Converged traffic characteristics

Constant small-packet voice flow competes with bursty data flow

Critical traffic must get priority Voice and video are time-sensitive Brief outages not acceptable

Main Campus

Order Entry, Finance, Manufacturing, HR, Training, Other

The figure illustrates a converged network in which voice, video, and data traffic use the same network facilities. Merging these different traffic streams with dramatically differing requirements can lead to a number of problems.

Although packets carrying voice traffic are typically very small, they cannot tolerate delay and delay variation as they traverse the network. Voices will break up and words will become incomprehensible.

On the other hand, packets carrying file transfer data are typically large and can survive delays and drops. It is possible to retransmit part of a dropped data file, but it is not feasible to retransmit a part of a voice conversation.

The constant, small-packet voice flow competes with bursty data flows. Unless some mechanism mediates the overall flow, voice quality will be severely compromised at times of network congestion. The critical voice traffic must get priority. Voice and video traffic is very time-sensitive. It cannot be delayed and it cannot be dropped, or the resulting quality of voice and video will suffer.

Finally, converged networks cannot fail. While a file transfer or e-mail packet can wait until the network recovers, voice and video packets cannot wait. Even a brief network outage on a converged network can seriously disrupt business operations.

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