Subject: RE: [mobile-ip] Thoughts on using handover capability extensio

From: "Mohamed Khalil" <[email-masked]>
Date: Thu, 14 Nov 2002 13:52:09 -0600

-----Original Message-----
From: Rajeev Koodli [mailto:[email-masked]] 
Sent: Thursday, November 14, 2002 1:13 PM
To: [email-masked]
Subject: Re: [mobile-ip] Thoughts on using handover capability extensio

Hello folks,

we had a good discussion on the topic. Let me try
to summarize.

- it seems to me that folks prefer moving the PrRtSol
   and PrRtAdv messages to an earlier time. Perhaps
   we should recommend that the MN should send
   PrRtSol after router discovery (RS/RA) or during router
   discovery (see the next issue) ? In this message,
   the MN sends a wildcard for target APs. The router
   sends a map of neighboring AP-AR information.
   The MN may send PrRtSol any time. However, the
    tunnel between the ARs is only established upon
    processing the FBU message. This should avoid
    handover state establishment and management between
    PrRtAdv and FBU processing instances.

- Should the "handover capability request/response"
    messages be options in RS/RA or separate messages ?
    There were some arguments that if we propose them
    as options, we need them standardized in IPv6 WG.
    If this is the case, I would stick with the current types.
    Otherwise, I would like to propose making them options,
    since that could reduce the number of messages sent.

Comments ?

MK>> I still believe that this option should be part of Proxy-RS/Proxy-RA.
The MN could send Proxy-RS with a request of "handover capability
request/response" and the response will be included in the proxy-RA. This
will allow only the routers who are supporting fast-handover to implement
this option; the other routers who don't support fast-handover, don't have
to implement it.

-Mohamed

---

From: "Mohamed Khalil" <[email-masked]>
Date: Thu, 14 Nov 2002 14:18:30 -0600

-----Original Message-----
From: Rajeev Koodli [mailto:[email-masked]] 
Sent: Thursday, November 14, 2002 1:55 PM
To: Hesham Soliman (EAB)
Cc: [email-masked]
Subject: Re: [mobile-ip] Thoughts on using handover capability extensio

Hi,

"Hesham Soliman (EAB)" wrote:

> => I haven't seen this argument before. Why should
> we standardise an RS/RA option in IPv6? Of course we
> can standardise a new option here.
>

perhaps my interpretation (specifically of Mohamed Khalil's remark) was not
accurate.

"MK>> I think if you include this extension in RA, then you are asking all
the routers whether they support mobility or not to implement this
extension. I think it is very difficult to convince the ipng WG with this
point of view, but you are welcome to try. Since, PrRtSol/PrRtAdv are
messages  introduced to extend the router functionality to support mobility,
I think the proper location for this extension is in PrRtAdv."

So, we could move the PrRtSol/PrRtAdv functionality as options to RS/RA.
Those routers that do not understand them gleefully silently discard them.
Is this OK ? MK ?

-Rajeev

MK>> I myself has no problem of including this options in RA/RS. What I
think that the IPv6 WG will not be happy about including this option in the
RS/RA, because it is related to specific mobility application and not to
IPv6 routing in general. But, as I said we could publish our proposal to the
mailing list of the IPv6 working group to solicit their opinion, or/and to
ask the IPv6 chairs about what they think. 

-Mohamed

---

From: "Hesham Soliman (EAB)" <[email-masked]>
Date: Sat, 16 Nov 2002 00:42:06 +0100

James, 

  > > I hear you. However, one could argue that purpose of BU is to
  > > provide authorization to bind two addresses.
  > 
  > My feeling is that we must be precise and clear in what 
  > this signaling does. I
  > believe the BU is not for binding two arbitrary addresses, 
  > but for binding a
  > host's node identifier to its routing identifier.

=> We clearly disagree on this, but I would like to
highlight that your statement is not supported by the 
BU's semantics so I don't understand the foundation
of your conclusion. The BU is there to request packets
addressed to one address to be forwarded to another....

Hesham

---

From: "Mohamed Khalil" <[email-masked]>
Date: Mon, 18 Nov 2002 09:15:44 -0600

One way that would be more consistent with the current handling of changes
in on link routing would be to use ICMP Redirect.  If the MN gets a
prehandover trigger, it sends ICMP Redirect to the current AR to redirect
routing to the new AR. This is just one message, instead of three, and
therefore less likely to be cut off. Besides, if the link layer only
provides the MN with prehandover notification, there is no other choice.

MK>> Redirect Message is a message which is sent from the router to the host
to select a better first-hop  node on the path to a destination (RFC2461).
Sending a Redirect message from a host to a router, changes the semantics of
this messages as it it is defined in RFC2461.