Next-generation optical access


Metro access

Businesses want high-quality video-conferencing, multi-site connectivity, teleworking and extranets, while home users want high-speed Internet and video-on-demand. The result: growing demand for optical metro access.

By Omri Guelfand, Senior Product Manager Iamba Networks

Both new applications and increased use of existing applications are driving demand for bandwidth and connectivity. Over the next five years Europe should see a compound annual growth rate (CAGR) of 40% in bandwidth demand for both business and residential users and a CAGR of over 60% in the number of broadband connections. Increased demand is creating new revenue opportunities for forward-looking carriers.

Network evolution
The telecoms industry has been successful in increasing capacity of local area networks (LANs) and enterprise networks by introducing optical interfaces, superior framing schemes and Gigabit switching. Long-haul and metropolitan area networks show similar advances, through optical interfaces, DWDM and ultimately all-optical switching.

But access networks have not experienced similar breakthroughs. They still rely mostly on copper to deliver voice, data and TDM services and have thus become the bottleneck in the network, inhibiting potential revenue streams.

xDSL technologies support data rates of a few Mbit/s, offer limited support for broadband applications and services as well as limited geographical reach, so they do not provide a viable long-term solution.

In contrast, current optical access systems are derived from metro-based SDH technology and use circuit-based transport, are expensive to purchase and operate, and are not optimised for transport of data or new services. Also, increasing their capacity will in most cases require a comprehensive network upgrade. A new access network is therefore called for.

Defining next-generation optical access
In next-generation optical access (NGOA) the network is a true multi-service environment, delivering optimally packaged services to end-users over fibre, supporting point-to-point, point-to-multipoint and access-ring topologies. It supports co-existence and integrated management of multiple services, while maintaining quality of service (QoS) and guaranteed performance levels.

Services can be transported either in their native form or re-packaged for optimal transmission, e.g. video re-packaged over IP, and TDM traffic circuit emulated over ATM. Based on a future-proof optical infrastructure, NGOA equipment enables multi-point connectivity, video, VPN, remote storage connectivity, QoS-enabled IP services and more.

By using modular equipment NGOA solutions can create a "pay-as-you-grow" network evolution and enable a controlled system deployment and introduction of services, processing and harmonising different protocols in a carrier's network (e.g. ATM, TDM, Ethernet and IP/MPLS) to streamline multiple services. Also, multi-protocol handling supports interworking with both legacy and next-generation network (NGN) metro and core networks.

So, as services ultimately shape the network, NGOA solutions must offer the flexibility that is essential for the carrier's network evolution.

Next-generation optical access in action
Figure 1 represents a next-generation optical access case study for delivering and managing Ethernet and IP connectivity to businesses.

Businesses enjoy a robust and uniform service while the carrier makes optimal use of its optical fibre infrastructure by using multiple network topologies and protocols. In this case, Ethernet VLANs are used to create user domains for multi-site connectivity. The use of traffic management mechanisms guarantees full separation between users and assures desired service levels. Topologies used include:

  • Gigabit Ethernet links to provide high-capacity (1Gbit/s) point-to-point fibre connectivity;
  • Gigabit Ethernet rings to connect to Ethernet switches for feeding small offices in a MBU environment at rates of up to 100Mbit/s;
  • Ethernet frames mapped over passive optical networks (PONs) to add point-to-multipoint connectivity connecting up to 32 businesses;
  • SDH interfaces running ATM or PoS at rates of 155Mbit/s to 2.5Gbit/s enable long-distance connectivity to remote locations, leveraging existing SDH networks.

TDM services are provided in a fully standard way running over SDH and PON to provide leased lines and PBX connectivity. IP handling allows additional connectivity options, VPN services and premium Internet access. This network easily scales to deliver residential services - VLANs can be used to broadcast video while IP handling effectively supports Internet access and content delivery services.

The introduction of new services forms the business case for next-generation optical access. Carriers can use NGOA to make the best of their fibre infrastructure by offering a wide range of services at low cost.

NGOA enables the convergence of optical networking, supporting multiple topologies, protocol processing and the ability to provide next-generation services on top of a scalable and future-proof infrastructure.

Carriers can harness the optical access network to generate extra revenue, while preserving current revenue streams and leveraging their existing networks.

Omri Guelfand has over 9 years experience in the telecoms and hi-tech industry, with expertise in networking and IP technologies. Prior to Iamba, he was a Product Manager at Nortel Networks.
Israel's iamba Networks says its iAxelent is the first NGOA platform available to carriers. E-mail:

More in Earnings Statements