Subject: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised Localized Mobility Management Requirement s)

From: James Kempf <[email-masked]>
Date: Fri, 20 Apr 2001 08:58:16 -0700 (PDT)

Raj and Erik,

>> Basically I see two approaches and I don't know how to resolve them:
>> 1. A domain might be huge (for whatever reason) hence for 
>> scaling reasons
>>    you need to be capable of having a arbirarely deep 
>> hirarchy of agents.
>
>Why? Would this not work just as well with a single level of hierarchy,
>but one where there are multiple top level agents, i.e a distributed
>set of top-level agents which can load balance if that is a concern.
>

No, because the signalling lines may depend on the depth as well
as the breadth of the routing topology. So in a large, multicontinental
routing domain, the signalling for a single per domain agent may be just
as expensive as signalling directly to the corresponding nodes
and home agent. 

In addition, changing a single top level agent requires the mobile to signal a 
regional care of address change to the home agent and all
corresponding nodes. It is therefore a heavyweight solution and
one that should not often be done, even if there is no reauthentication
involved. Making it the basis of dealing with load balancing is therefore
likely to lead to more signalling latency than if multiple levels
of LMM agents were allowed.

>> 2. Simplicity is good idea and a solution without hirarchy is 
>> likely to
>>    be simpler, if not to implement to operate, than one with 
>> a hirarchy.
>> 
>
>Completely agree here Erik. I know there have been arguments for
>having a hierarchy, but I still do not totally get it. 
>

I'm all for simplicity, which is why I would like the requirements
to preclude preferences or other complex attributes that need
additional standardization. But, in this case, I think not allowing multiple 
levels of LMM agents shuts out possible deployment scenarios that
I believe are realistic and will directly affect how well the
solution  fufills the fundamental requirement, namely localizing
signalling.

		jak

---

From: Phil Roberts <[email-masked]>
Date: Wed, 25 Apr 2001 16:29:20 -0400

I'm hoping we don't restart the protocol selection process.  If there are
compelling reasons to do so we shall.  The requirements gathering is more of
a way to get some convergence on what is really needed in the protocol.
There has been a fair amount of reflection that has gone on since the
working group selected the HMIP approach.

> -----Original Message-----
> From: Behcet Sarikaya [mailto:[email-masked]]
> Sent: Wednesday, April 25, 2001 3:20 PM
> To: [email-masked]
> Cc: [email-masked]
> Subject: Re: Multiple Levels of LMM agents (was: RE: 
> [mobile-ip] Revised
> Localized Mobility Management Requirement s)
> 
> 
> Hi Charlie,
>   I have a feeling that you are talking about regreg6. Is 
> regreg6 still a
> candidate protocol, i.e. after the requirements will the 
> protocol selection
> process for LMM  restart?
> 
> Charlie Perkins wrote:
> 
> >  Furthermore,
> > the upgrade is not a forklift upgrade.  One can put in 
> regional-aware routers
> > wherever they are needed, and not disturb the other configuration.
> >
> > We know that the code to do multiple levels is small, and that the
> > protocol isn't bad at all.
> >
> > Regards,
> > Charlie P.
> 
> Regards,
> 
> --
> Behcet
>

---

From: "Glenn Morrow" <[email-masked]>
Date: Thu, 26 Apr 2001 13:55:47 -0500

Phil,

I'm not sure either candidate is exactly what we want in the end. So I am
also not sure we should start calling these proposals protocols that have
been summarily accepted or rejected, yet. 

It seems to me that just because the WG has allowed another candidate to
become a WG document does not mean that the WG rejected another WG document.

I may have missed some hmmm, I admit, though. The way I see it is that two
groups have placed different strawmen on the table without any clear
requirements to begin with. Now we are going through the requirements
discussion.

I honestly think that levels of hierarchy (even only 2) gets into the real
routing domain unless you spin an LMM to be an application running on a
host.  

