mailing list archives
Re: Questions about Internet Packet Losses
From: Craig Labovitz <labovit () merit edu>
Date: Mon, 13 Jan 1997 18:28:20 -0500
at Mon, 13 Jan 1997 14:00:33 PST, you wrote:
of the packet loss is inadvertent, a large percentage of the public
exchange point connectivity problems reflect intentional engineering
decisions by Internet service providers based on commercial settlement
I think that this is an _extremely_ dangerous assertion on Merit's part.
As always, ascribing intent rather than raw data requires much more
justification which I have yet to see.
Unfortunately, a key word here was probably left out. The sentence should have
read "_may_ reflect"... Tony is right -- we cannot ascribe any
motives/rational to ISP engineering decisions.
We are walking a bit of a tightrope here. Although I believe the NetNow
statistics contain some valuable information on network performance, a number
of large ISPs have expressed significant concerns about the possible
misinterpretation of the data. Specifically, several ISPs have explained that
increasing amounts of their customer traffic do not traverse public exchanges.
These ISPs assert that measuring packet loss/latency between public exchange
points is not reflective of actual network performance as perceived by their
customers. These ISPs further explained that their priority is always to
optimize their customers' network performance. For the large ISPs, this
increasingly may mean prioritizing connectivity to direct/private exchange
points before public exchange points.
Of course, I have not seen publicly available statistics on the amount of
traffic traversing public exchange points versus private exchange points. The
text Bob quotes essentially reiterates the explanations/descriptions of the
NetNow data provided by the large ISPs. Lacking any evidence to the contrary,
we included the text as an attempt to provide a more balanced view of the
Where is the data on packet losses experienced by traffic that does not go
through public exchange points?
I suspect that you'd have to ask the parties involved in the private
exchange point. I suspect that there are not such statistics currently
kept, or if so, they would not be willing to disclose them. Thus IPPM...
A number of large ISPs have volunteered probe platforms at private exchange
points. We (Merit/CAIDA/NLANR) are now evaluating the possible deployment of
additional probe machines for inclusion in these network performance studies.
Craig Labovitz labovit () merit edu
Merit Network, Inc. (313) 764-0252 (office)
4251 Plymouth Road, Suite C. (313) 747-3745 (fax)
Ann Arbor, MI 48105-2785
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Re: Questions about Internet Packet Losses Perry E. Metzger (Jan 13)
Re: Questions about Internet Packet Losses Nathan Stratton (Jan 14)