Subject: Re: Short vs Long leases [Was *DRAFT* of minutes from Oslo WG

From: [email-masked] (by way of Ralph Droms <[email-masked]>)
Date: Fri, 30 Jul 1999 10:08:26 -0400 (EDT)

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Ted Lemon wrote:
> Nothing whatever.  If you want to use the client-supplied user class
> for authorization, you are barking up the wrong tree.  Using it to
> differentiate between clients so as to make the network run more
> smoothly, on the other hand, is a *good* idea.

Agreed.

> In the instance you cite, the reason why you want to have shorter
> leases for laptops is so that they renew their leases more often, and
> thus if they are disconnected from one subnet and moved to another,
> they will quickly re-establish IP connectivity.  Also, you get to
> reclaim their lease sooner.  On a well-maintained, DHCP-administered
> network, there really is no advantage to having a longer lease - I
> can't imagine why a user would even notice.

In a fairly large enterprise, shorter leases can (and most likely will)
cause a great deal of churning on the network, especially if they are
symptomatically synchronized (everyone coming in at 8am), resulting in
relatively unnecessary traffic and the potential for *some* congestion
(when processed in volume). Imagine the traffic patterns generated by
lease request/renewals in a company with 5000 nodes (all in the same
time zone) between 7am and 9am on a Monday morning.

There is certainly a case for shorter leases in the instance of a
transient users vs desktop users, and the ability to differentiate them
could be useful. I think I missed the posting (if there was one) of the
"DRAFT of minutes from Oslo WG meeting", so I cannot comment upon any
given proposal of such a facility.

Nevertheless, just food for thought.

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Michael Schneider                                      Network Engineer
                           [email-masked]
McKessonHBOC / Evanston Hospital                           847/570-5173
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