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Re: Heartbeats Straw Poll

As several people brought up in the meeting, "keepalives" under the
wrong circumstances tend to turn into "make-deads".  IKE and IPSEC
implementations should not delete SA's prior to their normal
expiration merely because they haven't heard from the other end in a

There appear to be two different properties people are looking for
from heartbeats/keepalives:

First, rapid recovery from loss of state on one end of a security
association (due to power loss/reboot/reset), so a new IKE SA can be
initiated on one end or the other.  Once this happens, the half-dead
state on one end can be garbage collected as a result of an
affirmative indication (IKE INITIAL-CONTACT) that the other side lost

Second, detection of loss of connectivity between two security
gateways so that traffic can be rerouted through an alternate gateway.
This is really a dynamic routing problem and could (and probably
should) be done without prematurely tearing down IKE SA's and IPSEC
SA's which may still exist and may still be useful once the
connectivity comes back.

It's not clear that the same protocol feature can/should provide both
of these properties..

						- Bill

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