Chapter 6 - Internet Protocol

Question 1

Network Protocol

Answer 1

A network protocol defines rules for communication between network devices.

Question 2

Without protocol ?

Answer 2

• We cannot make communication between the computers
• Message cannot be send/receive
• No proper data format

Question 3

The Internet Protocol (IP)

Answer 3

• IP prepares packet for transmission across the Internet
• IP is designed to control data transmission between two nodes and to ensures that a link has been established between source and destination.
• IP simply transmit the data, it does not care if the packet is delivered correctly. (No error detection)
• The IP header is encapsulated onto a transport data packet.
• The IP packet is then passed to the next layer where further network information is encapsulated onto it.

Question 4

Transmission Control Protocol (TCP)

Answer 4

• TCP layer creates a connection between sender and receiver using port numbers.
• It also ensures packets arrive intact and in correct order.
• TCP is a connection oriented protocol.
• TCP can perform end-to-end error correction.

Question 5

Internet Control Message Protocol (ICMP)

Answer 5

• ICMP Used by routers and nodes
- Perform error reporting for the Internet Protocol.
~ ICMP reports errors such as invalid IP address, invalid port address, and the packet hopped too many times.

Question 6

User Datagram Protocol (UDP)

Answer 6

• A transport layer protocol used in place of TCP.
• Where TCP supports a connection-oriented application, UDP is used with connectionless applications.
• UDP also encapsulates a header onto a application packet, but the header is much simpler than TCP.

Question 7

Address Resolution Protocol (ARP)

Answer 7

• Even through a destination workstation may have an IP address, a LAN does not use IP addresses to deliver frames.
• ARP translates an IP address into a MAC layer address so the frame can be delivered to the proper workstation.

Question 8

Dynamic Host Configuration Protocol (DHCP)

Answer 8

• An IP address can be assigned to a workstation permanently (static management) or dynamically.
• Dynamic IP address assignment is a more efficient use of fixed IP addresses.
• When DHCP client issues an IP request, DHCP server looks in its static table. If no entry exists, the server select an IP address from available pool.
• The address assigned by DHCP server is temporary.

Question 9

Network Address Translation (NAT)

Answer 9

• NAT lets the router represent the entire local area network to the Internet as a single IP address.
- Thus, all traffic leaving the LAN appears as originating from a global IP addresses.
- All traffic coming into this LAN uses this global IP addresses.
• This security feature allows a LAN to hide all the workstation IP addresses from the Internet.

Question 10

Hypertext Transport Protocol (HTTP)

Answer 10

• Basic Web pages are created with the Hypertext Markup Language (HTML)

Question 11

Uniform Resource Locator (URL)

Answer 11

• Web address
• It is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.
• All URLs consists of FOUR parts:
	- Service type
	- Host or domain name 
	- Directory or subdirectory information
	- Filename

Question 12

IP Addressses

Answer 12

• All devices connected to Internet have 32-bit IP addresses associated with them.
• IP address as a logical address (possibly temporary)
• 48-bit address on every NIC is the physical, or permanent address (MAC address).
• Computer, network, and routers use the 32-bit binary address, but a more readable from is the dotted decimal notation.

Question 13

Electronic Mail (E-Mail)

Answer 13

• E-mail programs can create, send, receive, and store e-mail, as well as reply to, forward, and attach non-text files.
• Early e-mail messages contained text information only and not the rich formats viewed today that include various fonts, pictures, sounds and multimedia.

Question 14

Multipurpose Internet Mail Extension (MIME)

Answer 14

• It is used to send e-mail attachments. MIME protocol encodes additional information known as mail attachments to e-mail protocols that normally could not transfer attachments such as graphics.
• MIME allows e-mail attachments to be transferred as separates files using SMTP as the transport protocol.

Question 15

Simple Mail Transfer Protocol (SMTP)

Answer 15

• It is part of the TCP/IP protocol suit and is designed to transfer plain text email from an email client to a mail server and from a mail server to a mail server.
• When setting up an email account, the mail server is designated as an SMTP server for sending mail and as POP3 or IMAP server for retrieving email mail.

Question 16

File Transfer Protocol (FTP)

Answer 16

• Used to transfer files across the Internet
• User can upload or download a file
• The URL for an FTP site begins with ftp://…
• The three most common ways to access an FTP site are:
- Through browser
- Using a canned FTP program
- Issuing FTP commands at a text-based command prompt

Question 17

Remote Login (Telnet)

Answer 17

• Allows a user to remotely log in to a distant computer site.
• User usually needs a login and password to access a remote computer site.
• After the connection is made, the client communicates with the Telnet server using text based commands. The telnet session allows a user to manipulate a file on the remote computer.
• Telnet is commonly used to remotely control WAN servers and routers.

Question 18

Voice Over IP (VoIP)

Answer 18

• The transfer of voice signals using a packet-switched network and the IP protocol.
• VoIP relies on existing TCP/IP technology and TCP/IP equipment.
• VoIP is less expensive for long distance cells when compared to existing telephone technologies. VoIP typically uses a series of UDP packets to send voice data across the network.