Cabletron Systems STS16-20D Force AC Bits on SR Frames, BRF MTU actual, Port MTU, Forwarding Mode

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Force AC Bits on SR Frames

This field specifies if AC bits will be set unconditionally when a port forwards certain LLC frames. Possible values are Yes and No (default).

BRF MTU (actual)

Display only. The MTU the BRF uses at the moment.

Port MTU

Configures the Maximum Transmission Unit size of the information field of packets to be sent or received. Possible values are 1,500 and 4,472, 8,144, 17,800 and USE Brf (default).

The actual value used is the lower of the configured value and the actual BRF MTU.

➽Note! See the description on frame length limit on page 41 in Chapter 3, “Preparing for Installation”.

Forwarding Mode

The forwarding mode that will be used by this port, when forwarding frames to other ports in this box. Cut-through is possible only if all exit ports are running 16 Mbps. Possible values are auto, cut-through, and store & forward. The default is auto. If the forwarding mode is set to auto, the actual mode will depend on the number of errors that occur on this port during the sampling interval. If the error rate is below the error low threshold, cut-throughmode is used. If the error rate is above the Error High Threshold value, store & forward is used. The store & forward mode is always used for ports with a media speed of 4 Mbps.

Error High Threshold

This field is only valid when Forwarding Mode is set to auto. It is used to force a port to store & forward mode when the percentage of errors detected in the Error Sampling Interval is greater than the Error High Threshold. Possible values are 0–100percent. The default value is 10 percent.

Error Low Threshold

This field is only valid when Forwarding Mode is set to auto. It is used to return a port to cut-through mode when the percentage of errors detected in the Error Sampling Interval is less than the Error Low Threshold. Possible values are 0–100percent. The default value is 1 percent.

Error Sampling Interval

This field is only valid when Forwarding Mode is set to auto. It specifies a sampling period in minutes. The sampling period is used when counting errors to determine a port’s forwarding mode. Possible values are 1–60minutes. The default value is 10.

SmartStack STS16-20D/STS16-20R Token Ring Switches Installation and User Guide Switch Configuration