Networking Topology Flashcards
What does network topology mean?
The way a network and its connected devices (computers, printers, servers etc) are connected.
Most common topologies?
Bus, star and mesh.
What is a physical bus topology?
A bus topology uses a single coaxial trunk cable or backbone that runs between all the nodes on the network.
When a new node is added, a t-connector is used to connect the new node to the cable. Each end of the backbone is connected to either a terminator or a computer which stops signals ‘bouncing back’.
What happens with transmissions in a physical bus topology?
Each node looks at each packjet and determines whether or not the address of the rtecipient matches the node address, if so the node accepts the packet and if not it’s ignored.
Only one computer can transmit successfully at any one time, and data is sent in one direction at a time only -using CSMA.
Pros/cons of physical bus topology
Cheap to install. No additional hardware beyond central cable.
Easy to add new devices. Quick.
Main cable is a point of failure.
Limited cable length.
Performance degrades heavily with increased traffic.
Security is poor as all comps on network can see all transmissions.
What is a physical star topology?
In this topology, all clients (workstations) connect to a central node, usually a hub
or switch. This is the most common topology for businesses. A switch sends each
communication to the specific computer it is intended for. A hub broadcasts the
message to every computer on the LAN.
Pros/cons of physical star topology
If a single cable fails, only that computer is affected.
Easier to isolate faults
Consistent performance even when network traffic is high.
No issues with data collision as each comp has its own cable.
More secure if switch is used as data is sent only to the recipient.
Client-Server model allows management oif all devices.
Can be costly to set up and install as lots of caballing
Central device is point of failure.
Useful for evolving networks where devices are frequently added or removed. Well suited to applications with heavy data traffic.
What is a mesh topology?
A mesh topology is mostly used in ad-hoc networks or home networks. There is no specific structure, and all nodes can connect directly or indirectly through other nodes.
Routing or flooding.
Pros and cons of mesh network
Easy to set up as little planning is required.
If one node goes down the rest of the network can carry on as normal.
Good privacy and security since packets travel along dedicated routes.
Difficult to manage and troubleshoot.
What’s a hybrid network?
Hybrid topologies are adapted to the particular needs of a network - a bus network might also be connected to a star etc.
Difference between network and stand alone?
One computer by itself is a standalone. Once two or more computers are joined they become a network usually connected by cables or wi-fi.
Why do you need a network?
Using a network allows you to share:
Hardware, such as a printer
Software, allowing multiple users to run the same programs on different computers
Data, so that other people can access shared work and you can access your data
from any computer on the network
Networking is critical if you want to use your computer to communicate. Without it, you couldn’t send an email, a text or an instant message.
Downsides to networks/vulnerabilities.
If the network breaks, this can make several tasks it is used for quite difficult.
If computers and devices are networked together, we can expose ourselves to hackers and viruses. Most viruses are spread over a network, and most hackers use a network to access other people’s computers. Without a network connection, a hacker would have to get to your computer physically.
Cabling and servers can be large initial expense.
What’s a LAN?
A Local Area Network is when two or more computers are connected within a small geographical area, for example, confined to one building, site or home. A LAN can be created to share data or hardware such as a printer or share an internet connection.
Consists of a number of comps/devices connected to hubs or switcbes. One of the hubs/switches willl be connected to a router or modem to allow the LAN to connect to the WAN.
What is a WAN?
A wide area network is when computers or devices are connected over a large geographical area via public communications networks such as telephone lines or satelites. For example, a company with an office in London and another in Beijing would use a WAN to allow the employees to share one network. Some companies will connect several LANs in different areas together to create a WAN.
