Cabletron Systems NB30 manual Out of Window Coll. Ethernet Port Only, CRC Errors, Frame Alignments

Models: NB30

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NB-30 Bridging

Out of Window Coll. (Ethernet Port Only)

The number of collisions at this port that were out of the standard collision window (51.2µs) due to a network problem experienced by the bridge. The problem may be that the network length exceeds speciÞcations, or that a node is transmitting without listening for carrier sense.

CRC Errors

The total number of frames received by the port that had Cyclical Redundancy Check (CRC) errors. A CRC error indicates the packet was damaged in transit Ñ since a frame check sequence of the packet does not match that recorded in the frame by the transmitting station.

Frame Alignments

The number of frames received by the port from the network that were misaligned Ñ that is, in which a byte of data in the packet contained less than 8 bits. This may indicate a packet formation problem on the part of a node, a problem of interference with the cabling, or a network design with cascaded multi-port transceivers (which does not meet IEEE 802.3 speciÞcations).

Giant Packets (Ethernet Port Only)

The number of giant frames the Ethernet port has received from the network. A giant frame exceeds the maximum Ethernet frame size of 1518 bytes (excluding the preamble).

Timeout (Remote Port Only)

The number of frames that were discarded because the maximum time for forwarding was exceeded before it could be transmitted by the remote port.

Total Errors

The total number of any errors processed by the selected port.

Nothing

The selected scale is not currently in use.

Configuring Performance Graphs

To conÞgure the Bridge Performance Graph:

1.Using the mouse, click on a scale button. A menu will appear.

For the Bridge Performance Graph, Frames Forwarded appears next to the blue scale by default; Frames Received appears next to the red scale.

For the Ethernet Port Performance Graph, Collisions appears next to the blue scale by default; Frames Received appears next to the red scale.

For the Remote Port Performance Graph, Forwarded Outbound appears next to the blue scale by default; Frames Received appears next to the red scale.

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Bridge Statistics

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Cabletron Systems NB30 Out of Window Coll. Ethernet Port Only, CRC Errors, Frame Alignments, Timeout Remote Port Only