A typical EtherSim project will go as follows:
First fill in the following fields:
- Stations : number of stations on your segment
- Generated load : the load (as a percentage) the stations will generate on the
segment.
This load will be generated at random.
- Interframe gap : the minimal gap between two sent packets. The standard value is
9.6 microseconds, which corresponds with 12 byte times. The unit of time in EtherSim is
byte times (the time it take to sent a byte which is .8 microseconds)
- Packet Length defaults : the minimum and maximum packet lengths that will be
used for the station. After creating the stations these values can be changed per station.
The standards are 64 bytes for the minimum and 1500 bytes for the maximum.
- Collision Window : in EtherSim the collision window is defined as the average
number of byte times it takes for a station to notice that it is involved in a collision
after sending a packet. The maximum value for real Ethernet is 64 byte times, so the
default value in EtherSim is 32.
Then press the Create Stations button and per station fill in the following
values:
- Load : defines the load for this station relative to the load of the other
stations. Equal numbers means equal loads. The absolute value is not important, only the
relative value compared with the other stations. All stations together will generate a
load as filled in in Generated Load.
- Min and Max Packet Length : minimal and maximal packet length per station. E.g.
min = 64 and max = 200 : this stations will only sent short packets.
Then press the Start button and the model will start generating packets. The
results are visible in the following fields:
- Clock : EtherSim is driven by a clock, each tick of the clock is a byte time.
- Generated Packets : the total number of packets generated by Ethersim and places
in the queues of the stations.
- Sent Packets : the total number of packets sent by the stations.
- Received Packets : the total number of packets received by the stations.
- Deferred Transmissions : the total number of deferred transmissions because of a
busy segment.
- Collisions : the total number of packets involved in a collision.
- Multiple Collisions : the total number of packets involved in a multiple
collision.
- Excessive Collisions : the total number of packets involved in a excessive
collision, i.e. more than 16 collisions on the same packet. such a packet will be dropped.
- Delay : the average delay for all sent packets. The best possible delay on a
quiet segment is equal to the length of the packet in byte times. (It takes at least 100
byte times to sent a packet of 100 bytes).
- Network Load : the network load measured by EtherSim, which is the total
transmission time of all successfully sent packets as a percentage of the available time.
Time spent on collisions is not part of the network load.
Per station the following results are given:
- Length : the length of the last sent packet.
- Sent : the number of packets sent by this station.
- Collisions : the number of packets involved in a collision.
- Multiple Collisions : the number of packets involved in a multiple collision.
- Queue : number of packets in the output queue, waiting to be sent.