Lag Hold Down Timers - Alcatel-Lucent 7750 Configuration Manual

LAG Hold Down Timers

LAG Hold Down Timers
Operators can configure multiple hold down timers that allow control how quickly LAG responds
to operational port state changes. The following timers are supported:
1. Port-level hold-time up/down timer
2. Sub-group-level hold-time timer
3. LAG-level hold-time down timer
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This optional timer allows operator to control delay for adding/removing a port from
LAG when the port comes UP/goes DOWN. Each LAG port runs the same value of the
timer, configured on the primary LAG link. See Port Link Dampening description in Port
Features section of this guide for more details on this timer.
This optional timer allows operator to control delay for a switch to a new candidate sub-
group selected by LAG sub-group selection algorithm from the current, operationally UP
sub-group. The timer can also be configured to never expire, which prevents a switch
from operationally up sub-group to a new candidate sub-group (manual switchover is
possible using tools perform force lag command). Note that, if the port link dampening is
deployed, the port level timer must expire before the sub-group-selection takes place and
this timer is started. Sub-group-level hold-down timer is supported with LAGs running
LACP only.
This optional timer allows operator to control delay for declaring a LAG operationally
down when the available links fall below the required port/BW minimum. The timer is
recommended for LAG connecting to MC-LAG systems. The timer prevents a LAG
going down when MC-LAG switchover executes break-before-make switch. Note that, if
the port link dampening is deployed, the port level timer must expire before the LAG
operational status is processed and this timer is started.
7750 SR Interface Configuration Guide