Homework 6

สุภาวดี ปัทมาวิไล 400323
ศิริวรรณ ระย้าทอง 400483

 

1. What are the two main performance characteristics one looks for in server technology? What are the main types of servers, and how do they differ from one another?
- The two main performance characteristics on looks for in server technology are scalability and reliability.
- The main types of servers are HIGH-END INTEL-BASED PERSONAL COMPUTERS, INTEL-BASED SUPERSERVERS ,RISC SUPERSERVERS AND MAIN FRAME SERVERS

2. Distinguish between symmetric muliprocessing, server clustering, load balancing, and geographical decentralization. Which of these improves scalability? Which of these improves reliability?
- Symmetric Multiprocessors obviously can do more work than one. Server clustering are link together to act as a single machine. There are two reasons to do server clustering. First, in line with our overall discussion, server clustering gives scalability. Server culsters have far more processing power than do single servers. The second reason to cluster is reliability. If one server in the cluster fails, there is no interruption of service. Load Balanceing routers can even support a server farm of single servers that support different services. Geographical Decentralization is a central server either is replicated at multiple servers around the world or has its most widely used webpages cached at multiple servers.

3. Distinguish between servers aimed primarily at end users and servers aimed at network administrators.
- Servers aimed primarily at end users have focused on servers that provide services to end users. File servers, client/server application servers, and the other servers that we have discussed so far in this book were created to help end users be more effective and efficient. Servers aimed at network administrators is a number of servers that support ther needs of network administrators, administrative servers use network technology to help administrators cope with the complexity of network technology.

4. How do directory servers help users? How do directory servers help administrators? What do x.500 and LDAP standardize? How are X.500 and LDAP different?
- Directory server, which maintains information about all resources on lthe network, allowing it to help users find resources they need and allowing it to help administrators control end user access to these resources.
- X.500 series of standards from OSI, LDAP standardization is managed by the IETF.
- X.500 standards were full-featured and extensible. This, unfortunately, also made them difficult and expensive to implement, LDAP is a simple protocol was developed, based on X.500 standards, to being simple than X.500, LDAP runs over TCP/IP, whereas X.500 was designed to run over an OSI protocol stack.

5. In network management, what should the network administrator be able to do from the network management console? Dis tinguish between network management programs, managed devices, network management agents, and MIBs. How do RMON probes differ from other managed devices?
- Network management console would also allow the network administrator to reconfigure devices hundreds or thoursands of miles away
- Network management program is the software on the network management console. It then digests the data and presents summarized information to the network administrator in ther form of statistical profiles and fauly (problem) diagnose.
- Managed devices are the devices controlled by the network management system are called managed devices .These can be client PCs, servers, hubs, switches, routers, carrier services, or any other piece of hardware on the network.
- Network management agents are communicates with the network management program on behalf of a managed device.
-MIB are contains information about that single device.

6. What are the two major standards for network management? What are comprehensive network management program, and why do we need them?
- The two Major standards for network managemaent are simple network management protocol(SNMP) and Common Management Infoemation Protocal/Common Management Information Services(CMIP/CMIS).
- Comprehensive Network managemaent program that can collect data using multiple network protocals and intergrate this information.
- Because vendors supported a single standard,that isn't the cast.Nor are SNMP and CMIS/CMIP tha on;y alternative.

7. What are the three layers of functionality for network management? Briefly characterize each layer.
-The 3 Layers are Trammission management have including Hubs,swicthes,Modems and Carries Tranmission lines, Tranmission management ,moves us up to the management of individual servers and client PCs ,Appilication management , the management of distibutes application such as databases application.

8. Characterize the following: authentication encryption, privacy, confidentiality, message integrity, denial-of-service attack, intrusion detection, and security self- anlysis. Why is intrusion detection, which is often ignored, critical for security?
- Authentication means requiring the person to prove his or her identify .
- Message integrity controls ensure that if the message is alternated,the reciving party will be able to detect the alteration.
-Denail-of-service attacks are aimed at making systems useless to their normail users.

9. Why is understanding the business the first step in developing a security policy? What are policy servers, and why are they important?
- Because in other bussinesses , industrail espionage may be a major concern.in some firms ,security threats 'll be fairly modest.

10. Characterize the following : plaintext, ciphertext, encryption methodology. and encryption key. Why is it important for keys to be as large as possible?

11. Distinguish between single key and public key encryption. Which reduces problems of key distribution?

12. In public key encryption, when A sends to B, what key does A uses? When A authenticates himself or herself to B, What key does A use? If A and B send messages to each other, what keys do A and B use? If A encrypts a message to B. canA read it afterward?
- When A sends to B , A encypts the message with B's pubilc key .When B sends a message to A , in turn , B encypts it with A's public key ,In other words a sender always encypts message with the reciver's pubilc key.

13. How are public key encryption and single key encryption usually combined? Why are they combined?
- The pubilc key encryption has strong advantages, it also has a major disadvantage .Compudationally ,public key encryption and decryption is far more processing intensive than single key encryption ,security protocals usually combine publice key encryption and single key encryption

14. In public key authentication, how do you prove you are who you say you are? What are the steps in creating a message containing a digital signature? How does a digital signature differ from a diginal certificate?

15. What is the function of a firewall? Distinguish between IP firewalls and application firewalls. What happens between the time that you send an HTTP request message and the time that you get the HTTP response message when you have an IP firewall? When you have an application layer firewall?

16. What are the levels of depth in filtering? What are the purposes of filtering? Explain what an integrated transmission network of the future is likely to look like.