Companies that need bandwidth in the fractional Gigabit range have often relied on OC12 SONET fiber optic service. While it remains a solid high-speed choice, it’s worth considering 600 Mbps Ethernet as well. Comparing these two options might yield some surprising results.
OC-12 (622 Mbps) is the next tier up from OC-3 (155 Mbps) in the SONET optical carrier hierarchy. This service is widely available in Metropolitan Area Networks (MANs) and as a dedicated internet access connection for mid-sized internet service providers. Larger organizations, particularly those with thousands of on-site employees or a need for high-bandwidth applications like medical imaging or video production and distribution, also utilize OC12 bandwidth connections.
In the past, OC12 was considered a strong option for a carrier fiber optic core network. However, most regional and national carriers have since upgraded to OC-48 at 2.5 Gbps or OC-192 at 10 Gbps. Long-haul and undersea fiber lines are now operating at OC-768 (40 Gbps) and are rapidly moving towards 100 Gbps support.
OC12 is frequently deployed in a protected SONET ring topology, utilizing two counter-rotating fiber rings. If one ring experiences a failure, whether due to equipment malfunction or a cable break, the other ring takes over 100% of the traffic within 50 milliseconds.
It’s important to note that OC12 service typically doesn’t occupy an entire fiber strand. At 622 Mbps, OC12 utilizes only a fraction of the fiber’s available bandwidth. SONET’s design as a Time Division Multiplexed (TDM) system allows for easy addition or removal of common OC service levels like OC3 and OC12. In addition to the electrically multiplexed services on the fiber, each fiber can also be optically multiplexed into numerous wavelengths using Dense Wavelength Division Multiplexing (DWDM) equipment.
Carrier Ethernet over fiber relies on packet switching rather than time division multiplexing. Without TDM’s rigid synchronized channels, Ethernet offers superior scalability. You can opt for 600 Mbps Ethernet as a replacement for OC12 SONET or choose 500 Mbps if that meets your needs. More importantly, you can easily scale up to 700 Mbps, 800 Mbps, 900 Mbps, and 1 Gbps as your business requirements evolve.
With SONET, the service provider installs a managed router as Customer Premises Equipment (CPE), which includes an interface module specifically designed for your installed OC service level. While modules for OC3, OC12, and OC48 all plug into the same router port, they are not interchangeable. The interface must match the OC service level. This becomes crucial during service changes, as the provider will need to dispatch a technician to either swap interface modules or replace the CPE router entirely.
In contrast, with Carrier Ethernet, your service provider installs a managed router that supports a specific port speed. For Ethernet over Copper, this is usually 100 Mbps. For fiber, it’s typically 1 Gbps, but you can often obtain equipment rated for 10 Gbps if you anticipate upgrading in the future. With a 1 Gbps port, you can order any service level between 100 Mbps and 1 Gbps in 100 Mbps or smaller increments. No equipment changes are needed when adjusting service levels within that range. You simply contact your provider to request a bandwidth increase, which can be implemented within a few days or even hours.
Besides scalability, Ethernet often proves more cost-effective than SONET. In some cases, the cost difference is substantial, with Ethernet costing half as much as SONET for the same bandwidth. One potential drawback is that SONET has been around longer and is more widely available than Ethernet over Fiber. Nevertheless, competitive carriers have been expanding their IP networks aggressively, so fiber service may be closer than you think.
If you require fractional Gigabit bandwidth services, it’s worthwhile to compare 600 Mbps Ethernet to OC12 SONET in terms of cost and availability. This recommendation also applies to other service levels, ranging from T1 copper bandwidth up to 10 Gbps and beyond.
