of the transport layer

1) Process to Process communication

What are the optional features of the transport layer

1) Segmentation and Reassembly 2) Reliability 3) Connection Control 3a) flow control (client-server) 3b) congestion control (network links)

How many bits in a port number

16

1ST Layer of the OSI Model

Application

ARQ stands for ___________.

Automatic Repeat Request

6th Layer of the OSI Model

Data Link

A server can use cookies to determine a user's postal address without the user's consent. True False

False

Consider an HTTP Web server using persistent connections. Suppose the server spawns a separate process for each client that connects to the server. Then each of these spawned processes will have different server port numbers. True False

False

DSL bandwidth is shared. True False

False

In BitTorrent, a peer's instantaneous download rate can never exceed its instantaneous upload rate: True False

False

In the connection flooding attack, the attacker sends a deluge of packets to the targeted host, clogging the target's access link with packets. True False

False

Suppose host A sends host B one segment with sequence number 38 and 4 bytes of data. Then in this same segment the acknowledgement number is necessarily 42. True False

False

The Date: header in the HTTP response message indicates when the object in the response was last modified. True False

False

The Web typically sends multiple objects in a Web page within a multipart MIME message. True False

False

The acronym API in this textbook stands for "Advanced Performance Internet". True False

False

The job of delivering the data in a transport-layer segment to the correct socket is called multiplexing True False

False

The size of the TCP RcvWindow never changes throughout the duration of the connection. True False

False

Transmission Delay is the amount of time a packet traveling on the wire between the source and destination. True False

False

Twisted-pair copper wire is no longer present in computer networks. True False

False

With non-persistent connections between browser and origin server, it is possible for a single TCP segment to carry two distinct HTTP request messages. True False

False

5th Layer of the OSI Model

Network

7th Layer of the OSI Model

Physical

2nd Layer of the OSI Model

Presentation

3rd Layer of the OSI Model

Session

4th Layer of the OSI Model

Transport

An HTTP server maintains no information about its clients True False

True

DNS lookups often involve a combination of recursive and iterative queries. True False

True

If a POP3 client does not send the dele command, copies of the messages that the client has retrieved remain in the mail server. True False

True

It is possible for a mail client to send e-mail messages over HTTP rather than SMTP. True False

True

Skype relay nodes are typically peers under the control of Skype users. True False

True

Slow start threshold (SSthresh) only changes during loss event. True or False?

True

Smoothed round trip time (RTTs) is only recalculated when get ACK from non-duplicated/non-resent packet/segment. True or False?

True

With a residential DSL service, each subscriber gets more downstream bandwidth than upstream bandwidth. True False

True

A message access protocol is a ________ protocol. pull push push and pull None of the choices are correct

a

An HTTP response message does NOT include: A response line A status line 6 header lines the entity body

a

In 1983, TCP/IP replaced ________ as the new standard host protocol for ARPANET. NCP IPC ALOHA SNA

a

In TCP, an ACK segment, if carrying no data, consumes ______ sequence number(s). no one two None of the choices are correct

a

In TCP/IP, a logical connection between an entity at the network layer can be made with another entity at the ________ layer. network transport data link physical

a

In TCP/IP, a message at the transport layer is encapsulated in a packet at the ________ layer. network transport link physical

a

In TCP/IP, a transport layer segment is encapsulated in a packet at the ________ layer. network transport data link physical

a

In __________ resolution, the server returns the IP address of the server that it thinks can resolve the query. iterative recursive straight None of the choices are correct

a

In a ___________ connection, the server leaves the connection open for more requests after sending a response. persistent nonpersistent persistent or nonpersistent None of the choices are correct

a

In the TCP/IP protocol suite, a logical address is the identifier at the _______________. network layer transport layer data-link layer application layer

a

Suppose a DNS resource record has Type=MX. Then: a) Value is the hostname of the mail server that has the alias hostname Name. b) Value is the hostname of the DNS server that is authoritative for name. c) Value is the IP address of the mail server that has the alias hostname Name. d) none of the above

