[Dnsmasq-discuss] slowing down dhcp
Rick Jones
rick.jones2 at hpe.com
Fri Jun 24 00:45:31 BST 2016
On 06/23/2016 02:34 PM, Eric Johansson wrote:
> I have some really old ip phones (polycom ip 430). they are sending
> lease requests but it ooks like they are not catching the reply. I put
> dnsmasq on a vm (on a slower system) and the phone starts to catch the
> requests after 4-5 tries. I'm interpreting this as phones that are too
> slow for the modern network
>
> any idea on how I can slow down just the dhcp exchange to test out
> this conjecture?
Under Linux there is something called "netem" (network emulator) which
can be pushed onto the stack as a tc qdisc to control bandwidth and
delay among other things. I've only used it "universally" rather than
trying to slow-down just a specific traffic type, but I suspect it may
be possible to do some filtering/marking/whatnot to get the DHCP traffic
as the only traffic affected.
Under *BSD I think similar functionality can be found in something
called "dummynet."
Of course, if you were to build dnsmasq from source, you could probably
just put a sleep/usleep/whatnot somewhere in the reply path.
happy benchmarking,
rick jones
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