IMG 1010 - N plus 1 Switchover and Switchback

Owned by Kelli Higdon
Last updated: Mar 01, 2024
5 min read

Overview:

The procedure below describes how to configure a Primary and Backup node to be part of an Redundant Node cluster. The procedure will explain how to configure the Redundant Node Cluster and then go through a switchover and switch back. The procedure below goes through configuring one Primary Node and one Backup Node. Follow procedure below.

Procedure:

Create Primary and Backup Nodes:

Primary node is an IMG 1010 with normal DS3 I/O.

  • Right Click on Dialogic IMG EMS and select New Logical IMG.

  • Create the Primary DS3 by right clicking on the Logical Node and selecting New Physical IMG. Enter the information needed. See IMG 1010 - Physical IMG for more information on configuring the Physical IMG.

  • Configure the Primary IMG for your network. (Facilities/Signaling/Interfaces etc)

  • Create the Backup DS3 by right clicking on the Logical Node Group and selecting New Physical IMG.  Enter the information needed. See IMG 1010 - Physical IMG for more information on configuring the Physical IMG. (The I/O on this IMG 1010 must be the backup I/O which has the six pairs of BNC Tx/Rx interfaces on the rear of the unit).

    • Allow the IP address etc just entered to get configured on the IMG 1010 Backup Node. Once configured the Physical Node Pane will display the IMG Type as 1010 Backup. See screen capture below.

The Backup Node cannot be configured. The backup node is simply a backup for the primary node. In the event of a switchover, all configuration from the primary node will be sent to the backup node.

Create a Redundant Node Cluster:

  • At this point the Primary and Backup Nodes have been configured. Right Click on the Dialogic IMG EMS object and select New Redundant Node Clusters. This is just a container object and no configuration needs to be done here.

  • Right Click on the Redundant Node Clusters object and select New Redundant Node Cluster. The Redundant Node Cluster pane will get created. See IMG 1010 - Redundant Node Cluster for more information.

  • Within the Redundant Node Cluster the Backup Node created will be displayed in the Backup IMG (+1) Name field. This field is a drop down list of all Backup nodes created. Select the correct Backup node from the menu.

  • In the Physical IMG at Interface 0 field, select from drop down menu the Primary Node created. This will be the node connected to BNC Tx/Rx pair located on the rear of the IMG 1010 Backup node. See screen capture below.

  • Allow this pane to configure. Once Configured the pane will look like the following. Note that the cluster state is standby, the Backup state is Standby, and the Actively Backing Up state is None. This is normal operation. See below.

  • The Redundant Node Cluster is now configured. The next few steps will describe the Switchover and Switchback process.

 

Switchover and Switchback:

Switchover:

  • In this example, the Primary DS3 IMG 1010 will lose power and shut down. Once the Primary unit loses power the Backup DS3 IMG 1010 will wait the time configured in the Switchover Delay field and then automatically get configured with the failed units configuration. During this process the Redundant Node cluster will go through a few states during configuration of the Backup node. Below are those states.

    • First the IMG 1010 loses power. The GCEMS waits the amount of time configured in the Switchover Delay field. While this is happening the Cluster stat displays Awaiting Timeout. See below.

       

    • After the Timeout period, the GCEMS sends the configuration of the failed unit. Once the backup unit is configured the status changes to 'Switching Over' and then finally 'Switched Over'. The original Backup/Standby is now a Backup/Active node as displayed below.

       

       

Within the object table the Redundancy State displays Link Down and Connection State as Node Link Down.

 

The initial Primary/Active unit which failed has been fixed and now needs to be put back into service so that the backup can get back to backing up the Primary units. First power up the failed unit and allow software to load. Once software is loaded and issues have been fixed the Object Table of the Redundant Node Cluster object displays the failed unit as shown below.

The redundancy state is now Offline and Connection State is Node Link Up.

 

Manual Switchback:

Once the Primary node comes back into service it comes back in the Offline state. To change it back to the Primary/Active state a manual switchback must be executed. To manually switch back, hit the button "Switchback To Primary" located in the Redundant Node Cluster. The Backup node will immediately reset and the configuration will be sent to the previously failed DS3 IMG 1010.  Below is screen capture of the different states the DS3 IMG 1010 goes through.

There is one other state between Waiting and Standby which is the 'Offline State'. This state flashes quickly and disappears quickly.

 

The system will now be in its original state and the Backup is ready for a failure to happen on any one of the Primary Nodes.

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