Metro Ethernet is a subset of the MAN or Metropolitan Area Network. Metro networks sprung up to address the needs of local businesses who didn’t necessarily need connections to other cities and states. What they really need is a way to connect from their headquarters location to their remotely located data center or backup data center miles away. Other connections are needed for branch offices and other operational locations. This need for high performance, but local, network connections led to the rise of MAN operators. Like telcos or ISPs, they provide a set of services. In this case, it is most often access to a fiber optic ring that encircles the city and includes key suburbs, office and industrial parks. Last mile connections are provided from each business subscriber to the fiber ring. These can be fiber optic links or twisted pair copper connections depending on the bandwidth needed.
Most Metro networks were constructed using dual SONET rings with a working ring and a protection ring carrying traffic in opposite directions. Standard SONET ring protection offers an automatic failover within 50 mSec if the main ring fails for any reason. This self-healing capability improves the resiliency of SONET fiber optic networks to survive equipment failures and severed lines called “backhoe fade.”
SONET services include OC3, OC12 and OC48 telecom services. DS3 is also often available multiplexed on OC3 services. One issue with SONET is that the service levels aren’t very granular. There a big step, for instance, between OC3 at 155 Mbps and OC12 and 622 Mbps.
Metro Ethernet, also called Carrier Ethernet, addresses many of the limitations of legacy SONET services. Metro E may be provided as a service on SONET networks called Ethernet over SONET. This way the underlying network can be kept in place avoiding large construction costs. Some newer metropolitan networks are IP based to begin with. They offer Ethernet services by default.
One issue is ease of interfacing with the MAN. Ethernet is the standard protocol of company LANs. With an Ethernet connection to the MAN, you simply plug an Ethernet patch cord, fiber or copper, between your network edge router and the carrier’s demarcation connection. SONET requires a special interface card to do the protocol conversion between Ethernet, a network protocol, and SONET, a telecommunications protocol. SONET interfaces are unique OC3, OC12, OC48 and so on. Ethernet interfaces are ports with maximum speeds. A typical Ethernet port is 100 Mbps, 1000 Mbps or 10 Gbps. These support any network speed up to the maximum the installed port can handle. This make it easy for service providers to offer an almost infinite selection of bandwidths to their customers.
Since everything stays in the Ethernet protocol end to end, Metro E can be used to bridge multiple company LANs in the metro area. This is called Ethernet LAN service or E-LAN. You can also get point to point private line connections called Ethernet Line service or E-Line.
Metro E also addresses another limitation of SONET, which is historically high costs. Ethernet services of similar bandwidth are often half the price of their SONET equivalent. Extensive scalability also means that companies can select a bandwidth level closer to what they actually need instead of being cramped for speed or having to order way more than can be practically put to use.
How can you be sure that you are getting the best Metro Ethernet or even SONET MAN service prices? The best way is to work through a bandwidth broker that represents dozens of top tier service providers. Not only do you save time with one-stop shopping, but it is likely that you’ll get quotes from competitive carriers that you may not even be aware of.
Are you currently using metropolitan area network services or have a new requirement for metro bandwidth? If so, get prices and availability of Metro E and SONET network services from providers that serve your business locations.
Note: Photograph of Pittsburgh skyline part of a panorama courtesy of Wikimedia Commons.