Why are we not looking at changing real routing protocols to achieve some of
these functions? We haven't even gotten into integrity, race conditions,
security associations, routing policy, levels of route propogation and
confidentiality amoung these entities. It seems these real routing protocols
have already been built with these things in mind and that adding the MM
levels might be fairly straight forward.

We might even find that we can get rid of single point of failure with this
approach. This and the fact that the people were obviating the fact that
they were actually doing single per host routes with a name change are my
big sticklers on this whole subject and the main reason for my earlier
tirade in which I compared RR to other proposed solutions that had the same
single point of failure issue but had not been accepted to the WG for this
reason in the past. This didn't mean HMIP. Please note - I didn't submit
these other solutions. 

I also think that with this approach, tunnel-relaying or source routing, the
scalability concerns in terms of route table size may completely vanish with
respect to supporting multiple levels of hierarchy.

We also might find that we can leverage the existing security associations
of these routers and domains to enhance handoff by adding a new mobile
dimension to the routing distance algorithms from a hierarchical point of
view.

I also seems to me that some other solutions that do not have the SPOF
problem have also not been accepted as candidates. The only reason I can
suspect for this is that people made up some lame excuse for summarily
rejecting the use of existing routing protocols or they wanted to just
re-invent the whole wheel from scratch.

We really need to start thinking like the network infrastructure owners and
their administrative staff instead of new protocol creators. I admit I am
also guilty of not doing this in some respects. I believe some vendors have
actually tried to make some inroads into these requirements  and direction
for solutions already. 

I hate to rehash old decisions but why are we not following this direction?

Thanks,

Glenn

p.s. Sorry about any percieved ranting.

---

From: "Glenn Morrow" <[email-masked]>
Date: Fri, 27 Apr 2001 14:50:47 -0500

Correction,
 
I believe some vendors have actually tried to make some inroads into these
requirements  and direction for solutions already
 
That's providers  - not vendors.

-----Original Message-----
From: Morrow, Glenn [RICH2:C330:EXCH] 
Sent: Thursday, April 26, 2001 1:56 PM
To: [email-masked]
Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised

Phil, 

Thanks, 

Glenn 

-----Original Message----- 
From: Phil Roberts [ mailto:[email-masked]
<mailto:[email-masked]> ] 
Sent: Wednesday, April 25, 2001 3:29 PM 
To: [email-masked]' 
Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised 
Localized Mobility Management Requirement s) 

> From: Behcet Sarikaya [ mailto:[email-masked]
<mailto:[email-masked]> ]

---

From: Phil Roberts <[email-masked]>
Date: Fri, 27 Apr 2001 15:58:28 -0400

Hi Glenn,
 
   I didn't mean to ignore your earlier post.  I responded to something
else, got pulled into a meeting, and forgot.
 
   I want to respond to your question about changing real routing protocols
to meet these requirements.  In seamoby there is a small team putting
together a problem statement to get some work started on the routing issues
in the IRTF.  There is a draft of this that SHOULD appear on the seamoby
mailing list early next week.  Your comments on that are more than welcome.
 
   As far as doing that sort of work here, we've tried to focus our work on
protocols based on MIP.  That doesn't mean there aren't other mobility
alternatives and part of seamoby was to figure out whether a good statement
could be put together for requirements that would point to the need for
alternatives.  The outcome of that work so far has been to get some work
done in the IRTF on the impacts of using a "real routing" protocol to
implement mobility rather than a MIP kind of scheme.  Another work item was
to produce a list of requirements to send to us for feedback on whether the
MIP set of protocols can meet them.
 
Phil

-----Original Message-----
From: Glenn Morrow [mailto:[email-masked]]
Sent: Friday, April 27, 2001 3:51 PM
To: [email-masked]
Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised

Correction,

-----Original Message-----
From: Morrow, Glenn [RICH2:C330:EXCH] 
Sent: Thursday, April 26, 2001 1:56 PM
To: [email-masked]
Subject: RE: Multiple Levels of LMM agents (was: RE: [mobile-ip] Revised

Phil, 

Thanks, 

Glenn