More about PET

Description of PET

PET can be used with any packet-switched-network hardware or protocol. It operates as a layer above the transmission of packets (ATM cells, etc.). Using advanced coding techniques, PET improves the quality of transmission over packet networks that have unpredictable losses. PET uses a unique multilevel forward-error-correction scheme which introduces a minimum increase in the transmission rate.

In the Internet, packet loss statistics are usually bursty. For example, consider the packet loss statistics (losses per 100 packets) during an nv session over Internet MBONE from Palo Alto to Boston:

[Packet Loss Chart]

The above chart shows the packet loss measured at one receiving host during the nv multicast session. Note the peak with loss ten times greater than the 4.5% average loss. Note also that, there are other bursty packet loss of smaller values, though still significant, during the monitoring of 130,000 transmitted packets.

As a result of these bursty losses, the data communication industry has been forced to broadcast video in the form of motion JPEG, which in our tests can sometimes require eight times the transmission speed of MPEG. The application of PET in this instance, would result in comparable quality without as much transmission overhead.

In addition, PET also makes it possible to broadcast to heterogeneous networks and to receivers of widely different capabilities. This allows the network and receiving workstations to discard arbitrary packets which cannot be handled due to limited bandwidth or processing power.

To continue to learn more about PET and its applications: [continue]

Back to PET Home Page
Go to ICSI home page
Join the PET mailing list
Submit your comments