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CCNA1 Knowledge
Chapter 3 questions
41
Computer Science
Undergraduate 1
04/15/2008

Additional Computer Science Flashcards

 


 

Cards

Term

 

 

 

What are the  application layer protocols used for?

 

                     

Definition

 

 

Protocols are used to exchange data between programs running on the source and destination host.

Term

 

 

What are the 3 primary functions of the Presentation Layer?

 

(C C E)

Definition
  • Coding
  • Compression
  • Encryption

1).   Coding and Conversion of Application layer data to ensure that data from the source device can be interpreted by the appropriate application on destination device.

 

2).   Compression of the data in a manner that can be decompressed by the destination device

 

3).   Encryption of the data for transmission and the decryption of data upon receipt by the destination.

 

Term

 

 

 

What does the application layer provide?

Definition

1.  Provides the intereface between the application we use to communicate.

 

                        and

 

2. The underlying network over which your messages are transmitted.

 

Term

 

 

 

What is the main function of the session

layer?

 

                (CHR)

Definition

1).  Creates and maintain dialogs between source and destination applications.

 

2).   Handle the exchange of information to initiate dialog, keep them active.

 

3).   Restart sessions that are disrupted or idle

Term

 

 

 

What do the Application layer protocols of the TCP/IP protocol specify?

Definition

 

 

The format and control information necessary for many of the common internet communication.

Term

 

 

What are the two forms of software programs of process that provide network access in the Application Layer?

Definition

1).  Application

 

2).  Services

 

- Network-Aware Application = application are the software programs used by people to communicate over the network.

 

- Application Layer Services = Uses protocols which defines the standards and data to format and redirect data.

Term

 

         

           What do protocols provide?

Definition

 

Protocols provide the rules and formats that govern how data is treated.

 

 All three components may be used by a single executable program and may even use the same name.

 

For example, when discussing "Telnet" we could be referring to the application, the service, or the protocol.

 

Term

 

 

What is the difference between an application and a service?

Definition

 

Applications are the software program used by people to communicate over the network.

 

Services are programs that interface with the network and prepare the data for transfer.

Term

 

 

What do application layer protocols do?

Definition

 

 

The application layer protocols define the standards and data formats to be used.

Term

 

 

 

What are the 6 things protocols do?

 

 

(PTSMHI)

Definition

1).   Define processes on either end of the communications

2).  Define the types of messages

3).  Define the syntax of messages

4).  Define the meaning of any informational field

5).  Define how messages are send and expected a response.

6).  Define interaction with the next lower layer.

Term

 

 

What is the difference between a client and a server?

Definition

 

 

Client is the device requesting the information .

 

Server is the device responding to the request.

Term

 

 

In general networking sense what is a server?

Definition

A server is any device that responds to requests from client applications is functioning as a server.

 

A server is usually a computer that contains information to be shared with many client systems.

Term

 

 

Describe the 2 processes a daemon uses (listening and hears)?

Definition

Listening = for a request from a client, because they are programmed to respond whenever the server receives a request for the service provided by daemon.

 

Hears= a request from a client, it exhange appropriate messages with the client, as requested by its protocol and proceeds to send the requested data to the client in the proper format.

Term

 

 

 

What is a peer-to-peer network?

Definition

 

 

Two or more computers are connected via a network.

                           and

 

Can share resources (Printer, Files) without having a dedicated server.

Term

 

 

     Are peer-to-peer networks easy to secure?

Definition

 

Peer-to-Peer, is not easy to secure because peer-to-peer usually do not use centralized user accounts, permission, or monitors, it is difficult to enforce security and access policies in networks containing more than just a few computers.

Term

 

 

 

What do port numbers identifies?

Definition

 

 

Port numbers identifies application layer protocols and services.

Term

 

 

             What do the DNS protocol do?

Definition

 

 

DNS Protocol communications use a single format called a message.

                                  and

 

DNS defines a automatic service that matches resource names with the numeric network address.

Term

 

 

 

   What does the nslookup utility allow you to do?

 

                   (MTV)

Definition

nslookup utility allows you to:

 

1).  Allows the user to manually query the name servers to resolve a given host name.

 

2).  used to troubleshoot name resolution issue.

 

3).  Verify the current status of the name server.

Term

 

 

 

What does the command ipconfig/display DNS show?

