CPSC 353 - Chapter 2

Choose the protocols that use the peer-to-peer paradigm a. secure shell b. email c. ***BitTorrent d. ***Skype

***BitTorrent ***Skype

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

***HyperText Transfer Protocol ***file transfer protocol

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: a. 304 Not Modified b. 404 Not Found c. 200 OK d. none of the above

304 Not Modified

In the DNS, the names are defined in ___________ structure. a. A linear list b. A distributed database c. A three-dimensional d. None of the choices are correct

A distributed database

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

A proxy

An HTTP response message does NOT include a. A response line b. A status line c. 6 header lines d. the entity body

A response line

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

A user agent

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.

All of the above

A server that holds the publicly accessible DNS records that map the names of an organizations publicly accessible hosts to their IP addresses is called a ___________ server a. Root DNS b. Top-level domain (TLD) c. Authoritative DNS d. Local DNS

Authoritative DNS

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

Dots

A TCP socket address consists of a pair of IP addresses, a local and a remote a. True b. False

False

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

False

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

False

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

False

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

False

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

ICANN

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

None of the choices are correct

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

SMTP

HTTP uses the services of _________. a. UDP b. IP c. TCP d. DNS

TCP

A Web cache, or proxy server, is a network entity that satisfies HTTP requests on behalf of an origin Web server a. True b. False

True

An HTTP server maintains no information about its clients a. True b. False

True

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

True

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

True

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

True

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

Value is the hostname of the mail server that has the alias hostname Name.

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

all of the above

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 a. approximately 10 seconds b. approximately 1000 seconds c. approximately 100 seconds d. approximately 1 second

approximately 100 seconds

There are ___________________ root name servers on the Internet. a. fewer than 100 b. between 100 and 200 c. between 200 and 400 d. more than 400

between 200 and 400

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

cache resource records, but discard them after a period of time that is on the order of a few days

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

caching

DNS can use the services of ________. a. UDP b. TCP c. either UDP or TCP d. None of the choices are correct

either UDP or TCP

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

header; body

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

iterative

The transfer of an html file from one host to another is a. loss-tolerant and time sensitive b. loss-intolerant and time insensitive c. loss-intolerant and time sensitive d. none of the above

loss-intolerant and time insensitive

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

nonpersistent

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

persistent

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

protocol

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

pull

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

push

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

recursive

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

request; header

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

root

In a client-server paradigm, a _______ program provides services to a (another) _______ program. a. Client; client b. Client; server c. server; client d. server; server

server; client

A mail access protocol is used to transfer mail fom a. the sender's user agent to the senders mail server b. the sender's mail server to the recipient's mail server c. the recipient's mail server to the recipient's user agent d. None of the above are correct.

the recipient's mail server to the recipient's user agent

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

the server must be running all the time but the client needs to be running only when it is needed.

SMTP is used to a. to transfer messages from one mail server to another b. to define the format of message headers c. to transfer messages from mail server to a user agent d. all of the above

to transfer messages from one mail server to another

In BitTorrent, each torrent has an infrastructure node called a ____________ a. swarm b. torrent c. chunk d. tracker

tracker

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

version number