Zusammenfassung der Ressource
Networks
- An interconnected set of devices
- Each device is called a node
- Most computing devices are
connected to many networks via
the internet
- Private networks
- Advantages:
- The institution controls security
- Security issues typically involve
who is allowed what privileges
- Software is totally under
the institution's control
- The institution is not reliant
on someone else providing
reliablility
- Disadvantages:
- They need specialised staff
- A need to make own
arrangements about security
and backups
- Precautions that can be
taken against loss of
data of functionality
include:
- Redundancy - duplicate servers and
other equpiment
- Backup regime
- Failover systems - automatic
transfer to backup system in
the event of a failure
- Disaster recovery plan - processes, procedures
and personnel responsibilities in the event of a
major incident
- Hardware:
- Network Interface Card/Controller
- Receives and sends
electrical signals.
- Router
- Device to connect networks
- Receives and forwards data packets
- Directs packets to next device. Uses a table
or an algorithm to decide the route
- MAC addresses
- 48-bit identifier
- Permanently added to a device by the manufacturer
- Human readable groups of 6 bytes (octets)
- 08:01:27:0E:25:B8
- Switches
- Devices to connect other devices on networks
- Use of packet switching to send data to
specific destinations making use of
hardware addresses
- Operate at level 2 or 3 of the OSI model
- Hubs
- Connect nodes together by broadcasting
a signal to all possible destionations
- The correct destination will
accept the signal
- Wireless Access Point
- Devices can use wireless to connect to a WiFi network
- Can cannot from distances of up to about 100 metres
- Transmission Media
- Networks use cables to connect the nodes
- Copper Conductors
- Fairly cheap
- Wireless is used for part of the network
- Slower than cables and poses security threat
- Security Issues
- Eavesdropping by intercepting the wireless signals
- Reduce risk by
- Hiding SSID (service set identification)
- Limits usefulness to new users
- Encrypition
- Most use WPA and WPA2 which use only-once
encryption keys
- Limiting access
- Only allow access to known MAC addresses