[SPAM-HEADER] - Re: Diversity - was: Fiber cut in SF area - Email has different SMTP TO: and MIME TO: fields in the email addresses

Wed Apr 15 21:34:12 UTC 2009

On Wed, Apr 15, 2009 at 06:37:36PM +0100, Rod Beck wrote:
> Hi Richard, 
> 
> I never said that protected LAN PHY 10 GigE was more expensive than
> two diversely routed waves.

Strange, the e-mail from you that I quoted specifically said:

> Bottom line is that it will cost more than two diversely routed 10 gig
> waves.

But at any rate...

> However, Hibernia's engineers have advised that route protected LAN
> PHY 10 GigE will tolerate a relatively high BER before switching. I
> stand by that statement. 
> 
> I said that protected STM64 service was more expensive and that is
> true. Not only do you need two diversely STM64 waves, but you need
> protection as well. 

Modern DWDM systems don't care about they content of the payload, they
use a system called OTN (optical transport networks) as a generic
digital wrapper around the payload, and then they deal entirely with the
OTN frame. This makes features like optical protection protocol
agnostic, and remove any kind of cost difference based on the type of
service.

I think you're confusing the old style system of implementing a 
SONET/SDH based ring as a method of delivering protected services, with 
the modern techniques of delivering 10G or other subrate services as LAN 
PHY or SONET/SDH or some other protocol. These are completely different 
things.

> I have sold almost 30 ten gig waves (leases) and I have only received
> one request (global bank) for protected service. When I priced at the
> twice the price of an unprotected service plus a 10% premium, that
> request was downsized to a protected STM16. 

Well, I DID point out some compelling reasons why one might want to do
2x (or more) diversely routed unprotected wavelengths rather than a 
protected service. There are many other reasons, such as statistically 
multiplexed oversubscribtion on multiple unprotected circuits during the 
normal non-failure state.

At any rate, I'm not in a position to explain the logic or motivations 
of the people who buy waves from you, all I can tell you is how the 
technology works and what it costs to deploy it. As such, my previous 
explanation was correct. :)

> Customers in general are simply not willing to pay for protection.
> Indeed, most of them prefer to load balance among diversely routed 10
> gig waves or buy waves on several network or cable systems. 

All perfectly legitimate reasons why one might want to do multiple 
diverse unprotected wavelengths, but this is still orthogonal to the 
assertions that protected wavelengths are not possible, not reliable, or 
cost more to implement than 2x unprotected waves.

Also, keep in mind that the availability of > 2-degree protection on 
modern DWDM platforms could *easily* result in optically protected 
wavelengths which are much cheaper to deliver than diversely routed 
unprotected paths. For example, lets consider the scenerio you 
previously gave of a 10G wavelength from Chicago to Frankfurt. Using an 
optical switching protection system, a provider could survive a fiber 
cut between Chicago and Cleveland in Detroit by wrapping the wavelengths 
via Chicago Indianapolis Cincinatti Cleveland, before continuing on its 
way to Frankfurt. This eliminates the need to provision capacity on two 
completely diverse paths, which may not even exist or which may have 
extremely poor latency choices, and reduces the cost to deliver the 
service. As always, the benefits of such a system depend on both the 
carrier's and the customers' footprints. I suspect you'll start to see 
more of this in the future, as Level3 seems to be adopting it.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)