RE: [dhcwg] <draft-ietf-dhc-agent-subnet-selection-03.txt> - Clas sfull ?

Van Aken Dirk <VanAkenD@thmulti.com> Thu, 10 October 2002 07:18 UTC

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From: Van Aken Dirk <VanAkenD@thmulti.com>
To: "'Ted Lemon'" <Ted.Lemon@nominum.com>
Cc: "'dhcwg@ietf.org'" <dhcwg@ietf.org>, Dedecker Hans <DedeckerH@thmulti.com>, Dekeyser Miek <DekeyserM@thmulti.com>, "'Dirk.Ooms@alcatel.be'" <Dirk.Ooms@alcatel.be>
Subject: RE: [dhcwg] <draft-ietf-dhc-agent-subnet-selection-03.txt> - Clas sfull ?
Date: Thu, 10 Oct 2002 09:16:06 +0200
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Hi Ted,

As you as you mentioned in the reply, it is indeed exactly the same problem
as with giaddr.

But why can this problem not be solved ? After all, the overloading of
giaddr (communication with the relay agent and address pool selection) was
defined 17 years ago (RFC951-1985). All networks were classfull at that time
but today almost all IP systems can operate in a classless environment..

As it is a totally new DHCP Relay Information Sub-Option, one can easily
define two fields: IP address and IP mask or IP address and Prefix length.

One could eventually reuse the syntax of <draft-ietf-dhc-csr-07.txt> - The
Classless Static Route Option for DHCPv4.

Best regards - Dirk

                     

-----Original Message-----
From: Ted Lemon [mailto:Ted.Lemon@nominum.com]
Sent: Tuesday 8 October 2002 11:32
To: Van Aken Dirk
Cc: 'dhcwg@ietf.org'.org'; Dedecker Hans; Dekeyser Miek
Subject: Re: [dhcwg] <draft-ietf-dhc-agent-subnet-selection-03.txt> -
Classfull ?


> I wonder though how the DHCP server can derive a subnet from a single
> quantity being an IP address. e.g. 20.0.0.0 can be an alias for 
> 20.0.0.0/8
> or 20.0.0.0/29.
> So my guess is that the only way the DHCP server can derive the subnet 
> form
> is based on the leading bits of the address being either class A, B or 
> C.

The DHCP server is configured with a list of subnets.   It has to be, 
to make address assignment decisions.

This is exactly the same problem that you have if you use giaddr for 
subnet selection.

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