FDDI Performance 6-11
FDDI Applications
Statistics are displayed in three ways:
¥ By count (i.e., the number detected of each for the selected interval).
¥ By rate (i.e., the number of each per second, as averaged over the selected
interval).
¥ Graphically, as a percentage of each with respect to total network load
processed by the HSIM-F6 during the last interval.
You can view the concentrator performance for three different intervals:
¥ Absolute Ð Counts recorded since the device was last started.
¥ Cumulative Ð Counts recorded since the Concentrator Performance window
was opened.
¥ Delta Ð Counts recorded during a single polling interval that is set for
SPECTRUM Element Manager (refer to the SPECTRUM Element Manager
UserÕs Guide).
To change the interval, click to select the desired radio button in the Count
Display panel in the top right hand corner of the window.
Available statistics are:
Transmit Frames
The number of frames transmitted by the HSIM-F6Õs MAC during the selected
interval.
Receive Frames
The number of frames received by the HSIM-F6Õs MAC during the selected
interval.
Frame Errors
The number of error frames detected by the HSIM-F6Õs MAC during the selected
interval that had not been detected previously by other stations. Error frames may
include frames with an invalid Frame Check Sequence (FCS), with data length
errors, or with internal errors that prevent the MAC from transferring the frame
to the Logical Link Control (LLC) layer.
Lost Frames
The number of frames detected by the HSIM-F6Õs MAC during the selected
interval that have an unknown error, so their validity is in doubt. When the
HSIM-F6Õs MAC encounters a frame of this type, it increments the Lost Frame
counter and strips the remainder of the frame from the ring, replacing it with idle
symbols.