Subject: RE: [mobile-ip] draft on random interface identifiers available

From: [email-masked]
Date: Tue, 5 Feb 2002 14:35:44 -0600

I have a question regarding section 3 on generation of random numbers. In the ID you state:

"... it should be noted that because of the randomness of the identifier, it is not necessary to create the identifier in real time, i.e.  when the node joins the network, but the identifier can be already created ... What is more, this random number can be pre-configured in the interface driver and the node can use always the same number without changing the probabilities calculations made above.  This reduces the needed complexity in the nodes."

My question is: how is this then any different from having a 62 bit interface identifier allocated to the mobile node? You just need to make sure that the identifier is unique. The identifier can be assigned to physical nodes such as mobile phones by e.g. the manufacturer, and for laptops either by the manufacturer or e.g. by the ISP when a subscription is activated.

Thanks for any clarifications,
Stefano

-----Original Message-----
From: ext Ignacio Soto Campos [mailto:[email-masked]]
Sent: Monday, February 04, 2002 9:52 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: [mobile-ip] draft on random interface identifiers available

Hi all,

    We have submitted the draft "Random generation of interface
identifiers" that is available from:

http://www.ietf.org/internet-drafts/draft-soto-mobileip-random-iids-00.txt

The abstract is included below. Comments are welcomed.

Abstract

   This document evaluates the use of random numbers to generate the
   interface identifier part of an IPv6 address on mobile environments,
   where Duplicate Address Detection (DAD) mechanisms are expensive.
   We have estimated the probability of having an address duplication
   using this mechanism and we conclude that the IPv6 addresses created
   in this way could be used without previously doing DAD to test the
   uniqueness of the address in a link.

Best regards,

Ignacio

---

From: Ignacio Soto Campos <[email-masked]>
Date: Wed, 06 Feb 2002 10:23:43 +0100

Stefano,

> My question is: how is this then any different from having a 62 bit interface identifier allocated to the mobile node? You just need to make sure that the identifier is unique. The identifier can b…

The difference is "you just need to make sure that the identifier
is unique". This is not an easy task, mainly if you think of a network
with a lot of different access technologies (it is not only for mobile
nodes because they can visit networks with desktop computers). If we'd
have a way of creating unique identifiers for any case, that would solve the problem. The draft says that you can generate the random number by
any means you want, for example when the network driver is installed
a random number can be generated and associated with the driver so that
the node can use it any time it joins a network. But we don't assume
a centralized mechanism or a procedure to guarantee that this random
number is unique, that wouldn't be realistic at this time.

Regards,

Ignacio