a

Suppose a client sends an HTTP request message with the If-modified-since: header. Suppose the object in a server has not changed since the last time a client retrieved the object. Then the server will send a response message with the status code: 304 Not Modified 404 Not Found 200 OK none of the above

a

The application layer in the TCP/IP protocol suite is usually considered to be the combination of ________ layers in the OSI model application, presentation, and session application, transport, and network application, data-link, and physical network, data-link, and physical

a

The first section of a URL identifier is the __________. protocol path host port

a

The formal protocol used to transfer messages from senders' mail servers to recipients' mail servers in the Internet is ___________. SMTP SNMP TELNET SSH

a

Traditional Telephone Networks use circuit switching packet switching

a

Which of the following functions are performed by UDP? process-to-process communication host-to-host communication node-to-node communication None of the choices are correct

a

Which of the following is present in both an HTTP request line and a status line? version number URL status code method

a

Choose the protocols that use the client-server paradigm (give two answers by reponding twice) ***HyperText Transfer Protocol ***file transfer protocol BitTorrent Skype

a b

A _______ server is a computer that, when it receives a DNS reply, temporarily stores the mapping in its local memory. Domain caching root primary

b

A registrar, a commercial entity accredited by ________, verifies the uniqueness of a domain name request and enters the domain into the DNS database. NIC ICANN ISOC IEFE

b

An e-mail message contains a ________ and a __________. header; envelope header; body envelope; body None of the choices are correct

b

In HTTP, _______ server is a network entity that satisfies HTTP requests on the behalf of an origin Web server. A regular A proxy An auxiliary A remote

b

In TCP, there can be ______ RTT measurement(s) in progress at any time. two only one several None of the choices are correct

b

In __________ resolution, the resolver expects the server to supply the final answer. iterative recursive straight None of the choices are correct

b

In a ___________ connection, one TCP connection is made for each request/response. persistent nonpersistent persistent or a nonpersistent None of the choices are correct

b

In the TCP/IP protocol suite, a port number is the identifier at the ____________. application layer transport layer network layer physical layer

b

In the TCP/IP protocol suite, the ______ layer is responsible for moving frames from one hop (node) to the next. physical data link transport network

b

Malware that can enter a device without any explicit user interaction are called: Viruses Worms Bots Facebook

b

Packet Switching was developed between 1955 and 1961 1961 and 1972 1972 and 1980 1980 and 1990

b

SMTP is primarily a __________ protocol. pull push push and pull None of the choices are correct

b

The Internet uses circuit switching packet switching

b

The first line of an HTTP request message is called the _________ line; the subsequent lines are called the _______lines. header; request request; header request; body header; body

b

The stop-and-wait protocol is highly inefficient when: a) when there is a short distance between source and destination and the transmission rate is large b) when there is a large distance between source and destination and the transmission rate is high c) when there is a large distance between source and destination and the transmission rate is low d) when there is a short distance between source and destination and the transmission rate is low

b

The transfer of an html file from one host to another is: loss-tolerant and time sensitive loss-intolerant and time insensitive loss-intolerant and time sensitive none of the above

b

To use the services of UDP, we need ________ socket addresses. four two three None of the choices are correct

b

UDP packets have a fixed-size header of _______ bytes. 16 8 40 32

b

We need to multiply the header length field by _______ to find the total number of bytes in the TCP header. 2 4 6 None of the choices are correct

b

_______ was formed to connect universities with no access to ARPAnet. a) BITNET b) CSNET c) NSFNET d) ANSNET

b

______________ means accepting items from more than one source. ______________ means examining data that could be intended for different destinatons and delivering the data to the correct destination. Demultiplexing; Multiplexing Multiplexing; Demultiplexing Encapsulation; Decapsulation Pulling; Pushing

b

A _______ server is a computer that provides the IP address of the TLD servers. Domain zone root primary

c

Consider the minimum time for P2P file distribution, as discussed in Section 2.6. Suppose the upload rate of the server is10 Mbps, the upload rates of all peers is 1 Mbps, and the download rates of all peers is 10 Mbps. Further suppose that there are 100 peers and the file is 100 million bits. The minimum distribution time is: approximately 10 seconds approximately 1000 seconds approximately 100 seconds approximately 1 second

