Re: [vnfpool] Overlap with SFC?

[Linda Dunbar <[e-mail]>]

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]<mailto:[e-mail]>; [e-mail]<mailto:[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]<mailto:[e-mail]>; [e-mail]<mailto:[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]<mailto:[e-mail]>'; [e-mail]<mailto:[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]<mailto:[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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