Cisco Cisco Prime Unified Service Monitor 8.7 White Paper
White Paper
© 2007 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
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keep from the C:\Program Files\CSCOpx\data folder.
Failover and Redundancy
Service Monitor supports failover for only sensor functionality. A primary and secondary Service
Monitor server can be configured to provide redundancy and failover support to Cisco 1040 Sensor.
In case of a primary Service Monitor server going down, the probe would automatically switch over
to the secondary Service Monitor server. However there is no synchronization between primary the
Service Monitor and secondary Service monitor servers.
Monitor server can be configured to provide redundancy and failover support to Cisco 1040 Sensor.
In case of a primary Service Monitor server going down, the probe would automatically switch over
to the secondary Service Monitor server. However there is no synchronization between primary the
Service Monitor and secondary Service monitor servers.
Cisco 1040 Failover Mechanism
The 1040 establishes a connection with the Service Monitor and periodically sends an SCCP Keep
Alive message. The Service Monitor acknowledges the Keep Alive message to maintain the
connection.
Alive message. The Service Monitor acknowledges the Keep Alive message to maintain the
connection.
The following scenario describes when a 1040 will fail over to the secondary server:
1. The Cisco 1040 stops receiving Keep Alive acknowledgement messages from the primary
Service Monitor server.
2. After sending three Keep Alive messages without any acknowledgement, the Cisco 1040
sends a Keep Alive message to the secondary Service Monitor server.
3. The secondary Service Monitor server sends a Keep Alive acknowledgement message.
4. The Cisco 1040 sends a StationRegister message with the station user ID set to the Cisco
1040's ID.
5. Secondary Service Monitor goes to the TFTP server to get the latest configuration file for this
Cisco 1040.
6. Secondary Service Monitor sends a StationRegister acknowledgement message.
7. Now Cisco 1040 will start sending syslog messages to the secondary Service Monitor server
while still sending Keep Alive messages to the primary Service Monitor server to see whether
it’s back up again.
it’s back up again.
Note: Users cannot set the time of a failover Cisco 1040. The only way to make any
configuration changes to a failover Cisco 1040 is to first make this Service Monitor server its
primary Service Monitor server.
configuration changes to a failover Cisco 1040 is to first make this Service Monitor server its
primary Service Monitor server.
The following scenario describes how the Cisco 1040 will revert back to the primary server:
1. Cisco 1040 begins to receive a Keep Alive acknowledgement from its primary Service Monitor
server once it comes back up again.
2. Cisco 1040 sends a StationUnregister message to the secondary Service Monitor server.
3. Secondary Service Monitor server sends a StationUnregister acknowledgement message to
the Cisco 1040.
4. Cisco 1040 sends a StationRegister message with the station user ID set to the Cisco 1040's
ID to the primary Service Monitor server.
5. Primary Service Monitor server sends back a StationRegister acknowledgement message.
6. Cisco 1040 starts to send syslog messages to this Service Monitor server now.
See Figure 4.