North American Network Operators Group
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Re: Do routers prioritize control traffic?

  • From: Danny McPherson
  • Date: Sat Feb 17 19:18:19 2007


On Feb 12, 2007, at 9:10 AM, <[email protected]> <[email protected]> wrote:

They are used for BUSINESS traffic. Also, since these controls make
routers work harder, there is no point in using them where there are no
traffic problems. 

I concur, it only matters when it matters (i.e., when there's
resource contention).

Most providers build their core networks with enough
headroom so that there are no traffic problems.


It's not a matter of just forwarding capacity, it's a matter of control
plane processing capacity, a variable typically orders of magnitude
less than the the former.

And the fundamental problem of QOS means that you only use it
where you have to. QOS works by delaying or discarding packets. It
is hard to sell that as a valuable service to ordinary users.


I believe Christos's query wasn't about ordinary users or transit
traffic, it was regarding "control (e.g., routing) traffic".  I wouldn't
consider network operations or control traffic "ordinary users" and
suspect that if network operators aren't limiting "what" and at what
rate that "what" is permitted to impact the control plane then their
ordinary users should be very concerned.

A usual example of this is DDOS attacks much larger than 10
Gbps sustained, throwing bandwidth at the problem yields little
or no return.

-danny