Enabling the Distributed Periodic Packet Management Process for VRRP
Typically, VRRP advertisements are sent by the VRRP process (vrrpd) on the master VRRP router at regular intervals to let other members of the group know that the VRRP master router is operational.
When the vrrpd process is busy and does not send VRRP advertisements, the backup VRRP routers might assume that the master router is down and take over as the master router, causing unnecessary flaps. This takeover might occur even though the original master router is still active and available, and might resume sending advertisements after the traffic has decreased. To address this problem and to reduce the load on the vrrpd process, Junos OS uses the periodic packet management process (ppmd) to send VRRP advertisements on behalf of the vrrpd process. However, you can further delegate the job of sending VRRP advertisements to the distributed ppmd process that resides on the Packet Forwarding Engine.
The ability to delegate the sending of VRRP advertisements to the distributed ppmd process ensures that the VRRP advertisements are sent even when the ppmd process—which is now responsible for sending VRRP advertisements—is busy. Such delegation prevents the possibility of false alarms when the ppmd process is busy. The ability to delegate the sending of VRRP advertisements to distributed ppmd also adds to scalability because the load is shared across multiple ppmd instances and is not concentrated on any single unit
 | Note: CPU-intensive VRRP advertisements, such as advertisements with MD5 authentication or those sent and received over logical interfaces, such as Aggregated Ethernet interfaces, continue to be processed by the VRRP process on the Routing Engine even when distributed ppmd is enabled. |
To configure the distributed ppmd process to send VRRP advertisements, include the delegate-processing statement at the [edit protocols vrrp] hierarchy level:
