Monday, May 19, 2014

What Dynamic CoS Means to You

By: John Shepler

Dynamic CoS lets you manage your network traffic more effectively under changing conditions.Most of today’s networks are converged networks. In other words, they carry a variety of traffic from disk backups, file transfers, cloud access, VoIP telephony, audio streaming, video conferencing & streaming and web services. With all of that going on, how do you ensure that your networks maintain the integrity of every process?

The Need for QoS
A network is more than a “dumb pipe” when Quality of Service (QoS) controls are implemented. What do you need that for? Can’t you just provide enough bandwidth so that every packet can traverse the network without limitation?

You certainly can if your pockets are deep enough. 10 Gbps? 100 Gbps? 1 Tbs? There is some bandwidth level short of infinite that will carry any traffic you throw at it with ease. Unfortunately, such capacity gets very expensive very fast. On a local network, you may find that even the fiber you have isn’t enough. When ordering MAN and WAN bandwidth, the cost can make your eyes bug out.

Different Applications, Different Requirements
This is where quality of service controls come into play. Not every file transfer needs to take place in a fraction of a second. Nobody expects those overnight backups to get done in minutes. Your emails need to get to their destinations, but not instantly. Even video downloads are expected to take some amount of time, considering their size.

What we do insist on is telephone conversations that don’t break up or make each party wait a second before responding. We wan’t video conferencing that doesn’t look jerky and responses from cloud software that don’t hesitate, especially long and random pauses.

The truth is that not all packets need equal treatment. Some need to get right through the network as quickly as possible. Others can wait a second. Still others can get through when they get through… within reason.

CoS to Implement QoS
What’s needed is traffic control that decides how your network capacity is allocated among all the packets that want it at any given time. Implementing this process is called Quality of Service. The mechanism that does that is called Class of Service (CoS).

Class of Service is a numerical tag that is inserted in the Ethernet header. There are three bits assigned for this, giving 8 possible classes from 0 to 7. Most of the time you won’t need this many. A few different classes will keep the insensitive traffic from damaging the highly time sensitive traffic.

Chances are that you have CoS tags implemented on your local network now. This is especially true if you’ve made the transition from analog telephones to SIP phones for VoIP. Phone conversations and huge file transfers don’t play well together… unless they’re kept separate.

Think of CoS as lane assignments on a superhighway. Voice packets go on the high occupancy lane. Cloud traffic gets the fast lane and data backups go in the slow lane on the right. CoS tags determine which lane a packet gets to use.

The Next Step: Dynamic CoS
As conditions change, you may wish to alter the class assignments. Local IT people can implement these changes on your network. The WAN is another matter. Legacy procedures for making changes tend to involve paperwork and delays of even weeks for implementations.

tw telecom has implemented something called Dynamic CoS that allows you as the customer to prioritize your applications dynamically and in real-time. Along with dynamic bandwidth control, it gives you, the user, wide ranging control of WAN network resources, as if they were your own.

Are you in need of more flexible bandwidth services that can respond to rapid changes in business requirements? You may well benefit from newer intelligent and dynamic network services. Find out what MAN and WAN network services are available that meet your requirements.

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

Follow Telexplainer on Twitter