Subject: G-MPLS on all-optical switches?

From: Darren Freeland <[email-masked]>
Date: Tue, 06 Feb 2001 14:24:20 +0000

Hi,

Can any vendor give me some information on exactly how they intend to
run G-MPLS on FULLY optical switches?  For the control signals, will you
use optical splitters or the like to tap off some of the lightpath
inband (amplifying to compensate for the power loss), or will you use an
outband network?

Any info much appreciated ....

Darren.

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From: "Alec Myers" <[email-masked]>
Date: Tue, 6 Feb 2001 19:33:32 -0000

Bearing in mind:

1. The crudity of pure optical memory (fibre delay lines)
2. The lack of pure-optical logic
3. The lack of a fast (packet rate) wavelength switching technology
4. The delay in line clock-recovery between differing transmitter/receivers
pairs at the start of each packet
5. The difficulty in dynamically recovering from non-linear effects in
optical paths whose length varies per-packet

I wouldn't expect to see a real FULLY optical switch any time soon.

There are a few papers around that describe possible control schemes, but
they are all rather crude, and make only passing reference to MPLS. If
you're interested I can forward the references.

-A

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From: "Shun Yao" <[email-masked]>
Date: Tue, 6 Feb 2001 11:58:37 -0800

I believe Darren was referring to all-optical ~circuit~ switch, not packet
switch. Up to now we haven't seen one working ~fully-optical~ (no
transponders, strictly non-OEO data plane) switch in the market, although
many companies are claiming to be building one. In-band signaling is not as
simple as split/amplify. First of all cascaded amplification add noise and
other physical impairments, then when you push the data rate higher, all
sorts of things will happen to the signal. If out-of-band signaling is used,
performance monitoring of the data path will be difficult. I would think
twice even if a vendor throws me a definite answer, because there is no
working product yet.

Shun

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of Alec
> Myers
> Sent: Tuesday, February 06, 2001 11:34 AM
> To: [email-masked]'
> Cc: Darren Freeland
> Subject: Re: G-MPLS on all-optical switches?
>
>
> Bearing in mind:
>

---

From: Darren Freeland <[email-masked]>
Date: Thu, 08 Feb 2001 13:05:06 +0000

Hi Shun,

Shun Yao wrote:

> switch.

Yes, that's what I was referring to.  How will G-MPLS run on an optical switch
with MEMs technology for example (indeed any fabric that is transparent to user
plane traffic).  Still haven't heard any real answers from vendors.  Does this
mean that there's a number of vendors building transparent optical switches, but
they're not sure how they will control them?  ;)

Vendors, if it's a proprietary thing that you don't want to share with the
exploder list, please feel free to mail me offline with some info!

Thanks,
Darren.