Internet Service Providers (ISP)HOW INTERNET SERVICE PROVIDERS WORK
What is the role of an (ISP)?
Internet Service Providers (ISP)
'An Internet Service Provider (ISP) is a company that provides a user with access to the Internet, usually for a fee.'
Networks
Internet Service Providers (ISP)
‘Home’
Local Area Network (LAN)
‘Business Network’
There are small, medium and larger computer networks all needing access to the Internet.
The Internet
Internet Service Providers (ISP)
‘Home Computer’
Packets of data are transmitted over the Internet using switched technology guided by the IP address of end computer.
The Internet
‘Another Computer’
21.34.129.86 28.203.156.94
Packet of data’
Transmitting Data packets
Internet Service Providers (ISP)
‘Home Computer’
Here is a more detailed arrangement of how data packets are transmitted across a network.
Modem
Public Telephone Network
RouterModem Pool ISP Port
Server
Router
ISP B
ack
bone
RouterRouter CSU / DSU CSU / DSU‘Another Computer’
LAN
21.34.129.86
28.203.156.94
Internet Service Provider (ISP)
Internet Service Providers (ISP)
‘Business Network’
Small and large networks connect to an ISP via a point of presence (POP).
‘Home’
‘Home Network’
POP• Conventional Phone• Digital subscriber
line• Cable Modem
Point of Presence (POP)
Internet Service
Provider (ISP)
Network Access Point (NAP)
Internet Service Providers (ISP)
‘Business Network’
The ISP then connects to a Network Access Point via a T3 line (night data speed through put)
POP• Conventional Phone• Digital subscriber
line• Cable Modem
Point of Presence (POP)
Internet Service
Provider (ISP)
‘Home’
NAP
Internet Service
Provider (ISP)
T1 Line
T3 Line
Internet Backbone
Internet Service Providers (ISP)
‘Business Network’
The data packets (datagrams) are then sent at high speed across the Internet backbone.
POP• Conventional Phone• Digital subscriber
line• Cable Modem
Point of Presence (POP)
Internet Service
Provider (ISP)
‘Home’
NAP
Internet Service
Provider (ISP)
T1 Line
T3 Line
Internet Backbone
Internet Backbone
Internet Service Providers (ISP)
‘Network Access Points’
This is a simplified diagram of how different networks interface.
Metropolitan Exchange (MAE) privately ownedInternet
Service Providers (ISP)
NAP
NAP
NAP
NAP
RegionalISP
RegionalISP
RegionalISP
RegionalISP
MAE
LocalISP
LocalISP
LocalISP
LocalISP
LocalISP
LocalISP
‘Regional ISP’
‘Local ISP’Internet Backbone
Internet Backbone
Internet Service Providers (ISP)
‘Network Access Points’
A backbone is typically a fibre optic trunk line (OC carrier) that can carry data at high speed.
There are many companies that operate their own high capacity trunk lines (NSP), such as:
- IBM- UUNet- CerfNet- BBN- SprintNet- PSINet
Metropolitan Exchange (MAE) privately ownedInternet
Service Providers (ISP)
NAP
NAP
NAP
NAP
MAE
Internet Backbone
Following Data Packets
Internet Service Providers (ISP)
You can follow a datagram through all the different paths taken to end up at the destination IP address.
In the windows command prompt tyle in, tracert www.bbc.co.uk
(or you can perform the following request online:
http://traceroute-online.com/