Networks Flashcards
What is the Internet?
Global network of interconnected networks that communicate using a common set of protocols,
What is an IP Address?
The address assigned to a device used to identify and communicate with devices on a network.
What is a domain name server?
Domain name servers are used to translate the domain name into its corresponding IP address. They store a table of domain names and their corresponding IP address.
What is a Domain name ?
A human readable address for any location on the internet.
What is the link between a Domain Name and an IP address?
IP - numerical values that make sense to computer but not humans.
Domain name - Functions as a link to IP as understood by humans.
What does a Router do?
Forwards data packets btwn networks
Subscriber vs enterprise router
Both :
Edge routers (One network to another)
Subscriber :
Small scale , Low cost and 2 Interfaces
Uses, homes + small businesses OR To link segments of larger networks internally.
Enterprise:
Large , handle high volumes of data and expensive.
Uses, Large businesses and Internet service providers (ISP’s).
What does a Gateway do?
Allows transmission of data btw dissimilar networks
What does ISP stand for?
Internet Service Provider
What is a packet and what are the main items in the packet header?
A small segment of a larger message.
Origin, Receivers address , Packets contents (where data to be transferred is held) , Time to live (No. hops before dropped) and Sequence no. (No. packets in message and it position within them so it can be reassembled in the correct order)
What is an NIC?
A NIC (Network Interface Controller) Connects devices to a network by converting data into signals to be transferred. Then when received converts them back into readable data.
What are the steps in packet switching?
- Data split into chunks (Packets)
- packets sent across network taking fastest route
- Packets arrive at destination and are reassembles
- Recipient sends message to sender confirming the data has been received
4b . If no confirmation received data will be sent again by sender.
What is Time To Live (TTL) in packet switching ?
After X number of hops (every time packet goes through router) , Packet is dropped (Deleted and recipient has to request again
How long are MAC addresses ?
48 bits
T or F MAC Adresses can be changed
FALSE They cant
Hub vs Switch
Hub : Repeats message to all connected devices.
Switch : Only sends message to specific device. Holds a table of devices, their ports and MAC addresses
What does a modem do ?
Changes electric signals so they are compatible with different cables and transfer methods (modulates them)
What is a protocol?
Set of pre-agreed rules that defines how data is transmitted over a network
What does TCP/IP stand for?
Transmission control protocol / internet protocol
What is the application layer of the TCP/IP protocol do?
Decides appropriate protocols depending on users choice of output.
eg. HTTP (HyperText), SMTP (Standard Mail) and FTP (File)
What is the transport layer of the TCP/IP protocol do?
Splits data into packets , each packet assigned source and destination port numbers and sequence numbers (position within packets for reconstruction)
eg. TCP (Transmission control)
What is the Network layer of the TCP/IP protocol do?
Encapsulate data with source and final destination IPs
What is the Link layer of the TCP/IP protocol do?
Encapsulate data with source and destination MAC’s (For next router -hop- not final destination). Link header stripped at each router and new source and destination MAC’s are assigned.
What is a MAC address?
Address embedded in NIC used to identify devices within a network
