How Much Bandwidth Do You Really Need?


By Art Reisman – CTO – www.netequalizer.com

Art Reisman CTO www.netequalizer.com

When it comes to how much money to spend on the Internet, there seems to be this underlying feeling of guilt with everybody I talk to. From ISPs, to libraries or multinational corporations, they all have a feeling of bandwidth inadequacy. It is very similar to the guilt I used to feel back in College when I would skip my studies for some social activity (drinking). Only now it applies to bandwidth contention ratios. Everybody wants to know how they compare with the industry average in their sector. Are they spending on bandwidth appropriately, and if not, are they hurting their institution, will they become second-rate?

To ease the pain, I was hoping to put a together a nice chart on industry standard recommendations, validating that your bandwidth consumption was normal, and I just can’t bring myself to do it quite yet. There is this elephant in the room that we must contend with. So before I make up a nice chart on recommendations, a more relevant question is… how bad do you want your video service to be?

Your choices are:

  1. bad
  2. crappy
  3. downright awful

Although my answer may seem a bit sarcastic, there is a truth behind these choices. I sense that much of the guilt of our customers trying to provision bandwidth is based on the belief that somebody out there has enough bandwidth to reach some form of video Shangri-La; like playground children bragging about their father’s professions, claims of video ecstasy are somewhat exaggerated.

With the advent of video, it is unlikely any amount of bandwidth will ever outrun the demand; yes, there are some tricks with caching and cable on demand services, but that is a whole different article. The common trap with bandwidth upgrades is that there is a false sense of accomplishment experienced before actual video use picks up. If you go from a network where nobody is running video (because it just doesn’t work at all), and then you increase your bandwidth by a factor of 10, you will get a temporary reprieve where video seems reliable, but this will tempt your users to adopt it as part of their daily routine. In reality you are most likely not even close to meeting the potential end-game demand, and 3 months later you are likely facing another bandwidth upgrade with unhappy users.

To understand the video black hole, it helps to compare the potential demand curve pre and post video.

A  quality VOIP call, which used to be the measuring stick for decent Internet service runs about 54kbs. A quality  HD video stream can easily consume about 40 times that amount. 

Yes, there are vendors that claim video can be delivered at 250kbs or less, but they are assuming tiny little stop action screens.

Couple this tremendous increase in video stream size with a higher percentage of users that will ultimately want video, and you would need an upgrade of perhaps 60 times your pre-video bandwidth levels to meet the final demand. Some of our customers, with big budgets or government subsidized backbones, are getting close but, most go on a honeymoon with an upgrade of 10 times their bandwidth, only to end up asking the question, how much bandwidth do I really need?

So what is an acceptable contention ratio?

  • Typically in an urban area right now we are seeing anywhere from 200 to 400 users sharing 100 megabits.
  • In a rural area double that rati0 – 400 to 800 sharing 100 megabits.
  • In the smaller cities of Europe ratios drop to 100 people or less sharing 100 megabits.
  • And in remote areas served by satellite we see 40 to 50 sharing 2 megabits or less.

Best Monitoring Tool for Your Network May Not Be What You Think


By Art Reisman

CTO – http://www.netequalizer.com

A common assumption in the IT world is that the starting point for any network congestion solution begins with a monitoring tool.  “We must first figure out what specific type of traffic is dominating our network, and then we’ll decide on the solution”.  This is a reasonable and rational approach for a one time problem. However, the source of network congestion can change daily, and it can be a different type of traffic or different user dominating your bandwidth each day.

When you start to look at the labor and capital expense of  “monitor and react,” as your daily troubleshooting tool, the solution can become more expensive than your bandwidth contract with your provider.

The traditional way of looking at monitoring your Internet has two dimensions. First, the fixed cost of the monitoring tool used to identify traffic, and second, the labor associated with devising and implementing the remedy. In an ironic inverse correlation, we assert that your ROI will degrade with the complexity of the monitoring tool.

Obviously, the more detailed the reporting/shaping tool, the more expensive its initial price tag. Yet, the real kicker comes with part two. The more detailed data output generally leads to an increase in the time an administrator is likely to spend making adjustments and looking for optimal performance.

But, is it really fair to assume higher labor costs with more advanced monitoring and information?

Well, obviously it wouldn’t make sense to pay more for an advanced tool if there was no intention of doing anything with the detailed information it provides. But, typically, the more information an admin has about a network, the more inclined he or she might be to spend time making adjustments.

On a similar note, an oversight often made with labor costs is the belief that when the work needed to adjust the network comes to fruition, the associated adjustments can remain statically in place. In reality, network traffic changes constantly, and thus the tuning so meticulously performed on Monday may be obsolete by Friday.

Does this mean that the overall productivity of using a bandwidth monitoring tool is a loss? Not at all. Bandwidth monitoring and network adjusting can certainly result in a cost-effective solution. But, where is the tipping point? When does a monitoring solution create more costs than it saves?

