4.9.2 Networking Notes Flashcards
How does a client server network work?
• In a client-server network, one or more central servers provide services to the clients on
the network.
• Servers are connected to the network in the same way as clients, but are
often more powerful machines than the clients
How are servers different to clients/
Servers are often more powerful machines than the clients.
How does a client server network work?
• The clients on the network request services from the servers, which then respond to the
client with the requested service.
• Services provided by servers in a client-server network could include file storage as well as management of emails, user accounts and print
queues.
What are some services provided by servers in a client server network?
Services provided by servers in a client-server network
could include file storage as well as management of emails, user accounts and print
queues.
What is a disadvantage of peer to peer networking?
• All of the clients which provide services must be running in order for the network to be fully operational.
What is an advantage of peer peer to networking?
• Peer-to-peer networking is more cost effective than client-server
networking as there is no need for a powerful server to provide services
• Peer-to-peer networks are easier to set up and maintain than their client-server
counterparts
Where are peer to peer networks used?
• Large file sharing networks and multimedia providers use peer to peer networking to provide high performance services without the requirement for a server.
Why are peer to peer networks more cost effective?
There is no need for a powerful server to provide services.
What does wireless networking allow for?
Clients to communicate within a network without being physically connected to it.
What do wireless networks require?
Wireless networks require a wireless access
point, which connects to a wired network just like
any other client would, and a wireless network adapter in the device that connects to the wireless
network.
What is WiFi used for?
Used to provide wireless networks.
What is WiFI?
WiFi is widely used to provide wireless networks
and refers to a wireless local area network that is
based on international standards.
This allows a
device made in one part of the world to connect seamlessly to wireless networks all over
the world.
What does WiFI allow for?
This allows a
device made in one part of the world to connect seamlessly to wireless networks all over
the world.
What does WPA stand for?
WiFi protected access
What is the purpose of WPA?
Requires that a new wireless client enters a password in order to connect to the network
How are wireless networks secured?
Secured by encrypting transmitted data using WPA or WPA2.
What is SSID?
Service Set Identifier.
Name which identifies a wireless network
What are the various methods of securing a wireless network?
- Encrypting transmitted data using WPA or WPA2
- Disabling SSID broadcast
- Setup a MAC address filter.
What is MAC address filter?
- Mac addresses are assigned to every wireless device by their manufacturer and are unique to that device.
- MAC address whitelists can be created to allow only specific devices to connect to a network.
- Mac address blacklists can be used to block specific devices from connecting to a network.
What does MAC stand for?
Media Access Control
What is CSMA/CA?
Carrier sense multiple access with collision avoidance.
• A protocol used in wireless networks to avoid data collisions caused by multiple devices communicating simultaneously.
What is a protocol?
Set of rules relating to communication between devices.
What is the purpose of CSMA/CA?
Protocol used in wireless networks to avoid data collisions caused by multiple devices communicating simultaneously.
How does CSMA/CA work?
- When a device is ready to transmit, it listens to its communication channel to check whether it is idle.
- If so then the data is transmitted.
- if the channel is busy, the device waits for a random period of time before checking the channel again.
- An exponential backoff algorithm can be used to increase the time period for which the device waits with each check of the channel.
What is the purpose of the exponential backoff algorithm?
Used to increase the time period for which the device waits with each check of the channel
What occurs if the communication channel is idle?
Data is transmitted
What occurs if the communication channel is busy?.
Device waits for a random period of time before checking the channel again.
What is CSMA/CA effective at?
Eliminating collisions in small networks
What is an issue with CSMA/CA?
it cannot overcome hidden nodes
What is the hidden node problem?
A problem that arises when the device checking for an idle channel cannot see some parts of the network on which communication may be occurring.
How do you get around the problem of hidden nodes?
A protocol called request to send/clear to send ( RTS/CTS ) is used.
How does RTS/CTS work?
- Protocol adds an additional step into the CSMA process.
- Once the transmitting device has checked whether the channel is idle, it sends a ‘request to send’ message to the server.
- If the server is idle, it will respond with a clear to send message at which point the transmitting device can begin communication with the server.
- If no clear to send message is received, the server is busy communicating with a hidden node and the transmitting device must wait before starting the CSMA process again
What occurs with RTS/CTS if the server is idle?
It will respond with a clear to send message at which point the transmitting device can begin communication with the server.
What occurs with RTS/CTS if no clear to send message is received?
The server is busy communicating with a hidden node and the transmitting device must wait before starting the CSMA process again.
