IET680 – Lab02
Lab02 was concerned with the utilization and throughput on a Token Ring network. The
variables being considered in this lab were the THT (Token Holding Time), the network
load, and throughput. We considered each of these items as they related to one another
using the ITGuru simulation software.
We first checked to see how network utilization and throughput would be affected by
using different THT values on the network. The load was balanced meaning that each
node was producing an equal volume of the network traffic. Secondly we checked to see
how different THT values affected a network that was not balanced. In this situation two
nodes were producing a much larger portion of the traffic than the remaining nodes. We
then checked to see how the network load being cut in half affected utilization and
throughput. Finally we checked to see how the utilization and throughput would be
affected by a single node on the network producing all of the traffic and no other node
communicating at all.
The first simulation showed that the THT value affects the utilization of the network.
However this value did not seem to have as great an affect on the throughput of the
network. It appears that increasing the THT value reduces the overhead (token passing)
on the network and thus allows for greater utilization of the network. Nodes spend more
time sending data and less time passing the token. The second simulation was
comparable to the first but we changed the arrangement of the network load. No longer
did we show an even balance from all nodes but we had two nodes producing a larger
portion of the traffic. With this arrangement we could again see that the THT affected
the utilization of the network. Again the throughput did not seem to be affected by this
value as much. Utilization and throughput were both down in this scenario. We then
checked utilization and throughput with only half of the network load. With only half the
network load the THT value did not have an affect on either utilization or throughput. In
both cases, these values were greatly reduced due to the lower traffic. We only a single
node producing a full network node we could again see how a higher THT value would
increase utilization. Throughput again was not affected by this as much. A single node
producing this load could almost but not quite reach the utilization and throughput levels
of a balanced network.
THT and network load appear to be the two primary factors influencing a token ring
network in this simulation. THT value provided some affect in almost every scenario and
network load also provided some variance in utilization and throughput. It appears that a
higher THT value allows more time on the network to be used for data traffic instead of
token passing giving better utilization. Total throughput appears to be more affected by
the total network load.