There are different types of connections to the Internet. Below is a explanation of each to help better understand the differences.
For residential users and small sized businesses requiring cost-effective alternative for high-speed access.
DSL and Cable Internet connections are connected via a shared, switched *ATM network. A number of customers are aggregated at multiple single connection points (DSLAM, Node, NOC, CO, etc.). Each aggregation point is a potential point of failure. DSL and Cable are also unregulated - There are no State and FCC regulations in place. Circuit cost escalations, defined quality levels, and customer service responsiveness are at the discretion of local Telco/CATV and the third party providers. Upstream (Upload) and Downstream (Download) speeds will be different.
DSL - Potentially can transmit data from 256 Kbit/s to 40 Mbit/s. Usually Upstream of up to 1.54Mbit/s and Downstream of up to 10.0 Mbit/s.
DOCSIS 1.x - Obsolete(Not used anymore).
DOCSIS 2.0 - Transmits data Upstream up to 2.0 Mbit/s and Downstream up to 16Mbit/s.
DOCSIS 3.0 - Transmits data Upstream up to 10.0 Mbit/s and Downstream up to 150.0 Mbit/s. Equilalent up to 6 T1 Lines Upstream and 33 T1 Lines Downstream. (Faster speeds will be available soon)
DOCSIS 3.1 - Transmits data Upstream up to 1.0 Gbit/s and Downstream up to 10Gbit/s. This new specification will do away with 6 MHz and 8 MHz wide channel spacing and instead use smaller (20KHz to 50KHz wide) orthogonal frequency division multiplexing (OFDM) subcarriers.
For organization with mission-critical need for high speed connectivity, including web hosting and company-wide access.
Dedicated connections are private point-to-point dedicated connection between the customer and the provider. They are rock-solid and based on proven, mature technology. High availability and reliability. Guaranteed fixed speeds with Service Level Agreements. Dedicated connections are regulated - State and FCC regulations mandate minimum cost escalation, defined quality levels, and customer service responsiveness.
T1/DS1 - Transmits data at 1.54 Mbit/s. 24 64 Kbit/s Channels or 24 Voice Channels. (T1 Circuits can be bonded togather to provide faster bandwidth.)
T3/DS3 - Transmits dataat 44.746 Mbit/s. Equivalent 28 T1 lines
OC-1 - Transmits Data at 51.84 Mbit/s. Equivalent to 28 T1 Lines or 1 x T3 Line
OC-3 - Transmits Data at 155.52 Mbit/s. Equivalent to 84 T1 Lines or 3 x T3 Lines
OC-9 - Transmits Data at 466.56 Mbit/s. Equivalent to 252 T1 Lines or 9 x T3 Lines
OC-12 - Transmits Data at 622.08 Mbit/s. Equivalent to 336 T1 Lines or 12 x T3 Lines
OC-18 - Transmits Data at 933.12 Mbit/s. Equivalent to 504 T1 Lines or 18 x T3 Lines
OC-24 - Transmits Data at 1.244 Gbps. Equivalent to 672 T1 Lines or 24 x T3 Lines
OC-36 - Transmits Data at 1.9 Gbps. Equivalent to 1,008 T1 Lines or 36 x T3 Lines
OC-48 - Transmits Data at 2.488 Gbps. Equivalent to 1,344 T1 Lines or 48 x T3 Lines
OC-96 - Transmits Data at 4.976 Gbps. Equivalent to 2,688 T1 Lines or 96 x T3 Lines
OC-192 - Transmits Data at 9.953 Gbps. Equivalent to 5,376 T1 Lines or 192 T3 Lines
OC-256 - Transmits Data at 13.271 Gbps. Equivalent to 7,168 T1 Lines or 256 T3 Lines
OC-768 - Transmits Data at 39.812 Gbps. Equivalent to 21,504 T1 Lines or 768 x T3 Lines
*Asynchronous Transfer Mode (ATM) is a switching technique for telecommunication networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from networks such as the Internet or Ethernet LANs that use variable sized packets or frames. ATM provides data link layer services that run over OSI Layer 1 physical links. ATM has functional similarity with both circuit switched networking and small packet switched networking. This makes it a good choice for a network that must handle both traditional high-throughput data traffic (e.g., file transfers), and real-time, low-latency content such as voice and video. ATM uses a connection-oriented model in which a virtual circuit must be established between two endpoints before the actual data exchange begins. ATM is a core protocol used over the SONET/SDH backbone of the Integrated Services Digital Network (ISDN).
A metropolitan-area Ethernet, Ethernet MAN, or metro Ethernet network is a metropolitan area network (MAN) that is based on Ethernet standards. It is commonly used to connect subscribers to a larger service network or the Internet. Businesses can also use metropolitan-area Ethernet to connect their own offices to each other. Internet can also be bundled either by using a VLAN or an MPLS cloud.
An Ethernet interface is much less expensive than a SONET interface of the same bandwidth. Ethernet also supports high bandwidths with fine granularity, which is not available with traditional SONET connections. Another distinct advantage of an Ethernet-based access network is that it can be easily connected to the customer network, due to the prevalent use of Ethernet in corporate and, more recently, residential networks. A typical service provider's network is a collection of switches and routers connected through optical fiber. The topology could be a ring, hub-and-spoke (star), or full or partial mesh. The network will also have a hierarchy: core, distribution (aggregation), and access. The core in most cases is an existing IP/MPLS backbone but may migrate to newer forms of Ethernet transport in the form of 10Gbit/s, 40Gbit/s, or 100Gbit/s speeds or even possibly 400Gbit/s to Terabit Ethernet network in the future.