Subject: [mobile-ip] RFC2002bis interpretation question

From: George Tsirtsis <[email-masked]>
Date: Tue, 5 Feb 2002 07:53:55 -0500

Hi all

I am trying to figure out how implementers have interpreted the Rbit part of
rfc2002. I have asked a few people privately and I do not get identical
feedback so some discussion here maybe helpful. 

I remind you that if the Rbit is set in a Foreign Agent Advertisement the
MIP client is required to register through the Foreign Agent even if it has
access to a collocated address...
But what does that mean exactly?
1. Should the client register its Collocated care-of-address (and thus
ignore the advertized CoA) but send the registration request to the FA and
the FA forwards it to the HA?
2. Should the client register with the care-of-address advertised in the
advertisement? If this is the case, can the mobile now also use a collocated
care of address as source address for some traffic??

Is one of the above the "correct" behavior? How does your MIP client
implementation behave and what does your Foreign Agent implementation
expect?

Are you aware of any interoperability tests in this area?

Thanks for your help
George
P.S: I am interested about what the intention of the spec is but also about
how current Mobile Node and Foreign Agent implementations behave and what
they expect so let me know privately if you do not want to do that on the
mailing list.

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From: Bjorn Andersson <[email-masked]>
Date: Tue, 5 Feb 2002 16:06:12 +0200

> care of address as source address for some traffic??

I think it is pretty clear that it is alternative 1. The purpose, as
said in draft-ietf-mobileip-rfc2002-bis-08.txt, is: "to allow sites to
enforce visiting policies (such as accounting) which require exchanges
of authorization." What would the use of the collocated CoA be if the
MN did not register it with anyone? It would be able to use the
address as any node, but it would not be a care-of address.

  Bjorn

-- 
Bjorn Andersson <[email-masked]>                       +358 50 341 2556
Lifix Systems Oy <http://www.lifix.fi/>                 PGP id 5AFC144B
Yliopistonkatu 5, 3rd floor; FIN-00100 Helsinki

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From: Hans Sjöstrand <[email-masked]>
Date: Thu, 07 Feb 2002 15:29:46 +0100

We register with the care-of-address advertised in the advertisement. We 
use the home address as source address. Collocated care-of-address we 
only use when registering directly with HA.

Have never thought of this as ambiguous, interesting to note that 
otheres have.

So, whats the score George ? It would be interesting to know even though 
not revealing who does what for those that haven't responded to the list.

Regards
/// Hasse

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From: Bjorn Andersson <[email-masked]>
Date: Thu, 7 Feb 2002 16:40:38 +0200

On Thu, Feb 07 2002, at 15:29:46 +0100, Hans Sjöstrand wrote:
> We register with the care-of-address advertised in the advertisement. We use
> the home address as source address. Collocated care-of-address we only use when
> registering directly with HA.

This is actually what our MN implementation does also, although I
interpreted it differently in my previous mail. So now we have three
MNs registering the FA care-of address.

  Björn

-- 
Björn Andersson <[email-masked]>                       +358 50 341 2556
Lifix Systems Oy <http://www.lifix.fi/>                 PGP id 5AFC144B
Yliopistonkatu 5, 3rd floor; FIN-00100 Helsinki

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From: "eskl" <[email-masked]>
Date: Thu, 7 Feb 2002 17:13:58 +0100

Our MN is also using the FA care-of-address. 

espen
Espen Klovning  
Birdstep Technology ASA 
www.birdstep.com

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Bjorn
Andersson
Sent: 7. februar 2002 15:41
To: [email-masked]
Subject: Re: [mobile-ip] RFC2002bis interpretation question

  Björn

---

From: Sivasundar Ramamurthy <[email-masked]>
Date: Thu, 7 Feb 2002 15:25:08 -0800 (PST)

Hello,

> implementation behave and what does your Foreign Agent implementation

I have not completely following the emails posted in this regard. So
please bear with me if this has already been mentioned. 

section 3.7.2.1 of rfc2002 bis8 indicates (indirectly) that the FA
could receive requests in which the D bit is set and the COA is not
one of its own, and that it should not reject these requests.

This would probably happen when a MN with a co-located COA
acknowledges the R bit in the advertisement and registers via the FA.

As far as the FA goes, it looks like it should be able to handle
both types of behaviour. Of course, behaviour #2 would appear to the
FA like a "regular" reg request.

Siva