Failure Scenarios Resolved with Redundancy

Description

You can configure LLC Redundancy to avoid disruption of service in a production environment. Avoid as many single points of failure as possible in your configuration.

The following diagrams illustrate a redundant configuration using two host computers.

Host 1 is acting as the primary host and is running the following:

• LLC (PLLC) connected to the CSP Matrix Series 3 cards in the CSP.

• The primary SwitchManager, connected to the PLLC manages the node.

• Any custom application, such as call processing applications and SNMP.

Host 2 is acting as the Secondary Host and is running the following:

• The RLLC, which is connected to the PLLC (rather than the CSP Matrix Series 3 card).

• A secondary SwitchManager, which takes over management of the node should the primary SwitchManager fail.

• A second copy of the custom application. The LLC shares traffic between the two applications.

Line Key

In the following diagrams we use different lines to illustrate different states of the connection.

• Solid Line
A solid line illustrates an established connection.

• Bold Solid Line
A bold solid line illustrates a new established connection.

• Dotted Line
A dotted line illustrates a lost connection.

Figure 4-1 SwitchKit Redundancy Setup

Primary Host Failure

Should the Primary Host fail, RLLC recognizes the failure by the lack of Poll message responses from the PLLC and it becomes the active LLC.

If the primary host fails, SwitchManager, the Converged Services Administrator (CSA), and custom applications, continue processing as before. When the applications attempt to connect to the LLC again, they first attempt to connect to the PLLC, which fails, and will then connect to the RLLC. This is done automatically and only requires that the IP addresses for the primary & redundant host are defined. There are no additional application requirements for this.

Primary SwitchManager Failure

If the primary SwitchManager fails, the secondary SwitchManager receives an application disconnect message. It then takes over control of the configuration and management of the switch.

Important! When SwitchManager starts, it configures the entire CSP unless an alternative option is used. It is recommended that both the primary and redundant SwitchManagers in a production environment are configured to use Smart Mode.

Primary LLC Failure

Should the primary LLC fail, the RLLC recognizes the failure by the lack of response to Poll messages between them.The RLLC becomes the active LLC. It takes over the connections to all matrices in the CSP and accepts connections from all applications.