next up previous
Next: Hardware Encryption Up: Application Classes Previous: Soft Real-Time Applications with

Hard Real-Time Applications

Latency Overhead


Network Communication Encryption Latency Network Latency Overhead
  (TD msecs) (TE msecs) %
Intranet 0.44 2.7 16
Internet 0.44 62 0.7
Serial Port 5.14 15 34

From the above table we find that, for communication over the internet, encryption latency is a very negligible fraction of the network latency. However, on a local intranet, where the network latencies are low, adding encryption could be a significant overhead. Considering the devices to be as powerful as a PentiumPro or a Pentium III, this overhead could be anywhere between 10% and 16%. This is the maximum overhead due to encryption, as we ignored all other latencies that could be introduced by the applications themselves. For small devices like a PalmPilot, this overhead could be large, up to 34%.



Ramadass Nagarajan
2000-05-11