Diffserv service classes

Sun Nov 21 18:04:53 UTC 2004

Hi,

Less-than-best effort traffic as implemented via the Internet2 Scavenger
Service (see: http://qbone.internet2.edu/qbss/ ) never really took off;
for example, see http://netflow.internet2.edu/weekly/20041108/#dscp
which notes that Scavenger Service (DSCP=8) tagged traffic makes up less
than 1% of all octets and less than 1% of all packets.

One can argue chicken-and-egg (e.g., had it been supported on the commodity
Internet, it would have been more successful), but I think the bottom line
reality was that because

-- Internet2 was/is uncongested, and because 
-- the typical university user of I2 pays $0/Mbps used anyhow,

the motivation for users to tag traffic as Scavenger was typically 
non-existent (offering a "discount" from a price of zero is hard unless 
the model would involve PAYING people who generate less-than-best-effort 
traffic, a model which strikes me as, well, somewhat 
unsustainable/politically difficult).

A network administrator at a site might unilaterally tag all traffic of a
particular type as less-than-best-effort, but again, unless there is 
congestion, that tagging would be to no effect.

Regards,

Joe St Sauver (joe at oregon.uoregon.edu)
University of Oregon Computing Center