Subject: RE: MPLS and Optical network - one possible solution is burst swi tching

From: Richard Barnett <[email-masked]>
Date: Sun, 30 Jan 2000 16:49:12 -0500

Bill,

> The MPLS packet label is carried out of band in a separate wavelength.
> Packet switching to different wavelengths and wavelength 
> merging is done at
> the optical level.  The OXC decodes in the optical domain the 
> burst label.
> The main data channels are put through a small time delay 
> fiber so that
> burst label can be decoded and OXC wavelength switch can be set up.
> 

It's a very interesting approach but I think that a possible problem with
this is where contention occurs at the egress port - i.e. if multiple
packets are received that need to egress on the same port and wavelength at
the same time. Some sort of optical buffering and queue control would be
needed to resolve this if I understand the situation correctly. An OTDM
approach would avoid this problem at the cost of relatively static bandwidth
allocation. This may not suit all applications but its simplicity does have
attractions.

Richard.

-------------------------------------------------------------
Richard Barnett
VP of System Architecture, Sirocco Systems.
Tel: 203 269 9919 x 126  Fax: 203 269 8291
Email: [email-masked]

---

From: "Alexander Marhold" <[email-masked]>
Date: Mon, 31 Jan 2000 07:05:58 +0100

Many thanks for all who responded to me and to the group and clarified the
topic

So in my opinion the point is now:

1. Currently we have only a OXC which can switch a wavelength from input to
output without wavelength conversion and with no packet recognition. (a
wavelength circuit switch)
that means in a label way, that the value of the incoming label needs to be
the same as the ougoing label on an OXC (with control plane). (label =
wavelength)
---> leads to a practical
maximum of number of LSPs = number of wavelengths (currently about 80)
then you have the possibility to optical switch to any redundant path in
case of link failure
(theoretically you can also have more LSPs if you have more optical paths
and interfaces through your core, but the restriction is that no 2 LSPs with
the same label(wavelength) may cross a single link. So imho the interesting
issue would be finding an optimizing algorithm which has the above mentioned
constraints.)

2. wavelength conversion on the fly, which would allow more flexibility
label invalue can be different of label outvalue
is not available yet

3. optical packet recognition and wavelength conversion and buffering is
future and would lead to an pure optical router, which can have Mpls but it
seems to be not considered in the efforts of the MPLS-WG now.

regards
Alexander

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> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of Richard
> Barnett
> Sent: Sunday, January 30, 2000 10:49 PM
> To: [email-masked]'
> Cc: [email-masked]
> Subject: RE: MPLS and Optical network - one possible solution is burst
> switching
>
>
> Bill,
>

---

From: "Bill St. Arnaud" <[email-masked]>
Date: Mon, 31 Jan 2000 22:15:07 -0500

Richard:

I note with interest that you are with Sirocco which has announced an edge
optical device.

MPLS and MPLmS and there many variants are not the only possible solutions
for controlling wavelengths:

Here are the MPLS solutions:

1. OEO where the SONET OC-x is the actual channel mapped to the LSP.  This
is the most common implementation of todays "optical" switches.

2. Wavelength routing and TE with MPLmS.  Again OEO to decode label and
forward packets.  Control of wavelengths is for provisioning and TE
purposes.

3. Label "burst" switching for initially wavelength steering and maybe in
the future per flow or per packet forwarding in an all optical environment.

All the above solutions are generally intended for single domain IGP
networks.  We are also exploring non-MPLS solution for EGP peering and
interconnection using concepts developed in distributed IX:

1. Wavelength Route Arbiter to manage optical peers, wavelength re-use,
disconnects and autonmous joins in distributed optical IX cloud with BGP
speaking peers

2. iBGP mapping to wavelengths for exterior transit of optical connected
networks

Bill

Bill St. Arnaud
Senior Director Network Projects
CANARIE
[email-masked]
+1 613 785-0426

> From: Richard Barnett [mailto:[email-masked]]
> Sent: January 30, 2000 4:49 PM