The solution: Be proactive, use a tool that prevents congestion before it affects the quality of your network.

An effective compromise with many of our customers is that they are stepping down from expensive, complex reporting tools to a simpler approach. Instead of trying to determine every type of traffic on a network by type, time of day, etc., an admin can head off trouble with a basic bandwidth control solution in place (such as a NetEqualizer). With a smart, proactive congestion control device, the acute problems of a network locking up will stop.

Yes, there may be a need to look at your overall bandwidth usage trends over time, but you do not need an expensive detailed monitoring tool for that purpose.

Here are some other articles on bandwidth monitoring that we recommend.

List of monitoring tools compiled by Stanford.

ROI tool , determine how much a bandwidth control device can save.

Great article on choosing a bandwidth controller.

Planetmy
Linux Tips
How to set up a monitor for free

Good enough is better: a lesson from the Digital Camera Revolution

Network Bottlenecks – When Your Router Drops Packets, Things Can Get Ugly


By Art Reisman

CTO – APconnections

As a general rule, when a network router sees more packets than it can send or receive on a link, it will drop the extra  packets. Intuitively, when your router is dropping packets, one would assume that the perceived slow down, per user, would be just a gradual shift slower.

What happens in reality is far worse…

1) Distant users get spiraling slower responses.

Martin Roth, a colleague of ours who founded one of the top performance analysis companies in the world, provided this explanation:

“Any device which is dropping packets “favors” streams with the shortest round trip time, because (according to the TCP protocol) the time after which a lost packet is recovered is depending on the round trip time. So when a company in Copenhagen/Denmark has a line to Australia and a line to Germany on the same internet router, and this router is discarding packets because of bandwidth limits/policing, the stream to Australia is getting much bigger “holes” per lost packet (up to 3 seconds) than the stream to Germany or another office in Copenhagen. This effect then increases when the TCP window size to Australia is reduced (because of the retransmissions), so there are fewer bytes per round trip and more holes between to round trips.”

In the screen shot above (courtesy of avenida.dk), the Bandwidth limit is 10 Mbit (= 1 Mbyte/s net traffic), so everything on top of that will get discarded. The problem is not the discards, this is standard TCP behaviour, but the connections that are forcefully closed because of the discards. After the peak in closed connections, there is a “dip” in bandwidth utilization, because we cut too many connections.

2) Once you hit a congestion point, where your router is forced to drop packets, overall congestion actually gets worse before it gets better.

When applications don’t get a response due to a dropped packet, instead of backing off and waiting, they tend to start sending re-tries, and this is why you may have noticed prolonged periods (3o seconds or more) of no service on a congested network. We call this the rolling brown out. Think of this situation as sort of a doubling down on bandwidth at the moment of congestion. Instead of easing into a full network and lightly bumping your head, all the devices demanding bandwidth ramp up their requests at precisely the moment when your network is congested, resulting in an explosion of packet dropping until everybody finally gives up.

How do you remedy outages caused by Congestion?

We have written extensively about solutions to prevent bottlenecks. Here is a quick summary with links:

1) The most obvious being to increase the size of your link.

2) Enforce rate limits per user.

3) Wse something more sophisticated like a Netequalizer, a device that is designed to specifically counter the effects of congestion.

From Martin Roth of Avenida.dk

“With NetEqualizer we may get the same number of discards, but we get fewer connections closed, because we “kick” the few connections with the high bandwidth, so we do not get the “dip” in bandwidth utilization.

The graphs (above) were recorded using 1 second intervals, so here you can see the bandwidth is reached. In a standard SolarWinds graph with 10 minute averages the bandwidth utilization would be under 20% and the customer would not know they are hitting the limit.”

———————————————————————-

The excerpt below was a message from a reseller who had been struggling with congestion issues at a hotel, he tried basic rate limits on his router first. Rate Limits will buy you some time , but on an oversold network you can still hit the congestion point, and for this you need a smarter device.

“…NetEq delivered a 500% gain in available bandwidth by eliminating rate caps, possible through a mix of connection limits and Equalization.  Both are necessary.  The hotel went from 750 Kbit max per accesspoint (entire hotel lobby fights over 750Kbit; divided between who knows how many users) to 7Mbit or more available bandwidth for single users with heavy needs.

The ability to fully load the pipe, then reach out and instantly take back up to a third of it for an immediate need like a speedtest was also really eye-opening.  The pipe is already maxed out, but there is always a third of it that can be immediately cleared in time to perform something new and high-priority like a speed test.”
 
Rate Caps: nobody ever gets a fast Internet connection.
Equalized: the pipe stays as full as possible, yet anybody with a business-class need gets served a major portion of the pipe on demand. “
– Ben Whitaker – jetsetnetworks.com

Are those rate limits on your router good enough?

