Network Topologies, Protocols and Layers Finished Flashcards
What is a node
A device connected to a network
What is a network topology
The arrangement in which all nodes are connected together
What are the common network topologies (2)
Star
Mesh (full or partial)
What is the configuration of a star topology
Al nodes directly connected to a central hub or switch (server is a node)
What model does a star topology typically use
Client-server model
What are the advantages of the star topology (3)
Each node is separately connected, therefore a failure of one node or link does not affect any of the other nodes
New nodes can be added to the network by connecting them to the switch
They tend to have higher performance as a message is passed on to its intended recipient only
What are the disadvantages of the star topology (2)
The whole network fails if the switch fails as no node can communicate
Can be expensive if wired due to the cabling
When are star topologies commonly used (2)
Large organisations
Home networks
What is the central connection for all nodes in a home network
Router/WAP
What is the configuration of a mesh topology
Each node is connected to at least one other node (partial mesh) or all other nodes (full mesh)
Why are wired mesh networks uncommon but wireless mesh networks becoming more popular
Wired mesh networks are expensive but it’s becoming easier to connect nodes wirelessly using radio signals
What are the advantages of using a mesh network (5)
Messages can be received more quickly is the route to the intended recipient is short
Messages should always get through as they have multiple routes on which to travel
Multiple connections mean that no node should be isolated
Multiple connections mean each node can transmit to an receive from more than one node at the same time
New nodes can be added without interruption or interfering with other nodes
What are the disadvantages to using a mesh network (2)
Full mesh networks can be impractical to set up due to the large number of connections required
Many connections require a lot of maintenance
When are mesh topologies often used (4)
Military organisations - to avoid breakdown of communication
Cities - help monitor traffic flow, sewage treatment and street lights
Emergency services - ensure communication is reliable
Utility companies - to allow smart meters to send readings automatically
What is ethernet
A protocol that describes how data is transmitted in wired networks
How does a wireless network connect nodes
Wi-Fi
What radio frequencies does Wi-Fi use (2)
2.4 GHz
5 GHz
How does a node connect to a WAP
By a radio transceiver
How are WAPs connected
By wire or wirelessly to a network switch or wirelessly to other WAPs
What are the advantages to using Wi-Fi as a connection in a network
New nodes can be added easily without interruption to the network
What are the disadvantages of using Wi-Fi as a transmission media(4)
Wi-Fi signals have a limited range (>50 metres)
Wi-Fi signals can suffer from electromagnetic interference from other devices and other Wi-Fi signals and can also be blocked by walls leading to dead spots
Each WAP only has so much bandwidth to share among connected nodes
Wi-Fi signals pose a security threat as they can be intercepted, meaning messages have to be encrypted
Why is Wi-Fi so popular (2)
It is easy to connect a node to a network
It’s wireless so there is a lot of freedom of movement
What is encryption
The process of disguising a message so that it cannot be understood by anyone but its intended recipient
What is an unencrypted message called
Plaintext
