Cajun P220G, Руководство по конфигурации и эксплуатации

Страница: 78 / 135

Analyzing Network Performance
Cajun P220G Switch Configuration and Operation Guide 6-7
Fragments Fragments or runts result from
normal collision activity in
Ethernet networks. A runt packet is
an incomplete packet that is long
enough to be detected by an
Ethernet interface. Cause: Interference on network
cabling.
Action: Inspect cable runs to see if
they are too close to noisy devices,
and check for problems with
network devices.
Cause: A Transceiver attached to
the Repeater is generating Signal
Quality Errors (SQE).
Action: Disable SQE on the
Transceiver.
Jabbers Jabbers indicate that devices on the
networks are sending improper
electrical signals. Because Ethernet
uses electrical signalling to
determine whether or not it is okay
to transmit, a jabber condition can
halt all traffic on a segment. Cause: Bad network interface card.
Action: Replace network interface
card.
Collisions Counts number of times that
packets have collided on the
network. Collisions increase as
network use of shared segments
increases. Therefore, if the collision
rate increases without an increase
of network use, it might indicate a
problem. Guidelines for appropriate
collision rates are as follows:
• 10 percent: Normal collision
rate for shared Ethernet
segment.
• 30 percent: Collisions begin to
interfere with performance.
• 70 percent: Practical limit for
network to remain
functioning.
• A full-duplex link should not
show collision activity.
In a switched network, collisions
should be rare, unless your
switched segments attach to
multiple ends stations (a perfectly
legal configuration option).
Cause: Busy network.
Action: If you have multiple
stations on a switch segment,
reconfigure network into segments
with fewer stations.
Cause: Broken adapter (not
listening before broadcasting).
Action: Isolate each adapter to see
if the problem ceases.
Cause: Network loop.
Action: Activate spanning tree to
resolve loops automatically.
Check that there are no
connections to the same station
where both connections are active
simultaneously.
$ !