Specifications

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 1 Understanding Networking and IP Addressing
Introduction to Networking
1–8
Fiber Optic Cable
Optical fiber transmits signals of light through a very fine strand of plastic or glass
fiber, which is encased in a tube made of glass called cladding, surrounded by a tough
outer sheath. The cladding is designed to reflect light back into the optical fiber,
which causes the light to bounce from side to side as it moves through the optical
fiber. There are single-mode cables (one optical fiber) and there are multi-mode
cables. Multi-mode cables have several optical fibers grouped at the center, each
providing a separate communications channel.
Wireless
Network
Communications
Wireless communications transmit data without the use of physical media (i.e., wire)
and conduit. Wireless communications include radio transmissions, laser, infrared,
and others. The greatest benefit of wireless communications is that the technology
supports non-traditional network configurations.
Radio waves can be used to transmit to a number of devices throughout a building
without concern for existing structures (i.e., walls or other solid obstructions).
Microwaves can be used to transmit across long distances, such as across a city or
rural area, without having to run wires or lease private telephone lines. Ultra-Low
Frequency radio waves can be used for great distances through the earth or through
bodies of water.
Wireless applications might include:
Local Area Network: An existing school is retrofitted with a radio transmitted LAN
that connects computers in each classroom to create a common network.
Extended LAN: Multiple schools in a district are connected together by the use of
point-to-point microwave transmissions.
Mobile Computing: Laptops are outfitted with modems that use cell telephone
technology to dial-in to the central system to join that network as needed.
Network
Interface Card
Network interface cards (NIC) act as the physical interface or connection between the
computer and the network cable. NICs are installed in an expansion slot in each
computer and server on the network, then cables are used to connect the PCs to other
devices—other PCs, hubs, routers, etc.—to form a network. A NIC can also be built
onto a motherboard, as is the case on a JACE-4/5.
Each NIC has a 6-byte address (called the Media Access Control or MAC address).
The first three bytes of the address are the manufacturer’s code and the last three
bytes are a serial number. The combination makes the address unique, world-wide.
The MAC address is used to pass data to and from the computer.
6 Coaxial 100 Mbps+ data
7 Fiber Optic 100 Mbps+ data
Table 1-1 Cable categories.
Category Cable Type Application