Re: [Actn] ACTN charter v1.0

[Leeyoung <[e-mail]>]

Hi,

I think the issue is the term 'signaling' is used in two different context. There is definitely RSVP-TE like signaling which is hop by hop from ingress to egress, which is 'horizontal'. That is what most folks are familiar with and tend to understand signaling from that perspective. On the other hand, there are several ways to set up path in a 'vertical' fashion. As Aihua indicated, the centralized entity (e.g., PCE +, or SDN controller) can indeed invoke a path setup command to each NE along the path. This vertical element of path setup can be regarded as 'signaling' in a broader sense.

Nonetheless, this portion of the charter statement is not really a central issue. We are simply discussing some tools available for transport networks. This is just a background information. So I suggest we move on with the latest resolution proposed by Sergio. Will this be agreeable?

Thanks,
Young

From: Aihua Guo [mailto:[e-mail]]
Sent: Tuesday, September 16, 2014 11:36 AM
To: Fatai Zhang; BELOTTI, SERGIO (SERGIO); Leeyoung
Cc: [e-mail]; Daniele Ceccarelli; Dhruv Dhody
Subject: RE: ACTN charter v1.0

Hi Sergio and Fatai,

What I consider for "centralized signaling" is in a scenario where there is a centralized service controller and a network consisting of multiple network elements (NEs). In this scenario, the centralized service controller issues "vertical" path setup requests from the controller to all NEs at the same time ("in parallel"). Each network element receives a segment of the path for NE itself. This can be done by using PCEP as a transport protocol carrying either standard or proprietary extensions for services, with other extensions e.g. draft-sivabalan-pce-lsp-setup-type-02.txt to specify alternatives other than RSVP-TE for each NE.

I am in line with you that there is no signaling with an NMS approach, and NMS for sure stores service information in some format. My question is if the above scenario or the similar is viewed as somewhat different from an NMS based approach.

And also the same question for the Openflow scenario Fatai raised.

Thanks.
Aihua



From: Fatai Zhang [mailto:[e-mail]]
Sent: Tuesday, September 16, 2014 5:45 AM
To: BELOTTI, SERGIO (SERGIO); Aihua Guo; Leeyoung
Cc: [e-mail]; Daniele Ceccarelli; Dhruv Dhody
Subject: RE: ACTN charter v1.0

Hi Sergio and Aihua,

I have the same feeling as Sergio , ie, I am not sure what is "centralized signaling".

Could someone point out where we can find the term about "centralized signaling"?

Let's have some brainstorm by giving an example. For example, when a MPLS-TE LSP is to be created by the Openflow controller, can we regard this  is "centralized signaling"?




Best Regards

Fatai

From: ACTN [mailto:[e-mail]] On Behalf Of BELOTTI, SERGIO (SERGIO)
Sent: Tuesday, September 16, 2014 12:32 AM
To: Aihua Guo; Leeyoung
Cc: [e-mail]<mailto:[e-mail]>; Daniele Ceccarelli; Dhruv Dhody
Subject: Re: [Actn] ACTN charter v1.0

Hi Aihua,

could you kindly clarify for my knowledge what "PCEP extensions carrying service related information" you're referring to?
If you consider RFC 4655, I do not see any architecture hint that exclude distributed signaling as basic method to path setup in a PCE context.
On the other hand , the newly draft considering the possibility to use "other" path setup method (draft-sivabalan-pce-lsp-setup-type-02.txt) is introducing a specifc TLV that you need to add if you want to use another method in your architecture. In fact , the default value proposed for path Setup Type field is 0 , implicitly considering RSVP_TE as default  setup method.

I have difficult to understand what you mean with "service provisioning requests may be issued from a centralized controller to all network elements vertically and in parallel.". What you mean with vertical and in parallel?
On the other hand I do not see when an NMS does not carry service info, whether for service info you consider the path setup info.
So I'm still uncomfortable with the term "centralized signaling"  in this context.

