Subject: RE: Should IP Security be Optional?[Was RE:draft-ietf-ipv6-cellu lar-host-00.txt -> wg last call?]

From: "Karim El-Malki (ERA)" <[email-masked]>
Date: Tue, 5 Mar 2002 15:17:51 +0100

> > > true enough.  but then you need the phone to act like an 
 > IPv6 router.
 > > 
 > > But what about if PPP is used?
 > 
 > I don't immediately see how the choice of link-level 
 > protocol changes this.
 > 
 > Keith
 > 
 > p.s. assuming this is a serial interface, PPP framing might 
 > be a reasonable
 > choice.  But PPP authentication, link negotiation, etc. (as 
 > I have experienced
 > them, I admit I haven't followed the specs in recent years) 
 > don't seem like
 > a good fit.  for instance, would use of PPP restrict the 
 > user to at most one 
 > IP host attached to the phone?  that would seem like an 
 > overly restrictive choice.

No. The terminal (phone) doesn't need to act as a router to allow
for multiple devices behind it to connect to the cellular interface.
You could eventually have multiple serial connections to the terminal
each having its own corresponding air interface connection. So it can
act as a host (if you're running the IP stack + app on it) or as
an L2 device (modem) for e.g. laptops behind it. That doesn't mean
that there's no advantages in making it a router but it's not
mandatory. Given that implementers need guidelines now, it's good if we
only limit the scope to hosts for the moment and go onto routers once
the first is complete.

/Karim
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From: Keith Moore <[email-masked]>
Date: Tue, 05 Mar 2002 09:53:18 -0500

> mandatory. 

The point, I think, is that the network that is seen by the devices
atached to the terminal must support all features of an IPv6 network
so that any IPv6 hosts can function when their connectivity is 
provided through such a terminal.  (subject to the normal bandwidth,
delay, packet loss etc. constraints)
 
Keith

---

From: Erik Nordmark <[email-masked]>
Date: Tue, 5 Mar 2002 22:47:50 +0100 (CET)

> only limit the scope to hosts for the moment and go onto routers once

Karim,

In the case of the terminal being an L2 device like a modem
and the IP device being a laptop there might be some care.

For instance, the laptop IPv6 stack might follow the specifications and
use NUD over that PPP link.
This requires that the 3G devices in the network actually support NUD
over the PPP link.

While the draft claims it scope is about the cellular hosts
I wouldn't be surprised if some folks read the MAY and conclude
that they don't need to implement it at the first hop IPv6 router.

So I wonder if it makes sense to make this more clear in an IPv6-over-3G
document which would say
	hosts MAY implement sending of NUD messages
	routers MAY implement sending of NUD messages
	routers MUST implement processing NUD messages (unicast NS messages)
	hosts ??? implement processing NUD messages

Such careful statements would make sense that things would always interoperate.

  Erik