Capitulo 1
There are many diferent types of computers available:
-Servers: Provide services to many end users. server hardware is optimized for quick response time to multiple network requests
- workstations high-powered devices, designed to run specialty applications
-desktop stationary devices for home or business
- laptops are smaller than desktops computers, but are comparable in usage an power
*Bits are grouped into bytes. each byte contains 8 bits, represent quantities of disk storage capacity and RAM.
*Bits per second is used as a measurement of speed: kbps, mbps or gbps
*Megabytes per second (MBps) measurement hard disk transfer speeds
*Pixels= measure for graphics and image resolution
*Hertz= measure speed of the computer processor and wireless transmission and radio frequencies.
Motherboard system components are:
*CPU processes all data, operating software and applications within the machine
*RAM is used to store programs and data while being processed by the CPU
*Adapter card functions include video and sound cards, network interface cards, modems, interface controler cards
*Hard drives main storage medium found in servers, desktops and laptops
Capitulo 2
An operating system, is the most important software in a PC. It is responsible for making all the components and software applications work together.
The kernel interacts with the hardware
the shell interacts with the applicatons and the user
the user interacts with the shell trough the command line interface or a graphical user interface
NOS= allows a device to share resources among many users
Redirector= Software that enables the Nos to send and recieve data from the network
Perform a pre-installation checklist before installing any new OS
OS is installed in a disk partition, is a defined section of the hard disk
NIC= Network Interface Card is configured with an IP address, subnet mask and default gateway
A network should be well planned, logically organized and well documented
Patch= Is a piece of program code that correects a problem or enhances the functionality of an OS.
Capitulo 3
- Information networks can carry voice, video, and data
- Information networks consist of peripherials, hosts, network devices and media
- Topology diagrams used to depict both logical and phisical network design
-Hosts can play the role of client or server or both
- All communication has a source, a destination and a channel
- Computer communications operate under special rules, called protocols
- Protocols define the characteristics of a message including: encoding, formatting, encapsulation, size, timing and patterns
- To communicate on a local network requires the computers share a comon protocol
- The most common protocol used on a local wired networks is industry-standard Ethernet
-Each local host in an Ethernet network is identified by a phisical MAC address, which is preconfigured into a host´s NIC.
It is common to divide larger networks into smaller, more maneageable, ones using a layered hierarchical design which can include the following layers:
* Access
*Distribution
*Core
Each of these layer has a primary function and associated devices.
Capitulo 4
-An ISP is a company that provides the connctions and support to access the internet.
-ISPs support small to large geographic areas, provide services such as e-mail, web pages, IP Telephony and DNS
- Individual computers and local networks connect to the ISP at a Point of Presence (POP)
-Connection to the ISP can be done vial dial-up, DSL, cable, wireless or satelite.
IP= (Internet Protocol) Most important internet´s protocol
- The internet protocol formats packets into packets that range from 46 to 1500 bytes in lenght for Ethernet networks and must contain a valid source and destination IP address. Ip addresses must be unique on the internet
Every ISP has a control facility for their network known as:
NOC= (Network Operations Center) controls traffic flow and houses services such as email and web hosting
Ping and tracert. Utilities that test connectivity to a destination device.
On network diagrams, a cloud is often used to represent the internet without showing the details of the connections. in the internet cloud, routers are used to provide alternate paths from source to destination.
ISP must consider the physical requirements, such as a power and air conditioning, of the networking equipment, and the servers it houses.
For communication to occur a channel must be present to carry the signals, the medium is usually a physical cable:
Network cables are grouped in two: cooper cables that carry electrical signals and fiber cables wich carry light waves.
Cooper wire is extremely vulnerable to both electromagnetic (EMI) and radio frequency interference( RFI). Fiber optic cable is made of glass or plastic and is immune to emi and rfi
Unshielded Twisted Pair (UTP) cable is used on most Ethernet networks
Coaxial cable, used for cable tv and internet, has an extremely large band width capacity wich allows many signals to be combines or multiplexed together
Fiber cable provides a tremendus amount of bandwith and is suitable for use as backbone cables
Utp cable types: Straight- through, crossover, rollover
TIA/EIA twisted pair terination schemes are T568A and T568B
Capitulo 5
Each logical IP address is made up two parts: network ID and the unique host ID on that network.
IP address is a series of 32 binary bits, grouped in octets
The ip address and subnet mask work togheter to determine wich portion of the IP address represents the network address and wich represents the host address
IP addresses are grouped into 5 classes: Classes A, B. C= are commercial. D= multicasting. E= experimental. Each class has its own default subnet mask
IP addresses are classified in private or public. PUBLIC= are unique and are used on the internet. PRIVATE= Can be used internally by hosts in any organization
Hosts can use IP addresses to communicate one.to.one (unicast) one-to-many (multicast) or one-to-all(broadcast).
