Wired and Wireless Networks Flashcards
What does IP stand for
Internet protocol
Domain name
A domain name is the name of a website
What does DNS stand for
Domain Name System
Searching for a website
- The request is sent to a DNS server
- The DNS server has a database of domain names and the corresponding IP addresses
- If the local DNS server doesn’t have the domain name, then the request is forwarded to a bigger server
Advantages of the DNS
- Humans don’t have to remember long sequences of numbers
- If an IP address changes, the DNS server can update the server, and the domain name can remain the same
- Having many distributed servers means everyone has access to all addresses from their local DNS server
MAC address
An address given to each NIC; it takes up 48 bits, although is written as 12 hex digits to make it easier for humans to read
What does WAN stand for
Wide-area network
What is a wide-area network
A collection of LANs joined together
What does LAN stand for
Local-area network
What is a local-area network
A collection of computers joined together
Circuit switching
A dedicated connection is set up between two computers/landlines(fine for telephone calls, but not for the internet
Packet switching
Packets are sent to their destination along different routes, and reassembled in the correct order at the end
Contents of a packet header
IP address of where its going, IP address of where it came from, sequence number of the packet, number of packets in the whole communication, error checking data
Advantages of using a network
- Folders and files can be easily accessed by authorised users
- peripheral devices such as printers and scanners can be shared
- internet connection can be shared, and any user can use email
- user profiles and security can be managed centrally
- software can be distributed across the network
- all files can be centrally backed up
Disadvantages of using a network
- Managing a large network is complicated
- Viruses can rapidly spread to every computer
Different network topologies
Star, Bus, Ring, Mesh(full/partial)
Star network
All computers are connected via a switch, hub or server
Advantages of a star network
- If one cable fails, other workstations are not affected
- Performance is consistent, even when the network is heavily used
Disadvantages of a star network
- Lots of cabling(expensive)
- If the server or central switch fails, then the whole network goes down
Advantages of a wireless mesh network
- Few cables
- More nodes make the network faster
- New nodes are automatically incorporated into the network without needing a network administrator
- The network can easily find alternative routes for messages
- Local networks run faster because packets don’t have to travel to a central switch or server
Hardware required to create a network
Router, switch and NICs
Router
Designed to route data packets across wide-area networks such as the internet. Each router acts as a node, and packets are passed from router to router to their destination. If a packet is destined for a computer in a LAN, it will typically be routed to a switch
Switch
A component of a LAN that knows the MAC address of individual computers locally connected to it. It forwards inbound packets to the intended recipient, using its MAC address
NIC
A Network interface Card is required to connect a device to a network. It is a physical component which can operate either wireless or wired.
Ethernet
A series of networking rules widely used in LANs, it prevents two devices from transmitting at the same time, if two devices transmit at the same time, they both wait a random period before reattempting
Virtual networks
Virtual networks are subsets of computers which create a larger physical networks
What does wi-fi stand for
Wireless fidelity
What is wireless fidelity
A series of protocols that allow for wireless networking