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From: Kireeti Kompella <kireeti.kompella@gmail.com>
In-Reply-To: <5506E75F.4080201@pi.nu>
Date: Wed, 18 Mar 2015 02:02:54 +0100
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Message-Id: <13074D3F-13AE-4DD4-BB14-D8B1B70DC832@gmail.com>
References: <5506E75F.4080201@pi.nu>
To: Loa Andersson <loa@pi.nu>
Archived-At: <http://mailarchive.ietf.org/arch/msg/mpls/LfkH5eSbm2Tgbn5QBGEIjKLv3IA>
Cc: "mpls@ietf.org" <mpls@ietf.org>,
 "mpls-chairs@tools.ietf.org" <mpls-chairs@tools.ietf.org>,
 "draft-cheng-mpls-tp-shared-ring-protection@tools.ietf.org"
 <draft-cheng-mpls-tp-shared-ring-protection@tools.ietf.org>,
 draft-kompella-mpls-rmr@tools.ietf.org
Subject: Re: [mpls] MPLS ring protection reconsidered ??
Precedence: list

Hi Loa,

Thanks for your mail!

I=E2=80=99m all for revisiting the question.  I was going to ask for WG =
adoption of RMR.

If the draft-cheng authors ask the same, I have no objection.  However, =
I think there are quite a few differences between the two drafts, and =
don=E2=80=99t think that merging them is the technically best solution.

Kireeti.

> On Mar 16, 2015, at 15:23 , Loa Andersson <loa@pi.nu> wrote:
>=20
>=20
> Folks,
>=20
> (taking my chair hat off for a while, i.e. this should not be
> read as a chair directive, just a bit of mumbling that comes out
> thinking about how to progress documents.)
>=20
> As far back s the 73rd IETF in Minneapolis John and Adrian made
> a report on "Requirements for Ring Protection=0Bin MPLS-TP". The
> conclusions were that we could do topology specific protection
> solutions if the benefits are big enough.
>=20
> Such solutions need to meet the same requirements as linear
> protection and it has to be show that it can't be done by linear
> protection only.
>=20
> At that time we did not see that there were things that would not
> be as readily done by the linear protection being specified at that
> time.
>=20
> Today we have to drafts that address ring topologies, one =
draft-kompella-mpls-rmr addresses Resilient MPLS Rings in an MPLS-TE
> environment. The other draft-cheng-mpls-tp-shared-ring-protection
> addresses protection in an MPLS-TP environment.
>=20
> Both recognizes that ring topologies are very common and that very
> efficient mechanism for keeping traffic flowing in case of failures
> are possible to design. Sometime far better than what is the case if
> the actual ring topologies are view as a linear topology,
>=20
> The first document (draft-kompella- ) looks primarily on the =
operations
> within a single ring and how fast and simple mechanisms for protection
> can be deployed. A ring topology is a very common deployment scenario.
> While, the draft-kompella from a solutions point is somewhat =
orthogonal
> to draft-cheng, it does also discuss the dynamic control plane for =
mpls
> ring, including auto-discovery and signaling. It seems that there are
> opportunities for co-operation between the two drafts in this area.
>=20
> The other (draft-cheng- ) looks at what is called MPLS shared ring, =
i.e.
> a rather high number can shared the same path around the ring, and all
> traffic can be protected by a single operation.
> Another aspect of the shared tunnel is that if part of the ring
> (typically 2 nodes and one link) are part of more than one ring. It
> becomes possible to protect against more than one failure.
>=20
> Maybe it is time to revisit the question and see if we want to adopt
> working group documents for the two scenarios outlined above.
>=20
> /Loa
> --=20
>=20
>=20
> Loa Andersson                        email: loa@mail01.huawei.com
> Senior MPLS Expert                          loa@pi.nu
> Huawei Technologies (consultant)     phone: +46 739 81 21 64