nanog mailing list archives

Re: FIBER CUT: Dallas to West Coast


From: Sean Donelan <sean () donelan com>
Date: 30 Aug 2001 15:36:03 -0700


On Wed, 29 August 2001, Patrick Greenwell wrote:
The difference is the carrier's response, in particular how well they
keep their customers informed.

That is certainly *a* point of differentiation, however if the goal of
these "basement dual-homers" is to not suffer downtime due to the
outage of a single provider(much like the organizations that "matter"),
all the responsiveness in the world from a provider whose circuit to
one of the "basement dual-homers" which has failed isn't going to prevent
them from being down, is it?

I don't know what the goal of "basement dual-homers" is.  I think that
is the other thread, which I haven't been keeping up with.

It is possible to reduce the impact of most provider problems.  I had
a seven year streak without a service affecting outage at my NOC longer
than the BGP route convergence interval. Even "hot-standby, fail-over"
systems require a finite time to recover.

Even with all the network insanity between 1993 and 2000, I was always able
to reach the working portion of the Internet.  If my own connection didn't
work, how could I post about those problems.  It was a lot of hard work,
and I'll admit I had a very steep learning curve.  And I'll be the first
to admit, there were force maejure events my network wouldn't be able to
handle.  But those were my choices, and I could make those decisions with
accurate information.

The first step of operating a reliable network is choosing carriers willing
to keep you, their customer, fully informed.  Only after you have accurate
information from the carriers can you make informed decisions concerning
your network.  Most of my biggest problems occurred due to inaccurate or
lack of information from a carrier.  If I know about the risk, I could
choose to mitigate it or  choose to do nothing.  If the carrier doesn't
keep me informed about jeopardy conditions in their network, managing that
risk is more difficult.

A side-effect of the lack of information is the extrodinary measures customers
feel they must take to protect their network connectivity.  Do you really
need to multi-home, have your own AS number, have your own CIDR block for
reliable network connectivity?

With DHCP, you could just unplug from one provider and plug into the new
one, and auto-magically have connectivity.  With Dynamic DNS update you
could automagically redirect your DNS name to your new address.  IP addresses
could be assigned geographically, instead of by provider, and aggregation
could take place anywhere from the census tract level to the hemisphere level.



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