Week 1: 1 Flashcards
What were the motivations for networking?
-Resource sharing
-Information sharing
-Improved Scalability
-Improved Reliability
What were the impacts on society?
-Delivery of content
-Online Services
-Numerous ways to reach people
-Many new not previously encountered problems
What telecommunication is?
Communication of signals
What data communication is?
-The exchange of data via some form of medium
The effectiveness depends on:
-Accuracy
-Delivery
-Timeliness
What are the components of communication?
- Sender
- Receiver
- Protocol
- Message
- Medium
What are the directions of data flow between the communication of two devices?
- Simplex: One direction, either transmitter or receiver
- Half-Duplex: Both directions, but one at a time
- Full-Duplex: Can transmit and receive simultaneously
For a network to be considered effective and efficient, a network must meet a number of criteria. List those criteria:
- Performance:
1. Number of users
2. Transmission medium
3. Software
4. Hardware - Reliability:
1. Frequency of Failure
2. Recovery time after failure
3. Catastrophe - Security:
1. Unauthorized access
2. Viruses
What is a computer network?
A computer network is a collection of interconnected autonomous computers.
- Interconnected: means that the computers exchange information.
- Autonomous: means that no computer can control another one in the network
List the types of connections:
- Point-to-Point: Dedicated link between two devices. (The entire capacity of the link is reserved for transmission)
- Multipoint: More than two devices share the same link. (The capacity of the channel is shared, either spatially or temporarily)
What is physical topology?
Physical topology is the way in which the network is laid out physically.
(It is the geometric representation of the relationship of all links and devices)
List the 4 Basic Topologies:
- Mesh: Every device has a dedicated point-to-point link to each other
- Star: Every device has a dedicated link only to a central controller (hub or switch)
- Bus: It is a multipoint connection
- Ring: Every device has a dedicated point-to-point connection with the two devices on either side.
What are the pros and cons of Mesh topology:
Pros:
- Guarantees full capacity
- Robustness
- Privacy/Security
- Fault identification/isolation
Cons:
- Expensive
- Amount of I/O ports
- Amount of cabling
What are the pros and cons of Star topology:
Pros:
- Fault identification
- Less expensive
- Robustness
Cons:
- Amount of cabling
What are the pros and cons of Ring topology:
Pros:
- Ease of installation
- Fault identification
Cons:
- Unidirectional traffic
What are the pros and cons of bus topology:
Pros:
- Less cabling
- Ease of installation
Cons:
- Hard fault identification
- Fault in the bus
