Chapter 8: Homework Problems

 

Review Questions

1.) Give five scenarios why a network manager would benefit from having network management tools.
2.) What are the five areas of network management defined by the ISO?
3.) What is the difference between network management and service management?
4.) Define the following terms: managing entity, managed device, management agent, MIB, network management protocol.
5.) What is the role of the the SMI in network management?
6.) What is the purpose of the ASN.1 Object Identifier tree?
7.) What is an important difference between a request-response message, and a trap message in SNMP?
8.) What are the seven message types used in SNMP?
9.) What is meant by an "SNMP engine"?
10.) What is the role of  ASN.1 in the ISO/OSI reference model's presentation layer?
11.) Does the Internet have a presentation layer?  If not, how are concerns about differences in machine architectures, e.g., the different representation of integers on different machines, addressed?
12.) What is meant by TLV encoding?
13.) What is the difference between using a filter, and using an application-level gateway approach in a firewall?

Problems

1) Consider the two ways in which communication occurs between a managing entity and a managed device: request-response mode and trapping.  What are the pros and cons of these two approaches, in terms of (i) overhead, (ii) notification time when exceptional events occur (iii) robustness with respect to lost messages between the managing entity and the device?

2)  In section 8.3 we saw that it was preferable to transport SNMP messages in unreliable UDP datagrams.  Why do you think the designers of SNMP chose UDP rather than TCP as the transport protocol of choice for SNMP?
 
3) What is the ASN.1 object identifier for the ICMP protocol (see Figure 8.3.1)?

4) Consider Figure 8.4-4.  What would be the BER encoding of {weight, 271} {lastname, "Jackson"}?
 

 Discussion Questions

1) In addition to the power plan and airplane cockpit analogies, what is another analogy of a complex distributed system that needs to be controlled?

2.) Consider the motivating scenario in Figure 8.1-1.  What other activities do you think a network administrator might want to monitor?  Why?

3.) Read RFC 789. How might the ARPAnet crash of 1980 been  avoided (or its recovery simplified) if the ARPAnet's managers had today's network management tools?