Thursday, October 06, 2011

When More Bandwidth Doesn’t Help

You’re probably familiar with this scenario. You’ve had a T1 line or DS3 bandwidth circuit for years. Everything ran just fine until recently. Now, all of a sudden, the Internet just crawls and your new VoIP telephone system sounds like calls from the far side of the moon. Employees are peeved because they can’t get anything done. Customers are livid because they can’t even carry on a civil conversation over the phone. Management is getting hot under the collar. Better get more bandwidth on order, right?

Sometimes increasing the pipe size isn't enough...Maybe. It’s entirely possible that you’ll call up your provider and double your dedicated Internet bandwidth only to find out that you still have the same problems and now you’re paying twice as much. Talk about adding insult to injury! What’s gone wrong here and what can you do to really fix it?

The problem is that we visualize broadband connections like water pipes. You can just see that traffic flowing smoothly through the pipe. Applications demand more capacity and the flow increases, just like opening a faucet wider. Obviously, the only way you’ll hit the limit on capacity is when you fully open all the faucets at once. Then each application, the lawn sprinkler, the shower, the dishwasher and the wash basin each get less than they would like.

The fix seems equally obvious. Just put in bigger pipes with higher capacity. The water meter will spin a lot faster, but now you can support a lot more users full-on and nobody will suffer a reduction in flow. The telecom equivalent of a bigger pipe is what is called in the industry a “bigger pipe.” That means a line with more Mbps or Gbps. The analogy is clear. Just order a bigger pipe and your troubles will be over. Or will they?

The snag in all of this is that network traffic isn’t homogenous like water. One water droplet may be just like the next. One Ethernet packet may be not at all like the next. Some applications, like file transfers, just brute force move packets from one place to another. Others, like video conferencing or VoIP telephony are highly sensitive to latency, jitter, lost packets and packets arriving out of sequence. If your network gets congested, the file transfer will work fine. It will just take a little longer. Get in the same situation with real-time applications and they’ll crumble in the battle for packet transfers.

So why not just increase bandwidth when business grows to the point where more users are trying to do more things simultaneously? It’s likely that at some point you’ll have to do just that. But also know that simply adding more capacity may not make a big difference. Why? It’s because some applications will take as much bandwidth as you give them regardless of what they really need. If you simply double the bandwidth, Web pages may load a little faster, files might move a little faster, but the telephone and video may still break up mid-conversation.

There probably is some line speed that is so fast that everything will work at the same time with no problems. That might be 10x or even 100x what you have now. You’ll pay a fortune just to have enough capacity at hand to support rare moments when everyone is on the phone and watching YouTube videos at the same time the system is doing full backups. Is that really necessary?

No. Not at all. What you really need is a way to prioritize traffic so that preference is given to real-time two-way streams that are extremely sensitive to network congestion. You need to establish CoS or Class of Service controls that carve out a certain capacity to meet the needs of your VoIP phone system and video conferencing system and then divvy up the rest among lower priority processes. You can go further to push time insensitive file transfers and backups into the background so that they won’t interfere with anyone working online.

That solution is called the converged network. It’s more than just plugging everything into the same LAN and WAN. You need Class of Service both on your LAN and on the WAN. Techniques for the LAN are well established. The WAN is another matter if you are using the Internet for access to your VoIP provider. The Internet strips off those CoS tags in the name of network neutrality. One solution is to use a SIP Trunk to connect to a single provider for VoIP and Internet broadband so that CoS can be maintained on that link. Another is to keep the broadband you have, but use a separate point to point connection to your VoIP provider.

MPLS networks can maintain CoS among multiple business locations. You may be using Internet VPN connections to make those multiple connections, but with limited success if voice or video are involved.

Another interesting option is the “intelligent bandwidth” approach being offered by Telnes, a major competitive carrier. They’ve developed a technique called IP Priority Class of Service to maintain CoS on an Internet circuit using managed routers. This recognizes that most of the congestion issues occur on the link between you and the core of the Internet. By cleaning up that connection, real time applications, such as hosted VoIP, can run much more smoothly that they will on uncontrolled Internet broadband services.

Are you suffering slowdowns, application breakage and poor telephone voice quality? You may need more bandwidth or you may just need better bandwidth management. Before you go out and spend a bundle to no avail, get a complementary telecom engineering consultation from Telnes and other competitive service providers and review your options. You may be able to get results for a fraction of what you thought you had to spend.

Click to check pricing and features or get support from a Telarus product specialist.

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