[smokeping-users] set QoS flag in smokeping

[Stephane Bortzmeyer]

On Wed, Feb 13, 2008 at 10:14:30PM +0100,
 Henze, Dirk <dirk.henze at lambdanet.net> wrote 
 a message of 87 lines which said:

> we have been using SmokePing for some time and we looking for a QoS
> monitoring features for our network. We would like to send pings
> with the icmp protocol via SmokePing over the different queues by
> setting the Type-of-Service (TOS) bit to different values for each
> queue.

Well, since nobody replied, I try.

AFAIK, you cannot do it without changing some files in
Smokeping. Smokeping relies on external programs (such as fping) to do
the actual measurement and so your question actually depends on these
programs. With fping, I have no idea. With echoping, yes, you can set
the ToS bits with options -p and -P. I do not think they are settable
from the Smokeping configuration file, you'll need to modify the
source.

But do note that "differentiated treatment" between packets do not
depend only on the ToS bits but also on the packet
type/protocol/etc. I assume you do not manage a network to run ping
but to run, say, a Web server. In that case, the difference of
treatment between ICMP (ping) and HTTP/TCP may be more important than
the one created by the ToS bits.

Last, but not least, ToS has been suppressed in december 1998, almost
ten years ago, and you should use "differentiated services" instead
(see RFC 2474). Yes, I know that Posix (and echoping's man page) still
use the old term :-)