By: John Shepler
As MAN and WAN telecom service users, we understand the limitations of our contracted bandwidth. What was once sufficient can become restrictive, impacting application performance and productivity. What can be done to increase bandwidth and eliminate this congestion?
Connection Speed Limits
While you can utilize less than the maximum capacity of a line, exceeding it is not possible. The maximum speed is determined by factors such as the type of transmission medium (e.g., copper, coaxial cable, fiber optic, microwave wireless) and the port capabilities of access routers or customer premises equipment (CPE). Let’s explore common connectivity solutions and their speeds.
T1 Lines
T1 lines operate at a synchronous speed of 1.5 Mbps. Synchronization between source and destination is characteristic of Time Division Multiplexing (TDM) technologies like T-Carrier (T1, T3) and SONET. These technologies divide a fixed line speed into smaller channels. A T1 line has 24 channels of 64 Kbps, suitable for carrying one phone conversation per channel. For data, all channels combine into a single pipe.
Achieving less than 1.5 Mbps is straightforward by using fewer channels or limiting data speed. While once cost-effective, 1.5 Mbps is now considered entry-level broadband. To exceed this, multiple T1 lines can be bonded to function as a single line, offering bandwidth from 3 to 12 Mbps. However, each additional line requires physical installation and potential CPE replacement by the carrier.
T3 Lines or DS3
T3 and DS3, while technically distinct, both operate at 45 Mbps. Delivered via coaxial cables to a router card, the DS3 signal is often multiplexed over SONET fiber. These services are essentially high-capacity versions of T1 lines.
SONET Fiber Optic
SONET (Synchronous Optical NETwork) standards provide a straightforward upgrade path from T-carrier. While compatible with 64 Kbps channels for telephone trunking, SONET offers a substantial data pipe.
Each SONET variant has a specific interface, requiring dedicated cards or routers for different speeds (e.g., OC-3 at 155 Mbps, OC-12 at 622 Mbps). Cost savings are sometimes possible with rate-limited bandwidth options.
Ethernet over Copper
Ethernet over Copper (EoC) utilizes the same twisted pair wiring as T1 but achieves higher speeds over shorter distances. Bandwidth typically ranges from 3 Mbps to 10-20 Mbps, with potential for 50-100 Mbps in specific situations.
Unlike TDM, Ethernet uses packets, with bandwidth determined by packets per second. Achievable bandwidth depends on carrier capabilities and CPE port speed, often a managed edge router.
Connecting to the router’s Ethernet port is done with a standard RJ-45 cable. Port speeds adhere to Ethernet standards (10 Mbps, 100 Mbps). Bandwidth adjustments are easily made through the carrier or, in some cases, a web interface.
Ethernet over Fiber
Ethernet over Fiber (EoF) mirrors Ethernet over Copper but operates entirely on fiber optic cabling, offering almost limitless speed potential. Access ports can be copper or fiber.
Fiber has become increasingly cost-effective, making Ethernet over Fiber viable even at 10 Mbps. With a 1000 Mbps port, future expansion needs are typically covered. Upgrades are often only necessary when exceeding Gigabit Ethernet bandwidth, moving to 10 GigE and potentially 100 GigE ports.
Cost Implications
While TDM services are established, they represent older technology. Modern carrier networks are built around Ethernet for scalability and compatibility. Ethernet often presents cost advantages over TDM in both copper and fiber formats, potentially saving 50% or more.
If your connectivity is bandwidth-constrained, an upgrade is worth considering. Obtain competitive quotes for copper and fiber optic services, ensuring the chosen port speed accommodates current and future requirements.
