Installation manual

TM
Network Management Manual
580-00511, rev B 24 of 34
CRC errors: Short for Cyclic Redundancy Check, CRC is a method of
detecting errors in data transmission. A CRC is data that is
sent with a block of data, that when received can be used to
verify that all data was received correctly. CRC errors
typically indicate physical defects in fiber or copper
cabling, or poor receive signal quality on a radio link. One
or less CRC error every 20 minutes on a fully-loaded
1000Mbps link would equal a bit error rate of under 10
-12
and is considered excellent performance for fiber or radio
connections. One CRC error every 2 minutes would equal a
bit error rate of 10
-10
on a 100Mbps copper connection,
which complies with 100Base-TX specifications. While
higher error rates should normally only be seen during
short periods of heavy rain downpours, most LAN
applications can easily tolerate up to 10
-8
bit error rates
without noticeable degradation.
Collisions: Total number of collisions detected. Collisions indicate that
more than one device is transmitting packets to an Ethernet
hub at the same time, and will normally be detected by the
device itself and be re-transmitted. Collisions should not
occur when devices are connected through Ethernet
switches.