Datacom 3

WAN

provides long-distance transmission of data, image, audio, and video information over large geographic areas that may comprise a country, a continent, or even the whole world.

physical topology

refers to the way in which a network is laid out physically.

networks

set of devices (often referred to as nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes on the network.

Local Area Network

usually privately owned and links the devices in a single office, building, or campus. LAN size is limited to a few kilometers.

1. Use of dedicated links guarantees that each connection can carry its own data load. 2. A mesh topology is robust. 3. Privacy or security. 4. Point-to-point links make fault identification and fault isolation easy.

Advantages of Mesh topology (4)

1.installation and reconnection are difficult. 2.the sheer bulk of the wiring can be greater than the available space can accommodate. 3.the hardware required to connect each link (I/O ports and cable) can be prohibitively expensive.

Disadvantages of Mesh topology (3)

MAN

It normally covers the area inside a town or a city. It is designed for customers who need a high-speed connectivity, normally to the Internet, and have endpoints spread over a city or part of city.

PERFORMANCE reliability security

Network criteria (3)

1. Easy to install and reconfigure. 2. Fault isolation is simplified.

Ring Topology ADVANTAGES (2)

Unidirectional traffic can be a disadvantage.

Ring toplogy DISADVANTAGES

Dependency of the whole topology on one single point, the hub.

Star Topology DISADVANTAGE

1. The controller acts as an exchange center. 2. A star topology is less expensive. 3. Robustness. If one link fails, only that link is affected. All other links remain active. 4. Easy fault identification and fault isolation.

Star topology Advatanges (4)

POINT-TO-POINT

a connection that provides a dedicated link between two devices. The entire capacity of the link is reserved for transmission between those two devices.

1. Difficult reconnection and fault isolation. 2. A fault or break in the bus cable stops all transmission.

bus topology DISADVANTAGES (2)

1. Ease of installation. 2. Uses less cabling than mesh or star topologies.

bus topology advantages (2)

MULTIPOINT

connection is one in which more than two specific devices share a single link. (If several devices can use the link simultaneously, it is a spatially shared) connection. If users must take turns, it is a timeshared connection

Drop Line

connection running between the device and the main cable.

tap

connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core.

TOPOLOGY

is the geometric representation of the relationship of all the links and linking devices (usually called nodes) to one another.