Passive Optical LAN (POL) is to the traditional Ethernet LAN what fiber-to-the-home is to traditional copper telephone lines. POL brings the power of fiber optic broadband technology to enterprises, university campuses, hospitals, hotels or anywhere else that needs a Local Area Network.
POL uses fiber-optic cable instead of copper and the Gigabit Passive Optical Network (GPON) transmission technology to transmit Ethernet frames. GPON is used to deliver commercial and mission-critical broadband services to millions of users worldwide.
However, Ethernet LAN does have one thing going for it: familiarity. Ethernet LAN is a 30-year old technology. It is tried and trusted and, by and large, does the job it’s meant to do.
But bandwidth needs in the office are growing as rapidly as at home. Perhaps more so. Ethernet LANs are reaching their capacity limitations and many enterprises are considering how their LANs will cope 5, 10, 20 years from now. Many are also looking to their IT managers to deliver cost savings from their local area networks and services.
Is Passive Optical LAN right for your business?
Their first point is about cable reach. Ethernet running on CAT-5/6 cable can travel only 90 meters before needing to be boosted. In contrast, POL signals can run for 30 kilometers. The benefit here is far fewer server rooms and lower power consumption. By extension, POL can be run on a centralized architecture – a rarity in Ethernet LANs larger than a few hundred end-points.
Their second point is about upgrades. While new standards deliver Gigabit speeds on the latest copper cables, the installation rules for new cabling to support these speeds make it an expensive exercise to upgrade. All for a couple of Gbps. Even vanilla POL starts at this speed and upgrade paths already exist to 10 Gbps and 40 Gbps - without needing to upgrade the cabling.
An area where Gartner advises caution is in calculating CAPEX and OPEX savings. POL requires less active equipment than Ethernet and cabling is easier to install, which translates into real estate, power and other savings. POL uses ‘statistical multiplexing’ to share bandwidth between users in a dynamic way and optimize the network performance. This concept needs to be understood when designing a POL but the bottom line is that there is a trade-off between cost and bandwidth per end-point. A large number of ports at the optical splitter will reduce the cost but may not provide sufficient bandwidth performance. Enterprises need to carefully consider their bandwidth objectives now and in the future when designing the LAN.
Last, but by no means least, is the familiarity aspect that I mentioned earlier. There is a large pool of talent with Ethernet LAN experience as well as an abundance of equipment providers. For most IT managers and support staff, POL installation and operation must be learned and there are fewer experienced POL providers to guide them. In telecoms networks, fiber is a no-brainer in greenfield deployments – it’s the only future-proof solution. The same argument can apply to a greenfield LAN deployment for exactly the same reasons.
The difficulty, therefore, is to do with LAN upgrades. While POL provides a number of significant advantages over Ethernet, businesses need to consider the above points to determine when the time is right to make the jump to fiber.
Interested? Be sure to download our white paper on “Addressing issues in the Local Area Network”.
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