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 Summary of last week Start Outcome 2 Practical

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

Last week A Server ? Server Hardware Basics 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 The ability to support multiple processors

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

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

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

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

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

Outcome 2 Identify components that make up a network

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

Fault Tolerance & Recovery Procedure A setup or configurations that helps prevent a computer or network device from failing in the event of an unexpected problem or error. 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 Power Surge Data Loss Device Failure Unauthorised access Over Load Virus

Fault Tolerance ? 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) Redundant power supplies and cooling fans to allow the system to continue to function when a power supply fails or a fan stops working.

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

Backup 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 1.44mb) 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. This is not the ideal (your computer may be stolen from your premises along with the backup).

Backup 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. With a DVD writer you can obtain about 10GB of data storage costing around £12 per disk.

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

Grandfather-Father-Son Backup

Raid 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 Striped set (minimum 3 disks) Requires all but one drive to be present to operate Drive failure requires replacement, but the array is not destroyed by a single drive failure. Upon drive failure, any subsequent reads can be calculated (Parity error checking) 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 ? Device Failure It is often best to have a spare device ready to install Some companies have duplicate servers on other sites that can be brought on line in the event of an outage or failure. Sometimes there can be a dual power supply to the building in case of electrical issues Some companies have their oven generators.

Install, configure and test ICT Networks Unit 408 Install, configure and test ICT Networks