Five Tips to Manage Network Congestion


As the demand for Internet access continues to grow around the world, the complexity of planning, setting up, and administering your network grows. Here are five (5) tips that we have compiled, based on discussions with network administrators in the field.

#1) Be Smart About Buying Bandwidth
The local T1 provider does not always give you the lowest price bandwidth.  There are many Tier 1 providers out there that may have fiber within line-of-sight of your business. For example, Level 3 has fiber rings already hot in many metro areas and will be happy to sell you bandwidth. To get a low-cost high-speed link to your point of presence, numerous companies can set up your wireless network infrastructure.

#2) Manage Expectations
You know the old saying “under promise and over deliver”.  This holds true for network offerings.  When building out your network infrastructure, don’t let your network users just run wide open. As you add bandwidth, you need to think about and implement appropriate rate limits/caps for your network users.  Do not wait; the problem with waiting is that your original users will become accustomed to higher speeds and will not be happy with sharing as network use grows – unless you enforce some reasonable restrictions up front.  We also recommend that you write up an expectations document for your end users “what to expect from the network” and post it on your website for them to reference.

#3) Understand Your Risk Factors
Many network administrators believe that if they set maximum rate caps/limits for their network users, then the network is safe from locking up due to congestion. However, this is not the case.  You also need to monitor your contention ratio closely.  If your network contention ratio becomes unreasonable, your users will experience congestion aka “lock ups” and “freeze”. Don’t make this mistake.

This may sound obvious, but let me spell it out. We often run into networks with 500 network users sharing a 20-meg link. The network administrator puts in place two rate caps, depending on the priority of the user  — 1 meg up and down for user group A and 5 megs up and down for user group B.  Next, they put rate caps on each group to ensure that they don’t exceed their allotted amount. Somehow, this is supposed to exonerate the network from experiencing contention/congestion. This is all well and good, but if you do the math, 500 network users on a 20 meg link will overwhelm the network at some point, and nobody will then be able to get anywhere close to their “promised amount.”

If you have a high contention ratio on your network, you will need something more than rate limits to prevent lockups and congestion. At some point, you will need to go with a layer-7 application shaper (such as Blue Coat Packeteer or Allot NetEnforcer), or go with behavior-based shaping (NetEqualizer). Your only other option is to keep adding bandwidth.

#4) Decide Where You Want to Spend Your Time
When you are building out your network, think about what skill sets you have in-house and those that you will need to outsource.  If you can select network applications and appliances that minimize time needed for set-up, maintenance, and day-to-day operations, you will reduce your ongoing costs. This is true whether your insource or outsource, as there is an “opportunity cost” for spending time with each network toolset.

#5) Use What You Have Wisely
Optimize your existing bandwidth.   Bandwidth shaping appliances can help you to optimize your use of the network.   Bandwidth shapers work in different ways to achieve this.  Layer-7 shapers will allocate portions of your network to pre-defined application types, splitting your pipe into virtual pipes based on how you want to allocate your network traffic.  Behavior-based shaping, on the other hand, will not require predefined allocations, but will shape traffic based on the nature of the traffic itself (latency-sensitive, short/bursty traffic is prioritized higher than hoglike traffic).   For known traffic patterns on a WAN, Layer-7 shaping can work very well.  For unknown patterns like Internet traffic, behavior-based shaping is superior, in our opinion.

On Internet links, a NetEqualizer bandwidth shaper will allow you to increase your customer base by between 10 to 30 percent without having to purchase additional bandwidth. This allows you to increase the amount of people you can put into your infrastructure without an expensive build out.

In order to determine whether the return-on-investment (ROI) makes sense in your environment, use our ROI tool to calculate your payback period on adding bandwidth control to your network.  You can then compare this one-time cost with your expected recurring month costs of additional bandwidth.  Also note in many cases you will need to do both at some point.  Bandwidth shaping can delay or defer purchasing additional bandwidth, but with growth in your network user base, you will eventually need to consider purchasing more bandwidth.

In Summary…
Obviously, these five tips are not rocket science, and some of them you may be using already.  We offer them here as a quick guide & reminder to help in your network planning.  While the sea change that we are all seeing in internet usage (more on that later…) makes network administration more challenging every day, adequate planning can help to prepare your network for the future.

Created by APconnections, the NetEqualizer is a plug-and-play bandwidth control and WAN/Internet optimization appliance that is flexible and scalable. When the network is congested, NetEqualizer’s unique “behavior shaping” technology dynamically and automatically gives priority to latency sensitive applications, such as VoIP and email. Click here to request a full price list.

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