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IP Address Takeover HA Workflows

The HA Configuration with One NIC figure shows an IP Address Takeover configuration prior to a switchover:

State Prior to Switchover

  • SIP Server 1 is in primary mode.
  • SIP Server 2 is in backup mode.
  • The Virtual IP address at the primary SIP Server (SIP Server 1) is enabled.
  • The Virtual IP address at the backup SIP Server (SIP Server 2) is disabled.

State After a Switchover

To see what happens in different scenarios, see the following:

HA Configuration with One NIC


Manual-Switchover Workflow

The following steps describe a primary to backup-switchover workflow for a IP Address Takeover configuration (the HA Configuration After a Switchover figure represents the end state of the workflow):

  1. The switchover is initiated manually from the Solution Control Interface (SCI).
  2. Through LCA, the SCS instructs the primary SIP Server (SIP Server 1) to go into backup mode.
  3. Through LCA, the SCS instructs the backup SIP Server (SIP Server 2) to go into primary mode.
  4. The SCS generates a log message with Event ID 00-5150 to indicate that SIP Server 2 has changed to primary mode and a log messages with Event ID 00-5151 to indicate that SIP Server 1 has changed to backup mode.
  5. The SCS activates the Alarm Conditions, which execute the associated Alarm Reaction scripts.
  6. The Alarm Reaction scripts trigger the Virtual IP address control scripts that are configured as applications.
  7. The SCS instructs LCA to launch the Virtual IP address control scripts on the SIP Server hosts.
  8. The Virtual IP address control scripts disable the Virtual IP address on the SIP Server 1 host (Host 1) and enable the Virtual IP address on the SIP Server 2 host (Host 2).
HA Configuration After a Switchover


Primary Server-Failure Workflow

The following steps describe a primary server-failure workflow for an IP Address Takeover configuration (the HA Configuration After Primary Server Failure figure represents the end state of the workflow):

  1. The primary SIP Server (SIP Server 1) fails.
  2. LCA detects the primary SIP Server failure and reports it to the SCS.
  3. Through LCA, the SCS instructs the backup SIP Server (SIP Server 2) to go into primary mode.
  4. The SCS generates a log message with Event ID 00-5150, to indicate that SIP Server 2 has changed to primary mode.
  5. The SCS activates the Alarm Condition, which executes the associated Alarm Reaction scripts.
  6. The Alarm Reaction scripts trigger the Virtual IP address control scripts that are configured as applications.
  7. The SCS instructs LCA to launch the Virtual IP address control scripts on the SIP Server hosts.
  8. The Virtual IP address control scripts disable the Virtual IP address on the SIP Server 1 host (Host 1) and enable the Virtual IP address on the SIP Server 2 host (Host 2).
HA Configuration After Primary Server Failure


Primary Server-Disconnected Workflow

The following steps describe a primary server-disconnected workflow for an IP Address Takeover configuration (the HA Configuration After a Primary Server is Disconnected figure represents the end state of the workflow):

  1. The SCS detects that the connection to the primary SIP Server host (Host 1) has been lost.
  2. Through LCA, the SCS instructs the backup SIP Server (SIP Server 2) to go into primary mode.
  3. The SCS generates a log message with Event ID 00-5150, to indicate that SIP Server 2 has changed to primary mode.
  4. The SCS activates the Alarm Condition, which executes the associated Alarm Reaction scripts.
  5. The Alarm Reaction scripts trigger the Virtual IP address control scripts that are configured as applications.
  6. The SCS instructs LCA to launch the Virtual IP address control scripts on the SIP Server hosts.
HA Configuration After a Primary Server is Disconnected


Because SIP Server 1 is disconnected, the script that disables the Virtual IP address on Host 1 cannot be run. When the connection to SIP Server 1 has been restored, the following workflow will occur (not represented in the HA Configuration After a Primary Server is Disconnected figure above):

  1. The SCS detects that the connection to the SIP Server 1 host has been restored.
  2. The SCS discovers that both SIP Servers are running in primary mode.
  3. Through LCA, the SCS instructs SIP Server 1, whose connection was just restored, to go into backup mode.
  4. The SCS generates a log message with Event ID 00-5151, to indicate that SIP Server 1 has changed to backup mode.
  5. The SCS activates an Alarm Condition, which executes the associated Alarm Reaction script.
  6. The Alarm Reaction script triggers a Virtual IP address control script that is configured as an application.
  7. The SCS instructs LCA to launch the Virtual IP address control script on the SIP Server 1 host.
  8. The Virtual IP address control script runs on the SIP Server 1 host and disables the Virtual IP address.


This page was last modified on September 22, 2015, at 11:53.

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