c

Geostationary satellites have a propagation delay of __________ milliseconds 2 28 280 2800

c

HTTP uses the services of _________. Group of answer choices UDP IP TCP DNS

c

In TCP, a FIN + ACK segment consumes _____ sequence number(s) if it does not carry data. two three one no

c

In TCP, the _______ timer prevents a long idle connection between two TCPs. retransmission persistence keepalive None of the choices are correct

c

In TCP/IP, a message belonging to the network layer is decapsulated from a packet at the ________ layer. network transport link physical

c

In TCP/IP, a packet at the third layer carries data belonging to the ________ layer and the header belonging to the _________ layer. third; third third; fourth fourth; third fourth; fourth

c

In a client-server paradigm: A) Both the server and the client must be running all the time. B) Both the server and the client need to be running only when they are needed. C) the server must be running all the time but the client needs to be running only when it is needed. D) the client must be running all the time but the server needs to be running only when it is needed

c

In the TCP/IP protocol suite, which of the following is a network layer protocol? The Stream Control Transmission Protocol (SCTP) The Secure Shell (SSH) The Internet Protocol (IP) User Datagram Protocol (UDP)

c

In the TCP/IP protocol suite, which of the following is an application layer protocol? The User Datagram Protocol (UDP) The Internet Protocol (IP) The Hypertext Transfer Protocol (HTTP) the Transmission Control Protocol (TCP)

c

In the domain name space, a full domain name is a sequence of labels separated by ________. Colons semicolons Dots Commas

c

Local DNS name servers: a) never cache resource records b) cache resource records and never discard them c) cache resource records, but discard them after a period of time that is on the order of a few days d) obtain resource records from Web caches

c

The acronym DSL stands for: Data Service Location Digital Service Line Digital Subscriber Line Data Subscriber Line

c

UDP is an acronym for _______. User Delivery Protocol User Datagram Procedure User Datagram Protocol None of the choices are correct

c

________ provides service to allow users to read, reply to, forward, save, and compose messages. A mail transfer agent A mail server A user agent None of the choices are correct

c

Choose the protocols that use the peer-to-peer paradigm: secure shell email ***BitTorrent ***Skype

c d

A browser will generate header lines as a function of browser type and version user configuration of browser whether the browser has a cached version of the requested object all of the above

d

For BitTorrent, which of the following is true: a) At a given instant of time, a peer A may upload to a peer B, even if peer B is not sending anything to A. b) Although a peer may have 50 concurrent TCP connections with other peers, at any given instant of time it sends data to less than 10 other peers. c) Among the chunks that a peer does not have, the peer will request chunks that appear to be relatively rare in the torrent. d) All of the above.

d

How many devices are estimated to be connected to the Internet by 2020 10 billion 15 billion 20 billion 25 billion

d

In BitTorrent, each torrent has an infrastructure node called a ____________ swarm torrent chunk tracker

d

In HTTP, the first line in a request message is called a _______ line; the first line in the response message is called the ________ line. request; response status; response status; status None of the choices are correct

d

In the TCP/IP protocol suite, the physical layer is concerned with the movement of _______ over the physical medium. programs dialogs protocols individual bits

d

In the TCP/IP protocol suite, which of the following is a transport layer protocol? The Internet Control Message protocol (ICMP) The Internet Protocol (IP) The Address Resolution Protocol (ARP) The Transmission Control Protocol (TCP)

d

Internet standards are developed by: The National Bureau of Standards The International Standards Organization The American National Standards Institute The Internet Engineering Task Force

d

The Internet Protocol (IP) is ________ protocol. a reliable a connection-oriented a reliable and connection-oriented an unreliable

d

The congestion window size, after it passes the initial slow start state, follows a saw tooth pattern called _________________________________. exponential increase, additive decrease additive increase, exponential decrease multiplicative increase, additive decrease additive increase, multiplicative decrease

d