DIA (Dedicated Internet Access) is connectivity from a customer's location to the Internet. DIA is comprised of two separate components: the local loop and the DIA port. The local loop is the actual connectivity from the customer's physical location to their DIA provider's POP. This loop can be ordered through their DIA provider or it can be a customer provided loop ordered through the customer's RBOC or LEC. The DIA port is literally the portal that allows for the Internet access.

With connection speeds ranging from 128Kbps on a T1 loop to a 2488 Mbps OC48, businesses can choose the speed and price point that best suits them.
Dedicated Internet can also be value added with features like domain and website hosting. For the service conscientious customer, an integrated T1 providing fractional Internet service with long distance access is available in many areas

Frame relay is a telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between end-points in a wide area network (WAN). Frame relay puts data in a variable-size unit called a frame and leaves any necessary error correction (retransmission of data) up to the end-points, which speeds up overall data transmission. For most services, the network provides a permanent virtual circuit (PVC), which means that the customer sees a continous, dedicated connection without having to pay for a full-time leased line, while the service provider figures out the route each frame travels to its destination and can charge based on usage. An enterprise can select a level of service quality - prioritizing some frames and making others less important. Frame relay is provided on fractional T-1 or full T-carrier system carriers. Frame relay complements and provides a mid-range service between ISDN, which offers bandwidth at 128 Kbps, and Asynchronous Transfer Mode (ATM), which operates in somewhat similar fashion to frame relay but at speeds from 155.520 Mbps or 622.080 Mbps.

Frame relay is based on the older X.25 packet-switching technology which was designed for transmitting analog data such as voice conversations.
Unlike X.25 which was designed for analog signals, frame relay is a fast packet technology, which means that the protocol does not attempt to correct errors.

When an error is detected in a frame, it is simply "dropped." (thrown away). The end points are responsible for detecting and retransmitting dropped frames. (However, the incidence of error in digital networks is extraordinarily small relative to analog networks.)

Frame relay is often used to connect local area networks with major backbones as well as on public wide area networks and also in private network environments with leased lines over T-1 lines. . It requires a dedicated connection during the transmission period. It's not ideally suited for voice or video transmission, which requires a steady flow of transmissions. However, under certain circumstances, it is used for voice and video transmission.

Frame relay relays packets at the Data Link layer of the Open Systems Interconnection (OSI) model rather than at the Network layer. A frame can incorporate packets from different protocols such as Ethernet and X.25. It is variable in size and can be as large as a thousand bytes or more.

Point to Point circuits, also known as Private Lines, are circuits that are utilized as connectivity between two locations. Customers can utilize this technology to connect host and remote location or locations in a secure dedicated connection WAN instead of using a service like FRS (Frame Relay Service) or ATM (Asynchronous Transfer Mode).

Point to point circuits can also be used by the customer to connect to a provider's POP for DIA or dedicated voice applications when provisioned through their RBOC or LEC as a "customer provided loop".

This allows the customer to maintain control of their connectivity with the ability to move to a different provider POP if necessary.
Each point to point circuit is distance sensitive, meaning that the price for the circuit will be dependant on the mileage between the two locations that are to be connected. Point to point circuits can be provisioned in full bandwidth allocations ranging from T1/DS1 (1.544Mbps) to OC48 (2488Mbps).

A VPN (virtual private network) is a way to use a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization's network. A virtual private network can be contrasted with an expensive system of owned or leased lines that can only be used by one organization. The goal of a VPN is to provide the organization with the same capabilities, but at a much lower cost.

A VPN works by using the shared public infrastructure while maintaining privacy through security procedures and tunneling protocols such as the Layer Two Tunneling Protocol (L2TP). In effect, the protocols, by encrypting data at the sending end and decrypting it at the receiving end, send the data through a "tunnel" that cannot be "entered" by data that is not properly encrypted. An additional level of security involves encrypting not only the data, but also the originating and receiving network addresses.

ATM is a high-speed networking standard designed to support both voice and data communications. ATM is normally utilized by Internet service providers on their private long-distance networks. ATM operates at the data link layer over either fiber or twisted-pair cable.

ATM differs from more common data link technologies like Ethernet in several ways. ATM does not involve routing for example. Hardware devices known as ATM switches establish point-to-point connections between endpoints and data flows directly from source to destination. Instead of using variable-length packets, ATM utilizes fixed-sized cells. ATM cells are 53 bytes in length, that includes 48 bytes of data and 5 bytes of header information.

The performance of ATM is often expressed in the form of OC (Optical Carrier) levels, written as "OC-xxx." Performance levels as high as 10 Gbps (OC-192) are technically feasible with ATM. More common performance levels for ATM are 155 Mbps (OC-3) and 622 Mbps (OC-12).

ATM is designed to support easier bandwidth management. Without routing and with fixed-size cells, one can much more easily monitor and control bandwidth under ATM than under Ethernet, for example. The high cost of ATM relative to Ethernet is one factor that has limited its adoption to "backbone" and other high-performance applications.

DSL (Digital Subscriber Line) is a technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, and RADSL. Assuming your home or small business is close enough to a telephone company central office that offers DSL service, you may be able to receive data at rates up to 6.1 megabits (millions of bits) per second (of a theoretical 8.448 megabits per second), enabling continuous transmission of motion video, audio, and even 3-D effects. More typically, individual connections will provide from 1.544 Mbps to 512 Kbps downstream and about 128 Kbps upstream.

A DSL line can carry both data and voice signals and the data part of the line is continuously connected. DSL installations began in 1998 and will continue at a greatly increased pace through the next decade in a number of communities in the U.S. and elsewhere. Compaq, Intel, and Microsoft working with telephone companies have developed a standard and easier-to-install form of ADSL called G.lite that is accelerating deployment. DSL is expected to replace ISDN in many areas and to compete with the cable modem in bringing multimedia and 3-D to homes and small businesses.

MPLS is a technology, not a service. Most carriers run MPLS underneath a wide range of services, including frame relay, wide-area Ethernet, native IP and ATM. The advantages accrue primarily to the carrier. User benefits include lower cost in most cases, greater control over networks, and more detailed QoS. In fact, QoS is the primary reason IT executives opt for MPLS - in a recent Nemertes benchmark, 62% of organizations told us they're using MPLS today or plan to deploy it, with 55% listing QoS as the main reason.

MPLS-based services are a good fit in the following scenarios:

Your company has a lot of any-to-any traffic. Any-to-any traffic requires N-squared number of connections - an expensive proposition in network technologies that charge by the circuit, such as frame or ATM. Most companies don't have a lot of any-to-any traffic, unless they're engaged in a convergence project. The majority of today's applications tend to be client/server, which generate hub-and-spoke traffic patterns. For these, switching to MPLS doesn't buy much: Firms report around 10% cost savings as compared with legacy frame or ATM. But the scenario changes dramatically when MPLS is used to converge voice and video - or with next-generation software architectures.

You're planning a convergence project. Most firms see immediate savings - 25% or more - when they begin combining voice and video traffic over the MPLS WAN. Video often is carried over ISDN circuits that are expensive. Consolidating this traffic onto a data network can eliminate the need for an ISDN network, generating immediate savings. Also, both video and voice tend to have any-to-any traffic patterns, unlike legacy data apps - so the any-to-any cost savings begin to kick in.

You're planning to deploy next-generation computing infrastructure such as Web services, peer-to-peer or grid computing. Web services and peer-to-peer generate any-to-any traffic patterns; grid computing does the same, and often requires QoS capability. In fact, for some financial services firms, grid computing is the primary driver behind MPLS.