Re: [bcause] [Bcause] interest and scope?

[Gregory Dalle <[e-mail]>]

Hi Aijun,

I hear you have to join the BBF meetings to get the answers to these questions 😉
That being said, this mailing list is not about BNG versus AGF and 5G core. You could use PFCP between BNG-CP and BNG-UP, without any form of 5G convergence.

Personally I don’t subscribe to a view that would split BNG domain into 2 clearly isolated segments: the “basic BNG” (TR178) and the “integrated BNG” (with wireless or convergence support). My view is that this is a continuum and we cannot just artificially build a wall in-between. For example, does Diameter Gx on a BNG make it “an integrated BNG”, since this is based on TR-300 (Policy Convergence)? I know “Fixed Network only” operators that use Gx/PCRF.

Regards,
Greg

From: Aijun Wang@China Telecom <[e-mail]>
Sent: Monday, March 25, 2019 3:56 PM
To: Gregory Dalle <[e-mail]>
Cc: Greg Mirsky <[e-mail]>; Vigoureux, Martin (Nokia - FR/Paris-Saclay) <[e-mail]>; [e-mail]
Subject: Re: [bcause] [Bcause] interest and scope?

Hi, Gregory:

Can the FMC vision described now in BBF accomplish the following aims:
1. Converge in the control plan for mobile and broadband subscribers for sessions negotiations/management etc. functions?
2. Can the BNG existing in the network be upgraded to support the UPF function with minimum costs(for example, control software upgrades)?

Control Plane in Mobile Network is more complex than the counterpart of broadband network, but BNG has more powerful forwarding capabilities than UPF.  If the converge consider more how to utilize the advantages of each side, not just defining additional function entities(AGF etc.), I think the solutions will be easily rolled out in real network.
Aijun Wang
China Telecom

On Mar 25, 2019, at 20:23, Gregory Dalle <gdalle=[e-mail]<mailto:gdalle=[e-mail]>> wrote:
Hi Greg M,

Commenting back on: “we have heard from several operators that they are interested only in FN (fixed network) DBNG CUPS (….) I don't think that requests by these operators should be ignored”.

From what I can track on this mailing list:

  1.  2 operators said they are interested only in fixed access BNG
  2.  5 operators said they don’t want to restrict the protocol discussion to fixed access only

The good news is that these 2 operators are not ignored, as the goal is  provide a superset that includes support for basic TR178 BNG as they want.

Thanks,
Greg D

From: bcause <[e-mail]<mailto:[e-mail]>> On Behalf Of Greg Mirsky
Sent: Monday, March 25, 2019 9:20 AM
To: Vigoureux, Martin (Nokia - FR/Paris-Saclay) <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]>
Subject: Re: [bcause] [Bcause] interest and scope?

Hi Martin, et al.,
I'd not discuss whether PFCP can be extended to suit yet undocumented DBNG CUPS requirements without changes to its architecture. Many stated that they believe that that is achievable and I'm not to argue with what people believe or don't believe in. I just want to point out that we have heard from several operators that they are interested only in FN (fixed network) DBNG CUPS. I interpret that these operators have and want to keep their fixed and mobile networks operated separately. And even though PFCP may be already is familiar to the operations team that manages their mobile network, introducing the new protocol into the operation of the fixed network will increase their operational cost. More so, operators that are not looking to introduce hybrid access or 5G FMC at any time soon may have a preference on which protocol selection as that is the reflection of their operational model. I don't think that requests by these operators should be ignored and the answer given by SDOs include only PFCP-based DBNG CUPS.
I've participated in the discussion and contributed to the charter. The charter intended to work on FN-only DBNG CUPS first and deliver results quickly. Adding hybrid access and 5G FMC could be discussed later, including, based on findings by experts at BBF.

Regards,
Greg

On Mon, Mar 4, 2019 at 2:22 PM Vigoureux, Martin (Nokia - FR/Paris-Saclay) <[e-mail]<mailto:[e-mail]>> wrote:
Hello,

as you might know, the RTGWG has hosted, for some time now, a set of
documents that relate to the separation of the user plane and control
plane of Broadband Network Gateways.
These documents can be found at
https://datatracker..ietf.org/group/rtgwg/documents/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_group_rtgwg_documents_&d=DwMFaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=VhX0NAIO1d7yQxdURKFPY59GAxttnQcfkn45tfRnREs&m=S-4EDvyPmus0NS5LXfp-Ms9zGC_m8iVOllO5lcwmVo0&s=96SauSW0hDod15fcQ8L7ylDy5HchcDuklDH6996dPic&e=> and start with
draft-cuspdt-* or draft-wadhwa-*

Please read them if you haven't already.

