Larger Input Queues
In a nutshell
If a BGP speaker is pushing a full Internet table to a large number of peers, convergence is degraded due to enormous numbers of drops (100k+) on the interface input queue. ISP foo gets ~½ million drops in 15 minutes on their typical route reflector.
Increasing the size of the input queue, thus reducing the number of dropped TCP Acks, improves BGP scalability