1 Ethernet and Fast Ethernet rules

1.1 When connecting network equipment together there are some network rules which you must follow.

These rules apply to:

  • The number of hubs that can be connected together
  • The length of cabling that is used
  • The type of cabling that is used
  

Note: If you connect two Dual Speed Hubs together, the connection between them is Fast Ethernet.

1.2To connect more users to your network, you simply connect another OfficeConnect hub or switch to the existing network equipment. This provides you with more ports.

Hubs simply pass on all the information they receive. This is comparable to a chain of people passing on a message, from person to person, over a long distance. Therefore, a large number of directly connected hubs cause a lot of traffic, making the network vulnerable to collisions.

This limits the number of hubs you can connect together.

 

1.3 In the first example below, communication between two PCs travels through five hubs. This is known as five repeater hops. In an Ethernet 10BASE-T network, this is an illegal configuration and the network will not operate correctly. The maximum number of allowed repeater hops is four.

The problem can be corrected by adding a switch between the hubs. Switches operate differently to hubs and divide the network into sections. Adding a switch would result in only two repeater hops between the first PC and switch, and two repeater hops between the second PC and the switch. This complies with Ethernet rules, allowing the network to operate correctly.

 

1.4 For Ethernet 10BASE-T the maximum number of repeater hops is four. You can use Category 3 or Category 5 twisted-pair 10BASE-T cables of maximum length 100m (328ft).

Category 3 or Category 5 twisted pair cables are not telephone cables. The network will not work if telephone cables are used toconnect the equipment.

1.5For Fast Ethernet 100BASE-TX the maximum number of repeater hops is two for a Class II hub.

A Class II hub can be connected directly to one other Class II Fast Ethernet hub. All OfficeConnect Fast Ethernet hubs are Class II hubs.

A Class I hub cannot be connected directly to another Fast Ethernet hub.

Category 5 twisted-pair 100BASE-TX cables must be used.

To adhere to Ethernet and Fast Ethernet standards and avoid bad network performance, the distance between a PC or laptop and a hub or switch should never exceed 100m (328ft). When connecting two Fast Ethernet devices it is recommended that the maximum length of cable used to connect them is 5m (16.4ft).This is so that PCs and laptops can be connected to those devices with 100m (328ft) cable, without exceeding the Fast Ethernet maximum total cabling length between any two PCs and laptops of 205m (627ft).

 

1.6 If you have a network with a Dual Speed Hub connected to both Ethernet and Fast Ethernet devices, ensure that:

  • the Ethernet devices conform to Ethernet rules, and
  • the Fast Ethernet devices conform to Fast Ethernet rules

For further information about network rules when using a Dual Speed Hub, refer to the Hub's user guide.