The Internet is composed of many interconnected networks and/or subnets.
These networks and subnets are interconnected byrouters. Routers
connect End/Edge systems or Hosts to other networks and /or subnets.
The IP datagram travels from router
Most dominant wireless standard released in 1997 as IEEE 802.11 wireless
LAN (known as WiFi)
Since then further improved standards have been released. The table below
summarises the versions:
An Ethernet switch has a similar function to a hub, in fact switches are
sometimes called "switching hubs".
The difference is that a switch examines the MAC-level destination address of
every frame it receives, and transfers it dir
In 2002 it was estimated that the number of handheld devices reached one
billion (http:/www.itu.int/en/ITU-D/Statistics/Pages/stat/default.aspx). In 2013
that number has reached 6.8 billion! (There are about 7 billion pe
Twisted Pair (10BASE T) Ethernet
In early LANs the predominant form of Ethernet used so-called thin wire
coaxial cabling. Whilst this is no longer the most common hardware used for
Ethernet/802.3, it exemplifies the shared medium idea that it is
Recall (yet again!):
The Internet is composed of many networks and/or subnets interconnected by
Where the networks and/or subnets to be connected are not geographically
adjacent, it is common for a permanent point-to-poin
Token Ring (IEEE 802.5)
A token passing technology created by IBM and IEEE. A LAN of N nodes of
routers and hosts are connected in a ring. Node can transmit only when it gets
a token ( a special packet). When it sends a frame the frame
The History of the Internet begins in the USA with the development of the
first packet-switched network, the Advanced Research Projects Agency
Network (ARPANET) which connected Universities and Research centres in a
7 bytes of 0101010101. This is used to synchronise the receiver.
Start Of Frame
1 byte, thus: 01010111.
Source and Destination Address
each 6 bytes (48 bits!), and are uniquely assigned by IEEE. This is called a
station's MAC address (or MAC-leve
Digital Subscriber Line (DSL)
Asymmetric Digital Subscriber Line provides a high-speed (in the
hundreds-of-kbps to several-Mbps range) data service over an existing phone
line. The "Asymmetric" aspect is that the "downstream" data rate is usually much