Re: [ntpwg] [dhcwg] Re: Network Time Protocol (NTP) Options for DHCPv6

"David L. Mills" <mills@udel.edu> Wed, 21 November 2007 04:44 UTC

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Date: Wed, 21 Nov 2007 04:43:54 +0000
From: "David L. Mills" <mills@udel.edu>
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Subject: Re: [ntpwg] [dhcwg] Re: Network Time Protocol (NTP) Options for DHCPv6
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Danny,

The one-way delay on a fast Ethernet is usually in the weenieseconds on 
a fast Ethernet, so I wouldn't worry to much about it. The scenario 
where the DHCP delay would be useful is when for some reason or other 
the client cannot use the client/server volley to measure it. A nonzero 
delay value in the DHCP response would be an explicit indication of that.

Davev

Danny Mayer wrote:

> Brian Utterback wrote:
>
>> Benoit Lourdelet (blourdel) wrote:
>>
>>> Considering a central DHCP server, the use of remote-id [RFC4649] or
>>> just link-id may tell the server from where the request is coming then
>>> giving it the knowledge of the delay to
>>> apply.
>>> In the case of a DHCP server hosted by the first hop, the DHCP server is
>>> well positioned to know the delay.
>>
>> Oh, agreed, it is possible for the delay to be known.
>
>
> I consider that it is most unlikely for the DHCP server to know the
> delay. Consider DHCP server D, client C and NTP server N. Each are in
> different locations on the physical wire (wireless and other medium are
> similar). D may know its own delay to N but C is elsewhere on the
> wire. You might be able to figure out the delay between D and C but how
> does it relate to the delay between C and N? They are in different
> locations on the wire. Is C closer to N, further away, on another
> segment of the network?
>
> Danny
> _______________________________________________
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> ntpwg@lists.ntp.org
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