Process Analysis

The final step of conducting your audit is process analysis. Process analysis means learning the various processes used to design, maintain, and troubleshoot the network. By understanding how things get done in your organization, you will be able to more effectively make process changes to help document your network.

Specifically relevant to this chapter, the following will help determine how effectively you can maintain the information gathering:

• Is there a change control process? If so, is it adhered to?

• How does each form of documentation get updated?

• How does a fault get created and tracked?

• How are the causes of outages determined and documented?

• How is customer satisfaction tracked?

The study of organizational processes is not for the faint of heart. There are plenty of resources and consultants available to assist you with this process. Kornel Terplan provides an excellent discussion on process analysis for a network management organization in Benchmarking for Effective Network Management (see "References").

Summary

You must first learn and document your network before introducing performance and fault management. Tracking and documenting network devices and their connectivity is vital when analyzing performance data, as well as during fault isolation.

When determining what and how to document, be sure to track the information in a timely and correct manner. Otherwise, the documentation will become less reliable over time, and it will cause operators to look elsewhere for their information.

Understanding device ownership and processes in place to manage leads to the effective implementation of low-impact and maintainable documentation.

After you have documented the network as described in this chapter, you will be prepared for the next chapter, "Policy-Based Network Management," in which you conduct a baseline analysis of the network.

References

Books

Leinwand, A. and K. Fang Conroy. Network Management: A Practical Perspective . Reading, MA: Addison-Wesley, 1996.

Stallings, W. SNMP, SNMPv2, and RMON: Second Edition. Reading, MA: Addison-Wesley, 1996.

Terplan, Kornel. Benchmarking for Effective Management . New York, NY: McGraw-Hill, 1995.

Terplan, Kornel. Communication Networks Management . Upper Saddle River, NJ: Prentice Hall, 1992.

Paper

Berthet, Gerard and Paul Della Maggiora. "Cisco Network Monitoring And Event Correlation Guidelines." Cisco White Paper , 1998.

Internet Resource

Cisco Discovery Protocol MIB

http://www.cisco.com/public/mibs/v2/CISCO-CDP-MIB.my

Chapter 2. Policy-Based Network Management

Routers have become quite complex when compared to their original task of simply routing. To name a few features: routers now provide QoS, firewall, packet-encryption, tunneling, filtering and web-caching capabilities. These features require that multiple routers be configured similarly in order to be able to deliver a consistent level of capabilities. If QoS packet coloring and queuing features, for example, are not implemented consistently through your network, packets will not be colored and queued similarly as they travel through the network.

Likewise, Layer 2 LAN switches have become more complex since their original bridging intentions. Some Catalyst switches now make forwarding decisions based on Layer 3 network and Layer 4 transport portions of a packet. Consistent implementation across your network of features, such as portfast/uplinkfast/backbonefast, dynamic port VLAN membership, Layer 3 protocol filtering, and QoS becomes increasingly difficult.

What these router and switch features provide, though, is the capability to control how traffic is passed through the network. Time-sensitive applications such as voice over IP and video require that packets make it to their destination on time. Additionally, network managers want to limit bandwidth for some applications (such as file transfers and backups ) in order to let other traffic through.

Unfortunately, configuring these features and determining whether they actually do what you configured them to do can be difficult. Also, as configuration changes take place in the network and new applications are introduced, previous network device configurations may no longer meet their original objectives.

Traditionally, the configuration of router or switch features has been done on a device-by-device basis. If you wanted to restrict access to various parts of a network to a particular group, you had to configure the access lists from the device command line for each device that the group 's traffic may traverse.

More recently, network management tools have shifted (or attempted to shift) their focus away from device-centered management to network-centered management (also called policy-based management ). This chapter discusses three areas of policy-based management that pertain to the fault and performance management of your network:

• Defining network policies

• Baselining the network to determine network policy suitability

• Using service level agreements to measure and report on the effectiveness of policies

The chapter concludes with an example scenario in which these aspects of policy-based management are applied to a network.