Cabletron Systems CSX400 - Manual (Page 57)

The Bridge Port Forwarding Statistics Window 3-37
CSX Bridge View
Viewing Source Routing Frame Type Statistics
A Source Routing bridge uses various broadcast messages to determine the
optimum route for a frame, so there are a few more frame statistics to view. When
displaying Source Routing rather than Transparent Bridging information, the
Statistics window activates the Frame Breakdown button, which lets you view
frame type statistics as either absolute values or as slices of a pie chart.
To view Source Routing frame type statistics:
1. In the SR Statistics window, click mouse button 1 on the Frame Type
Breakdown button.
SR Frame types include the following:
Total Frames Received
The total number of frames, of all types, received at the selected port.
Spec Frames
SpeciÞcally routed frames. These frames have data and routing information and
are following a known route from source to destination.
APE Frames
When a sending station needs to determine the best route to an intended
destination, it transmits an APE (All Paths Explorer) frame. The APE frame
contains no routing information; it is propagated along all available paths to the
destination station, which then sends speciÞcally routed frames as replies back to
the source. The Þrst reply received by the original sending station is considered
the most efÞcient route and is used in subsequent transmissions.
STE Frames
Spanning Tree Explorer frames, also known as Single Route Broadcast frames,
follow the topology established by the Spanning Tree Algorithm. This speciÞcally
routed frame can be used by end stations, instead of the APE frame.
NOTE
DeÞnitions for the port summary statistics are included in the next section, which deÞnes
the types of frame statistics available via the Frame Type Breakdown button.
TIP
The statistics shown in the Bridge Port Statistics window reßect a ÒsnapshotÓ of the
statistics from the time the window was opened. To refresh the statistics, you must close
this window and open it again.