Previous: Interactions with WaveLAN
In this paper, we presented the results of several experiments
performed to evaluate the performance of Metricom's Ricochet network.
We investigated the performance of the experimental deployment as part
of the Daedalus project, as well as the commercial service. Our main
conclusions and observations are summarized below.
- TCP throughput is between 15 and 30 kb/s, across a wide range of
packet and socket buffer sizes. In the commercial service, peak
throughputs are observed for a packet size of 512 bytes and socket
buffer sizes of 4-8 KBytes.
- TCP performance suffers from long idle periods caused by reverse
channel contention; large variations in round-trip time estimates
(between 250 and 5000 ms) greatly increase loss recovery times and
significantly degrade performance.
- Maximum UDP throughput is between 50-58 kb/s, when there is
no reverse channel contention; parallel UDP streams in the same
direction show a roughly linear performance degradation.
- UDP jitter under lightly loaded optimal conditions are between
10 and 30 ms across the range of supportable transmission rates. This
implies the viability of real-time video and audio transmissions at
- Measurements of interactions with the WaveLAN device show that
the performance of the Ricochet network does not degrade as much as
the WaveLAN network when simultaneous transmissions occur.
- The performance of the experimental
deployment is roughly similar to the commercial service, implying
that improvements made to the former are likely to improve the
performance of the latter as well.
Tue May 7 18:07:57 PDT 1996