OT Route Flaps (was RE: New Python Dev... & SourceForge considere d...))

[Doug Stanfield]

[kc5tja at garnet.armored.net ]

> On Thu, 05 Oct 2000 14:18:25 -0700, Eric Lee Green wrote:
> >Title         : Route flapping for valinux/sourceforge etc.
> 
> OK, I gotta ask -- what is Route Flapping?

Route flapping occurs when there is an unstable link between two routers.
Unstable meaning it is not up good or completely down dead but rather going
up and down.  Routing in the Internet works from the exchange of
connectivity information from a router to its adjacent neighbors.  If there
is an unstable link that changes state more rapidly than the routes would
propagate router to router to router that would be a route flap. That
connectivity information won't be correct for some number of routers through
the network, and worse, it will be different for different routers.  This
could mean that two routers with different information about the best place
to send packets might send them back and forth between each other until they
get thrown in the bit bucket for exceeding their time to live.

There is a mechanism, route dampening, that acts to add hysteresis to route
change propagation so that route flapping doesn't get out of hand.

HTH

or-at-least-satisfied-your-interest 'ly yr's

-Doug-