Re: [altoext] [alto] FW: New Version Notification for draft-xie-alto-sdn-extension-use-cases-00.txt

Hi Haiyong, Tina, Hongtao, and Diego,

A good document! Here are some quick feedback:

- One take-away message that the document appears trying to convey is
Vertical (V) vs Horizontal (H) architectures. My understanding of your 
definition
is that V is a one-to-many setting, i.e., one ALTO Server to m SDN 
Controllers (SC),
while H is one-to-one, i.e., one ALTO Server to one SC. Why is the 
information flow
in H only SC <- ALTO S (Sec. 3.2), not the other way around? In an SDN 
setting, I
agree that an SC should already collect fine-grained, dynamic 
information for its
controlled domain. ALTO current does not define how its information is
collected/provisioned, but SC provides a good source (Sec. 4.3.2) of 
information
for ALTO Server to aggregate and conduct abstraction. I see good value 
in this
direction of information flow. I feel that this is mostly a common 
problem across H
and V. Hence I would not discard the H architecture right away. A 
concern is
whether we are ready to define the SC -> ALTO Server information flow,
given the "early-stageness" of SDN. A related general comment is that it 
maybe quite
helpful to extract common problems (e.g., unknown/dynamic network cost as
you mentioned) and new possibilities for ALTO when introducing SDN, 
instead of
a specific setting of a network being partitioned into many sub-networks 
in a V
architecture. What do you think? A curious question, does the ALTO servers
(as well as the SC) in H form some kind of mesh (peering) among themselves?

- The document seems to imply some kind of exclusive SC/net app setting: 
either
SC or net app, but not both. Do I misunderstand it? This depends on how one
define the scope of SC. There can still be net apps running. Does it 
make sense to
include (explicitly) the net apps into your discussions/figures to 
include 4 types
of entities: devices, SC, ALTO Server, and net apps? I like your 
distinction between
SDN-aware and SDN-unaware apps. I am not sure I fully agree or 
understand your
statement that SDN-aware apps would prefer direct communications with 
SC, but
this will be an important architecture discussion at the ALTO meeting.

Thanks.

Richard

On 6/29/12 6:15 AM, Haiyong Xie wrote:
> Hi All,
>
> This is a proposal on the interaction between ALTO and SDN we'd like to discuss at our next meeting in Vancouver. This draft replaces the older submission draft-xie-alto-sdn-use-cases-01.txt which was withdrawn already.
>
> Comments or discussions are extremely welcome and appreciated.
>
> Best regards,
> Haiyong
>
> -----Original Message-----
> From: internet-drafts@ietf.org [mailto:internet-drafts@ietf.org]
> Sent: Thursday, June 28, 2012 3:07 PM
> To: Haiyong Xie
> Cc: diego@tid.es; Hongtao Yin; Tina TSOU
> Subject: New Version Notification for draft-xie-alto-sdn-extension-use-cases-00.txt
>
>
> A new version of I-D, draft-xie-alto-sdn-extension-use-cases-00.txt
> has been successfully submitted by Haiyong Xie and posted to the
> IETF repository.
>
> Filename:	 draft-xie-alto-sdn-extension-use-cases
> Revision:	 00
> Title:		 Use Cases for ALTO with Software Defined Networks
> Creation date:	 2012-06-28
> WG ID:		 Individual Submission
> Number of pages: 28
> URL:             http://www.ietf.org/internet-drafts/draft-xie-alto-sdn-extension-use-cases-00.txt
> Status:          http://datatracker.ietf.org/doc/draft-xie-alto-sdn-extension-use-cases
> Htmlized:        http://tools.ietf.org/html/draft-xie-alto-sdn-extension-use-cases-00
>
>
> Abstract:
>     The introduction of SDN fundamentally changes the way that the ALTO
>     works.  This draft describes the Vertical Architecture and the
>     Horizontal Architecture allowing coherent coexistence of application
>     layer traffic optimization (ALTO) with software defined network
>     (SDN).  Unique requirements for design and operations are identified
>     and summarized, suggesting that the Vertical Architecture allows
>     better division, management, flexibility, privacy control and long-
>     term evolution of the network.  We also define the main interactions
>     and information flows, and present a set of use cases to illustrate
>     how we extend ALTO to support SDN, in the Vertical Architecture.
>
>                                                                                    
>
>
> The IETF Secretariat
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