NETWORK PROTOCOL

Network Protocols

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The structure of a data packet

CompSci

Packets

A small piece of data that is broken down so that the data transmission can be accommodated properly.

Sections of packets

There are three sections in each packet of data:

1. Packet header
2. Payload
3. Trailer

Packet header

Packet header is contains some important information about the data, they are:

- Destination address
- Packet number
- Originator address

Payload

Payload is the actual data that is sending.

Trailer

Trailer known as the footer, this contains two main pieces of information:

1. Marker to indicate it is the end of the packet
2. Data for any error detection systems that are being used.

All methods of communication need rules
in place in order to pass on the message
successfully. These sets of rules are called
protocols.

What protocol exists for meeting someone
new?

Is this the same in all countries?

Protocols

14

Activity 5

DHCP

Dynamic Host Contfiguration Protocol - Leases address to clients/nodes on a network. It can also manage the available addresses.

Can be used in a closed private network, LAN or WAN. Can be used by Internet Service Providers (ISPs) to distribute IP address to it's customers/clients.

Internet Protocol (IP)

Protocol where data is sent from one computer to another. IPs can be temporary and are not fixed to a specific machine.

These are interpreted by each router and translated based on DNS entries.

Internet Control Message Protocol (ICMP)

Responsible for message delivery. Most common use is for pings. Confirms requests and responses.

Transfer Control Protocol

Used to send data across a network. Reliable and connection oriented because it happens at Layer 4: Transfter

User Datagram Protocol (UDP)

Used by programs/applications running on different computers on a network. Used to send datagrams (the packet header and data combined)

Hypertext Transfer Protocol (HTTP)

Primarily used for internet data. Stateless and connectionless protocol. Simply delivers the data to be presented.

Layer 7

Hypertext Transfer Protocol Secure (HTTPS)

Secure HTTP transferes through a secure socket layer (SSL) or transport layer security (TLS) protocol connection. Connection is confirmed, secure, and remains open as long as needed.

Layer 6 - SSL & TLS operate at layer 6 as well when isolated

File Transfer Protocol (FTP)

Used for transferring files to or exchanging files with a host computer. Uses TCP and IP networks

Layer 7 - Can work on IP or TCP

Post Office Protocol (POP)

Used to extract and retrieve email from a remote mail server. Used to retrieve email from mobile and portable devices.

Layer 7

Internet Message Access Protocol (IMAP)

used to retrieve mail from a server. Allows you to have more control over how you manage your email and email account.

Simple Mail Transfer Protocol (SMTP)

Allows you to push email to a mail server.