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.

NetEqualizer Bandwidth Shaping Solution: Business Centers


In working with numerous Business Center network administrators, we have heard the same issues and challenges repeatedly. Here are just a few:

Download Business Centers White Paper

  • We need to do more with less bandwidth.
  • We need a solution that’s low cost, low maintenance, and easy to set up.
  • We need to support selling fixed bandwidth to our customers, by office and/or user.
  • We need to be able to report on subscriber usage.
  • We need to increase user satisfaction and reduce network troubleshooting calls

In this article, we’ll talk about how the NetEqualizer has been used to solve these issues for many Business Centers around the world.

Download article (PDF) Business Centers White Paper

Read full article …

The Real Killer Apps and What You Can Do to Stop Them from Bringing Down Your Internet Links


When planning a new network, or when diagnosing a problem on an existing one, a common question that’s raised concerns the impact that certain applications may have on overall performance. In some cases, solving the problem can be as simple as identifying and putting an end to (or just cutting back) the use of certain bandwidth-intensive applications. So, the question, then, is what applications may actually be the source of the problem?

The following article works to identify and break down the applications that will most certainly kill your network, but also provides suggestions as to what you can do about them. While every application certainly isn’t covered, our experience working with network administrators around the world has helped us identify the most common problems.

The Common Culprits

YouTube Video (standard video) — On average, a sustained 10-minute YouTube video will consume about 500kbs over its duration. Most video players try to store the video (buffer ahead) locally as fast as your network  can take it.   On a shared network, this has the effect of bringing everything else on your network to its knees. This may not be a problem if you are the only person using the Internet link, but in today’s businesses and households, that is rarely the case.

For more specifics about YouTube consumption, see these other Youtube articles.

Microsoft Service-Pack Downloads — Updates such as Microsoft service packs use file transfer protocol (FTP). Generally, this protocol will use as much bandwidth as it can find. The end result is that your VoIP phone may lock up, your video’s will become erratic, and Web surfing will come to a crawl.

Keeping Your Network Running Smoothly While Handling Killer Apps

There is no magic pill that can give you unlimited bandwidth, but each of  the following solutions may help. However, they often require trade offs.

  1. The obvious solution is to communicate with other members of your household or business when using bandwidth intensive applications. This is not always practical, but, if other users agree to change their behavior, it’s usually a surefire solution.
  2. Deploy a fairness device to smooth out those rough patches during contentious busy hours — Yes, this is the NetEqualizer News blog, but with all bias aside, these types of technologies often work great. If you are in an office sharing an Internet feed with various users, the NetEqualizer will keep aggressive bandwidth users from crowding others out. No, it cannot create additional bandwidth on your pipe, but it will eliminate the gridlock caused by your colleague  in the next cubicle  downloading a Microsoft service pack. Yes, there are other  devices on the market that can enforce fairness, but the NetEqualizer was specifically designed for this mission. And, with a starting price of around $1400, it is a product small businesses can invest in and avoid longer term costs (see option 3).
  3. Buy more bandwidth — In most cases, this is the most expensive of the different solutions in the long term and should usually be a last resort. This is especially true if the problems are largely caused by recreational Internet use on a business network. However, if the bandwidth-intensive activities are a necessary part of your operation, and they can’t afford to be regulated by a fairness device, upgrading your bandwidth may be the only long-term solution. But, before signing the contract, be sure to explore options one and two first.

As mentioned, not every network-killing application is discussed here, but this should head you in the right direction in identifying the problem and finding a solution. For a more detailed discussion of this issue, visit the links below.

  • For a  more detailed discussion on how much bandwidth specific applications consume, click here.
  • For a set of detailed tips/tricks on making your Internet run faster, click here.
  • For an in-depth look at more complex methods used to mitigate network congestion on a WAN or Internet link, click here.

$1000 Discount Offered Through NetEqualizer Cash For Conversion Program


After witnessing the overwhelming popularity of the government’s Cash for Clunkers new car program, we’ve decided to offer a similar deal to potential NetEqualizer customers. Therefore, this week, we’re announcing the launch of our Cash for Conversion program.The program offers owners of select brands (see below) of network optimization technology a $1000 credit toward the list-price purchase of NetEqualizer NE2000-10 or higher models (click here for a full price list). All owners have to do is send us your old (working or not) or out of license bandwidth control technology. Products from the following manufacturers will be accepted:

  • Exinda
  • Packeteer/Blue Coat
  • Allot
  • Cymphonics
  • Procera

In addition to receiving the $1000 credit toward a NetEqualizer, program participants will also have the peace of mind of knowing that their old technology will be handled responsibly through refurbishment or electronics recycling programs.

Only the listed manufacturers’ products will qualify. Offer good through the Labor Day weekend (September 7, 2009). For more information, contact us at 303-997-1300 or admin@apconnections.net.

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