Thanks
Sergio


From: Aihua Guo [mailto:[e-mail]]
Sent: sabato 13 settembre 2014 00:26
To: Leeyoung; BELOTTI, SERGIO (SERGIO)
Cc: [e-mail]<mailto:[e-mail]>; Daniele Ceccarelli; Dhruv Dhody
Subject: RE: ACTN charter v1.0

Hi Sergio,

Regarding your comment,
"There is no signaling in my view .
Another case is PCE: PCE is providing path computation phase , and can exploit on a distributed control plane to make a signaling of the setup calculated. But again , it is not a centralized signaling , signaling is distributed , it is the routing, if anything,  that is centralized in my view.

So I would suggest to delete the term signaling associated to centralized and change the sentence into:
"Allow for distributed signaling or centralized model (e.g.an NMS-based) for set up...."
"

Today with e.g. PCEP extensions carrying service related information, service provisioning requests may be issued from a centralized controller to all network elements vertically and in parallel. This is IMHO one form of centralized signaling.

Service provisioning can be made through NMS, and NMS may or may not include service related information in the management protocols. Hence I still see a difference between NMS based and centralized signaling. Would it be worth to reflect the difference in the wording with something like this: ?

"Allow for distributed signaling or centralized model (e.g.an NMS-based or centralized signaling) for set up...."

Thanks.
Aihua

From: ACTN [mailto:[e-mail]] On Behalf Of Leeyoung
Sent: Friday, September 12, 2014 3:23 PM
To: BELOTTI, SERGIO (SERGIO)
Cc: [e-mail]<mailto:[e-mail]>; Daniele Ceccarelli; Dhruv Dhody
Subject: Re: [Actn] ACTN charter v1.0

Hi Sergio,

I am OK with your suggested wording. Thanks.

Young

From: BELOTTI, SERGIO (SERGIO) [mailto:[e-mail]]
Sent: Friday, September 12, 2014 10:34 AM
To: Leeyoung
Cc: Daniele Ceccarelli; Dhruv Dhody; [e-mail]<mailto:[e-mail]>
Subject: RE: ACTN charter v1.0

Hi Young, Daniele

Please see in line .

Thanks
Sergio


From: ACTN [mailto:[e-mail]] On Behalf Of Leeyoung
Sent: venerdì 12 settembre 2014 17:08
To: Daniele Ceccarelli; Dhruv Dhody; [e-mail]<mailto:[e-mail]>
Subject: Re: [Actn] ACTN charter v1.0

Hi Daniele,

Thanks for providing your good comments here. Some of your comment (1) is for charter discussion while the others (2 & 3) are architecture discussion. As a few folks are already working on the architecture document, we may start a new email thread on architecture discussion while developing the draft.

Please see inline for my response.

Regards,
Young

From: Daniele Ceccarelli [mailto:[e-mail]]
Sent: Friday, September 12, 2014 9:27 AM
To: Dhruv Dhody; Leeyoung; [e-mail]<mailto:[e-mail]>
Subject: RE: ACTN charter v1.0

Dhruv, Young,

Excellent progresses!
Let me just add some notes/questions.
I'm collecting them here and not inline as the reading of the whole thread is becoming pretty complex.


1.      On centralized signaling: We need to clearly state what centralized signaling means. NMS based is one of the possibilities but it's not limited to NMS. A network implementing e.g. Open Flow or any other similar protocol should be considered as well IMHO. Here I'm not sure whether we can speak about centralized signaling in both cases or not. In the case of NMS we use the management plane to dynamically provision connectivity (whatever protocol is used). In the case of e.g. Open Flow can we speak about management plane or is something else? Please note that I speak about OF as it's the only example that comes to my mind but any other possibility can/must be considered.

