Topologies

Question 1

What is a Node, and what are the general types?

Answer 1

Devices that send, receive and forward data.
The types are:
Intermediate nodes- Performs forwarding functions.
End systems- Sends and receives data traffic also called hosts.

Question 2

What is a link?

Answer 2

The communication pathways that connect nodes.
e.g. cables, fiber Wi-Fi etc.

Question 3

What can End system nodes be classified as?

Answer 3

Clients: Consumes the services provided by serves.
Servers: Makes the network applications and resources available to other hosts.

Question 4

Describe a client- server network.

Answer 4

Where some nodes act mostly as clients and the servers are more powerful computers that are centrally managed, provisioned and secured.

Question 5

Describe a peer-to-peer network.

Answer 5

Each host on this network acts as both the client and the server.
A decentralized model where provision, management and security of services and data are distributed around the network.
Also referred to as a workgroup.

Question 6

What is a network application?

Answer 6

Applications that allow the network to do useful work.
i.e. sharing files or sending emails.

Question 7

What is a network function?

Answer 7

How networks can be configured with additional properties to perform different functions.
Ex. QOS or security properties of VPN allowing devices to join a local network across the internet

Question 8

What is a network appliance?

Answer 8

A computer with a OS and software designed to perform a particular network role.

Question 9

How can a networks size and scope be measured?

Answer 9

Size- measured as the number of nodes
Scope-the size of the area you’re covering with nodes sharing the same network address.

Question 10

What is a topology?

Answer 10

Describes the physical or logical structure of the network in terms of nodes and links.

Question 11

What is a Star Topology?

Answer 11

Where each endpoint node is connected to a central forwarding appliance.
The central node mediates communications between the endpoints.
Most widely used topology.
Easy to reconfigure and troubleshoot
E.g. A switch or a router.

Question 12

What is the hub-and-spoke topology?

Answer 12

Has the same physical layout as a star topology but is more commonly used in WANs while star topologies are more commonly used in LANs.

Question 13

What is a mesh topology?

Answer 13

A full mesh requires that each device has a point to point link with every other device on the network.
Provides excellent redundancy, can be very pricey so its more practical for a partial mesh where the most important devices are interconnected for fault tolerance and redundancy.
Number of links required can be calculated by n(n -1)/2 (n= nodes).

Question 14

What is a bus topology?

Answer 14

All nodes are connected to a trunk (backbone) cable.
Signal travels from one node to all the other nodes.
A device called a terminator is placed ay both ends of the trunk cable to prevent them from reflecting repeatedly across the cable.
Broken cable anywhere breaks the termination and prevents communications between all devices on the network.
Difficult to isolate cabling problems.

Question 15

What is a ring topology?

Answer 15

Connects neighboring nodes until they form a ring or a circle.
The signal travels in one direction around the ring, and each device acts as a repeater to send the signal to the next device.
Requires careful planning, a node malfunction or cable break can prevent signals from reaching nodes beyond the malfunction.
Difficult to isolate the issue to troubleshoot.
Legacy topology.