Day03 – Architecture of Computer Networks

Architecture of Computer Networks

In computer networks, the problems involved in communication between computers are very complex. fromUser submits information to begin, to the other computer where the information is transmitted through the communication line,final delivery to the receiving user

This communication process involves:

network application program, network communication program, computer operating system, computer hardware system, network communication interface, communication line and communication transmission network.

Therefore, it is quite difficult to design the communication protocol of this network to allow all computers to be connected to a computer network. Even if a perfect network communication protocol is designed, due todevelopment of computer hardware,software system upgradeas well asCommunications network,communication lineThe changes will affect the performance of the communication protocol.

4 Characteristics of Internet Architecture

safety

If the public wants to be able to use the Internet whilekeep privacyIf so, then network security is very important.

People who use the Internet for business activities need network security to protect their financial transactions, and governments and some businesses that require personal information (such as hospitals) must protect their customers’ personal privacy. Just as the citizens of a town want insurance and safety, so does the community of Internet users. Without security, like the citizens of towns, these users will look elsewhere for their business activities. Information encryption and security devices at LAN gateways are both methods and means used to achieve network security . However, encryption and firewalls are not enough to protect a network. As people use the Internet to exchange confidential and business-critical information, expectations for security and privacy are high and beyond the capabilities of current architectures. Therefore, more work has been devoted to R&D in this area. At the same time, various tools and procedures will be utilized to overcome the inherent security flaws in the network architecture.

fault tolerance

Redundancy, or duplication of devices and media, is a key factor in fault tolerance.

If a server fails, a backup server performing the same function can take over the job until the original server is repaired. If the data connection fails on a fault-tolerant network, the message will be routed to the destination on the backup router.

service quality

Quality of service shows what the network offersservice level.

Providing services like online video and voice requires more resources than services such as email. Because many technologies converge on a platform where separate handling of different service types can allow one service to be prioritized over another . For example, a network administrator can decide that data for web conferences has a higher priority than e-mail service. Prioritize different types of data by configuring the device.

Scalability (adaptability)

Extensibility describesnetwork adaptability.

A scalable network can add new users and devices without having to redesign the network, and a network with adaptability, or scalability, can directly add new users without having to rebuild the entire network . A scalable network should be able to expand internally and externally, connect to other networks to form an Internet connection, and be able to keep pace with user needs.

Fault-tolerant network architecture

A communication medium that can withstand the disruption of multiple sites and transmission facilities without service interruption.

Circuit Switched – Connected Networks (Physical Connections)

The network infrastructure of the very early days was a network oriented towards circuit-switched connections . The operator and the original dialing system connected telephone calls by establishing a temporary circuit , which was a physical connection capable of transmitting telephone signals from the sender to the receiver. This technique is connection-oriented, as any physical link loss or device problem between the two users will end the call . This requires starting a new call and providing a new circuit.

Disadvantage: One phone line occupies all circuits, and no other calls can use the circuit until the original call is over. High cost, not suitable for long distance calls ! !

Packet switching – connectionless network

In order to solve the problem of fault tolerance, the network gradually develops intoPacket switched connectionless network .

In a packet-switched network, a single message is divided into multiple data blocks, called packets , which contain the address information of the sender and receiver. These packets travel through one or more networks along different paths and are reassembled at their destination.

Packet switching technology is connectionless because it does not require a dynamic connection to be established for the call . This is more efficient than circuit-switched networks because multiple users can use the network circuit. Packet switching technology is fault tolerant because it avoids the danger of relying on a single circuit to provide reliability for services . If one network path fails, other network paths can still deliver the message complete.

Scalable Network Architecture

A scalable network canThe core is basically unchangedextension. The Internet is an example of scalable design. The Internet has grown exponentially over the past 10 years or so, and the core design has not changed . The Internet is a collection of private and public networks interconnected by routers.

High-tier Internet service providers have a large number of Domain Name Servers (DNS) that track Internet addresses. This information is replicated and shared with lower layers in the system. This layered, multi-level structure allows most traffic to not be handled directly by upper-layer servers. This distribution of processing work means that changes to the underlying structure, such as adding a new Internet Service Provider (ISP), do not affect the upper layers.

Architecture that provides Quality of Service (QOS)

When the Internet was first put into public use, people were amazed at what the network could do and tolerate network delays and message drops. Now, however, users have adaptedFaster rates and higher quality of service.

Quality of service refers to the mechanism used to manage network traffic congestion . Congestion is caused by network resources exceeding its carrying capacity . The use of network resources is subject to some unavoidable conditions. These constraints include technical limitations, overhead, and local availability of high-bandwidth services. Network bandwidth is a measure of the data carrying capacity of a network . When concurrent traffic attempts to pass through the network, the demand for network bandwidth may exceed its own effective use of bandwidth. Obviously this case is handled to increase the amount of available bandwidth. However, this is not always possible due to the constraints introduced earlier.

With Quality of Service, network administrators can choose which traffic can be prioritized on the network . Different organizations and individuals have different needs and priorities, and these different needs can be achieved by classifying network traffic and assigning priorities to each category.

Architecture that provides cybersecurity assurance

A network security breach can lead to a variety of serious consequences such as:

Network failure, resulting in loss of communications and economic business

loss of personal or business funds

intellectual property theft

Customer data exposure

and many more.

Provides two aspects of security:

network infrastructure security

Content Security

Network infrastructure security means protecting devices from outside connections. Locking the computer room door and securing network equipment and software with a high-quality password is one of the simplest of many ways to secure your network infrastructure.

Consolidating the security of network content means securing the data stored in network devices and the data packets transmitted over the network. Web content security means ensuring confidentiality, maintaining the integrity of communications and ensuring network availability.

Measures to provide cybersecurity

measure content

ensure confidentiality 1. Maintain data privacy by allowing access to data only by intended and authorized recipients (persons, processes or devices). 2. Selected as a person to experience the Jiang family.

Maintain communication integrity 1. Ensure that the information is not changed during the transmission from the source address to the destination address. 2. Verify the identity of the sender (digital signature, hash algorithm, verification mechanism, etc.)

ensure availability 1. Ensuring the availability of resources is also an important aspect of a cybersecurity program. In order to prevent the computer from being attacked by viruses, legitimate users cannot use resources. 2. You can use a firewall to defend against viruses.