Lesson 2: Server and clients and Lesson 3: Network management

SERVER AND CLIENTS

1. LESSON 2 : SERVER AND CLIENTS

2. A client-server network is a type of network composed of a central computer also, known as a server, which hosts data and other forms of resources and clients such as laptops and desktop computer which usually contact the server and request to use data or share its other resources with it.

3. HARDWARE FOR SERVERS This includes the physical components of a computer, its memory processing performance and storage capacity. The larger the number of clients is expected to the connection to a single server, the greater the volume of requests will be handled and process, thus it is required that server should have a big storage volume and faster processors. HARDWARE FOR CLIENTS Computers which are clients tend to perform requests and execute processes that do not require high performing processors compared to the server’s processor’s capacity. Its storage volume is lesser compared the server’s since its files could be directly stored to the server .

4. SOFTWARE FOR SERVERS An operating system is essential for any computer to function properly and enable users to utilize its capabilities. Modern Operating system like Windows, Linux, and Mac offer in built-in network capabilities for file sharing and management, while Network Operating System (NOS) are specialized for network management SOFTWARE FOR CLIENTS In specialized operating systems like NOS, clients are configured using network settings for server access and request reception. Remote management requires clients to have software installed as hosts. A socket program connects servers and clients, with servers listening to incoming connections and clients requesting connections using the connect command.

5. CENTRALIZED SYSTEM This type of client-server architecture is the easiest to set up, install, and maintain. It is being constructed using cables, a server and multiple clients; the latter are being connected directly to one server. Clients will make requests and the server will respond to the requests.

6. ADVANTAGES OF CENTRALIZED SYSTEM Easy to physically secure. It is easy to secure and service the server and client nodes by virtue of their location Smooth and elegant personal experience - A client has a dedicated system which he uses (for example, a personal computer) and the company has a similar system which can be modified to suit custom needs Dedicated resources (memory, CPU cores, etc.) More cost-efficient for small systems up to a certain limit - As the central systems take less funds to set up, they have an edge when small systems have to be built Quick updates are possible - Only one machine to update. Easy detachment of a node from the system. Just remove the connection of the client node from the server and voila! Node detached. DISADVANTAGES OF CENTRALIZED SYSTEM Highly dependent on the network connectivity - System can fail if the nodes lose connectivity as there is only one central node. No graceful degradation of system - abrupt failure of the entire system. Less possibility of data backup. If the server node fails and there is no backup, you lose the data straight away Difficult server maintenance - There is only one server node and due to availability reasons, it is inefficient and unprofessional to take the server down for maintenance. So, updates have to be done on-the-fly (hot updates) which is difficult and the system could break.

7. DECENTRALIZED SYSTEM This type of client-server architecture is composed of a low structure of networks being connected together to form a powerful global network. It has no dedicated central server at all but the components and structure of a decentralized architecture is strong and influential.

8. ADVANTAGES OF DECENTRALIZED SYSTEM Minimal problem of performance bottlenecks occurring – The entire load gets balance on all the nodes; leading to minimal to no bottleneck situations. High ability – Some nodes ( computers, mobiles, servers) are always available/online for work, leading to high availability. More autonomy and control over resources – As each node control its own behavior, it has better autonomy leading to more control over resources. DISADVANTAGES OF DECENTRALIZED SYSTEM Difficult to global big task – No chain no command to command others to perform certain task. No regulatory oversight. Difficult to know which node failed – Each node must be pinged for availability checking and partitioning of work has to be done to actually find out which node failed by checking the expected output with what the node generated. Difficult to know which node responded – When a request is served by a decentralized system, the request is actually served by one of the nodes in the system but it is actually difficult to find out which node indeed served the request.

9. DISTRIBUTED SYSTEM Distributed systems share software components among multiple computers for improved efficiency and performance. Resources are stored on servers in different locations for reliable response. If a server fails, requests are passed to the nearest active server, preventing outages. Distributed systems have low latency due to their geographical spread, but face challenges in consensus and logging events by absolute time. Proper decision-making and study of network architecture is crucial to avoid disruptions to business processes, organization, and management.

