Bsa 376 - Systems Analysis and Design - Network Technology

Network Technology

Vickie Jones

Professor Dwayne Gipson

BSA/376 Systems Analysis and Design

June 6, 2011

Network Topology

This document will define and compare network topology. Network configuration is comprised of the physical and logical shape of a network. Network topology refers to arrangement of the nodes in the network. Topology is the geometrical representation of linking devices or nodes to each other in LAN (Weirdo, 2009, para, 1). The physical topology of a network is the shape you can see, the logical topology of a network is the shape in which the data travels (Computer Networking, 2010, para, 1). Network topologies explored in this document include: Mesh, bus, ring, and star topologies as well as Ethernet, token ring, FDDI, and wireless technologies. The exploration will begin with a look at Mesh technology.

Mesh Topology

Mesh topology means simply that every node has a dedicated to point-to-point link to every other node in the network. This method generates traffic only between the two nodes that it connects. If n is the total of nodes in a network, then the number of links to connect the nodes in mesh= N (N-1)/2 (Weirdo, 2009, para, 2). In mesh topology each node should have a (N-1) I/0 ports as it requires a connection to every other node (Weirdo, 2009, p, 3).

Advantages of Mesh

* Reduction in traffic

* Failure of one link does not affect the entire system

* More security as data travels along a dedicated line

(Weirdo, 2009, para, 3)

Disadvantages of Mesh

* Hardware can be expansive as every two links require a dedicated line and ports

* Mesh wiring can be difficult to manage as it uses more cabling than other methods (Weirdo, 2009, para, 4).

* High administrative overhead (Computer Networking, 2010, p, 8)

* Installation can be difficult

Bus topology is another form of network configuration.

Bus Topology

In Bus topology a long backbone cable is used to link all devices in a network. Drop lines and taps which are used to connect the backbone cable to all nodes in the network comprise bus topology (Weirdo, 2009, para, 5).

Advantages of Bus Topology

* Requires less cabling than Mesh

Easy to install (Weirdo, 2009, para, 5)

* Low cost

* Coax cable is durable

* Well suited for small companies when speed is not an issue (Computer Networking, 2010, p, 6)

Disadvantages of Bus Topology

* Difficult to add new devices

* Difficult to reconfigure/fault isolation

* Unlike Mesh, a fault stops all transmission because of noise generated by faulty point (Weirdo, 2009, para, 5). Ring topology is less problematic when adding nodes.

* Bus technology is not intended to be used in large buildings

* Performance is reduced as additional nodes are added and traffic increases (Computer Networking, 2010, p, 6)

Ring Topology

In Ring topology all nodes are connected in a ring structure. Each node contains repeater. A signal passes node to node, until it reaches its destination. If a node receives a signal intended for another node its repeater regenerates the signal and passes data on (Weirdo, 2009, para 5)

Advantages of Ring topology

* Relatively easy to install and configure

* Easy to add new nodes-only two connections need changes

Disadvantages of Ring Topology

* A fault in the ring can disable the entire network. According to Weirdo, (2009) the problem can be solved by using a dual ring

Token Ring

Another configuration of ring technology is the token ring. One method of transmitting data around a ring is called token passing. The token is passed from computer to computer until it gets to a computer that has data to send (Computer Networking, 2010, p, 8). If the primary ring breaks a secondary ring can be used as backup

Advantages of Token Ring

* Data transmission is simple-data travels in one direction

* Data can be transferred without "bottleneck"

* Additional nodes do not affect bandwidth

* Configuration of token ring prevents network collisions

* Each node has equal access

(Computer Networking, 2010, p, 8)

Disadvantages of Token Ring

* Connected stations require network temporarily shutdown to add station.

* Data packets must pass through every computer making system slower

* A token ring may be difficult to troubleshoot

* Ring topology fails if any node in the ring is broken- data cannot be transmitted

(Computer Networking, 2010, p, 8). Star topology is one of the most common network configurations.

Star Topology

Star topology is relatively simple-each device has its own cable that connects to a central hub or switch. Each hub in Star topology acts as a transmitter of data. Each device can only transmit data by communicating with the central hub. A faulty hub is isolated allowing other devices to continue running (Computer Networking, 2010, p, 4).

Advantages of Star Topology

Star topology has definite advantages, among them:

* Easy to install- a cable running between it and the