Distributed periodic packet management (PPMD) support for VRRP

Typically, VRRP advertisements are sent by the VRRP process (vrrpd) on the primary VRRP router at regular intervals to let other members of the group know that the VRRP primary router is operational. When the VRRP process is busy and does not send VRRP advertisements, the backup VRRP routers might assume that the primary router is down and take over as the primary router, causing unnecessary flaps as the takeover occurs, irrespective of the fact that the original primary is still active and available, and might restart sending advertisements after the load has decreased. To address this problem and to reduce the load on VRRPD, the JUNOS Software now uses the Periodic Packet Management process (PPMD) to send VRRP advertisements on behalf of VRRPD.