Stateful SRP Switchover Redundancy Modes

The switch route processor (SRP) modules can operate in one of two redundancy modes—file system synchronization and high availability.

File System Synchronization Mode

File system synchronization is the default behavior mode for E Series routers that contain redundant SRPs. Available only to SRP modules, this mode has been available since the JunosE Software 2.x release. In this mode:

For additional information about the default SRP functionality, see Managing Module Redundancy.

High Availability Mode

Currently applicable to the SRP module, Juniper Networks high availability mode uses an initial bulk file transfer and subsequent, transaction-based mirroring to ensure rapid SRP module recovery after a switchover. This process is referred to in this chapter as stateful SRP switchover.

In addition to keeping the contents of NVS, high availability mode keeps state and dynamic configuration data from the SRP memory synchronized between the primary and standby SRP modules.

When stateful SRP switchover is enabled, an SRP switchover keeps line modules up and forwarding data, and the newly active SRP module continues from the point of switchover.

By using transaction-based mirroring instead of file synchronization, high availability mode keeps the standby SRP module synchronized with the active SRP module. Mirroring occurs from memory on the active SRP module to memory on the standby SRP module by way of transactions. When a transaction is committed on the active SRP module, the data associated with the transaction is sent to the standby SRP module.

In high availability mode:

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