Enterasys C5G124-24 User Manual

Understanding and Configuring Loop Protect
Fixed Switch Configuration Guide 15-35
Enabling or Disabling Loop Protect Event Notifications
Loop Protect traps are sent when a Loop Protect event occurs, that is, when a port goes to listening
due to not receiving BPDUs. The trap indicates port, SID and loop protection status.
Use this command to enable or disable Loop Protect event notification. By default, this is disabled:
set spantree lptrapenable {enable | disable}
Setting the Disputed BPDU Threshold
A disputed BPDU is one in which the flags field indicates a designated role and a learning state,
and the priority vector is worse than that already held by the port. If a disputed BPDU is received,
the port is forced to the listening state. Refer to the 802.1Q-2005 standard, IEEE Standard for Local
and Metropolitan Area Networks – Virtual Bridged Local Area Networks, for a full description of the
dispute mechanism, which prevents looping in cases of one-way communication.
The disputed BPDU threshold is an integer variable that represents the number of disputed
BPDUs that must be received on a given port and SID before a disputed BPDU trap is sent and a
syslog message is issued. For example, if the threshold is 10, a trap is issued when 10, 20, 30 (and
so on) disputed BPDUs have been received. The trap indicates port, SID and total Disputed BPDU
count.
Use this command to set the disputed BPDU threshold:
set spantree disputedbpduthreshold value
Default value is 0, which means that traps are not sent.
Monitoring Loop Protect Status and Settings
Use the commands in Table 15-10 to monitor Loop Protect settings.
Example
The following example shows a switching device with Loop Protect enabled on port lag.0.2, SID
56:
Enterasys->show spantree lp port lag.0.2 sid 56
LoopProtect is enabled on port lag.0.2, SID 56
Enterasys->show spantree lplock port lag.0.2 sid 56
Table 15-10 Commands for Monitoring Loop Protect
Task Command
Display the Loop Protect status per port, per SID, or
both.
show spantree lp [port port-string] [sid sid]
Display the Loop Protect lock status per port, per
SID, or both.
Note: A port can become locked if a configured
number of Loop Protect events occur during the
configured window of time. Once a port is forced into
blocking (locked), it remains locked until manually
unlocked with the clear spantree lplock command.
show spantree lplock [port port-string] [sid sid]
Display the Loop Protect capability of a link partner
for one or more ports.
show spantree lpcapablepartner [port port-string]
Display the reason for placing a port in a non-
forwarding state due to an exceptional condition.
show spantree nonforwardingreason [port
port-string] [sid sid]

Enterasys C5G124-24 Specifications

General

Brand	Enterasys
Model	C5G124-24
Category	Switch
Language	English