| Description | This object is used to configure a PVC protection
group (or redundant group) with the PVCs protecting
each other. Currently only two PVCs are supported
in a protection group. One of them is primary and
the other one is secondary. This is intended for
PVCs designated to carry control traffic and needs
to be protected. However the same PVC may also be
used to carry VoIP bearer traffic or other traffic.
Channels that are 'protected (1)' share the
following characteristics:
1. They are monitored for their health (including
emission of traps in case of state changes).
2. An active channel is protected by another
protected channel which is standby. This means
when an active channel fails, switchover to
another channel will happen if one is available.
3. It is also possible to do a forced switchover
(through locking). Even in the case of forced
switchover, switchover to another channel, which
is in standby, will happen.
4. Channels may be locked to force switchover and/or
to take the channel out of service in a graceful
fashion.
This object takes the default value of 'unprotected (2)'
during the creation of the table entry. Once the
primary and secondary channels have been created as
'unprotected (2)' channels, they can be 'protected (1)'
by doing a SET on the primary channel by specifying
the vismChanProtection as protected and by specifying
the vismChanFallbackLcn as the LCN number of the
secondary channel.
The sequence of operations for setting up the
'protection (1)' group is:
step 1: Add primary channel as unprotected
step 2: Add secondary channel as unprotected.
The PCR value for the secondary should be
the same as that of the primary.
step 3: Do a SET on the primary channel with
vismChanProtection set to 'protected (1)'
and vismChanFallbackLcn set to the
LCN number of the secondary channel. This
operation sets-up the protection group. The
primary channel becomes active and the
secondary channel becomes standby.
Please note that all the CAC related parameters
for the both the PVCs in the protecting group
should be same. In other words the vismChanCacMaster,
vismChanCarrierLossPolicy, vismChanCacRejectionPolicy,
VAD tolerance etc.. should have the same value
for the PVCs that are protecting each other, else
the set request to protect two channels will
be rejected.
Once the protection group is setup, if the active
channel fails, it automatically switches over to
the standby. The standby channel then becomes
active.
The channels can be removed from the protection
group by setting this object to unprotected.
Deletion of a 'protected (1)' channel is not
allowed. Channels have to be removed from
the protection group first before deleting. The
sequence of operations for deleting 'protected (1)'
channels are:
step 1: Remove the channels from the
protection group by setting
vismChanProtection to unprotected.
step 2: Delete secondary channel.
step 3: Delete primary channel. |