Subject: RE: Optical link bundling. Was Re: Draft Minutes From Pittsburgh

From: [email-masked]
Date: Thu, 19 Oct 2000 10:53:01 +0100

Hi Alex,

>>> - "server layer trails (in an OTN) = client layer links", and
>>> networks operators *will* have to support multiple client
>>> layers for a very long time...including some large BW servives
>>> directly off the L1 fabric.
>>> 
>>> This is a really important point.  It is a fundamental
>>> characteristic of a layered network architecture.
>
> [AZ] Got it. I didn't realize what layers you meant.

This is the first time I have actually seen anyone on the MPLS or IPO lists
publicly acknowledge the "client layer links = server layer trails" fact.  I
assume then that you now also acknowledge the single control plane 'Peer'
model as being impractical?  Okay, using a single 'best of breed' routing
protocol and a single 'best of breed' signalling protocol across the IP and
optical layers may be feasible (I stress may), but it follows from the above
simple concept (as Neil Harrison stated before) that the addresing scheme
used by the optical layer cannot be related to any particular clients (ie
not from the same addressing space in terms of possible trail connectivity
at layer network access points).  Sure this would not be the case if IP was
the only client of the optical layer, but (*reality check*), operators WILL
still be making most of their revenue from non-IP clients for a long time to
come, and therefore an optical transport network WILL have to support
multiple clients.

Are we now seeing a realisation of this in the IETF?  I think it's obvious
that what was defined as the 'Overlay' model in
draft-awduche-mpls-te-optical-02.txt and
draft-many-ip-optical-framework-01.txt must be developed first.

Cheers,
Darren.

---

From: Alex Zinin <[email-masked]>
Date: Thu, 19 Oct 2000 09:08:17 -0700

Hi Darren!

> publicly acknowledge the "client layer links = server layer trails" fact.

I think this was quite clear. If you establish an LSP across your
optical network, it will look like a link to your client.

> I assume then that you now also acknowledge the single control plane 'Peer'
> model as being impractical?

Wrong assumption.

> Okay, using a single 'best of breed' routing
> protocol

Wrong assumption (OSPF+ISIS).

>  and a single 'best of breed' signalling protocol

Wrong assumption (RSVP-TE + CR-LDP).

> across the IP and
> at layer network access points).

Wrong assumption.
I does not have to be related, but it can.

>   Sure this would not be the case if IP was

Do you mean there is a contradiction with the work currently being
done?

> draft-many-ip-optical-framework-01.txt must be developed first.

I would say we should develop the OTN control plane first.

Regards,
Alex.