Alcatel-Lucent 7710 SR SONET, Configuration Manual

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LAG
Page 98 7710 SR OS Interface Configuration Guide
Active-Standby LAG Operation without LACP
Active/standby LAG is used to provide redundancy while keeping consistency of H-QOS
enforcement. Some devices do not support LACP and hence an alternative solution is required.
The active/standby decision for LAG member links is local decision driven by pre-configured
selection-criteria. This decision was communicated to remote system using LACP signalling.
As an alternative, the operator can disable-transmitter at the port member level. As a
consequence, the transmit laser will be switched off for all LAG members in standby mode. On
switch over (active-links failed) the laser will be switched on all LAG members will become
active.
Note that this mode of operation cannot detect physical failures on the standby link, which means
that the network operator cannot be certain that the standby links are capable to take over in case
of active-links failure. This is an inherit limitation of this operational mode.
The operation where standby ports are powered down is mutually exclusive with LACP and,
therefore, is modelled as separate mode of LACP operation of
power-off . For this mode, the
selection-criteria best-port can be used. This criteria means that it will be always a sub-group with
the test-port (the highest priority port) which will be chosen to be used as active sub-group.
It will not be possible to have an active LACP in power-off mode before the correct selection
criteria is selected.
Figure 20: Active-Standby LAG Operation without LACP
LAG
MC-LAG
MC-LAG MC-LAG