Alcatel Carrier Internetworking Solutions Switch/Router - page 572

Creating a New Group
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Auto-Switch. The default setting for all Ethernet ports. This mode is appropriate for dedi-
cated connections requiring a switch-over to bridge mode when multiple devices are
detected. A port in Auto-Switch mode will start in Optimized Device Switching mode (see
description above). The port will remain in Optimized Device Switching mode until a
Spanning Tree BPDU is detected or more than one MAC address transmits data. Once
either of these conditions is met, the port will switch to Spanning Tree Bridge mode and
Spanning Tree will start (if configured in the switch).
An Auto-Switch port will remain in Spanning Tree Bridge mode as long as there are
BPDUs and multiple MACs. However, the port can revert back to Optimized Device
Switching Mode if the time specified in the next field (Switch Timer) transpires without
BPDUs and multiple MACs. Also, if the port is disconnected or configured to be adminis-
tratively down, then an Auto-Switch port will revert back to Optimized Device Switching
mode when it becomes operational again. Enter 3=a and press <Enter> to select Auto-
Switch mode.
How Auto-Switch Bridge Mode Works
31) Switch Timer
If you selected the Auto-Switch bridge mode, then you can configure this field. Enter the
time-out period, in seconds, for an Auto-Switch port that has turned to Spanning Tree
Bridge mode port to revert back to Optimized Switching mode. When in Auto-Switch
mode, a port switches to Spanning Tree Bridge mode as soon as it detects a BPDU or
more than one MAC address. The port will switch back to Optimized Switching mode after
the time-out value you define here.
Optimized
Device
Switching
Mode
Greater
Than 1
MAC?
No BPDUs
Detected?
No
Yes
Spanning
Tree
Bridge
Mode
Yes
Switch
Timer Period
Elapsed?
BPDU
Detected?
Only 1
MAC Address
Detected?
No
Yes No
Yes
No
Yes