YOUNG>> The intention here was giving some overview of the tools that current transport networks have. Of course thing are quickly changing with other initiatives like OF and even PCE based signaling in a research circle that can be viewed as centralized signaling. Perhaps good compromise would be putting NMS based as an example. How about restating like:

Allow for distributed signaling or centralized signaling (e.g., an NMS-based, etc.) for set up...."

SB> I have still problems with this definition. In my view when you think about to an NMS based path setup, I have a centralized station that is providing command towards managed equipment functions that are virtualized in a MIB , and these command provide the "resource reservation" phase (not only but just to make the comparison with normal signaling protocol) using a "vertical" management protocol .
There is no signaling in my view .
Another case is PCE: PCE is providing path computation phase , and can exploit on a distributed control plane to make a signaling of the setup calculated. But again , it is not a centralized signaling , signaling is distributed , it is the routing, if anything,  that is centralized in my view.

So I would suggest to delete the term signaling associated to centralized and change the sentence into:
"Allow for distributed signaling or centralized model (e.g.an NMS-based) for set up...."



2.      On multidomain issues: One question here: How do we want to manage multi-domain? I see two ways:

a.      A coordinator of virtual network controllers - i.e. 1:1 relationship between virtual network controller and physical network controller plus a coordinator of virtual network controllers on top

b.      A coordinator of physical network controllers - i.e. a coordinator of physical network controllers (1:N relationship between coordinator and PNCs) with a virtual network controller on top? (1:1 relationship between PNC coordinator and the VNC)

Maybe we should consider both architectures, maybe pick one.

YOUNG>> These options seem to be detailed architecture that the upcoming architecture document should address in detail. My personal opinion is that both architectures need to be considered as a starting point. There may be other variations. Then we may narrow the scope as an initial baseline architecture.


3.      Again on multiodomain: maybe we could improve the architecture draft saying what is centralized and what is distributed. E.g. VPN prefixes exchange could be distributed (controllers speaking MP-BGP with each other) while provisioning could be hierarchical (i.e. the coordinator asks controller A to provision a path with domain A and asks controller B to provide a path within B so to have an end to end path crossing domains A and B)...H-PCE like.

YOUNG>> Good point. I agree that the architecture draft should discuss these dichotomy of control regimes (e.g., centralized vs. distributed). One question I have: are you assuming the coordinator also speaks MP-BGP with lower level PN controllers? If not, would the coordinator need to collect the VPN prefixes using the interface between the coordinator and each PNC (that speaks MP-BGP)? Then can this be viewed as a centralized component?

BR
Daniele

From: ACTN [mailto:[e-mail]] On Behalf Of Dhruv Dhody
Sent: venerdì 12 settembre 2014 04:33
To: Leeyoung; [e-mail]<mailto:[e-mail]>
Subject: Re: [Actn] ACTN charter v1.0

Hi Young,

Please see inline..

From: Dhruv Dhody
Sent: Wednesday, September 10, 2014 10:48 PM
To: Leeyoung; Leeyoung; [e-mail]<mailto:[e-mail]>
Subject: RE: ACTN charter v1.0

Hi Young,

Please find some comments on the proposed charter.

* Do we need some text in charter also to specify what we consider as Transport networks?

YOUNG>> That may clarify the scope. Do you have any suggestion?  One definition from the Problem Statement draft (https://datatracker.ietf.org/doc/draft-leeking-actn-problem-statement/) is as follows. Would this be good enough or need more work?

Transport networks are defined as network infrastructure that
   provides connectivity and bandwidth for customer services. They
   are characterized by their ability to support server layer
   provisioning and traffic engineering for client layer services,
   such that resource guarantees may be provided to their customers.
   Transport networks in this document refer to a set of different
   type of connection-oriented networks, which include Connection-
   Oriented Circuit Switched (CO-CS) networks and Connection-
   Oriented Packet Switched (CO-PS) networks. This implies that at
   least the following transport networks are in scope of the
   discussion of this draft: Layer 1 (L1) optical networks (e.g.,
   Optical Transport Networks (OTN) and Wavelength Switched Optical
   Networks (WSON)), MPLS-TP, MPLS-TE, as well as other emerging
   network technologies with connection-oriented behavior.


