COMPUTER NETWORKS
Security is very important not only in real life even for computer networks too
and the last phase of the computer network will cover the need for security and
how security is provided in computer networks. A computer network is a set of
nodes connected by communication links. A computer is a node because a
computer can send data as well as receive data. A node can be a computer
printer or any other device capable of sending or receiving data. Many devices
like switches bridges and routers are also called as nodes.
It is a set of nodes connected by communication links where that link can be a
wired link or a wireless link. The devices which are the source or the destination
in the communication are called as n devices the devices which forwards the
data from one side to another side are called n devices.
Basic Characteristics
• Fault tolerance
• Scalability
• Quality of service
• Security
Fault Tolerance
Fault tolerance is the ability of a computer network to continue working despite
failures and ensuring that there is no loss of service. For example, if there is a
problem within the network, it should still work even after the failure.
One example of fault tolerance is when a router fails, and instead of forwarding
data through the failed route, it forwards it to another route to ensure that
communication between two entities is not affected.
Scalability
Scalability is the ability of a computer network to grow based on its needs and
have good performance even after growth. The best example of a scalable
network is the internet, which handles new devices connecting and
communicating with each other efficiently.
Quality of Service
Quality of Service is the ability of a network to set priorities and manage data
traffic to reduce data loss and delays. For example, if a router receives two
, packets at the same time, it should prioritize which data to process first. This is
especially important in real-time communication, where delays are not
accepted.
Security
Security is the ability of a computer network to prevent unauthorized access,
misuse, or forgery. It should also provide confidentiality, integrity, and
availability of data. Attackers can steal confidential information, involve in
forgery, and deface web servers, making security an essential characteristic for a
computer network.
Network Protocols & Communications
Protocols are a set of rules that govern data communication, determining what is
communicated, how it is communicated, and when it is communicated. The five
elements of a protocol - message encoding, message formatting and
encapsulation, message timing, message size, and message delivery options -
are reviewed. Protocols convert data into signals or waves, with message
formatting and encapsulation adding source and destination IP addresses to
packets. Message timing is important to ensure that flow control is maintained,
and protocols help with this by specifying how much data can be sent at once.
Overall, protocols help to maintain effective communication by ensuring that
communication is standardized and organized.
The sender must wait for an acknowledgment to ensure that the data has been
received by the destination. The video also explains the concept of message
size, highlighting how larger files are broken down into smaller segments and
numbered sequentially to ensure proper reassembly and to identify any missing
packets. The three types of communication - unicast, multicast, and
broadcasting - are explained, along with the concepts of peer-to-peer and client-
server networks.
Components of a Computer Network
The components of a computer network, including nodes, media, and services.
Nodes
• A node can send or receive data and can be an end device or an
intermediary device.
• End devices are the starting or ending point of communication between
two devices.
Security is very important not only in real life even for computer networks too
and the last phase of the computer network will cover the need for security and
how security is provided in computer networks. A computer network is a set of
nodes connected by communication links. A computer is a node because a
computer can send data as well as receive data. A node can be a computer
printer or any other device capable of sending or receiving data. Many devices
like switches bridges and routers are also called as nodes.
It is a set of nodes connected by communication links where that link can be a
wired link or a wireless link. The devices which are the source or the destination
in the communication are called as n devices the devices which forwards the
data from one side to another side are called n devices.
Basic Characteristics
• Fault tolerance
• Scalability
• Quality of service
• Security
Fault Tolerance
Fault tolerance is the ability of a computer network to continue working despite
failures and ensuring that there is no loss of service. For example, if there is a
problem within the network, it should still work even after the failure.
One example of fault tolerance is when a router fails, and instead of forwarding
data through the failed route, it forwards it to another route to ensure that
communication between two entities is not affected.
Scalability
Scalability is the ability of a computer network to grow based on its needs and
have good performance even after growth. The best example of a scalable
network is the internet, which handles new devices connecting and
communicating with each other efficiently.
Quality of Service
Quality of Service is the ability of a network to set priorities and manage data
traffic to reduce data loss and delays. For example, if a router receives two
, packets at the same time, it should prioritize which data to process first. This is
especially important in real-time communication, where delays are not
accepted.
Security
Security is the ability of a computer network to prevent unauthorized access,
misuse, or forgery. It should also provide confidentiality, integrity, and
availability of data. Attackers can steal confidential information, involve in
forgery, and deface web servers, making security an essential characteristic for a
computer network.
Network Protocols & Communications
Protocols are a set of rules that govern data communication, determining what is
communicated, how it is communicated, and when it is communicated. The five
elements of a protocol - message encoding, message formatting and
encapsulation, message timing, message size, and message delivery options -
are reviewed. Protocols convert data into signals or waves, with message
formatting and encapsulation adding source and destination IP addresses to
packets. Message timing is important to ensure that flow control is maintained,
and protocols help with this by specifying how much data can be sent at once.
Overall, protocols help to maintain effective communication by ensuring that
communication is standardized and organized.
The sender must wait for an acknowledgment to ensure that the data has been
received by the destination. The video also explains the concept of message
size, highlighting how larger files are broken down into smaller segments and
numbered sequentially to ensure proper reassembly and to identify any missing
packets. The three types of communication - unicast, multicast, and
broadcasting - are explained, along with the concepts of peer-to-peer and client-
server networks.
Components of a Computer Network
The components of a computer network, including nodes, media, and services.
Nodes
• A node can send or receive data and can be an end device or an
intermediary device.
• End devices are the starting or ending point of communication between
two devices.
