Introduction
TERMINOLOGY
Topology
There are two types of Topologies:
Physical:
The ACTUAL physical arrangement or how they are connected by use of cabling) of the components of a network such as cables, network devices and endpoints
Bus Topology - Cabled in a line like co-ax cable 10 Base 2. Nowadays, the bus is established in a hardware device and connect the host device to the bus using twisted pair wiring
Ring Topology was used by Token Ring and FDDI , whereby the last device was connected back to the 1at device thus forming a "ring"
Star Topology, one of the most common typologies, a central device had other devices connected to it
Mesh Topology - redundant links and reliability.
Logical
This can be very different to the physical topology and describes the PATH over which DATA is transferred in a network.
For example a 'hub" is physically a star topology but logically acts as a bus topology
Speed
Speed is the measure of the data rate over a given kink and id measured in bits per second (bps). Don't get confused with Bytes (8 bits = 1 Byte)
Cost, Security and Availability
Cost is the expense for purchasing the network components as well as the cost for installing and maintaining the equipment
Security - how well a network is protected from both inside and outside threats. Security is very important especially because of the number of attacks on companies by hackers etc
Availability is the measure of probability that a network will be available for use when it is required .Its represented as a percentage of time that the network is available and its represented by the UPTIME. To calculate the uptime:
Availability = (No of min per year - down time)/ (no min per year)*100
Example 15 min of outage therefore
Availability = [(24*365*60 - 15)] / (24*365*60) *100 = 525585/52560 * 100 = 99.9971%
Scalability
Scalability indicates how easily the network can grow and accommodate more users and transmission requirements. Must be designed with growth in mind
Reliability
Indicates the dependability of the components that make up the network and is often measured as a probability of failure or Mean Time Before Failure (MTBF)
Network Diagram
A network diagram captures network related information and the amount of information varies between different organisations
A network diagram is essentially a "map" of a network and illustrates the logical representation of the devices in the network and helps clarify how the devices are interconnected
In addition, a well designed network diagram provides information such as the:
interface id's of devices
device identifiers as well as,
network addressing
network icons such as lane switches, routers , wireless access points, servers, end points, Ethernet links, serial links, wireless links and networks (cloud symbol) which could indicate the cloud, different networks, internet network or lab network etc.
Application Types and Network Performance
Different types of applications can affect network performance, and network performance can affect user experience of applications. Some application types and points to consider:
FTP and TFTP are considered "batch" applications. Other types of applications include Inventory updates, file copies (within Windows) and Software downloads require no or little human intervention.
"Interactive" applications like Inventory inquiries and database updates require a lot more human intervention. In these instances a user will usually "wait" for a response etc.
Real Time applications (like Voice and Video), require very good quality of service and little or no delay. These applications are used for human-to-human interaction and any delay or latency will degrade the user experience.
Initial Setup Commands
Enable Password
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