Subject: [ANCP] Access-Node Partitioning

From: "Wojciech Dec \(wdec\)" <[email-masked]>
Date: Fri, 11 Aug 2006 13:55:31 +0200

Dear All,

During our IETF 66 ANCP meeting we briefly discussed the issue of
access-node partitioning and I took the action to attempt to commence a
discussion on what is actually required. The outcome of this would go
into the protocol requirements framework.

Brief background.
The GSMP protocol (citing RFC3292 here ) allows for a mode of operation
whereby an access-node may be controlled by more than one controller by
using the technique of partitioning. In effect the "physical"
access-node can be partitioned into several virtual access-nodes that
are referred to as partitions. The partitions of a physical access-node
are isolated from each other by the implementation and the controller
assumes that the resources allocated to a partition are at all times
available to that partition. No controller redundancy mechanisms are
described.

In other words, as applied to our ANCP use, the GSMP base protocol
allows for what may term a 1-1 control relationship between a particular
access-ports in one partition and a controller, with other access-ports
in other partitions having the same 1-1 relationship with their
controller. For the sake of the discussion, I'll call this partitioning
method "hard partitioning"

Taking the partitioning concept above a step further, it is possible to
imagine what one may term as "functional partitioning" scheme. In such a
scheme, specific functions and/or data elements of a particular
access-port would have a 1-1 relationship with a controller uniquely
allowed to modify these functions or access data elements. 
In terms of the ANCP use-cases, this could translate to a set-up whereby
for a single access-port, say the access-port's modem train rate
information would communicated to one controller (let's call it
controller X), while the OAM function, or configuration parameters would
be communicated with another controller (let's call it Y). 
More elaborate combinations of such a scheme could also be possible, eg
having the modem train rate be communicated to both X and Y, while
retaining the OAM function's control only on controller Y.

Given all of the above several questions appear to be appropriate for a
start:
- Is there interest in enabling ANCP with "hard partitioning"?
- In case of "hard partitioning", is it expected that each controller
will be a separate entity, or is there also a need to consider
controller partitioning? (Two different partitions on the same
access-node have an ANCP adjacency to the same controller)
- Is there interest in enabling ANCP with "functional partitioning"?
- In any partitioning scheme (hard of functional), is there a need to
allow for controller redundancy?

I hope that the above is sufficient to stimulate a discussion and make
some progress on the issue of partitioning.

Kind Regards,
Woj.

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---

From: "Sanjay Wadhwa" <[email-masked]>
Date: Mon, 14 Aug 2006 10:34:44 -0400

IMHO, it will help to initially target "hard partitioning" and
controller redundancy.  The former is useful for instance in scenarios
where we would like to terminate residential and business DSL lines on
different IP edge nodes. 
Graceful restart on a single controller helps with resiliency. However
controller redundancy eliminates any single point of failure and is
explicitly listed in the scope of ANCP charter.
Once we are done with the work items in the initial charter we can
consider visiting "functional partitioning" (which is more relevant to
multi-edge architectures).
 
Regards
-Sanjay

-----Original Message-----
From: Wojciech Dec (wdec) [mailto:[email-masked]]
Sent: Friday, August 11, 2006 7:56 AM
To: [email-masked]
Subject: [ANCP] Access-Node Partitioning

Dear All, 

Brief background. 

Kind Regards, 
Woj.

---

From: Avri Doria <[email-masked]>
Date: Tue, 15 Aug 2006 10:11:49 +0200

Hi,

I don't if you will find it useful, but the GSMP group did put out an  
informational of partitioning:

http://www.ietf.org/rfc/rfc3532.txt

It gets into the complexities of dynamic partitioning somewhat and  
suggests some terminology.

And while http://www.watersprings.org/pub/id/draft-ietf-gsmp-v3-base- 
spec-08.txt (i will uprev in the next week so it remains an active  
reference) discusses link redundancy, we never got very far into  
controller redundancy.

ForCES has done a little work in this area that may serve as a useful  
reference, though they still maintain the notion of a master control  
and backups.  It may serve as a useful reference, though the draft is  
not yet RFC (soon now, we hope)

cheers
a.

On 14 aug 2006, at 16.34, Sanjay Wadhwa wrote:

> controller redundancy.  The former is useful for instance in  
> scenarios where we would like to terminate residential and business  
> DSL lines on different IP edge nodes.
> Graceful restart on a single controller helps with resiliency.  
> However controller redundancy eliminates any single point of  
> failure and is explicitly listed in the scope of ANCP charter.
> consider visiting "functional partitioning" (which is more relevant  
> to multi-edge architectures).
>
> Regards
> -Sanjay
> access-node partitioning and I took the action to   attempt to  
> commence a discussion on what is actually required. The outcome of  
> this would go into the protocol requirements framework.
>
> Brief background.
> The GSMP protocol (citing RFC3292 here ) allows for a mode of  
> operation whereby an access-node may be controlled by more than one  
> controller by using the technique of partitioning. In effect the  
> "physical" access-node can be partitioned into several virtual  
> access-nodes that are referred to as partitions. The partitions of  
> a physical access-node are isolated from each other by the  
> implementation and the controller assumes that the resources  
> allocated to a partition are at all times available to that  
> partition. No controller redundancy mechanisms are described.
>
> allows for what may term a 1-1 control relationship between a  
> particular access-ports in one partition and a controller, with  
> other access-ports in other partitions having the same 1-1  
> relationship with their controller. For the sake of the discussion,  
> I'll call this partitioning method "hard partitioning"
>
> Taking the partitioning concept above a step further, it is  
> possible to imagine what one may term as "functional partitioning"  
> scheme. In such a scheme, specific functions and/or data elements  
> of a particular access-port would have a 1-1 relationship with a  
> controller uniquely allowed to modify these functions or access  
> data elements.
>
> In terms of the ANCP use-cases, this could translate to a set-up  
> whereby for a single access-port, say the access-port's modem train  
> rate information would communicated to one controller (let's call  
> it controller X), while the OAM function, or configuration  
> parameters would be communicated with another controller (let's  
> call it Y).
>
> More elaborate combinations of such a scheme could also be  
> possible, eg having the modem train rate be communicated to both X  
> and Y, while retaining the OAM function's control only on  
> controller Y.
>
> Given all of the above several questions appear to be appropriate  
> for a start:
> - In case of "hard partitioning", is it expected that each  
> controller will be a separate entity, or is there also a need to  
> consider controller partitioning? (Two different partitions on the  
> same access-node have an ANCP adjacency to the same controller)
>
> - In any partitioning scheme (hard of functional), is there a need  
> to allow for controller redundancy?
>
> I hope that the above is sufficient to stimulate a discussion and  
> make some progress on the issue of partitioning.
>
> Kind Regards,
> Woj.
>
>