The Five Components of Traffic

We have said that traffic consists of five components—voice, image, video, file transfer,
and transactions. In the past, we might have built a revenue stream on voice or data, but
now we can potentially build five revenue streams, which can become part of a large
and complex bill. The question then becomes this: how to build and bill complex value?
Each of the traffic types can be characterized in terms of its rate sensitivity/rate tolerance,
error sensitivity/error tolerance, sensitivity to delay, and sensitivity to delay
variability. Delay is sometimes described as latency. Latency is the amount of delay
introduced between a sender and receiver in a simplex or duplex exchange (in a duplex exchange it will be round-trip delay). Delay variability is sometimes described
as jitter. Jitter is the amount of variation in latency. As a rule of thumb, jitter should not
exceed 10 percent of the latency budget.
Jitter can be divided into macro jitter and micro jitter. Macro jitter is congestioninduced
jitter caused by a shortage of delivery and memory bandwidth. Micro jitter is
the small effects at the physical layer—receiver noise, clock jitter, sampling jitter, time,
phase, and frequency effects. Micro jitter increases bit error rate. If this triggers “send
again” protocols at a higher level in the protocol stack, then the result is macro jitter.
This means there is a direct relationship to (in wireless) the radio physical layer (that is,
radio bandwidth quality and network bandwidth quality). Radio and network bandwidth
quality must be matched to the required service class.