[Sdnp] Example Use Case - Bandwidth on Demand for Hybrid Cloud

[David Meyer]

On Tue, Aug 9, 2011 at 7:20 AM, Anton Ivanov <aivanov at sigsegv.cx> wrote:
> On 09/08/11 15:04, Thomas Nadeau wrote:
>>
>> On Aug 8, 2011, at 11:33 AM, David Meyer wrote:
>>
>>
>>>
>>> Hey Dave,
>>>
>>> On Sun, Aug 7, 2011 at 6:18 AM, Mcdysan, David E
>>> <dave.mcdysan at verizon.com>  wrote:
>>>
>>>>
>>>> Hi,
>>>>
>>>> I mentioned in the IETF SNDP Bar-Bof  a potential use case. Attached are
>>>> a
>>>> few slides on this providing more detail on this potential use case for
>>>> SDNP -- Bandwidth On Demand (BOD) for Hybrid Cloud for your review and
>>>> comment.
>>>>
>>>>
>>>> OpenFlow could be used in some cases, but I believe much more is needed.
>>>> I
>>>>
>>>
>>> I was under the impression that OF was out of scope here.
>>>
>>
>>        To be precise in answering Dave McDysan's question, since this is
>> still
>> an informal effort, what is in and out of scope is up to the people in the
>> discussion.
>> I think from my end, I personally don't think it is worth distracting
>> things with
>> discussions of replacing Openflow; IMHO OF might be a subset of the
>> architectural picture we are drawing here, but that isn't completely set
>> in
>> stone, so we don't know. What I would like to do is narrow down that
>> picture so
>> we know precisely what components it is were are trying to make
>> work together first.
>>
>
> +1. I do not see a reason why a SDN  controller cannot control  a compatible
> OF instance.

Its a matter of what a "controller" actually is/does. Since OF is an
open interface you can of course write code to talk to it. The
question is whether it makes sense to mix two (or more) control planes
that as of now wouldn't know about each other; the two are the
existing control plane and the new, OF based control plane (of course,
you could always take a ships in the night approach, but these are
implementation issues which aren't or shouldn't be the subject of
standardization). In any event, since neither control  plane would
know what the other was doing in the forwarding plane, neither would
be able to reason about the state of the network. Hence it will be
difficult (if not impossible) to ensure many of the properties we want
from a control plane such as loop-free paths and the like.

So yes, you can write code to talk to an OF device (again, that much
is trivial), but that isn't the hard part of the problem if you want
to mix the models. So far from what I can tell programming the control
plane (whatever that means), programming the forwarding plane (a la
OpenFlow), configuration and management are all part of SDNP.

Perhaps a better question at this point is "what is *not* part of SDNP?"

Dave