Zusammenfassung der Ressource
3e Network components
and Servers
- Servers
- File servers
- Stores users and shared files on a network.
Usually a set amount of storage set for each user.
- Proxy Servers
- Manages internet access
- Stores visited webpages in cache for faster access for next visit
- Filter access to webpages to block unwanted pages
- Firewall to examine data and block undesirable data
- Application Servers
- Stores software to be used across network
- Store software so it can be run
from server by client's computer
- Increases network traffic but saves
storage, memory and processing on client
- Store installation files to deploy
software to client computers.
- Reduces traffic but increases
storage and processing needed on
client computer
- Mail Servers
- Manages all email for an organisation
- Receives all mail and puts each
in appropriate inbox
- Only authorised user can view mail
- Virus check and SPAM filter
- Provides central address book
- Sets mailbox size limits
- Sends email through LAN or WAN
- Print Server
- Manages access to printers
- Can restrict access to printers or number
of pages to be printed at once
- Send jobs to be processed by printer servers reducing
amount of processing by client computer
- Put print jobs into queue and can prioritise jobs
- Can charge users and provide
report on who printed what
- Back up Server
- Backs up all data on network so users don't have to.
- Schedules backup jobs can be done overnight each day
- Switch
- Connects several devices together through ports to enable devices
to communicate. Devices are connected to serve by cable
- Data packets are received and analysed by
switch and sent to correct destination port
- Core Switch
- Several switches connected to a core switch
- Core switch manages all data packets received
by switch and can send data between switched
- Used in large organisations
- Bandwidth can be limited or priority given to data on certain ports
- Configuring for Quality of service (QoS) to give priority to applications
that need guaranteed bandwidth e.g. video conferencing
- Can be configured to set up VLAN or monitor traffic
- Hubs
- Like a switch but doesn't examine data packets
- Data packets sent to all ports and
filtered individually by each device
- More collisions and more
susceptible to interception
- Wireless Access Point (WAP)
- Communicates wirelessly with radio signals
- Usually connected to main
network through cable to a switch
- Recipient devices need to be wirelessly
enabled e.g. laptops, mobile phones
- Signals from wireless devices received and
sent to network or another wireless device
- Easier for hackers to intercept
- WAPs have to use encryption
- Network Interface Card
(NIC)
- Enables a computer to be connected to a network using cable
- Usually automatically included on motherboard as part of computer circuitry
- Has a Media Access Control (MAC) address to uniquely identify the device
- Wireless Network Interference Card
- Used by device in order to communicate to WAP
- Can be part of internal circuitry, be in the form of
a USB wireless dongle or and adapter card
- Router
- An advanced switch
- Store address of devices
- Uses headers and tables to send data to device
in the most efficient route
- Acts as a gateway for a network
- Repeater
- Repeats signal over regular distance to prevent
the signal from deteriorating
- Used on cables, but can be wireless
- Gateway
(application)
- The exit of one network and entrance of another -
Creates a bridge between two networks
- Is part of a router, switch or proxy server
- Used to send data from LAN to WAN
- Firewall
(application)
- Configured on a computer or network to present
unauthorised access to or from a network
- Can be part of router, proxy sever or PC
- Examines all data coming in or going out of a network
and blocks access to unacceptable traffic
- Can use application gateway to allow or deny certain
application traffic e.g. email or file transfer
- Can be used to only give access to certain users
- Prevents hackers, viruses or worms getting access to LAN