November 29, 2011

Tech Update: Packet Optical Networks

Today’s cable network operators are challenged by constant demands from customers for new services so, naturally, data and video requirements are growing rapidly. With the introduction of high definition (HD) and 3D TV, the network designs for carrying this traffic are under pressure. This situation creates an opportunity for new approaches using emerging technologies.

Video-distribution networks often have been router-based: The operator distributes the video traffic using a router network to devices at the edge of the network. This video traffic is forwarded as multicast traffic in the network, and all edge devices see the traffic. However, growing demand for such high-capacity services as HD and 3D TV have driven the need for better distribution technologies that can increase capacity while reducing costs and complexity.

One approach that has shown key benefits is to move video distribution into a packet-optical-transport network. Optical-transport networks are easier to manage than are router-based networks, requiring simpler management tools. Router networks need to meet other needs, and they typically are more complex and expensive to implement and manage, thus demanding the attention of senior technical resources.

The increasing availability of packet-optical-transport solutions combining Wave Division Multiplexing (WDM) transport and Layer 2 switching and aggregation creates a platform for a new approach for video distribution by cable operators. Packet-optical-based solutions rapidly have evolved to meet the needs of service providers migrating from SONET/SDH networks to packet-based Ethernet.

A packet-optical device supporting optical transport and Layer 2 switching features can use two standards — IGMPv3 and Source Specific Multicast — to listen to Layer 3 traffic flows, to decide what actions to take and to perform Layer 2 switch function for the broadcast traffic. This enables the traffic to be optimized as required, but it also provides low latency and jitter characteristics for this kind of a transport network. In addition, integrating these capabilities into the transport network without adding a separate layer provides operational simplicity and lower costs. upc cablecom, the largest broadband cable operator in Switzerland, has announced plans to use this capability on a new network serving at least 2.1 million households and approximately 240 smaller broadband cable operators.

“By delivering a highly simplified network operation, moving video distribution to the optical layer brings relief to the operators that are faced with the increasing risk of network complexities brought by high volume data transmission,” notes Charanya Balasubramanian, a research analyst at Frost & Sullivan.

Packet-optical-network solutions are evolving rapidly in response to industry demand driven by rapid increases in mobile traffic. These new solutions not only will meet those needs, but they also will enable new applications.

-Linda Faust, director/Product Marketing, Transmode