Provide an advantage and disadvantage of using the layered approach for computer

Question

Provide an advantage and disadvantage of using the layered approach for computer networks. When using web caching, we saw that the proxy server still contacted the origin server for each HTTP request it received. As a result, is the amount of traffic in the core of the network reduced? What is the purpose of the HTTP "Cookie" field? Are the values in the HTTP message's cookie field stored at the client or server or both? Explain briefly. Briefly explain how the traffic intensity at a certain node will affect the corresponding node's queuing delay. Suppose that we want to change the IP address of from 128.119.40.186 to 128.119.40.186 and change this mapping in the DNS authoritative name server for Once this mapping is changed in the authoritative name server, will all future references (generated anywhere in the Internet) to be sent to 128.119.40.187? Briefly explain why or why not.

Explanation / Answer

A)

Advantages of layered :

1. Provide a way to give different abstraction at each layer

2. different error control at different layer

3. Layered architecture increases flexibility, maintainability, and scalability.
In a Layered architecture we separate the user interface from the business logic, and the business logic from the data access logic. Separation of concerns among these logical layers and components is easily achieved with the help of layered architecture.

4. Multiple apps can re-use the components.

5.Layered approach enables teams to work on different parts of the application parallely with minimal dependencies on other teams.

6.Layered approach enables develop loosely coupled systems.

7. It makes it possible to configure different levels of security to different components deployed on different boxes.

Disadvantages :

1 . There might be a negative impact on the performance as we have the extra overhead of passing through layers instead of calling a component directly.

2. Development of user-intensive applications can sometime take longer if the layering prevents the use of user interface components that directly interact with the database.

3. The use of layers helps to control and encapsulate the complexity of large applications, but adds complexity to simple applications.

4. Changes to lower level interfaces tend to percolate to higher levels, especially if the relaxed layered approach is used.

Ans(B)-

The goal of caching in HTTP is to eliminate the need to send requests in many cases, and to eliminate the need to send full responses in many other cases. The former reduces the number of network round-trips required for many operations hence the traffic is reduced. Also sometime proxy server contact origin server for the cache correctness and more many other reasons.

Ans(3). Both

An HTTP cookie (web cookie, browser cookie) is a small piece of data that a server sends to the user's web browser, that may store it and send it back together with the next request to the same server.
It remembers stateful information for the stateless HTTP protocol.

For explanation for any of above questions please comment me.

Please do not post full paper in a single query since it is hard to answer all question in a single query so as per the guidelines of Chegg please do post single question in a single query.

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