labovit at merit.edu
Mon Jan 13 14:46:09 UTC 1997
The EE Times writer stumbled across the May/June BoardWatch article that
somehow warped the May NANOG discussions on routing stability into a story on
"Cisco's dirty little secret." The EE Times author apparently thought this
would make a great basis for a vendor-bashing story, so he gave both Merit and
Cisco a call.
Both Cisco and the RA tried to carefully (and at great length) explain to the
EE Times writer the same things discussed at NANOG. Particularly, we (Merit)
tried to emphasize that we were/are not finger-pointing at Cisco, nor any
other single vendor/ISP. Basically, the content of the discussion was:
* there are an awful lot of withdraw/announcements out there
* we don't know were they are comming from, and no, it is not Cisco's fault
* some valid, and standards-compliant vendor implementation decisions are
contributing a small fraction of extra withdraws (yes, Cisco is one of
these vendors, but there are probably others)
* there are differing opinions on how much of a problem all of this extra
withdraws pose for Internet
* even though it is not clear there was/is a significant problem, vendors
(Cisco) have created fixes to limit some of the extraneous routing
* a recently noticed 30-second periodicity to updates tends to suggest a
systematic problem in the infrastructure. This 30 second periodicity
occurs with both widthraws and announcements (and seems independent of
the extra withdraw problem). This problem may be a widespread
problem with: data collection errors, leased lines (DSU/CSU), common
configuration errors, bugs in router software, and even
self-synchronization problems or base, theoretical problems in the
routing protocols themselves.
At the end of this discussion, I felt somewhat comfortable that the author
understood the issues. I was disappointed, and a bit discouraged to see the
Unfortunately, this article seems to be one of the more widely-read pieces on
routing stability. Cisco and Merit even received calls from the NY Times and
Washington Post about it. But after explaining the issues, the Times/Post
reporters correctly decided that there was not a good -- and certainly not a
"Cisco is at fault" -- story in the issues -- only a complicated, poorly
A discussion of the BoardWatch article
NANOG home page (with pointers to the meeting notes)
at Mon, 13 Jan 1997 12:57:58 GMT, you wrote:
> > Has anyone heard of E.E. Times that did a piece on the Internet and blame
> > Cisco routers for all the bottlenecks? They quote www.ra.net/statistics
> > www.academ.com/nanog as well as Craig Lebowitz and Fred Baker. I have a
> > locally translated copy but I would be interested in seeing the original.
> > It's on their web site if you wanna dig for it. A very sad article...
> The URL is http://www.techweb.com/se/directlink.cgi?EET19970106S0051.
> The first paragraph really sets the tone for the rest of the article:
> : A report by a federally funded networking research group here suggests
> : that severe Internet congestion might be linked to "routing instability,"
> : wherein heavy traffic emanating from routers bogs down the public network.
> : The researchers further claim to have turned up evidence that Internet
> : autonomous systems supplied by the dominant maker of routers, Cisco
> : Systems Inc., have inherent router flaws that may exacerbate the problem.
> The comment at the end is pretty good, too:
> : Cisco routers might have IP-compatibility problems
> These people ought to stick to roads and bridges.
Craig Labovitz labovit at 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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