1.5 Packet Switching & Layers

Select all the True statements:

• A network protocol is an agreed way of how to communicate over a network.

• WiFi networks use radio frequencies in the 2.4 GHz or 5 Ghz frequency ranges.

• WAP stands for Wide Area Protocol

• 2.4 GHz frequency networks are slower than 5GHz networks, but have a stronger signal range.

• WiFi networks typically create a ring network topology

Select all the correct statements:

• The IP address of a device is fixed by the hardware manufacturer.

• The MAC address of a device is fixed by the hardware manufacturer.

• MAC addresses are used to ensure node-to-node transmission of a data frame (in the Link Layer)

• MAC addresses is a 12-digit hexadecimal number.

• An IP address is a 12-digit decimal number

What are advantages of dividing network transmission into layers?

• Network communication components are standardised which helps to ensure that different types of hardware and software are able to communicate.

• Through separating the overall network communication processes it makes troubleshooting easier should an error occur.

• To ensure that if changes are made in one layer they do not affect any other layers

• Through dividing overall network communication into smaller, individual components it makes the software development process more straightforward.

• Its easier

Which of these is correct?

• The APPLICATION layer encodes/decodes the message in a form that is understood by the sender and the recipient.

• Transport layer - breaks down the message into small chunks (packets). Each packet is given a packet number and the total number of packets.

• Network layer - adds the sender’s IP address and that of the recipient. The network then knows where to send the message, and where it came from.

• Data link layer - enables the transfer of packets between nodes on a network, and between one network and another.

• MAC addressing is used by the Network/Internet layer.

List all ITEMS a TCP/IP packet switching network packet contains

• Source and Destination IP Address

• Packet number / sequence

• Error detection codes

• Payload

• The encryption key

Which of these statements are NOT true

• Data is encrypted in the Internet Layer

• Packets must arrive in order

• Packets must all follow the same route

• After a time-out interval the transport layer (using the TCP protocol) will resend a packet if no acknowledge packet has been received.

• Routers route packets through the network in the Network/Internet layer using the IP protocol.

The 4-layer network model in ORDER are:

• Transport / Application / Link Layer / Physical

• Application / Transport / Internet / Network (Data Link Access)

• FTP / TCP / IP / ETHERNET

• Physical / Link Layer / Transport / Application

The purpose of the Application layer is

• Prepares or presents the data (email, file, message) for /from transmission - including applying encryption/decryption

• Ensures reliable transmission of data across the network.

• Ensures the data is correctly routed through the network

• Responsible for encoding the data to be transmitted on the actual cabled or wireless channel.

The purpose of the Transmission layer is

• Prepares or presents the data (email, file, message) for /from transmission - including applying encryption/decryption

• Ensures reliable transmission of data across the network.

• Ensures the data is correctly routed through the network

• Responsible for encoding the data to be transmitted on the actual cabled or wireless channel.

The purpose of the Internet (or Network) layer is

• Prepares or presents the data (email, file, message) for /from transmission - including applying encryption/decryption

• Ensures reliable transmission of data across the network.

• Ensures the data is correctly routed through the network

• Responsible for encoding the data to be transmitted on the actual cabled or wireless channel.