INCREASING BANDWIDTH: YOUR OPTIONS

Today’s network manager has to decide how much data to store on the cloud and how much they need to keep in house. They usually feel more secure when their mission-critical data is kept under their own control. The result tends to be a combination of storing data locally, on the cloud, and at a secondary, geographically separated site. This prompts another issue when the need for bandwidth increases. Accommodating growing data needs to be balanced with maintaining low running costs.

Increasing the capacity in an existing network depends on what is already installed and whether access to a dark fibre exists. If there is no dark fibre, then it’s likely that a provider is leasing service. Monthly costs can soon spiral out of control and even lower speed of 1Gbps and 2.5Gbps can soon spiral out of control. So if there is no dark fibre between the sites and multiple data and storage protocols need to be simultaneously transported and/or replicated, it could be worth gaining access to a dark fibre network.

If fiber is available, then there are multiple ways of transporting data over that network. The common approaches being ELWL circuits (individual extra-long wavelength circuits), traditional transponder based C/DWDM (coarse and dense wavelength division multiplexing) platforms or embedded C/DWDM platforms. A pre-requisite to all of these approaches is access to a dark fiber network (either owned or leased.) The downside: higher cost. If there is access to a dark fibre network, a maximum number of services should be carried over it. A motorway is never restricted to a single carriageway when it has the capacity to carry many parallel types of traffic, right?

With an ELWL circuit each circuit requires access to its own dark fiber, and the monthly rental costs for this approach can soon run out of control.By changing the ELWL transceiver to a DWDM transceiver, the distance is increased form 25km (usually the limit on an ELWL transceiver) to 70km. The connecting multiple DWDM transceivers can now be transported simultaneously over a dark through a focal multiplexer unit or multiple traffic channels with no impact on the monthly rental costs. Up to 80 channels of 1/10Gigabit Ethernet and or 4/8/16GFC can be transported simultaneously over the same dark fiber previously used to transport just one ELWL service.

With a transponder based DWDM platform each individual storage (SAN) or data (IP) service is transported over an individual DWDM wavelength. This time however, the transponder converts the short distance output signal from the SAN and IP switches in to a DWDM signal. This is the job of the transponder which usually takes the form of a vertical plug-in card to a chassis based system. When new channels are required, new transponders and the corresponding short range and DWDM transceivers can be purchased per channel. But, again, this gets expensive. Instead, a much simpler approach is to upgrade with new channels using the same approach as previously where new channels are added simply by connecting a new DWDM transceiver in to the SAN or IP switch itself and connecting it to the DWDM multiplexer which is already in place as part of the installed DWDM system.

By replacing ELWL and transponder-based systems with a more cost effective and simple plug-in embedded DWDM approach, there are many desirable side effects. Monthly rental and maintenance opex is kept low, footprint is low and so too are unwanted emissions. Resulting in a network that can be upgraded with up to 80 channels over the same dark fiber with no power requirements – the ultimate green data center.