Need details info and url for bug on velocloud

Symptoms

For BGP filter changes, Velos do not perform a delta check at per filter change granularity but rather retract all filters and reinsert them as per the new BGP configuration.

Cause

This can induce a window (of a few seconds) where expected filters would momentarily disappear and re-appear, which can likely cause route churn (add/remove routes) based on filters.

Impact/Risks

There is a potential for a brief interruption when making this change.