Subject: [netlmm] Validity of multihomed hosts

From: "Narayanan, Vidya" <[email-masked]>
Date: Fri, 12 Oct 2007 00:23:52 -0700

Folks,

<Chair hat on>

It is absolutely not helping to go in circles here.  I've yet again seen
several emails today questioning the validity of the case where an
unmodified multihomed host connects to a PMIP-enabled network.  I'll try
to provide some meta-level clarifications here. 

To clarify, by "unmodified" hosts, we are referring to hosts that have
IETF standards compliant IP stacks with no additional changes or
awareness of NETLMM.  This does not reflect anything running above the
IP stack on that device. 

A fundamental goal of NETLMM is to develop a solution that allows hosts
attaching to a NETLMM-enabled network, with no knowledge that this
protocol is used, to receive IP connectivity in the same manner as they
would if attached to an IP network with no NETLMM functionality.  

IP hosts, with standards compliant IP stacks, can connect via any number
of interfaces, regardless of the technology type, to a given IP network
today and be fully functional using all active interfaces.  

We are not designing a protocol here exclusively for today's use cases
or the presently envisioned deployments of the protocol.  Given that,
the features of IP are crucial to preserve.  We cannot go backwards on
functionality that IP already provides to end hosts.  

Regards,
Vidya

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---

From: "DE JUAN HUARTE FEDERICO" <[email-masked]>
Date: Fri, 12 Oct 2007 11:03:13 +0200

Hi Vidya,

sorry for the dummy question but what should I understand by an IP stack?
  - everything below the IP layer.
  - everything below the socket API (can the socket API be considered a layer?)
  - only the IP and TCP/UDP/SCTP layers.
I presume ICMP+ARP (v4) and/or /NDP (v6) do belong to the IP stack, and I presume that NDP brings SeND along.
I guess that an FTP client is supposed to be an application (thus not part of the IP stack), but is a DHCP client comprehended as part of an IP stack?

Vidya> IP hosts, with standards compliant IP stacks, can connect via any number of interfaces, regardless of the technology type, to a given IP network today and be fully functional using all active interfaces.  
[FDJ] A reference to the standards referred to in "standards compliant IP stacks" would be very appreciated.
Specifically, the standards that cover the scenario of one host using the same host identifier when connecting via multiple interfaces to the same administrative domain

Regards

federico

-----Message d'origine-----
De : Narayanan, Vidya [mailto:[email-masked]] 
Envoyé : vendredi 12 octobre 2007 09:24
À : Netlmm
Objet : [netlmm] Validity of multihomed hosts

Folks,

<Chair hat on>

It is absolutely not helping to go in circles here.  I've yet again seen several emails today questioning the validity of the case where an unmodified multihomed host connects to a PMIP-enabled network.  I'll try to provide some meta-level clarifications here. 

To clarify, by "unmodified" hosts, we are referring to hosts that have IETF standards compliant IP stacks with no additional changes or awareness of NETLMM.  This does not reflect anything running above the IP stack on that device. 

A fundamental goal of NETLMM is to develop a solution that allows hosts attaching to a NETLMM-enabled network, with no knowledge that this protocol is used, to receive IP connectivity in the same manner as they would if attached to an IP network with no NETLMM functionality.  

IP hosts, with standards compliant IP stacks, can connect via any number of interfaces, regardless of the technology type, to a given IP network today and be fully functional using all active interfaces.  

We are not designing a protocol here exclusively for today's use cases or the presently envisioned deployments of the protocol.  Given that, the features of IP are crucial to preserve.  We cannot go backwards on functionality that IP already provides to end hosts.  

Regards,
Vidya

---

From: "Ahmad Muhanna" <[email-masked]>
Date: Fri, 12 Oct 2007 07:58:42 -0500

Hi Vidya,

It does not help anyone here nor the advancement of the protocol, we are
trying to develop here, by trying to continuously dance around the
issue. Please see more comments inline.

Regards,
Ahmad

> -----Original Message-----
> From: Narayanan, Vidya [mailto:[email-masked]] 
> Sent: Friday, October 12, 2007 9:24 AM
> To: Netlmm
> Subject: [netlmm] Validity of multihomed hosts
> 
> Folks,
> 
> <Chair hat on>
> 
> It is absolutely not helping to go in circles here.  I've yet 
> again seen several emails today questioning the validity of 
> the case where an unmodified multihomed host connects to a 
> PMIP-enabled network.  I'll try to provide some meta-level 
> clarifications here.

[Ahmad]
I am sorry this paragraph is not quite precise. I would prefer that you
use a precise sentences to describe the sticky point. IMO, as a leader
of this wg, I humbly would suggest that you have to be extremely precise
in occasions like this one. General statements which may have multiple
meanings do not help in resolving the issue nor moving forward.
 
> 
> To clarify, by "unmodified" hosts, we are referring to hosts 
> that have IETF standards compliant IP stacks with no 
> additional changes or awareness of NETLMM.  This does not 
> reflect anything running above the IP stack on that device.

[Ahmad]
I thought that we have had this in mind in all of our discussions and I
am not aware of any violations. Did you find any?
 
> 
> A fundamental goal of NETLMM is to develop a solution that 
> allows hosts attaching to a NETLMM-enabled network, with no 
> knowledge that this protocol is used, to receive IP 
> connectivity in the same manner as they would if attached to 
> an IP network with no NETLMM functionality.

[Ahmad]
Vidya, which "fundamental" goal in RFC4381 which exactly captures what
you just stated above? A pointer is highly appreciated.
  
> 
> IP hosts, with standards compliant IP stacks, can connect via 
> any number of interfaces, regardless of the technology type, 
> to a given IP network today and be fully functional using all 
> active interfaces.

[Ahmad]
I have to read this sentence 20 times. I still believe that the proposed
protocol works just fine. If there is any violations, please identify.
  
> 
> We are not designing a protocol here exclusively for today's 
> use cases or the presently envisioned deployments of the 
> protocol.  Given that, the features of IP are crucial to 
> preserve.  We cannot go backwards on functionality that IP 
> already provides to end hosts.

[Ahmad]
Now, with my great respect to you as a co-chair, I wish that you did not
say this paragraph with your <chair hat on>!

IMO, this is debatable and to some extent is a judgment call and has
nothing to do with what we are trying to do. Otherwise, we should not
have spent our time to come up with RFC4830 to specify the problem
statement and RFC4831 to identify and specify the goals that the
proposed protocol has to satisfy. Unfortunately, what you are saying
here is NOT listed under any of these Goals. If it is, I appreciate it
if you give me a pointer.

If we apply your above opinion to every protocol that IETF would
develop, you know what would happen .. , we probably would never develop
any meaningful protocol.

Finally, IMO, in times of confusion, low visibility, and chaos, strong
leaders are those who are able to clearly see what the troops can not
see and provide a crisp, precise, and clear instructions/directions to
the way moving forward.

Best Regards,
Ahmad