Unit 7

• SAN provides high-speed access, and is easily scaled. However, it is more expensive
• NAS is a easy to install and manage storage solution, that can easily share data within a network. However, it is not as fast as a SAN
• Network models are how connections between devices are treated, such as peer to peer
• What are the three types of network model?

  Thin client

  peer to peer

  Client server
• Peer to peer doesn't use a central server instead each peer acts as a node. This reduces costs and improves fault tolerance, however it is less secure and can be difficult to maintain
• Client server networks use a central server that handles resources over a network. This gives centralised control, leading to more security and makes it easier to manage; however it can expensive, and makes the network more dependent on the server
• Thin client uses a centralized server to handle all the computing tasks of client devices. It receives inputs and sends outputs to the minimally powerful "thin clients". This reduces cost per device, and is more secure due to centralisation. However this can lead to high network traffic and a dependence on a single server for all operations
• Bandwidth is the rate of data transfer
• Latency is time for a packet to be transmitted
• Networks have two topologies the physical topology of cables and devices, and logical the way data flows
• BOth network topologies can be considered as both the roads in a city for the cables, and the traffic lights and signs for the data flow
• Bus topology has one cable with multiple connections, which means there are no switches or hubs needed. The signal travels along the bus until it reaches its destination. If any part of the bus breaks then the whole system fails.
• Ring topology has a ring shaped cable connecting every device together. Therefore it doesn't require much cabling, however it is susceptible to failure.
• Star topology has a central hub. Each device is directly connected to the hub so if one child node goes down the rest still work.
• Mesh topology uses multiple paths between devices, meaning that if one path fails another can take over. However this requires lots of cabling and equipment.
• Cloud sourcing is getting computer resources and services from the cloud
• Cloud portability is the ease of transferring cloud service provider
• If a cloud service is portable then that makes it more flexible and can reduce cost as it is easy to change service provider
• CLoud sourcing is very scalable, compatible, and available
• Service providers care about cloud sourcing and portability as it provides?

  Competition and innovation
• Customers care about cloud sourcing and portability as it offers?

  Cost efficiency

  Flexibility
• A virtual environment is a system that allows multiple instances of a system to be simulated on a single device. These devices can be isolated from each other.
• 4 key features of virtual environments?

  Increased security

  Centralised control

  Flexibility

  Isolation
• The benefits of virtual environments are it's?

  Flexibility

  Cost savings

  Enhanced Security
• The drawbacks of virtual environments?

  Complexity

  Compatibility

  Performance overhead
• The 4 layers of the TCP/IP model are NITA?


  Network access

  Internet

  Transport

  Application
• The application layer in TCP/IP is equivalent to?

  SPA
• The Transport layer in TCP/IP is equivalent to?


  T
• Internet layer is equivalent to?

  N
• Network access is equivalent to?
• 5 main ways to ensure digital resistance:

  Data and system redundancy

  Back-up systems

  Hot, cold and warm sites

  Data back-up and recovery procedures

  Device hardening
• TCP is transmission control protocol and establishes a reliable connection between 2 devices
• Internet protocol, routes packets using addresses that are a location, and creates a route based off it
• HTTP governs how browsers commmunciate. When you visit a website, your browser sends a HTTP requrest, which responds with website content
• HTTPS is an encrypted connection, that uses credentials
• DNS translates domain names into IP addresses, it does this by sending a dns query to a DNS server, which will recursively search other servers until the IP is found
• DHCP (dynamic host configuration protocol), assigns IP addresses to devices on a network. All leases (assigned IP addresses) expire eventually, at which point the device can renew or get a new one
• FTP is a protocol for transferring files between a client and a server. It is efficicient , and uses two connections (1 for files, 1 for commands) to ensure secure and stable transfer
• NTP synchronizes computer clocks across a network
• POP 3 downloads emails from a server to a client. Ths reduces inbox storage needs on the mail server