Re: [Autoconf] Self-addressing using local information

Alexandru Petrescu <alexandru.petrescu@gmail.com> Wed, 04 February 2009 14:57 UTC

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Date: Wed, 04 Feb 2009 15:57:06 +0100
From: Alexandru Petrescu <alexandru.petrescu@gmail.com>
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To: Ricardo Schmidt <super.ismiti@gmail.com>
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Subject: Re: [Autoconf] Self-addressing using local information
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Ricardo Schmidt a écrit :
> Hello all,
> 
> I am developing a short introducing research on autoconfiguration in
> MANETs. Right now I am writing about some protocols for
> self-addressing.

'Self'-addressing?  Maybe the use of the loopback address is pertinent?
  127.0.0.1

> I noticed that, most of the proposed solutions implement a randomly 
> choice of address. For example, a node picks an address from the
> range 1-2047 for temporary address and later an address from the
> range 2048-65534 for the tentative address.

Are we talking about an article (which?) or an Internet Draft or an RFC? 
    Or a non-standard implementation?

For IPv6 there's the forming of a link-local address from the MAC 
address of the interface RFC2464, and the 'privacy' extensions for 
global addresses (basically a random choice) RFC4941.

> Well, I would like to know if there available works where a formula
> is implemented for creating an address, in order to avoid the 
> duplication. Something like Prophet. However, I am looking for a 
> proposal that uses information such as the MAC from the interface to 
> calculate a tentative address.

Sorry what is Prophet?

MAC is used directly to form the IPv6 link-local address over Ethernet 
and the IPv6 global address some times.

For IPv4, there are IPv4 link-local addresses 169.254.x.x RFC3927, and 
within the text there's recommendation to use the MAC address as a seed 
for the random generation.  These addresses are used for example by 
Microsoft's ActiveSync IP over USB, and I guess by Apple's Bonjour; for 
example some ActiveSync devices show:

> Carte Ethernet Connexion au reseau local 5:
> 
>         Suffixe DNS propre a la connexion : 
>         Description . . . . . . . . . . . : Windows Mobile-based Device
>         Adresse physique . . . . . . . . .: 80-00-60-0F-E8-00
>         DHCP active. . . . . . . . . . . : Oui
>         Configuration automatique activee . . . . : Oui
>         Adresse IP. . . . . . . . . . . . : 169.254.2.2
>         Masque de sous-reseau . . . . . . : 255.255.255.0
>         Adresse IP. . . . . . . . . . . . : fe80::8200:60ff:fe0f:e800%16
>         Passerelle par defaut . . . . . . : 
>         Serveur DHCP. . . . . . . . . . . : 169.254.2.1
>         Serveurs DNS . . . . . . . . . .  : fec0:0:0:ffff::1%1
> 	                                    fec0:0:0:ffff::2%1
> 	                                    fec0:0:0:ffff::3%1
>         Bail obtenu . . . . . . . . . . . : mercredi 4 fevrier 2009 15:10:20
>         Bail expirant . . . . . . . . . . : vendredi 6 mars 2009 15:10:20

(remark how this is USB and has no IEEE-assigned MAC address, but it has
  a 'self'-generated MAC address on 48bit and is used to form an IP
  address over USB even if there's no IP-over-USB RFC :-)

There are sometimes contradictory requirements between uniqueness and 
privacy of an address.


Alex

[Autoconf] Self-addressing using local information Ricardo Schmidt
Re: [Autoconf] Self-addressing using local inform… Carlos Jesús Bernardos Cano
Re: [Autoconf] Self-addressing using local inform… Alexandru Petrescu