What should I see if my network is running efficiently?

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Article ID: 167372

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PacketShaper

Issue/Introduction

PacketShaper with properly applied traffic management controls make your network run more efficiently.

This article discusses what PacketWise measurements indicate that your network is running efficiently.

Resolution

What is An Efficient Network?

A network is efficient if

  • Packet retransmission is minimal
  • Network utilization is reduced
  • Users get a good network experience

The last item is a subjective measure, but is still a benefit of an efficient network. Let’s look more closely at the first two since PacketWise objectively measures these network attributes.

If packet retransmission is minimized on our network, there is less wasted bandwidth. The waste that is eliminated from unnecessary retransmissions results in the availability of more bandwidth that can be used by network users to accomplish their desired tasks.

By reduced network utilization, we are referring to reducing the amount of bandwidth needed to complete the tasks users perform on the network while maintaining good response time.

Using the Report Tab to Analyze Network Performance

PacketWise allow you to easily monitor overall network performance using the Report tab. For further information, see Show Link Utilization in PacketGuide. The Network Performance Summary report shows three graphs for each direction, inbound and outbound:

  • Network Utilization
  • Network Efficiency
  • Top Ten pie chart

Network Utilization Graph

The Network Utilization graph shows how much bandwidth you are using. The scale peaks at your maximum rate or slightly more. The graph shows two lines -- the peak-bps and avg-bps used. These are shown by time of day over the last month, week, day, or hour.

If you see a graph with high network utilization (almost the whole link) is that good? It depends.

Most likely the answer is no because you probably have significant bandwidth-wasting packet loss resulting in retransmission. This retransmission robs you of efficiency and wastes bandwidth.

Another telltale sign to look out for is average versus peak utilization. You want these two measures to be relatively close to each other, but not at the expense of network efficiency.

Network utilization by itself is not a sufficient measurement.

Network Efficiency Graph

The second graph in the series, Network Efficiency, is the most revealing.

If the graph shows less than 80-85% efficiency, your network is inefficient. A network of 75% efficiency is wasteful and unacceptable even if your network utilization shows a very high link utilization. 75% efficiency translates into 25% waste. You are throwing away ¼ of your bandwidth through packet retransmission.

The first thing you need to do is get the network efficiency up into the 85-95% range. Once you have an efficient network, the network utilization becomes important. In most cases, a well-running, highly efficient network will have lower network utilization because there is little or no bandwidth waste.

A very efficient network can still have lulls when all the bandwidth is not needed. It’s just like the freeway; during rush hour it’s congested and fully utilized, but if traffic is still moving at the speed limit, it’s relatively efficient. Outside of rush hour, you can still move at the speed limit even though the full bandwidth isn't being fully utilized.

Top Ten Pie Chart

The Top Ten pie chart can help you deal with any network inefficiency issues. It tells you what’s tying up the network and how much of the bandwidth it’s using. Hopefully, most of it (> 50-60%) is your mission-critical traffic. If it isn't then its time to tune the policies and/or partitions in order to increase network efficiency.

Use priority policies for short, latency-sensitive traffic and rate policies for long, bursty traffic. Partitions allow you the equivalent of s