Re: [vnfpool] Overlap with SFC?

["Susan Hares" <[e-mail]>]

Linda:

 

I agree with your use example, but would like to clarify it. 

 

VNF Pools  is about redundancy needs rather than chaining paths.   Pools
provide the redundancy.   You may need the redundancy for even a short chain
if it is High-availability.   You may have parallel chains to support the
redundancy. 

 

Cheers, 

Sue 

 

From: vnfpool [mailto:[e-mail]] On Behalf Of Linda Dunbar
Sent: Friday, January 24, 2014 5:55 PM
To: Qin Wu; LAC Chidung
Cc: [e-mail]; [e-mail]
Subject: Re: [vnfpool] Overlap with SFC?

 

Here is my take of the differences and the overlap with SFC:

 

If a service function has a small number of instances, say less than 5, and
they are relative stable, then it is doable for Service Chain to specify the
specific instances, the so called “Service Chain Path” by SFC drafts. 

 

 

But if there are large number of instances, say in hundreds, and those
instances’ location/presence change over time (e.g. in NFV environment),
then it is not scalable to have Service Chain path to specify the specific
instances. 

 

The service function instances’ management, e.g. selection, replacement when
failure occurs or over-utilized from a pool of available instances,
notification should be  the scope of VNFpool. 

 

Linda

 

 

 

From: vnfpool [mailto:[e-mail]] On Behalf Of Qin Wu
Sent: Wednesday, January 22, 2014 7:38 PM
To: LAC Chidung
Cc: [e-mail]; [e-mail]
Subject: Re: [vnfpool] Overlap with SFC?

 

Hi, Chidung:

That’s one good interpretation.

You are right, I should add assumption that the service node that is
bypassed is optional service node in the chain.

 

Regards!

-Qin

From: vnfpool [mailto:[e-mail]] On Behalf Of LAC Chidung
Sent: Wednesday, January 22, 2014 7:26 PM
To: Qin Wu
Cc: [e-mail]; [e-mail]
Subject: Re: [vnfpool] Overlap with SFC?

 

Hi Qin,
"in service chain, when a service node is down, what SFC is doing is to
bypass this service node": is the following interpretation ok ?
A service chain needs X+Y service nodes in order to provide the full
service: the X service nodes are mandatory, while the Y service nodes are
(kind of) optional, i.e., if one (or more) of these Y service nodes is (are)
down, the service chain can still provide the service, but in a degraded
mode. In this case, the bypassing can only happen for one of the Y service
nodes, i.e., if one of the X service nodes is down, there is no service at
all.
NB: in this example, we consider, of course, that there is no redundancy
anywhere, i.e., if a service node is down, the only thing to do is to fix
it, and while waiting for the reparation, we face a degraded service, or no
service at all.
Best,
Chidung
 

Le 22/01/2014 06:05, Qin Wu a écrit :

My Understanding is 
in service chain, when a service node is down, what SFC is doing is to
bypass this service node while
What nfvpool is doing is to replace the failing one with the new service
node which provide the same functionality.
Please correct me if I am wrong.
Regards!
-Qin
-----Original Message-----
From: vnfpool [mailto:[e-mail]] On Behalf Of Zongning
Sent: Wednesday, January 22, 2014 9:42 AM
To: Zongning; [e-mail]; [e-mail]
Subject: Re: [vnfpool] Overlap with SFC?
 
Sorry, item 1) is obviously not finished. :-)
1) SFC targets on steering packets among service function nodes. vnfpool
focuses on redundancy for service nodes, e.g., selecting standby nodes,
handling nodes transition/failure cases, without caring about how to
construct the data path.
Again, my fault.
-Ning
 

-----Original Message-----
From: Zongning
Sent: Wednesday, January 22, 2014 9:34 AM
To: '[e-mail]'; [e-mail]
Subject: RE: [vnfpool] Overlap with SFC?
 
Hi, Adrian,
Thanks for raising this question. Actually vnfpool folks have been
discussing this
question a lot since the very beginning of this work.
We believe vnfpool and SFC are independent and complementary mainly due to
the below reasons:
1) SFC targets on steering packets among service function nodes. vnfpool
focuses on redundancy for service nodes, e.g., selecting standby nodes,
handling nodes transition/failure cases, without caring how
2) vnfpool manager in our proposal could interact with SFC control entity
to: 1)
advertise redundant service nodes; 2) notify status of redundant nodes when
required; 3) receive resiliency requirements from SFC control entity (if
any); and
so on.
3) vnfpool is not only used in "chained service nodes", but applicable to
other
cases where service nodes are not necessarily sequentially connected.
I appreciate any further feedback and advice from you or IESG, as I believe
these feedback will greatly improve the quality of our proposed charter.
Thanks.
-Ning
 

-----Original Message-----
From: vnfpool [mailto:[e-mail]] On Behalf Of Adrian Farrel
Sent: Wednesday, January 22, 2014 1:57 AM
To: [e-mail]
Subject: [vnfpool] Overlap with SFC?
 
Hi,
The IESG is looking at the BoF requests for London, and a question came upon
the overlap between the proposal here and items 4 and 5 in the SFC Charter.
I think it would be valuable if you could discuss the overlap and the
interaction between the two efforts so that there is a clear view.
Thanks,
Adrian
 
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