Chapter 3 Flashcards
(22 cards)
The application layer is ___________ of the OSI model
A. Layer 1
B. Layer 3
C. Layer 4
D. Layer 7
D. Layer 7 is the application layer and its components: applications, services, and
protocols.
The TCP/IP application layer consists roughly of which three OSI layers?
A. Application, session, transport
B. Application, presentation, session
C. Application, transport, network
D. Application, network, data link
B. The functionality of the TCP/IP application layer protocols fits roughly into the
framework of the top three layers of the OSI model: application, presentation, and
session.
HTTP is used to do which of the following?
A. Resolve Internet names to IP addresses
B. Provide remote access to servers and networking devices
C. Transfer files that make up the web pages of the World Wide Web
D. Transfer the mail messages and attachments
C. Hypertext Transfer Protocol (HTTP) is used to transfer files that make up the web
pages of the World Wide Web. DNS is used to resolve Internet names to IP addresses,
and Telnet is used to provide remote access to servers and networking devices.
Post Office Protocol (POP) uses which port?
A. TCP/UDP port 53
B. TCP port 80
C. TCP port 25
D. UDP port 110
D. Post Office Protocol (POP) uses UDP port 110.
What is GET?
A. A client request for data
B. A protocol that uploads resources or content to the web server
C. A protocol that uploads information to the server in plain text that can be intercepted
and read
D. A response from a server
A. GET is a client request for data
Which is the most popular network service?
A. HTTP
B. FTP
C. Telnet
D. E-mail
D. E-mail, the most popular network service, has revolutionized how people communicate through its simplicity and speed. Choice A. is incorrect, because HTTP is a protocol, not a service.
FTP requires ___________ connection(s) between client and server to successfully transfer files.
A. 1
B. 2
C. 3
D. 4
B. To successfully transfer files, FTP requires two connections between the client and
the server: one for commands and replies and another for the actual file transfer.
DHCP enables clients on a network to do which of the following?
A. Have unlimited telephone conversations
B. Play back video streams
C. Obtain IP addresses
D. Track intermittent denial of service attacks
C. The Dynamic Host Configuration Protocol (DHCP) enables clients on a network to
obtain IP addresses and other information from a DHCP server
The Linux and UNIX operating systems use SAMBA, which is a version of which
protocol?
A. SMB
B. HTTP
C. FTP
D. SMTP
A. The Linux and UNIX operating systems provide a method of sharing resources with
Microsoft networks using a version of SMB called SAMBA.
Which of the following is a connection using Telnet?
A. File Transfer Protocol (FTP) session
B. Trivial File Transfer Protocol (TFTP) session
C. Virtual Terminal (VTY) session
D. Auxiliary (AUX) session
C. A connection using Telnet is called a VTY session, or connection
Is eBay a peer-to-peer or client/server application?
eBay is a client/server application. eBay is implemented as a web server that responds
to web client (browser) requests using HTTP.
In the client/server model, the device requesting the service is referred to as the
___________.
client. Even though a device can serve as a client and a server at times, the device
requesting a service is defined as the client and the device providing the service is
defined as the server.
HTTP is referred to as a request/response protocol. What are three typical message
formats?
GET, PUT, and POST. GET is a request; PUT and POST provide uploading.
DHCP allows the automation of what?
Assignment of IP addresses, subnet masks, and default gateway. The protocol automates the assignment of IP addresses, subnet masks, gateway, and other IP networking
parameters
What does FTP stand for, and what is it used for?
FTP stands for File Transfer Protocol. It is used to move files on the network. FTP was
developed to allow file transfers between a client and a server. An FTP client is an
application that runs on a computer that is used to push and pull files from a server.
List the six-step process for converting human communications to data.
- The user inputs data using a hardware interface.
- The application layer prepares human communication for transmission over the data network.
- Software and hardware convert data to a digital format.
- Application services initiate the data transfer.
- Each layer plays its role, and the OSI layers encapsulate data down the stack. Encapsulated data travels across the media to the destination. OSI layers at the destination decapsulate the data up the stack.
- Data is ready to be processed by the end device.
Describe the two forms of application software and the purpose of each.
- Applications are designed to interact with us. Application is software for the user.
If the device is a computer, the application is typically initiated by the user.
Although there can be many layers of support underneath, application software
provides an interface between humans and the hardware. The application will initiate the data transfer process when the user clicks the Send button or performs a
similar action. - Services are background programs that perform a particular function in the data
network. Services are invoked by a device connecting to the network or by an
application. For example, a network service can provide functions that transmit
data or provide conversion of data in a network. In general, services are not directly
accessible or seen by the end user. They provide the connection between an application and the network.
Elaborate on the meaning of the terms server and client in the context of data networks.
The source end of data communication is referred to as the server, and the receiving
end is called the client. The client and server processes are application layer services
that provide the foundation for data network connectivity.
Compare and contrast client/server with peer-to-peer data transfer over networks.
Client/server data transfer specifically refers to the centralized source end of data communication as the server and the receiving end as the client.
With peer-to-peer data transfer, both client and server services are used within the same
conversation. Either end of the communication can initiate the exchange, and both
devices are considered equal in the communication process. The devices on either end
of the communication are called peers.
In contrast to a client/server model, where a server is typically a centralized repository
and responds to requests from many clients, peer-to-peer networking has distributed
data. Furthermore, after the communication is established, the peers communicated
directly; the data is not processed at the application layer by a third device on the
network.
List five general functions that application layer protocols specify
- The processes that are to occur at either end of the communication
- The types of messages.
- The syntax of the message.
- The meaning of the fields within specific message types.
- The message dialogs.
Give the specific purposes of the DNS, HTTP, SMB, and SMTP/POP application layer protocols.
- Domain Name System (DNS) provides users with an automated service that matches or resolves resource names and e-mail domains with the required numeric device
network addresses. - HTTP was originally developed to publish and retrieve HTML pages and is now
used for distributed, collaborative, hypermedia information systems - Server Message Block (SMB) describes the structure of sharing network resources,
such as directories, files, printers, and serial ports, between computers. - Simple Mail Transport Protocol (SMTP) transfers outbound e-mails from the
e-mail client to the e-mail server and transports e-mail between e-mail servers and
so enables e-mail to be exchanged over the Internet. - POP/POP3 delivers e-mail from the e-mail server to the client.
Compare and contrast the messages that application layer protocols such as DNS, HTTP, SMB, and SMTP/POP exchange between devices to enable data transfers to occur
DNS, HTTP, SMB, and SMTP/POP use client/server, request/response messages.
Whereas users see the applications that use HTTP (a web browser), SMB (file manager), and SMTP/POP (e-mail client), a DNS operation underlies these applications and is
truly transparent to the user.
