Why doesn't BGP...

Vadim Antonov avg at pluris.com
Mon Nov 11 19:35:08 UTC 1996

Peter Lothberg <roll at Stupi.SE>  wrote:

>On the radio1::
>                "101 north is congested, take 280 instead"
>Guess what hapens 5 minutes laster;
>On the radio2::
>                "280 north is congested, take 101 instead"

>goto on the radio1

Goto the theory of control systems :)

This is a textbook case of a system with too strong negative
feedback loop.

There are two ways to deal with that -- reduce the feedback
(say, make the announcement in a barely intelligible speech,
so only 1/3rd of drivers will get it :),  or increase inertia
of the system (by posting 10MPH speed limit :), so announcements
can come fast enough to compensate each other.

Seriously, the load-sensitive traffic management _can_ be done,
but to do it you a) need full knowledge of the load patterns,
plus some historical data, and b) have a way to control system
in steps less drastic than rerouting an entire flow.

Can't be done with ciscos, or any existing routers...


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