Subject: RE: [mobile-ip] New BETH Draft

From: "Patil Basavaraj (NET/Dallas)" <[email-masked]>
Date: Wed, 19 Sep 2001 17:58:42 -0500

James,

>
>Hi Raj,
>
>>
>>Here's a scenario on HOs that I would like to get your opinion on what
>>happens w.r.t BETH:
>>
>>BETH is a network initiated HO and as such the MN is kept in the dark
>>about the change in AR. Once a HO decision has been made the oAR
>>creates a Bi-directional tunnel between the oAR and the nAR. The MN is
>>not consulted at all. 
>>There may be scenarios where the MN may be capable of handing off to
>>another network (via another i/f). The oAR that the MN is currently
>>attached to is not aware of this network/AR as it may not be in its
>>configuration or neighbor list. There may be a possibility that the
>>network may be in the process of performing a BET HO while the MN may
>>initiate a Mobile originated HO. While this may be considered to be a
>>race condition or a special case, the fast HO I-D should specify the
>>precedence that would exist in such cases. In this case I would think
>>that the BET HO would be abandoned and the Mobile originated HO
>>request would take prerogative.
>>
>
>I agree.
>
>Specifically, when the MN decides to hand over to another interface,
>it issues a SolPrxyRtAdv to the AR that is handling the active
interface,
>requesting handover to the AR handling the new interface. Upon
>receipt of the SolPrxyRtAdv, the current AR proceeds to do
>an FMIPv6 handoff to the new AR, issuing a standard FMIPv6 HI/HACK, and
>sending the PrxyRtAdv to the MN. Upon receipt of the PrxyRtAdv, the
>MN proceeds to configure its IP stack so that the home address is
>on the new interface, then it does F-BU and F-NA, just like standard
>FMIPv6, but now on the new interface. 
>
>This procedure is exactly the same as for an FMIPv6 handover. The
difference
>w.r.t. BETH is that the old AR terminates the bidirectional tunnel
>upon receipt of the F-BU. In additon, the procedure for a MN doing BETH
would
>be exactly the same should it handover to an AR that was not
>BETH capable on the same interface, except in that case, the current AR
would 
>signal the MN to do FMIPv6 handover by sending it a PrxyRtAdv, rather
>than having the MN signal it by doing the SolPrxyRtAdv.
>
>I don't believe this case is mentioned in the spec,  but I can
>add it.

Thanks. That would be good. Just for clarification (in BETH) , I guess
the time at which you start forwarding packets to the MN via the
tunnel to the new AR is at the time when you get an L2 indication that
the MN is no longer connected to the AP. I may have to reread the BETH
spec to ensure that is the case.

>		jak

-Basavaraj

---

From: Behcet Sarikaya <[email-masked]>
Date: Thu, 20 Sep 2001 11:25:17 -0400

Hi Raj,
  I extracted the following from the minutes you distributed earlier. Are
there answers to these questions now? Or they are still up in the air?

- What destination address to use in the F-BU? It was confirmed by
  group that global IP address should be used instead of local address
  as suggested by current specifications
- Creating binding cache entry on previous access router (after
  receiving Hack and after sending F-Back to the old link). It was
  concluded that this is implementation specific and doesn't really have
  any protocol impact.
- What source address to use when sending F-BU from newer AR?
- Issues may be related to sending of F-NA (including only one IP
  address suffices). The group provided comments that it is essential to
  know both Hack and F-Back.
- When to change default router? There are two options proposed: after
  receiving proxy PA (may be not) or after actually attaching to the new
  link (the new AR).

"Patil Basavaraj (NET/Dallas)" wrote:

Thanks in advance.

--
Behcet