Optical transmission innovations underpin service growth

Michael Kennedy, Network Strategy PartnersOptical transmission innovations are tightly linked to the emergence and rapid growth of Internet video, cloud-centric services, 4G mobile, and financial trading networks. Advances in video technology, server and storage virtualization, flow-based routing, and wireless technology combined with innovative new business models spawned these new services. However, the high capacity, flexibility and declining unit costs of optical transmission systems are essential to transforming these service concepts into commercially successful offerings.

Performance, cost, quality, flexibility and operational hurdles must be overcome to achieve large-scale commercial success for the new services.  Internet video, cloud-centric services and 4G mobile broadband all require substantially more bandwidth than legacy services. The FCC's National Broadband Plan, for example, estimates that a YouTube streamed video download requires 300 Kbps versus 3 Mbps for a Standard Definition streamed video classroom lecture. Current implementations of 3D video require 32 Mbps of download speed. 3G broadband data rates, furthermore, are below 1 Mbps while multi-channel 4G to be introduced next year will have a data rate in excess of 100 Mbps. While the new services require a lot more bandwidth service revenue does not scale with bandwidth. For example, a text message produces $20 per kilobyte of data while a mobile video call produces $0.003 cents per kilobyte of video content. New optical transmission systems must have drastically reduced unit costs ($/bit) for the new services to be commercially viable.

Service protection and recovery schemes must be flexible and robust across transport, switching and routing network functions.

Network availability and quality of experience expectations for the new services are high especially as compared to Internet access services of the recent past. Service protection and recovery schemes must be flexible and robust across transport, switching and routing network functions. Finally, the need to minimize costs and reduce time-to-market requires that network operations, provisioning and service monitoring be automated across all network elements.

GMPLS (Generalized Multi-Protocol Label Switching) differs from MPLS as it supports multiple types of switching.  In particular, GMPLS offers support for TDM, wavelength and fiber switching.  It is used to reduce operations expense and service provisioning times by combining operational control of transport and optical elements in a single software solution. HEAnet-Ireland's National Education and Research Network in partnership with Juniper Networks (NYSE: JNPR) and ADVA (XETRA: ADV.DE), for example, have demonstrated a control plane that enables the initiating router to discover, reserve and then build an optical circuit across the optical network without any user intervention beyond the original user commands on the initiating router. GMPLS also enables protection and recovery schemes that go well beyond schemes such as SONET/SDH counter-rotating rings and MPLS Fast ReRoute. GMPLS also can be used to invoke entirely different network topologies for the peak period of residential demand versus the business day.

Optical port speeds are increasing dramatically. 10 GE ports are being deployed widely now while 100 GE port shipments are just beginning. Having successfully ratified the 802.3ba 40Gbps and 100Gbps Ethernet standards, the IEEE 802.3 group has recently developed the Ethernet Bandwidth Assessment Ad Hoc to gauge what the next Ethernet speeds should be. Developments in advanced modulation formats and coherent receivers are important to building cost effective transmission systems at these higher speeds. They improve noise tolerance in receivers. This has many economic benefits through elimination of dispersion compensation, reduction in optical grid spacing, and increasing the distance between optical amplifiers. Ciena (Nasdaq: CIEN) claims leadership in this field through its acquisition of Nortel's optical assets.

P-OTS (Packet Optical Transport Systems) incorporates a number of technologies that combine electrical and optical switching capabilities. The incorporation of the full functionality of Carrier Ethernet into optical transponders represents an important integration of functions that reduces cost and improves network functionality. This is being extended to include centralized control of Layer 2 Ethernet via protocols such as MPLS-TE. Fujitsu advocated Ethernet Tag Switching for this purpose. OTN (Optical Transport Network) also supports flexible use of wavelengths and packet switching. This technology sometime referred to as digital wrapper technology supports the combination of SONET/SDH and Ethernet packets on the same wavelength. This provides an alternative to MPLS for multi-service transport and also can be used in router bypass strategies on core networks.

Today 250 ns can make the difference between winning and losing a trade.

Optical transmission systems with ultra low-latency are providing automated financial trading systems with a competitive advantage by reducing the time between the time a trading instruction is issued and when it is executed. Today 250 ns can make the difference between winning and losing a trade. Transmission system latency can be reduced by optimizing transponders, optical amplifiers, and dispersion compensation for reduced latency.

Emerging new services require very high capacity transport, network availability and end-to-end network flexibility and adaptability. Service provider business models, however, require solutions with dramatically reduced unit costs. The market's high competitive intensity also is driving competitors to reduce their prices. Fortunately the equipment market is in the midst of a cyclical upswing after several years of reduced demand and new demand is being created by the new services. This growth will help vendors make the necessary investments in new technology needed to sustain their businesses.

Michael Kennedy is a FierceTelecom columnist and is the co-founder and Managing Partner of Network Strategy Partners, LLC (NSP), management consultants to the networking industry. He can be reached at [email protected].