1. IEEE standards

2. Who are the IEEE
Institute of Electrical and Electronics Engineers IEEE is an organization composed of engineers, scientists, and students. The IEEE is best known for developing standards for the computer and electronics industry. You will learn about the IEEE 802 standards that are widley used in computer networks.

3. What standards do I need to know?
802.3 Ethernet
802.4 Token passing bus
802.5 Token passing ring
802.7 Broadband LAN
802.8 Fibre-optic LAN/MAN
Wireless LAN

4. Ethernet
We know the as Ethernet. This dictates the type of cable that is used and how data is transferred between two devices. There are various different IEEE standards and these are transferred either over copper cables of fibre cables.

6. Standard Ethernet has a data rate of 10 Mbps and allows frame sizes of between 64 and bytes. The frame format can be seen below.

7. Collision detection 802.3
On a network all computers talk in the same “medium”. Because of this “collisions” occur when two packets are attempted to be sent at the same time. Collision detection exists as any hardware will listen to the network and detecting when other traffic is being transmitted in order to reduce the chance of collision. If it happens that a collision does occur then both stations involved will wait a set amount of time before retransmitting (each is set randomly)

8. 802.4 Token passing bus
This defines how a Bus topology functions as a logical ring.
This type of network passes a “token” around the network so that only the computer with the token is allowed to transmit. This token is passed either by the station relinquishing control or a time limit expiring.
It is not important to how the stations are connected within this network.

9. 802.5 Token passing ring
A token ring has multiple copmuters connected within a ring.
No computer may communicate without a token. Computers must relay information around the network in one direction.
On a token ring network traffic is given a priority so that some data is parked or held until higher priority traffic has been delivered.

10. 802.7 Broadband LAN
This is a set of standards used to define Broadband LAN. It is largely unused and it no longer supported by IEEE.
This should not be on your checklist!

11. 802.8 Fibre-optic LAN/MAN
This standard defines fibre optic cables and how they can be used.
It is used to discuss how FDDI (Fibre Distributed Data interface) works on a LAN

12. Wireless LAN
This is the standard for WiFi. It dictates how two computers can be connected together using radio signals.
This has been covered in a previous lesson.