Unit 408 Install configure and test ICT Networks

Unit 408 Install, configure and test ICT Networks

Outcome 2 Identify components that make up a network Today's session n Summary of last week n Start Outcome 2 n Practical

Last week n Two types of Network n Peer to peer n In a peer-to-peer network there are no dedicated servers or hierarchy among the computers. n All of the computers on the network handle security and administration for themselves. n Client Server n The network includes a File server and network Operating system

Last week n A Server ? n n A server is simply a computer that is running software that enables it to serve specific requests from other computers, called "clients. “ Server Hardware Basics Hot-swappable drives (drives that can be replaced while the computer is running) to speed adding or replacing hard disks n The ability to support multiple processors n

Last week n A server will include some applications Mail n Web (Internet Information services IIS) n SQL Database n Security (Internet Security and Acceleration ISA) n

Last week n What about the Clients how do they access the network n Clients are authenticated onto the network via the network server and its NOS.

Last week n The firewall ? A firewall's basic task is to regulate the flow of traffic between computer networks of different trust levels n Typical examples are the Internet which is a zone with no trust and an internal network which is a zone of higher trust. n

Last week n VPN n n A virtual private network (VPN) is a communications network tunnelled through another network, and dedicated for a specific network. Secure ID token n Pre-authenticating users before they gain access to any servers

Last week Basic types Internet Connections ADSL? n Asymmetric Digital Subscriber Line n Upload speed is lower than download speed SDSL? n Symmetric Digital Subscriber n Has same download speed and up load speed

Outcome 2 Identify components that make up a network

This week n Fault tolerance Power Failure n Data loss & Backups n Raid Arrays n

Fault Tolerance & Recovery Procedure Fault Tolerance ? n A setup or configurations that helps prevent a computer or network device from failing in the event of an unexpected problem or error. n To make a computer or network device more fault tolerant requires that the user or company think of how a computer or network device may fail and take the necessary steps to help prevent the computer or network device from failing

Fault Tolerance ? Key areas Power Failure n Power Surge n Data Loss n Device Failure n Unauthorised access n Over Load n Virus n

Fault Tolerance ? n Power Failure UPS to properly turn off the computer after a few minutes if the power is not restored to help prevent the computer from data corruption (Power surge also) n Redundant power supplies and cooling fans to allow the system to continue to function when a power supply fails or a fan stops working. n

Fault Tolerance ? n Data Loss? n Run a backup strategy n Grandfather-Father-Son Backup n Redundant Array of Inexpensive Disks n Mirror The server

Backup n Making a copy of an important file or files and putting them onto a floppy disk or another computer is the simple way of backing up your data although it is not the Ideal way especially for large files (greater that 1. 44 mb) n One way of backing up data is to install a second data drive and use the backup tool that comes with some versions of windows (98 upwards) and backup the data onto this second drive. n This is not the ideal (your computer may be stolen from your premises along with the backup).

Backup n A good way is to use a cd-writer in order to backup your files onto a separate removable CD allowing you to take the data Home or place it in a Fire safe. n With a DVD writer you can obtain about 10 GB of data storage costing around £ 12 per disk.

Backup n For £ 200 a better way to backup data is to install a tape drive and backup your data to a tape this will allow 24 GB of data to be backed up.

Grandfather-Father-Son Backup

Raid n n n RAID 0 Striped set (minimum 2 disks). Provides improved performance and additional storage but no fault tolerance. Any disk failure destroys the array, which becomes more likely with more disks in the array. A single disk failure destroys the entire array because when data is written to a RAID 0 drive, the data is broken into fragments. The number of fragments is dictated by the number of disks in the drive.

Raid 5 RAID 5 n Striped set (minimum 3 disks) n Requires all but one drive to be present to operate n Drive failure requires replacement, but the array is not destroyed by a single drive failure. n Upon drive failure, any subsequent reads can be calculated (Parity error checking) n The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failed drive is rebuilt onto a replacement drive

Fault Tolerance ? n Device Failure It is often best to have a spare device ready to install n Some companies have duplicate servers on other sites that can be brought on line in the event of an outage or failure. n Sometimes there can be a dual power supply to the building in case of electrical issues n Some companies have their oven generators. n

Unit 408 Install, configure and test ICT Networks