Definition

 

The command ipconfig displays all the cached DNS entries on windows XP or 2000 computer system.

Term

 

 

 

What happens if a DNS server does not have a name in its stored records?

Definition

 

 

DNS contacts other servers in order to resolve the name.

Term

 

If the same request is made again where does the DNS server look?

Definition

 

 

 

The first server can return the address by using the value stored in its name cache.

Term

 

 

When is a server declared to be an authoritative server?

Definition

 

 

If given server has resource records that corresponds to its level in the domain hierarchy.

Term

 

 

Define the three parts of a url as listed on the page?

Definition

1).  http= (The protocol or scheme)

 

2).  www.cisco.com = (The server name)

 

3).  Web-server.htm ( The specific filename requested)

Term

 

 

What type of request is sent to the server when retreiving a web page?

Definition

 

 

 

Browser will ask for the file web-server.htm

Term

 

 

              What does the POST command do?

Definition

 

 

The POST command send messages that upload data to the web server. 

 

Post messages upload information to the server in plain text that can be accepted and read

Term

 

 

 

         What does the the PUT command do?

 

Definition

 

 

PUT uploads resources on content to the web server.

Term

 

 

 

What protocol is used for secure transmission across the web?

Definition

 

 

 

https protocol is used for accessing or posting web server.

Term

 

 

What 2 Application layer protocols are used in sending and receiving email?

Definition

 

 

Simple  Mail Transfer Protocol (SMTP)

 

Post Office Protocol (POP)

Term

 

 

 

What is another name for an email application?

Definition

 

 

 

Mail User Agent  (MUA)

 

Retrieves mail using POP

 

Client used to access and read mail

Term

 

 

What are the two processess that email servers perform MTA and MDA?

Definition

1.  Mail Transfer Agent (MTA) = Process is used to forward email between servers using SMTP.

 

Recieves mail from client

 

2.  Mail Delivery Agent (MDA) = Mail is addressed to a user whose mail box is on the local server is passed to the MDA.

 

Resolves final delivery issues

 

Perform actual delivery to user mail box

Term

 

 

What happens to emails in many companies once the email reaches the internal server?

Definition

 

 

Emails clients typically communicate with the email server using a proprietary protocol.

Term

 

List and describe some of the commands used by the SMTP protocol.

 

 

              (HEMMD)

Definition

1. HELO = identifies the SMTP client process to the SMTP server process.

 

2. EHLO = is a newer version of HELO, which includes services.

 

3. Mail From= identifies the sender

 

4. Mail To = identifies the receipient

 

5. Data = identifies the body of the message

 

 

 

 

Term

 

 

 

         What is File Transfer Protocol (FTP)?

Definition

 

 

- Used at the application layer

 

- Was developed to all file transfer between client and server. 

Term

 

 

What are the 2 ports used and their purpose in FTP?

Definition

Port 20 & 21

Port 20 = Connection is for actual file transfer and is created everytime there is a file transfer.

 

Port 21 = Is used for control traffic, consistings of client commands and server replies.

 

Term

 

 

What does Dynamic Host Confirmation Protocol (DHCP) do for a network?

Definition

 

DHCP service enables clients on the network to obtain IP addresses and other information from a DHCP Server.

  

Allows a host to obtain an IP address dynamically when it connects to the network.

Term

 

 

What are the 4 types of messages sent and received in DHCP?

 

                      (DORA)

Definition

1).  DHCP Discover

 

2).  DHCP Offer

 

3).  DHCP Request

 

4).  DHCP Acknowledge

 

 

 

 

 

 

 

 

 

Term

 

 

     What is SMB (Server Message Block)?

Definition

 

Is client/server file sharing protocol.

 

- It is a request-response protocol

 

- Servers can make their resources available to clients on the network.

Term

 

 

 

What are the 3 messages types of SMB(Server Message Block) messages?

Definition

1).  Start authenticate and terminate protocol

 

2).  Control file and printer access

 

3).  Allow an application to send or receive messages to or from another device

 

Term

 

 

 

 

What does the Telnet application provide?

Definition

 

 

A standard method of emulating text-based terminal devices over the data network.

Term

 

 

 

What protocol is recommended alternative to Telnet when security is a concern?

Definition

 

1).  Secure Shell (SSH) protocol offers an alternative and secure method for server access.

 

2).  Must always use (SSH) instead of VOIP.

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