[e2e] Queue size of routers

[Long Le]

Hi all,

I'd like to seek comments on how to choose the size of router queues.
There are recommendations to set the queue size to 2-4 times the
bandwidth-delay product of the link. Does this imply that queue
sizes of core routers are much larger than those of edge routers?
What would be "typical" queue sizes of backbone routers, assuming
that they do see some congestion.

Does anyone have any comments or pointers?

Thanks,
-- long