[dhcwg] Edit #2 of DHCP spec
Ralph Droms <rdroms@cisco.com> Tue, 14 May 2002 20:09 UTC
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Date: Tue, 14 May 2002 16:06:29 -0400
From: Ralph Droms <rdroms@cisco.com>
To: dhcwg@ietf.org
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Subject: [dhcwg] Edit #2 of DHCP spec
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Narten:
> 17.1.2. Transmission of Solicit Messages
>
> The first Solicit message from the client on the interface MUST
> be delayed by a random amount of time between MIN_SOL_DELAY and
> MAX_SOL_DELAY. In the case of a Solicit message transmitted when DHCP
> is initiated by IPv6 Neighbor Discovery, the delay gives the amount
> of time to wait after the ManagedFlag changes from FALSE to TRUE (see
> section 5.5.3 of RFC2462). This random delay desynchronizes clients
> which start at the same time (for example, after a power outage).
Hmm. I see a couple of potential problems here. First, we have to be
careful about tying this to the change of the value from FALSE to
TRUE. Consider a misconfiguration, where there are two routers, and
one sends out RAs with the bit set to 0, the other router sets it to
1. This will result in a flip-flop with every RA. Do we really want to
restart DHC everytime that happens?
A better approach might be to say, if the managed bit changes from
FALSE to TRUE, *and* the client isn't currently already using DHC on
that interface, then start the process. note: if the flag changes from
true to false, does the client drop all its DHC-learned stuff and
issue a release? There is no text that suggests this be done, and I
don't think we want to do this.
Also, the delay should be tied to receipt of the first RA that says
use DHC. On a power outage, all the clients will get the first RA at
the same time. This is the issue where having a random delay would
seem to be most important.
Response: Changed the second sentence as follows:
***************
*** 1923,1932 ****
be delayed by a random amount of time between MIN_SOL_DELAY and
MAX_SOL_DELAY. In the case of a Solicit message transmitted when DHCP
is initiated by IPv6 Neighbor Discovery, the delay gives the amount
! of time to wait after IPv6 Neighbor Discovery causes the client to
! invoke the stateful address autoconfiguration protocol (see section
! 5.5.3 of RFC2462). This random delay desynchronizes clients which
! start at the same time (for example, after a power outage).
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- [dhcwg] Edit #2 of DHCP spec Ralph Droms