Paul Ferguson said:
Funny you should mention this. Actually, aren't most data circuits (excluding copper pairs into the home) fed into the telco DACS network(s), which subsequently may be muxed into a fiber infrastructure along with traditional TDM voice traffic? The DACS network can certainly be an overlay on a fiber infrastructure, and usually is just that.
I don't recall the exact figure, but something like 50% of US circuits are on SONET rings. So yes, the voice and data traffic are equally effected. However, on older non-SONET networks the carriers have a "hot circuit switch" technology that will switch voice circuits in the event of a fiber cut. However, most data circuits do not have such protection. Private data networks are severly affected by fiber cuts, but the Internet is less affected because of its own intrinsic self healing protocols.
Define "reliable".
Good point. Many carriers and telco manufacturers are coming to the Internet business saying that we have the knowledge and expertise to build 99.99999+ reliable networks - therefore eventually we are going to take over the business. Reliable is easy to define in terms of voice calls. But it has whole different set of meanings in the IP world, which most carriers and telco manufacturers fail to understand. For example I can have a 99.9999+ SONET network, but if I can't access my DNS root server, then I clearly don't have a reliable network. Bill