collisions rate

[pichi]

hi everybody, i have a question, does anybody knows how can i calculate the collision rate, if i have the collisions and number of packets transmited in an x period of time??, and secondly which are the values for perfect performance of a network (how many collisions)

thanks in advance

Pichi

 

[urgl]

Tx Packets --> 100%
Collisions --> x%
Close enough ??

Perfect performance means no collisions at all - a full duplex switched net should have no collisions. A repeated net with hubs or coax repeaters will have collisions - how many of them are acceptable depends on the current load of your net.
A rule of thumb is that above 30 to 35% network utilization the collision rate increases to a value where your actual throughput is lower than before.
If you have just 2 workstations you can utilize the link to a way higher degree as less collisions will occur (but thats protocol dependant too).
In general I'd say less that 5% collisions is a reasonable value.

Hope that helps.

 

[adam108]

If you are curious enough about collisions to want to know how many are acceptable, you may want to consider eliminating collisions altogether. Is it possible to migrate your network to full duplex instead of half and forget about collisions altogether?

 

[jimbopalmer]

Just a slight nit: A full duplex network will still have collisions, but they are about 5 orders of magnitude rarer than a half duplex network. Ethernet always responds to congestion with collisions, it is just MUCH harder to congest a full duplex network. I tried to remain child-like, all I acheived was childish.