The traditional high bandwidth network connection is DS3, a 45 Mbps service. This is also the speed of a T3 line. Today, most DS3 services are provisioned over fiber optic cables with a copper handoff at the demarcation point. In some cases, you can get DS3 brought in over coaxial copper or wireless transport.
DS3 is popular for dedicated Internet access in larger organizations, video transport, links to offsite backup and storage and smaller ISPs. DS3 telephony bundles hundreds of outside phone lines for large companies and call centers.
The competitor to DS3 is Carrier Ethernet, especially Metro Ethernet in larger cities. Ethernet services offer standardized speeds of 10, 100 and 1000 Mbps to match the common LAN speeds. But most Ethernet providers also offer other increments in 1, 5 or 10 Mbps steps. A 50 Mbps Ethernet service provides similar bandwidth to DS3.
So how do you choose one service over another? If you need the channelization of traditional TDM services for telephony or other applications, DS3 already meets this standard. It is easily multiplexed and demultiplexed to interface with T1 lines on the low end to OCx SONET fiber optic services on the high end.
Most networking applications are now packet based and more easily interfaced to Ethernet WAN services than legacy telco standards. But since the interface circuitry is generally an off the shelf router module, it may not matter all that much. If you go with a managed router, the service provider will take care of providing the proper customer premises equipment and monitoring the line and interfaces for proper operation.
To muddy the waters a bit more, fractional DS3 services are available that offer less than 45 Mbps for a lower monthly lease cost. You can often get the bandwidth you need by bonding T1 lines together to create increments of 1.5 Mbps up to around 10 or 12 Mbps bandwidth. Or you can get fractional DS3 bandwidth at the speeds where T1 bonding becomes impractical. On the Ethernet side, you can specify nearly any bandwidth from 1 Mbps up to 10 Gbps and often upgrade to higher levels with just a phone call to your service provider.
The fact is that DS3 and Ethernet bandwidths compare favorably. Which you choose for your particular application will most often be determined by which service offers the best pricing for your particular business location. How can you find that out? The easiest way is to check DS3 and Ethernet prices and availability using the GeoQuote online search tool.