PDF of this tutorialThe DTM network solution has several features that make it suitable to handle aggregate traffic from emerging residential communications. The possibility for residents of modern society to use information technology (IT) in their daily life has increased during the last decade, mainly through the widespread use of the personal computer (PC), the expansion of the Internet, and the growth of services for the home market. With the fast development and deployment of new access technologies such as digital subscriber line (DSL), a high-speed communication infrastructure becomes a reality. The availability of high-speed access to the home will establish new requirements for the network that aggregate traffic up to the service-access points.
The future aggregation network must have the following qualities:
- capable of handling large amounts of traffic
- capable of handling different types of traffic streams such as synchronous video, bursty data, and synchronous voice
- adaptable to traffic variations
- scalable in connections as well as capacity
- easy to manage
Digital subscriber line access multiplexers (DSLAMs) are often used to aggregate traffic from subscribers connected with DSL modems. Many of the DSLAMs are built with an ATM user network interface (UNI) on the uplink or an Ethernet interface. DTM can efficiently be used to transport heavy traffic introduced by DSL users from the DSLAMs to the service-access point, which is normally the Internet point of presence (PoP).
Figure 7. DSLAM Aggregation Network for Internet Connections
Integrated access devices are used to offer homes and small offices voice services as well as data services over the same physical line. The physical medium may be copper, radio link, or other media, but the concept is likely to be the same. A subscriber modem combines the telephone and data services over the media and connects to an integrated access multiplexer that separates voice traffic to E1s and data traffic to Ethernet. The DTM transports the divided traffic up to the service-access points—the voice switch and the Internet PoP—by supporting both Ethernet and E1s efficiently.
Figure 8. DTM Network for Integrated-Access–Device Aggregation
The benefits of using a DTM network for DSLAM and integrated-access–device aggregation include the following:
- DTM may dynamically adapt to traffic generated by the DSLAMs and thus eliminate the need for over-dimensioning.
- DTM may dynamically distribute bandwidth resources (time slots) between the DSLAMs, which allows for better over-time utilization.
- By using 10/100 Base-T interfaces and the DLE service, only one network layer is required between the DSLAMs or integrated-access devices and the Internet PoP.
- The transparent support of E1 ensures interoperability .
- New DSLAMs, integrated-access devices, and service-access points can be added easily to the DTM architecture.