[Dhruv]: Yes that would be good with Eve suggestion and removing 'in the document'/'of this draft'.


* "Transport networks have a variety of mechanisms to:
-               Facilitate separation of data plane and control plane,
-               Allow for distributed or centralized signaling  for path setup and protection, and
-               Provide traffic engineering mechanism via centralized path computation."

Term 'centralized signaling' is confusing to me, do you mean, the use of NMS?

YOUNG>> Yes. We can reword the second point: "Allow for distributed signaling or an NMS-based centralized signaling for set up...."

[Dhruv]: That works!
----------------------------

* "The architecture work will lead to requirements for information models and protocol extensions between the virtual network controller and the physical network domain controllers and between the virtual network controller and multi-tenant customer controllers."

It would be nice to add "multi-domain coordinator" with "virtual network controller" to explicitly link them together. Also multi-tenant customer controllers doesn't convey the intention to have different customer controllers for each tenant, how about...

"The architecture work will lead to requirements for information models and protocol extensions between the virtual network controller (embedded in a multi-domain coordinator) and the physical network domain controllers and between the virtual network controller and multiple tenant customer controllers."

YOUNG>> This sounds good to me. Thanks.

* "The working group will determine if new protocol extensions are necessary. If the working group determines they are necessary, then it will develop the new protocols within the working group where necessary, while interacting with other working groups to enhance existing protocols where possible."

Suggest to re-word this as it's not clear - is it about extension to existing protocols or new protocol and where that work might be taken up. Also Protocol extensions is mentioned as a work item after re-chartering.

YOUNG>> New protocol extensions mean a brand new protocol (say, "ACTN" protocol per se) that cannot be extended from existing protocols. But there may be some areas where we need to expand from existing protocols. In such case, we need to interact with the corresponding WGs. Perhaps an analogy would be that CCAMP WG is chartered to work on OPSF-TE for specific technologies while OSPF WG needs to be informed of the protocol changes.

[Dhruv]: How about we reword this to - "The working group will determine if new protocol or extensions to existing protocols are necessary. If the working group determines they are necessary, then it will develop new protocols within the working group, on the other hand any extensions to existing protocols would be done  with interactions with other working groups where possible."

* You may want to do charter text formatting in RFC text format taking care of word-wraps and indentation
YOUNG>> Not sure what you meant here. Please clarify it for me.
[Dhruv]: Refer attachment, this format would help when we upload it to the data tracker and charter diff tool can help track it better.
This version has all the changes suggested by me and Eve.
Regards,
Dhruv
Hope you find them useful in making the charter text crisp.

YOUNG>> Definitely. Thanks a lot for your review and great comments.

Dhruv


From: ACTN [mailto:[e-mail]] On Behalf Of Leeyoung
Sent: 10 September 2014 04:53
To: Leeyoung; [e-mail]<mailto:[e-mail]>
Subject: [Actn] ACTN charter v1.0

Sorry, I forgot the Subject of this email. Here's a retransmission with the subject.

From: Leeyoung
Sent: Tuesday, September 09, 2014 3:47 PM
To: [e-mail]<mailto:[e-mail]>
Subject:

Hi,

I hope your summer break was a good one.

We'd like to give you some updates and plans on the ACTN work. We are going to request a formal BoF in Honolulu IETF meeting. In doing so, we need a charter draft as part of the due diligence. Here's an initial charter draft developed by the small set of proponents of the work based on the discussions and use-cases and other published documents.  We hope this captures a workable ACTN scope.  This version 1.0 draft charter is also posted in the wiki: https://sites.google.com/site/actnbof/home/charter-propor

Your review and comment will be greatly appreciated to come up with a good charter developed by the community of interest.

