Dell PowerConnect B-RX - Port Transition Hold Timer; Port Flap Dampening

144 BigIron RX Series Configuration Guide
53-1002253-01
Port transition hold timer
6
NOTE
With the wait-for-all-cards command enabled,10G ports will come up before 1G ports because
Multi-Service IronWare software processes 10G port’s state changes first.
Port transition hold timer
Using the delay-link-event command will delay the sending of port "up" or "down" events to Layer 2
protocols. While link down events are reported immediately in syslog, their effect on higher level
protocols such as OSPF is delayed according to how the delay-link-event is configured. This
command affects the physical link events. However, the resulting logical link events are also
delayed. This is a per-interface command.
For example, if VSRP is enabled on the port, the ownership would not change until the port status
has remained up or down for the configured amount of time to ensure that minor transient states
of a link do not unintentionally cause a disruptive topology change in the network.
NOTE
All trunk ports must have the same delayed-link-down-event configuration.
The following command will delay the sending of port "down" event for 100ms when a port state is
detected "down". If the port state is detected "up" afterwards within 100ms, the delayed "down"
event is cancelled; otherwise, the "down" event is sent after 100ms. This allows the upper layer
applications not to be affected by a port state flapping.
BigIron RX (config-if-e1000-1/2)# delay-link-event 2 down
Syntax: delay-link-event <time> up | down
The <time> parameter is the number of 50-ms units. The default is 0.
The <up> parameter means only "up" events are delayed.
The <down> parameter means that only the down events are delayed.
Port flap dampening
The port flap dampening feature allows you to configure a wait period before a port, whose link
goes down then up, becomes enabled.
If the port flap state toggles (from down to up or from up to down) for a specified number of times
within a specified period, the interface is physically disabled for the specified wait period. Once the
wait period expires, the port’s link state is re-enabled. However, if the wait period is set to zero (0)
seconds, the port’s link state will remain disabled until it is manually re-enabled.
Configuration notes
• When a link dampening port becomes a member of a trunk group, that port, as well as all other
member ports of that trunk group, will inherit the primary port’s configuration. This means
that the member ports will inherit the primary port’s link dampening configuration, regardless
of any previous configuration.
• The Brocade device counts the number of times a port’s link state toggles from "up to down",
and not from "down to up".