Chapter 9: Network Optimization
Core Idea
The central topic of this chapter is network performance, particularly how to measure it and
how to improve it.
Instructor Focus
Network Objectives covered in this Chapter/Lesson
o Compare and contrast business continuity and disaster recovery concepts.
Terminology
Make an effort to define the following terms for the designated areas. After defining these,
calling on the students for repeat definitions as you progress through the slide deck will help
them retain the terminology.
Network Performance Metrics:
x Availability
x Reliability
Network Performance Challenges:
x Latency
x Jitter
x Traffic shaping
x Committed information rate (CIR)
x Link efficiency
Focus Questions
x Why is high availability a requirement in today’s network designs, and what mechanisms can
help provide that high availability?
x What various technologies optimize network performance?
Icebreaker Discussion
Choose one or both of the following:
1. What is necessary to have network availability and why is it beneficial?
This opening discussion should speak to the need for performance in networks. To be
available, a network must be operational and capable of accepting and routing traffic. This is
2. What information is most important for describing a network?
This discussion should move students from considering the basic terminology of networks
and the early descriptions of geography and topology to a description of a network by the
services it provides and the qualities that it maintains. Service descriptions may include the
Icebreaker Activity
1. Diagram a network connecting two devices on two different broadcast domains via a central
router that is fault tolerant, meaning that it has no single point of failure in connecting the
two machines provided the machine can reach the switch on its broadcast domain.
This exercise is meant to reinforce concepts on routing and broadcast domains. You can
start the students with the following diagram if they are stuck, but encourage them to plan
the network and discover the best way to link everything such that any link can go down and
the path can still be maintained.
In this example, you would need to reinforce the connections between the switches and the
router. Because there is only one router, it acts as a single point of failure as well. You must
therefore back it up as well as making sure the switches are able to reach either router even
if their link to the router goes down. The discussion may tend to more elaborate designs,
but the following will satisfy the requirement, though different configurations could easily
be argued.
Main Activities
1. Chapter 9 Case Study: SOHO Design Example
The textbook has an excellent case study in this chapter that you should complete with your
class. You can decide whether you want to walk through the entire scenario or stop at a certain
point to assign the rest as individual or group work. The best part of this scenario is that it can
be met by many different configurations, so there is no single solution. Keep in mind, though,
The following is the design criteria for the network to consider:
x Company ABC leases two buildings (building A and building B) in a large office park, as
shown in Figure 9-15. The office park has a conduit system that allows physical media to
run between buildings. The distance (via the conduit system) between building A and
building B is 1 km.
x Company ABC will use the Class B address of 172.16.0.0/16 for its sites. You should
subnet this classful network to support not only the two buildings (one subnet per
building), but to allow as many as five total sites in the future, as Company ABC
continues to grow.
x Company ABC needs to connect to the Internet, supporting a speed of at least 30 Mbps,
and this connection should come into building A.
The topology for this is shown here.
Figure 9-15
The following goals should be the focus of the exercise:
x Meeting all requirements
x Media distance limitations
x Network device selection
x Environmental factors
x Compatibility with existing and future equipment
The following should be included in the solution:
x Network address and subnet mask for building A
x Network address and subnet mask for building B
Chapter 9: Network Simulator Activities
x Contrast Virtualization Technologies and Services
x Identifying Network Performance Terminology
Quiz Questions
You can ask the following questions either in class for a group discussion or for individual practice. If
1. What is meant by five nines of availability? How is this different from reliability?
2. What are the benefits and drawbacks of having no single point of failure in a network?
The benefit is that any link can or device can fail in a network without compromising the ability
to deliver the traffic from the sender to the receiver, which positively impacts the availability
3. Briefly summarize the three basic steps of quality of service (QoS) configuration.
1) Determine network performance requirements for various traffic types including voice, video,
and data (along with any specific data that has its own requirements).
4. What is the difference between congestion management and congestion avoidance?
Congestion management is the division of a device’s buffer for storing traffic that cannot
immediately be sent out on the network until bandwidth becomes available; this determines the