Network Protocols
- Define the term network protocol.
- Explain the purpose and use of common network protocols.
What are Network Protocols?
All networks work by preparing an electrical signal and then transmitting the signal until the signal reaches its destination address. This transmission is controlled by protocols.
A set of rules that determine how data is transmitted between devices on a network.
Ethernet
- A family of protocols used to connect devices in a wired LAN.
- Define how data should be physically transmitted between different devices.
- Uses MAC addresses to determine which device the data should be sent to .
- Also define what should happen if collisions occur on the network.
- Can be used on copper or fibre-optic cables.
Wi-Fi (WLAN)
- A family of protocols that define how devices can communicate wirelessly using radio waves.
- The Wi-Fi standards determine:
- the frequency band and channel that to be used,
- data transmission rates,
- how devices are authenticated when joining the network.
Wi-Fi (WLAN)
- Normally use two frequency bands, 2.4 GHz or 5 GHz.
- 2.4 GHz has longer range, but lower transmission rates.
- 5 GHz has shorter range, but high transmission rates.
Transmission Control Protocol (TCP)
- Splits data from applications into smaller data packets for transmission across a network.
- Each packet is made up of a header and a payload.
- The header contains the sequence number of the packet and a checksum to allow the recipient device to check that it has been sent correctly.
- The payload contains the actual data from the application that needs to be sent.
- When the data is correctly received, an acknowledgement message is sent back to the server.
User Datagam Protocol (UDP)
- Used by applications to deliver data more quickly.
- It does not tell the server the data was correctly received - there are no checks at all, the data is just sent.
- Generally used for live broadcast or online gaming.
- If packets are lost the video or audio will continue to play but will be distorted for a moment.
Internet Protocol (IP)
- Defines how data packets should be sent between networks.
- Every device on a network has a unique IP address.
- Made up of four 8-bit numbers (e.g. 192.168.1.110).
- An IP header is added to each data packet contain both the source and destination IP addresses.
- The router then decides how to sent the data packet, either on the local network or to another network.
- Once received, the switch determines which device on the network should get the data packet.
HyperText Transfer Protocol (HTTP)
- Used by web browsers to request web pages from web servers to the user's browser.
HyperText Transfer Protocol Secure (HTTPS)
- Secure version of HTTP.
- Adds Secure Socket Layer (SSL) encryption to the communication.
- Used originally for online banking and shopping, most web sites now uses HTTPS.
File Transfer Protocol (FTP)
- Used to transfer computer files between a client and a server.
- Most commonly used for transferring web pages to web servers.
Simple Mail Transfer Protocol (SMTP)
- Used to send email to an email server or between servers.
Internet Message Access Protocol (IMAP)
- Used for accessing email messages.
- Allows multiple devices to have synchronised access to the same inbox.
- The messages are retained on the email server.
- The most commonly used email protocol, due to the ability to keep email synchronised.
Questions
- Explain what is mean by a network protocol.
- Identify the most appropriate protocol to be used when uploading a file from a computer to a web server.
- Identify the most appropriate protocol to use when web page communications between a client and host need to be encrypted.
- Explain the purpose of SMTP.
- TCP and IP are two protocols used in network communications. State what the initials TCP and IP stand for and describe the function of each protocol.
Answers
- Explain what is mean by a network protocol.
A set of rules that allows devices to transmit data to one another.
Answers
- Identify the most appropriate protocol to be used when uploading a file from a computer to a web server.
FTP: File transfer protocol
Answers
- Identify the most appropriate protocol to use when web page communications between a client and host need to be encrypted.
HTTPS: Hypertext transfer protocol secure
Answers
- Explain the purpose of SMTP.
Used to send emails to an email server, or from one email server to another.
Answers
- TCP and IP are two protocols used in network communications. State what the initials TCP and IP stand for and describe the function of each protocol.
TCP - Transport Control Protocol
Splits data into small packets and adds the header, which includes the packet number, number of packets and checksum.
IP - Internet Protocol
Defines how data should be sent across networks, by including source and destination IP addresses within each data packet.
Network Protocols Define the term network protocol. Explain the purpose and use of common network protocols.