Recently, a group of persons has worked together and produced few
paragraphs in support of their willingness to see a working group on
this topic formed.

Considering this, I am sharing this text with the IETF community in
order to evaluate
* the wider interest in, and willingness to work on, this topic,
* the appropriateness of creating a focussed and short-lived working
group (as opposed to continuing in rtgwg).
To that effect, please read and comment on the text further down, it is
here for being debated.
As a matter of clarification: me sharing it, instead of the authors
doing it, does not carry any special meaning.

Important note: this topic has its roots in BroadBand Forum (BBF) with
which IETF has exchanged few liaisons on the topic recently. These are
important reads:
https://datatracker.ietf.org/liaison/1619/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_liaison_1619_&d=DwMFaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=VhX0NAIO1d7yQxdURKFPY59GAxttnQcfkn45tfRnREs&m=S-4EDvyPmus0NS5LXfp-Ms9zGC_m8iVOllO5lcwmVo0&s=WR5EeaTa7vVKvnvgUSwSif_tFMJATrrdUp85D9Wauww&e=>
https://datatracker.ietf.org/liaison/1615/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_liaison_1615_&d=DwMFaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=VhX0NAIO1d7yQxdURKFPY59GAxttnQcfkn45tfRnREs&m=S-4EDvyPmus0NS5LXfp-Ms9zGC_m8iVOllO5lcwmVo0&s=0siKbwwdh2W6FBBMHKJid3k-SaVYNP1bfqYkVAZMWWU&e=>
https://datatracker.ietf.org/liaison/1600/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_liaison_1600_&d=DwMFaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=VhX0NAIO1d7yQxdURKFPY59GAxttnQcfkn45tfRnREs&m=S-4EDvyPmus0NS5LXfp-Ms9zGC_m8iVOllO5lcwmVo0&s=ntY5jLiyuv6zQcLI7sHo0U-_oSajcmPcqdSQViQ7FAY&e=>
https://datatracker.ietf.org/liaison/1566/<https://urldefense.proofpoint.com/v2/url?u=https-3A__datatracker.ietf.org_liaison_1566_&d=DwMFaQ&c=HAkYuh63rsuhr6Scbfh0UjBXeMK-ndb3voDTXcWzoCI&r=VhX0NAIO1d7yQxdURKFPY59GAxttnQcfkn45tfRnREs&m=S-4EDvyPmus0NS5LXfp-Ms9zGC_m8iVOllO5lcwmVo0&s=8AnBB1mLQepiil0dgmBKNL1NDtxWktzl2IOEZ9XXNyI&e=>


---
Current Broadband Network Gateways (BNGs) that terminate residential
broadband subscribers at the edge of service provider networks run as an
integrated system where both the subscriber management control plane and
traffic forwarding user plane are combined in a single system. In a
large network, where the subscriber density is high, it is better to
distribute and locate BNG systems closer to the subscribers, especially
when the content caches are distributed to reduce backhaul costs and
latency. In this scenario, as the BNG footprint grows, the subscriber
management control points also proliferate, increasing operational
complexity. This trend motivates the broadband network access industry
to adopt new architectures that take advantage of the increasing ability
to disaggregate and virtualize appropriate network access functions.
Additional benefits can be realized by separating subscriber management
control plane (CP) and traffic forwarding user plane (UP) for BNGs
(referred to as Control and User Plane Separation (CUPS)). That
simplifies operations, provides independent location, and scaling for CP
and UP functions. A single CP function, running as a centralized VNF,
can control and manage multiple UP instances, which may be distributed
and separated from the CP via a multi-hop L2 or L3 network.  CUPS
requires protocols for communication between CP and UP instances: from
the CP to the UP to create and manage subscriber state instances and
from the UP to the CP to handle relevant solicited or unsolicited events.

The proposed Working Group is a narrowly scoped WG tasked to specify
communication protocol(s) between the CP and UP of a BNG, a network
element whose functions are defined by BBF. A BNG can deliver broadband
services to subscriber over wireline access or over multiple access
types to accommodate different deployments. The goal of the WG is to
define protocol(s) for CUPS that may support multiple deployment
scenarios for the BNG.

The scope of the work covers protocol requirements, specification of the
communications protocol, the information elements to be transferred with
that protocol, and YANG data model(s) for Operations and Management as
well as security, operational, and transport considerations.
---


Thank you
Martin
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