Cisco Cisco IOS Software Release 12.0(22)S
E F T 2 D R A F T - C I S C O C O N F I D E N T I A L
SNMP for Stateful Switchover
Feature Overview
2
Cisco IOS Release 12.0(22)S
Note
Synchronization of SNMP data between RPs is available only when the networking device is
operating in SSO mode.
operating in SSO mode.
Network management services for SSO address a number of issues, which are described in the following
sections:
sections:
•
•
•
Uninterrupted Service
When a networking device uses SSO, the network management engine of the standby RP should be
indistinguishable from the network management engine of the active RP. A network management system
(NMS) should not interpret a switchover to mean that a new device has come up.
indistinguishable from the network management engine of the active RP. A network management system
(NMS) should not interpret a switchover to mean that a new device has come up.
The sysUpTime MIB object reports the system uptime. To prevent a switchover from being flagged as a
restart, this object is synchronized between the active and the standby RPs. As a result, no coldStart or
warmStart traps will be generated as a result of the switchover—the ciscoRFSwactNotif notification is
used to signal a switchover.
restart, this object is synchronized between the active and the standby RPs. As a result, no coldStart or
warmStart traps will be generated as a result of the switchover—the ciscoRFSwactNotif notification is
used to signal a switchover.
Communication with the NMS
Counters and Statistics
The various counters and statistics maintained in the RP are not synchronized because they may change
often and the degree of synchronization they require is substantial. They also are not critical to the
system operation. Because of this lack of synchronization, counter objects experience a discontinuity
after a switchover. The cRFStatusFailoverTime will be the value of sysUpTime when any one or more
of the counters experiences a discontinuity.
often and the degree of synchronization they require is substantial. They also are not critical to the
system operation. Because of this lack of synchronization, counter objects experience a discontinuity
after a switchover. The cRFStatusFailoverTime will be the value of sysUpTime when any one or more
of the counters experiences a discontinuity.
Switchover Notification
The ciscoRFSwactNotif notification informs the NMS about a switchover. This notification provides
information regarding the unit ID of the originator of the notification, the newly active redundant unit,
the sysUptime data, and reason codes for why a switchover has occurred. The NMS can then use the
ciscoRFSwactNotif notification to resynchronize the counter statistics values, if necessary. For more
information, see the “
information regarding the unit ID of the originator of the notification, the newly active redundant unit,
the sysUptime data, and reason codes for why a switchover has occurred. The NMS can then use the
ciscoRFSwactNotif notification to resynchronize the counter statistics values, if necessary. For more
information, see the “
” section.
Traps
Only notifications generated on the active RP are sent to the notification destination. None of the
notifications generated on the standby RP are sent to the notification destination. Furthermore,
notifications might be lost if they were generated on the active RP before a switchover. The NMS should
be aware of these constraints.
notifications generated on the standby RP are sent to the notification destination. Furthermore,
notifications might be lost if they were generated on the active RP before a switchover. The NMS should
be aware of these constraints.