10. LESSON 3 : NETWORK MANAGEMENT

11. Network Administrator are people who protect the whole management of the company with regards to network processes, organization, and management. They are held responsible for maintaining computer networks and solving any problems that may occur with them. Their typical assignments and responsibilities may include but not limited to the following: Installing and configuring computer networks and systems. I dentifying and solving any problems that arise with computer networks and systems. C onsulting with clients to specify system requirements and design solutions. Budgeting for equipment and assembly costs assembling new systems Maintaining existing software and hardware and upgrading any that have become obsolete monitoring computer networks and systems to identify how performance can be improved working with IT support personnel providing network administration and support.

12. Large networks are expected to have extravagant forces time and effort to be spent on managing it. Equipment being used is volatile since different users will just come and go, devices will always have its terminating points and software keeps on upgrading. These are just some of those workloads on every shoulder of network administrators. Small networks do not require so much attention to be man aged. Occasional network problems may occur since computers are limited and small in number, therefore, network failures can easily be identified and troubleshoot.

13. A network administrator does not just end his task on network management alone but is extended. Every time a company decided to upgrade their network or at least there is a strong recommendation for an upgrade, a network administrator must be involved in every decision involving the need to buy new equipment as there are necessary versions and requirements in both hardware and software that requires compatibilities. New computers to be added to the network need new user accounts for authentications. It is being included in his job to assign new computer names, configure physical cables, and granting user rights. If new updates are available for software, the network administrator should carefully make a decision to whether to upgrade the whole network while disrupting some of the network operations and its users as little as possible or at least shut down the whole network but quickly performs the upgrade (not suggested) but there are cases it happened. Maintains data integrity like archiving old data for future purposes, backing up those data in case of archived failure and clearing network disks that contain too obsolete files. Trace the entire software installation history as a network administrator may remember a certain network functionality that really fits with the current network process.

14. The three "ups“ Network managers have a routine in maintaining, monitoring and securing their network away from possible intrusions and or illegal network activities. These are being summarized into the so-called three ups: Back up is a copy generated in order to restore possible loss files after a data loss event, deletion or corruption. It is specifically stored somewhere by network administrators most especially if these files are all related to networks. File restoration does not define a hundred percent process and re-installation however, data loss is minimal and files are recovered. (Further discussions on the next lesson). Lock up is a process of hardening and putting network securities. This is another herculean task needed to be performed by every network administrators in order to protect his network away from outside attackers such hackers, spies, scam artists and other types of intruders. Clean up is like a to-do-list job needed to be performed by network administrators. Network admins are responsible of cleaning messes brought by end-users in order to maximize the performance for databases and to avoid the scenario of having "storage is full". Now, try to imagine big social media players like facebook and twitter. In what way do you think they clean their databases and network disks?

15. Network Software Tools Administering networks is actually a challenging job just like engineers for building structures, architects for overall building architectures and astronauts figuring out unexplained celestial objects. Network administrators are unsung heroes of modern-day computing. In order to get their jobs done, they are being paired with software tools any other types of jobs don't have. The software tools that will surely help them get along with future network problems are the following: TCP/IP utilities (review previous lessons) This software tool includes commands such as: arp netstat nbtstat ping ipconfig n slookup route tracet

16. • System Information A software utility program that comes in the package with any distributed operating systems is very useful. • Hotfix checker This is a handy tool from Microsoft in order to check possible patches' updates. This tool can be downloaded for free from Microsoft's website. • Baseline Security Analyzer •Protocol Analyzer This tool can help network administrators analyze the packets that went inside and outside of the network. He can then formulate statistical analysis and address possible network issues based on the captured packets • Network monitor This tool provides basic protocol analysis and can help network admins solve pesky network problems.