N1. Internet Overview Flashcards
What is the internet?
A global interconnection of different data networks
What are services?
Programs provided by applications, that perform useful functions for users.
What are communication systems?
Computer networks that allow applications to transfer data and information.
(Applications typically run as distributed systems.
What is an end-system in a computer network?
Host/workstation (user/client applications), servers (shared applications/services) at the edge of a network.
Connectivity in networks
- radio (WIFI)
- electrical (Ethernet)
- optical (Fibre to home/between servers)
Possible architecture/forms of connectivity found in a home network (LAN).
- Broadband modem
- Internet router
- Ethernet switch
- Bridge
DSL modem definition.
‘Local’ connection to WAN through your ISP (only).
WAN
Wide Area Network
global network, point-to-point links
LAN
Local Area Network
e.g home/school
ISP
Internet Service Provider
provider of global internet connectivity
Internet router
- Global packet relay.
- Can communicate with ISP.
- Interconnects two (or more) different networks
- Needs suitable transceivers
Ethernet Switch
- Local packet relay.
(Local forwarding/delivery of frames of data) - Provides wired connections for local devices (within a
network). - Devices wired to physical ports on switch.
Bridge
- Local packet forwarding.
- Provides connections for local devices (wireless access
point)
(hides low-level physical connectivity). - Transparent connection between wired and wireless in
LAN
Modem
- Modulator/Demodulator
- creates signal compatible with WAN technology (framing
of bits) - Transceiver creates/reads physical signal
Home/business gateway
Packages everything into one box - commonly known as a router.
May include firewall and other functions
