1: Networks Intro Flashcards
What is a host?
A device connected to a computer network that is connected to other devices/hosts on the network that runs network applications.
What is an end system?
A computer connected to a network that are used by end users, i.e. the people intended to use a system (web surfers with the Internet network).
What is multiplexing?
Methods of splitting analogue or digital signals into distinguishable channels that allow for multiple signals to be sent as one over a single shared physical medium.
What is routing?
Routing is the process by which a network as a whole determines the paths deciding how packets go from source to destination: forwarding tables are built.
What is a protocol?
A communications protocol is a set of rules determining the format and order of data and actions taken when different data are received.
What is a cable network?
A physical medium implementing end-user access networks for the Internet that uses FDM to split channels between multiple Internet and TV devices.
What is a network edge? What is an edge device?
Network edges are hosts on computer networks: servers or clients on the Internet.
Edge devices connect network edges to a wider network, e.g. consumer home computers in a LAN (access network) to the Internet. Edge devices are usually routers.
What is an access network?
A network designed for general and end users that allows them to connect to the core of the network, such as Ethernet-based LANs in homes connecting people to the Internet.
What is the network core?
A subset of a network containing connections between routing devices, both of high bandwidth, that act to connect systems towards the network’s edge.
What is an edge router?
A router is a networking device that data are forwarded in computer networks.
An edge router is a specialised router that connects two networks, usually an access network to the Internet, or two LANs into a WAN.
What is DSL?
Digital Subscriber Line is a group of technologies allowing access to digital data, usually from the Internet, via preexisting telephone lines.
What is FDM?
Frequency-division multiplexing is splitting a single signal into multiple channels along the lines of frequency bands which allows you to send multiple signals as one over a single shared physical medium.
What is twisted pair?
A physical medium compromised of two insulated copper wires that are commonly used in LAN and Ethernet networks.
What is throughput?
The rate at which data are transferred between sender and receiver nodes on a network.
How do you find packet transmission delay?
Packet transmission delay = packet length, L (bits) ÷ link transmission rate, R (bits / sec)
What is a transmission rate?
The amount of information a data link can transmit per unit time; usually measured in Bits/sec.
aka link capacity and link bandwidth
What is a link?
Physical infrastructure between the transmitting and receiving node on a network that facilitates the propagation of data between the two.
What is a physical link?
Infrastructure between the transmitting and receiving node on a network that facilitates the propagation of data between the two.
What are guided and unguided media?
In guided media, signals move along the physical courses of physical media which are wires and cables, and in unguided media, signals propagate through open space (air), such as Wifi and Bluetooth radio signals.
What is coaxial cable?
A bidirectional physical medium compromised of two copper wires, with one wrapped around the other.
What are peering links, in terms of global Internet infrastructure?
Data links directly between different ISPs that aren’t routed through the remainder of the Internet.
What is the idea of store and forward?
The idea that a packet must arrive at a router in its entirety before it can be transmitted through another link in the next hop.
What is packet queueing?
The idea that packets are stored in a queue in routers before they are transmitted because packets are transmitted once at a time at full capacity. This happens when packets arrive more rapidly (higher rate in bits/sec) than they can be transmitted (also rate in bits/sec).
What is TDM?
Time-division multiplexing is splitting a single signal into multiple channels along the lines of timed turns which allows you to send multiple signals as one over a single shared physical medium.
