Updates using idle bandwidth

[Bruno Wolff III]

> >
> > In case of dynamic throttling we won't be having any _fixed_ rate at which
> > the connections assigned for updates will be able receive the packets. It
> > means packets would be dropped frequently to implement policing.  Isn't this
> > waste of resources?

Yes and a protocol change was made to help. I believe this is the purpose of
ECN (explicit congestion notification).

> > Tools like tc and tcng implement queues to control outbound data. Is there
> > any similar _kind of_ option available for inbound data?
> > (Obviously we can't have queues because once the packet has been received
> > must be processed)

Shaping on the wrong side of a link is problematic. You can implement queues
on the receiving side which might allow you to better control which flows
get slowed down using IFBs (which replace the older IMQs). While you can't
absolutely prevent the other side from swamping the link with low priority
packets, things should work reasonably with well behaved applications.