Anyone familiar with the SBC product lingo?

Fri Apr 15 12:29:28 UTC 2005

> > On the contrary, you get better redundancy by sticking to 
> > one carrier and making sure that they really provide
> > separacy though the entire span of the circuit. If you
> > have two carriers running fibre to yoiur building down
> > the same conduit, then you do NOT have separacy and as
> > a result, the redundancy is not there.
> 
> Which is the case in about 99% of the commercial buildings
> providers serve. 

Do you have any sources of data to back up that number?
I believe that you are wrong and that it is not 99%.
In Manhattan and similar city centers, I believe that
your view is mostly correct but even there I don't
believe that it is as high as 99%. And in places like
Silicon Valley or Sacramento, the majority of 
commercial buildings are surrounded by parking lots,
patches of grass and trees. In those areas, if your
building doesn't have dual entrance, it is feasible
to make it so. Maybe not easy, but definitely within
the realm of feasibility.

> Service delivery inside of the prem is insidiously complicated
> unless you understand a little RE and how OSP is linked to
> the ISP (in side plant).

No argument there. People who want to buy separacy have got
to learn all of these things in order to guarantee that
they are getting what they think they are getting. Once
the market has matured a bit, I expect that 3rd party
network suppliers will take over that duty. These 3rd party
separacy providers won't have their own networks for the
most part, but will do the donkey work to make sure that
their carriers are supplying true separacy. In cities
like New York and Philly, I would expect this type of
third party to put in some of their own metro network
links to work around hot-spots where it is too hard to
guarantee that the carrier is really providing separacy.

This is not unlike the way in which the tier 2 ISPs of
the 90's were able to provide better uptime than the
tier 1's because they aggregated access to several 
tier 1 networks.

> Im a metro loop, they are almost certainly going to share
> the same path. It is less certain that they will share a
> conduit. This is standard if you have the route diversity,
> which is why you want the provider diversity to make it 
> all work. 

I'm not sure what you mean by "path" here, but people who
want to buy separacy want those circuits to be physically
separate at all points and they want the distance between
circuits to be sufficiently great that they two circuits 
do not share fate. Two sides of the Baltimore tunnel
would not qualify as truly separate paths by those standards.

This is why I use the term "separacy" rather than "diversity".
Separacy seems to have originated among people planning 
SANs (Storage Area Networks) to interconnect mission-critical
data centers in the same metropolitan area.

--Michael Dillon