AON – Active Optical Network

Defination

AON is a point-to-point network structure (PTP), each subscriber has their own fibre optic line that is terminated on an optical concentrator. AON can be designed differently, depending on specifications. Usually Metro-Ethernet-Switches, IP-Edge routers or Multi-Service Access Nodes (MSANs) with optical Ethernet interfaces. The fibre optics can be terminated by an ONT too, but also by any Ethernet switch or IP router with an optical uplink interface. If the last mile to the subscriber is to be bridged using copper wire, DSLAMs or other MSANs are used. When MSANs are used, both copper and optical lines can be used for the last mile from the same access node.

AON’s Advantage

AON clearly has the edge because of its flexibility. Due to the static splitting factor and the interfaces on the OLT. AON technology is clearly better as regards the bandwidth per subscriber. The maximum bandwidth per subscriberis a lot higher. The flexibility to allocate different bandwidths to individual subscribers is also greater than when PON systems are used. Depending on the splitting factor, a PON connection via fiber optics supplies less bandwidth than a VDSL2 connection via copper wire. The PTP architecture is superior to the PONs PMP architecture. Just by converting boards, subscribers can obtain an upgrade, without the network architecture or the service of other subscribers having to be changed.

Active optical technology is more suitable for private network operators, that either lay their own fiber optic infrastructure, or use debundled fiber optic lines (Fiber Local Loops). AON is perfect for high-profi t end customer segments (such as for example business customers, multi-dwellings, universities, local authorities etc…), as in these cases flexibility, quality and security are demanded. And because of the way they are structured, PON networks struggle to fulfi l these requirements. As standardised ONTs are used, the commercial aspects of supplying households on a large scale should be weighed up too and can compete with PON systems. Nevertheless, as PON networks are on the increase, it is likely that some of the disadvantages of PON listed here will gradually be eliminated. However some of the inherent features of a PON will remain. But one thing is almost certain, the fibre optic based access network, and therefore end customer products too, will constantly be upgraded to handle more than 50 Mbps. The whole issue is set to stay an exciting one.

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