-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Michael.Dillon@radianz.com Sent: Friday, April 15, 2005 6:34 AM To: nanog@merit.edu Subject: Re: Anyone familiar with the SBC product lingo?
you'll never get better redundancy than having more than one carrier.
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. Unless you're designed as a carrier hotel or a colo (even some colos aren't diverse entrance facility), this is the de-facto standard. The reason why is carriers et. al. must pay for conduit access to a building and it impacts pricing, especially if you're not servicing a huge load of service to the building. From the entrace facilities, carriers typically also pay riser conduit fees. 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).
Of course, you can get separacy with two carriers but it is generally more work to verify that the two companies do not share fibre or conduit or tunnels.
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. Hope that helps. -M<