Best regards,
Young (on behalf of the proponents)

-------------------------------draft charter 1.0 ----------------------------------------------------------------------------------------------------

Transport networks have a variety of mechanisms to:

-       Facilitate separation of data plane and control plane,

-       Allow for distributed or centralized signaling  for path setup and protection, and

-       Provide traffic engineering mechanism via centralized path computation.

These represent key technologies for enabling flexible and dynamic networking, and efficient control and recovery of resources. Although these technologies provide significant benefits within a single domain control boundary, they do not meet the growing need for transport network virtualization in multi-domain transport networks. More and more network operators are building and operating on multi-domain transport networks. These domains (collections of links and nodes) may be each of a different technology, administrative zones, or vendor-specific islands. Establishment of end-to-end connections spanning multiple domains is a perpetual problem for operators because of both operational concerns (control plane and management plane) and interoperability issues (control plane and data plane).  Due to these issues, new services that require connections that traverse multiple domains need significant planning and often manual operations to interface different vendor equipment and technology.

The aim of Abstraction and Control of Transport Networks (ACTN) is to facilitate a centralized virtual network operation: the creation of a virtualized environment allowing operators to view and control multi-subnet, multi-technology, multi-vendor domain networks. Abstraction of transport networks also allows operators to consolidate their network services into multi-tenant virtual transport networks. This will enable rapid service deployment of new dynamic and elastic services, and will improve overall network operations and scaling of existing services. Discussion with operators has also highlighted a need for virtual network operation based on the abstraction of underlying technology and vendor domains.

Multi-domain network coordination function in ACTN is built on a control hierarchy where a multi-domain coordinator interacts with each domain controller (e.g., EMS/NMS, GMPLS/PCE control plane, SDN controller) for abstracting network resource information to provide virtual network control functions. This virtual network control functions are embedded in a multi-domain network coordinator to support various services/clients/applications to create and manage their own virtual networks that share the common transport network resources.


The ACTN working group will work to develop a high-level architecture for transport network abstraction and control that facilitates seamless vertical service coordination across multi-tenant customers (primarily internal service organizations with respect to a network operator), the virtual network control and the physical network domain controls as well as a horizontal E2E service coordination across multi-domain networks. It will identify key building components and the corresponding interfaces among these components.  The architecture work will lead to requirements for information models and protocol extensions between the virtual network controller and the physical network domain controllers and between the virtual network controller and multi-tenant customer controllers. Well-defined use cases from operators perspective with clearly stated need for transport network virtualization are critical in scoping the work and thus to achieve the deliverables of the working group.

The working group will work on the following items:

-       High-level architecture that describes the basic building blocks to enable transport network virtualization to support use cases.

-       Operator-driven use cases to address the following initial items:

o   Virtual network control and operation for core transport Packet Optical Integration (POI). (e.g., MPLS-TP, OTN/WSON)

o   Virtual network control and operation for mobile backhaul multi-technology transport (e.g., MPLS-TP and MPLS/OTN)

o   Data Center Operator's interconnection with optical transport network infrastructure providers to support dynamic virtual circuit services.

o   Multi-tenant support to allow virtual network information query, virtual network negotiation, creation/deletion and modification.

o   Synchronization of network resources view across physical domain controls and virtual network control.

o   Dynamic service control and monitoring across all entities.

Initial work within the working group will be limited to a single operator administrative domain with an exception for the Data Center operation use case.

-       Evaluation of Information model/data model to support the use cases.

-       Requirements to support APIs/protocols, encoding languages, and data models

-       Gap analysis of existing IETF and other protocols, encoding languages and data models to fulfill the requirements.

-       Protocol extensions (if necessary after re-chartering).

The working group will determine if new protocol extensions are necessary. If the working group determines they are necessary, then it will develop the new protocols within the working group where necessary, while interacting with other working groups to enhance existing protocols where possible.