Subject: RE: [Mip4] WG adoption call on draft-kulkarni-mobileip-dynamic-as signment-02.txt

From: Tsirtsis George <[email-masked]>
Date: Fri, 12 Dec 2003 12:51:21 -0500

-----Original Message-----
From: Henrik Levkowetz [mailto:[email-masked]]
Sent: Friday, December 12, 2003 5:43 PM
To: Tsirtsis George
Cc: 'Alpesh'; 'Kent Leung'; [email-masked]
Subject: Re: [Mip4] WG adoption call on
draft-kulkarni-mobileip-dynamic-as signment-02.txt

Hi George,

On Friday, 12 Dec 2003, George Tsirtsis wrote:

> I am suggesting two things:
>  
> 1) Allow the HA to send a positive RREP with an optional HA redirection
> extensions. This will allow a MN to change to the new HA at a time that is
> convenient to it i.e.: when it is idle and thus sessions will not be
> interrupted

But if the MN is idle it doesn't send RRQ and won't get a RRP anyway,
while as soon as it needs to leave idle and sends an initial RRQ it can
be dynamically assigned a new HA, no?

GT> Well, I assumed that RREQs are sent based on some timer expiring and are
orthogonal to any data traffic. What you describe seams to assume that you
return the dynamic HoA when you go idle and then request a new one when you
want to start a session.....I am not sure I like this but I guess it could
be done this way too.

> 2) Allow the HA to send a negative RREP with a compulsory HA redirection
> extensions. This will allow an HA to offload a MN for whatever reason to
> another HA (with which it may or may not share state)

Yes, but it will only let you offload it at the time of re-registration,
not at an optional time.

GT> Correct. This is not good enough for real load balancing. I guess this
is where your draft comes in.

>  
> Suggestion (1) above does not cause any session interruption and I sense
> that you guys are ok with? Suggestion (2) may cause session interruption
and
> at least Henrik was not a big fan of this.

I'm undecided on this one at the moment.

GT> OK, sorry for putting words in your mouth.

> Henrik's draft, if I understand this correctly, allows HA redirection at
any
> time but only between HAs that *share* state.

That was the intention. But as that mechanism requires a message originated
by the HA anyway, we might open it up for both cases...

GT> Ack.

George

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From: Henrik Levkowetz <[email-masked]>
Date: Fri, 12 Dec 2003 19:14:41 +0100

Hi again George and all,

On Friday, 12 Dec 2003, GeorgeTsirtsis wrote:

[...]
> want to start a session.....I am not sure I like this but I guess it could

Right, I see. I wasn't thinking of 'returning' the dynamic HA, on the
contrary I'd expect that the first HA contacted on a following initial
registration would be the most recently used HA. 

But I guess that in your network, you might have sessions which
stretch for days or weeks, as long as a user don't turn off his mobile;
and in that case it seems silly to sit around and wait for the next
session if you need to change HA.

> is where your draft comes in.

Yes, that's what I intended.

> GT> OK, sorry for putting words in your mouth.

No prob. 

> > by the HA anyway, we might open it up for both cases...

Ok, let's see where we end up here.

	Regards,
		Henrik