Transitioning to the all-optical mesh net

The Internet is changing the telecommunications industry. Internet applications such as e-commerce, streaming audio and video, and Internet-based software distribution are eating up bandwidth on fiber-optic networks. Data traffic accounts for more than half of the traffic on the public network and is expected to equal 26 times the amount of voice traffic by the end of 2003.

Traditional point-to-point networks do not offer the scalability, low cost per bit, provisioning speed or operational simplicity required to carry next-generation Internet traffic. Network operators that intend to compete in the new Internet-driven economy must take an aggressive approach to expanding their networks by building an optical infrastructure that will support the growth of Internet traffic.

All-optical mesh networks are the most promising solution to the coming IP bandwidth boom. They enable network operators to scale their networks to accommodate terabit capacity for growth, support point-and-click service provisioning, complement existing and next-generation IP routers, and reduce costs through the decrease of electronics at regeneration and hub locations.

Today's ring-based SONET architectures are sufficient for carrying voice traffic but do not have the flexibility or bandwidth efficiency required to carry the amount of Internet traffic expected in the future. The ring-based infrastructure is essentially a network of point-to-point pipes that requires extensive use of redundant equipment to transport data through the net. In addition, these networks require that at least 50% of fiber capacity be available at any given time for restoration and protection. This is an expensive and inefficient way to transport Internet traffic.

To meet the exploding demand for IP bandwidth, networks must be configured in an all-optical mesh architecture. This topology complements the multipoint-to-multipoint nature of Internet traffic. Mesh networks also reduce the amount of equipment needed to transport traffic while increasing network transmission capacity.

The mesh may be organized into many logical architectures, permitting flexible configurations that support various traffic and protection requirements across large nets. Multiple routes exist between each network intersection, so traffic can easily be rerouted to an alternate path in the event of a fault or fiber cut. Network operators can provide protected services for mission-critical, time-sensitive applications as well as unprotected services for Web browsing and other business applications.

All-optical mesh architectures further simplify networks by eliminating electronics from the core net. With ultra-long-reach optical transport, electronic regeneration is eliminated for up to several thousand kilometers, which translates into a five- to eight-fold reduction in the number of electrical regenerator sites in a long-distance net. In addition, optical switches and optical add-drop multiplexers can route wavelengths directly through the network, eliminating overlay of electrical switches in the core network locations where multiple fibers intersect or at drop sites. The combined reduction of network elements and electronics results in higher reliability.

When mesh networks are combined with integrated network management systems, the benefits increase dramatically. In traditional optical nets, a "truck roll" is required when additional capacity is needed to deploy regenerators at each regenerator site along that circuit. With the all-optical mesh network, new traffic routes can be provisioned remotely using network management software. Traffic can be established on new routes by installing a transmitter-receiver pair at the beginning and endpoint of the desired transmission path without any modification to the equipment along the route. This enables service providers to provision services in a matter of minutes, so they can turn up new IP services months before competing service providers can do the same on traditional networks.

All-optical mesh networks provide ultra- long-reach optical transmission, all-optical switching and ultra high capacity, key requirements of the next-generation Internet. Service providers that adopt and deploy an all-optical mesh network architecture will accommodate the growth of bandwidth demand, quickly provision customer circuits and operate more efficient networks. This will let them compete in the Internet-driven economy. More important, these providers will offer new IP applications and differentiated IP services such as high-bandwidth streaming media and Internet content distribution.

Jha, vice president of marketing at Corvis, can be reached at sjha@corvis.com.

Calient demonstrates compact, high-volume all-optical gear
The Edge, 06/06/00.

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