Bandwidth Capacity vs Bandwidth Utilization

There are many tools available that measure bandwidth, most of them providing Bandwidth Utilization (“BU”) measurements. BU measurement tools utilize metering technique and count the number of bytes that go through a device. Then by applying a time interval, such as 5 seconds, can provide BU measurements.Say you have a T3 line (bandwidth of 45Mbps), and your utilization is 50%. BU measurements will show the link is operating at 22.5Mbps. Knowing BU is important, however it does not reveal the complete picture.

Bandwidth Capacity (“BC”) measurement tools, on the other hand, utilize technology to measure end-to-end bandwidth capacity of a network or data link. So in the example above, if WAN truly was a T3, BC measurement will be 3Mbps.  BC measurements show results even if utilization is zero.

BC works when a sending side device injects packets into a network to a remote device. The two devices calculate end to end BC. BC measurements can be achieved using many techniques, which fall into one of two categories: * Link flood techniques - operate by filling the link. Essentially sending connection-less (UDP based) packets across the network as fast as possible to fill the link. Receiving side measures the maximum throughput of this. This method impacts the performance of users utilizing the network during the time the test is running, so usually is only performed outside of busy times. * Non-flood techniques – in the non-flood scenario, sophisticated packet algorithms are used to accurately determine BC without the need to bring the link to full utilization. This has the benefit of not being intrusive to users on the network and can therefore operate more frequently and without impact.

Sinefa WANtrue utilizes the 'Non-flood' technique to measure Bandwidth Capacity.

Measuring BC is important as it allows organizations to check the quality of their network, and to ensure that the line is actually capable of performing at the line speed that it is rated. Many organizations have a Service Level Agreement (SLA) that needs to be met, but without BC measurements don’t have the tools to audit or the data to comply with the SLA.

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