WAN Applications

Wide area networks encompass an enormous range of architectures. Here we'll consider just a few which are likely to be of special interest to cable operators. In particular, we'll focus, first, on specialized applications where multiple long distance data transport is required in a secure and fiber efficient manner. One example of such an applications is the centralization of VoD servers at a single location and the need to provide multiple GigE drops to various hub locations hundreds of miles away from the headend.

One cost effective solution for providing long haul transport of GigE, OC-3, OC-12 and OC-48 utilizes a DWDM transponder which accepts an optical input and places it in one of 40 DWDM wavelengths of a fiber. This Layer 1 optical signal can then be amplified using indoor as well as outdoor EDFAs to extend the reach of this WAN link. For extremely long distances exceeding 100 miles, dispersion compensators can be used to compensate for scattering effects of light as it travels over these longer distances within single mode fiber. This long reach DWDM transport solution is applicable for signals between 155 MHz to 2.5 GHz and is also suitable for Aurora's convergent digital return and Ethernet transport technologies.

A second example is based on two cities, 100 miles apart, that have several companies which would like to employ secure private links between the cities. Due to their demand for high security this precludes the use of typical Layer 2 and Layer 3 solutions because of the existence of a broad range of potential software attacks and possible user errors that, due to a single malicious or false command at a switch, could take down an entire network or, worse, compromise the security of a link without the operator's knowledge. One option would be to lease a dedicated fiber to a single customer; however, this generally greatly limits the return on investment of that fiber's construction and maintenance. Another option would be to use a DWDM solution to provide 40 DWDM wavelengths, multiplying the potential commercial services WAN revenue by a factor of 40.

Yet a third approach would be to use Aurora's NI3030E Network Management Units (installed in CH3000 Chassis) that utilize 16 TDM channels per wavelength to deliver a highly secure Layer 1 pipe between any two locations. In this last solution, up to 640 highly secure Layer 1 Fast Ethernet links can be created across just two fibers and can straddle hundred of miles. This simple "bookends" approach (employing NI3030Es in chassis located in each city), in fact, makes bulk transport of highly secure Layer 1 FastE pipes a most effective solution that would be difficult to match in capex or opex.

The advantage of all these solutions is that they are highly cost effective even at the outset of deployment, and capital expenses are recovered faster as more businesses sign up for this highly secure WAN transport solution. Wherever an operator needs to use fiber efficiently and possibly traverse long distances, Aurora provides a complete line of DWDM active and passive modules as well as optical amplifiers for both indoor and outdoor use.

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