Subject: RE: [nemo] Explicit Prefix Length Option

From: "Pascal Thubert (pthubert)" <[email-masked]>
Date: Tue, 25 Nov 2003 13:21:01 -0000

> -----Original Message-----
> From: Alexandru Petrescu [mailto:[email-masked]]
> Sent: mardi 25 novembre 2003 12:54
> To: Pascal Thubert (pthubert)
> Cc: Alexandru Petrescu; [email-masked]
> Subject: Re: [nemo] Explicit Prefix Length Option
> 
> Pascal Thubert (pthubert) wrote:
> >>> Agreed: this is for the usage draft
> >>
> >> So why not moving the prefix len option together with its yet-to-be
> >>  written authorization entirely in the "usages" draft?
> >>
> > "Usages" is not normative. If we need to standardize something, it's
> > not the right place.
> 
> Yes, combine this with: if we need to standardize something it should
be
> advantageous, secure and straightforward implementation.
> 
Changing subject are you? 

> The only advantage of explicit prefix len mode up to now is savings in
> bit-space in the BU messages.  Please analyze these savings for us.
> 
I was arguing the opposite. I was arguing that it can be used in a
simple implicit authorization model, based on an adapted config/policy
at the HA.

> With respect to security: it is in no way more secure to use the
prefix
> len mode rather than the implicit or the explicit network modes.  It
is
> less secure, see Alexis' post.
> 
I answered that but you assertion was certainly not my conclusion

> Straightforward implementation: there is an implementation of the
> explicit prefix len mode.  It is not straightforward in that it poses
> limits in the ways the Home Addresses are assigned to several mobile
> routers of same HA such that MNP's don't overlap.  It is even less
> straightforward in that it requires an implementer to read the
"usages"
> draft too.
??? When mobile networks are not multihomed then obviously MNPs do not
overlap.
Seems you're confusing things up here.

Pascal

---

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 25 Nov 2003 15:50:35 +0100

Pascal Thubert (pthubert) wrote:
>>> "Usages" is not normative. If we need to standardize something, 
>>> it's not the right place.
>> 
>> Yes, combine this with: if we need to standardize something it 
>> should be: advantageous, secure and straightforward implementation.
>> 

Showing that I can deviate as much as you do.  What was that "if we need
to standardize something"?

>> The only advantage of explicit prefix len mode up to now is savings
>>  in bit-space in the BU messages.  Please analyze these savings for
>>  us.
>> 
> simple implicit authorization model, based on an adapted 
> config/policy at the HA.

I was arguing that both the implicit authorization model as well as the
adapted config/policy at the HA are all, maybe simple, but surely not
yet specified.  I was trying to say the the advantages of the explicit
prefix len mode are maybe good ideas but surely not yet specified.

> ??? When mobile networks are not multihomed then obviously MNPs do 
> not overlap. Seems you're confusing things up here.

I was not thinking multi-homing at all.

It's not the MNP's that originally overlap, but the Home Addresses of
the MR's might overlap up to a different length than what their
BU-prefix-len's say.  If these Home Addresses happen to overlap in that
way, then there will surely be confusion at HA to deduce the right MNP.

So I think you're right: I'm not quite sure in all this conversation, so
I'll stop.

Alex

---

From: Alexandru Petrescu <[email-masked]>
Date: Tue, 25 Nov 2003 15:50:35 +0100

Alex