Subject: Re: PPP and Global Addresses

From: Siva Veerepalli <[email-masked]>
Date: Wed, 13 Feb 2002 14:30:35 -0800

At 03:28 PM 2/13/2002 -0600, Lilian Fernandes wrote:

>Hi,
>
>I have a question about RFC2472 - "IP Version 6 over PPP". The RFC talks
>about the negotiation of the Interface-Identifier and specifies the
>Interface-Identifier Configuration Option. In this case the upper 64 bits
>are just fe80::
>
>It does not mention if there is any standard way to configure a
>global/site-local prefix on a point-to-point link i.e. are there
>configuration options to let one side tell the other about a global
>prefix?
>
>Or is it just left upto the users at both ends to decide on a prefix
>somehow and then configure it on each end?

The prefix is provided using the Route Advertisement Message (see RFC2461).

As an aside, I saw a draft on Automatic Prefix Delegation a while back. It 
talked about providing a router with a prefix it could use to advertise on 
its attached subnet. It does this using two new ICMPv6 messages. Does 
anyone know what the status of this draft is?

Siva

>I'm sorry if there is an RFC about this that I missed...
>
>Thanks,
>Lilian
>
>_____________________________________________________________________
>
>Lilian Fernandes
>AIX TCP/IP Development - IBM Austin
>Tel: 512-838-7966       Fax: 512-838-3509
>
>
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---

From: Lilian Fernandes <[email-masked]>
Date: Wed, 13 Feb 2002 16:38:22 -0600 (CST)

Since PPP does not support multicast, this will involve a smart NDP that
takes into consideration the type of interface as well i.e. we cannot send
a router solicitation to the all-routers address/send a router
advertisement to all-nodes and so on.

Is this what most implementations do? I would like to know if most
implementations use NDP over PPP in some way.

Thanks,
Lilian

Lilian Fernandes

---

From: Francis Dupont <[email-masked]>
Date: Thu, 14 Feb 2002 00:22:45 +0100

In your previous mail you wrote:

   Since PPP does not support multicast,

=> I disagree:
x% uname -sr
FreeBSD 4.5-RELEASE
x% ifconfig ppp0
ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
                             ^^^^^^^^^     

   Is this what most implementations do?

=> they implement multicast (all of them, I know no exception)
   
Regards

[email-masked]