Fast EtherHub 3500 System User’s Guide
5-8 Hardware Reference
There are 5 LEDs representing the percentage of network
bandwidth in use by the attached (or isolated) segment. When
active, these LEDs look like a stereo’s equalizer display. The
hub updates this display every 0.5 seconds.
For example, if network utilization reaches 1%, the LED
labeled 1 will light. However, if network utilization rises above
1% (e.g., 30%), the LED labeled 30 and all the other LEDs
before it (i.e., 1, 5, and 15) will light in rapid succession.
These LEDs monitor the share of valid network frames
transmitted by this hub within a 100 Mbps bandwidth. They
provide a quick way to monitor the current traffic load relative
to the capacity available to the attached/isolated segment.
Collision Indicators
Color: Green and yellow
Label: Collision
Label (%) Color Function
1, 3, 5 Green Shows percentage of packet collisions occurring
10, 15+Yellow out of the total packets received by the hub.
Table 5.12 Collision Indicators
Collisions occur when two or more devices connected to a hub
attempt to transmit data simultaneously on the network. When
a collision occurs, devices pause and then re-transmit after a
pseudo-random wait period. Because wait periods differ among
devices, successive collisions become increasingly improbable.
The Collision LEDs assist the network manager in monitoring
the percentage of packet collisions occurring relative to the total
packets received by the hub. Similar to Utilization LEDs, the
Collision LEDs have 5 numbers representing collision percentage.
When collisions reach a level marked on the LED display, the
corresponding LED lights up.