The optically enabled data center is the essential next step as advances in networking and optical technology force managers to rethink how data centers are connected to the world and how to best serve widespread clients.

On the supply side, an optical revolution has swept across the metropolitan area network (MAN) and wide area network (WAN). Dense wavelength division multiplexing (DWDM) technology enables carriers to build optical network backbones wherein a single fiber can transmit more than 1 trillion bits of information each second. And with optical capacity doubling every nine months — far surpassing advances in central processing unit (CPU) processing power — it now makes sense to invest in increased bandwidth to save CPU processing power.

While the optical revolution has produced abundant inexpensive WAN bandwidth, it also has brought us cost-effective optical technology that can be deployed outside the network core to „optically enable” data centers and servers.

On the demand side, the Internet has changed fundamentally network traffic patterns, giving birth to entirely new business models and players, such as application service providers (ASPs) and storage service providers (SSPs). Bandwidth-intensive hosted content, applications and storage have become increasingly critical in today’s market, and the data center — located in a different building or even a different country from the clients –has emerged as the front line for providing these services.

Factors adding to the bandwidth crunch facing data centers include widespread deployment of DSL, fixed wireless, and cable modem services that give end users faster access than ever.

Additionally, enterprises have consolidated their data centers, so nearly all data traffic from enterprise clients reaches the data center across the MAN/WAN.

Also, interconnecting storage area networks (SANs) across the MAN/WAN through new technologies like Fiber Channel over IP (FCIP) will double requirements for WAN access. As a result, traditional data center connectivity speeds of 45mbps (DS3) or 155mbps (OC3) no longer can meet these skyrocketing traffic requirements.

The way to eliminate the resulting bottlenecks is to optically enable the data center, leveraging optical technology to extend high bandwidth services to the data center and within the data center.

Two options for bringing optical-speed connectivity to the data center are packet over SONET (PoS) and gigabit Ethernet. Each provides adequate bandwidth for many applications, and they should be considered complementary rather than competitive. Data centers may need to support SONET/SDH and gigabit Ethernet links.

Storage traffic plays a key role in driving optics into the data center, as many data centers receive as much traffic from storage-to-storage transactions as they do from server to client.

Storage traffic, increasingly carried over SANs rather than over an internal SCSI bus, is an additional traffic load not normally considered in defining MAN/WAN access requirements.

Once a data center has embraced the SAN philosophy, extending the SAN beyond the data center becomes essential. Only then can storage services such as data backup and disaster recovery be offered over significant geographic distances.

Optical connectivity is essential to deliver the high speed and low latency storage networking requires.

Optically enabling the data center can be done incrementally, beginning with an optical edge router device and gradually extending throughout the data center. The optical edge router becomes the meeting point among the LAN, SAN and MAN/WAN. From the optical edge router, IP traffic is sent over the backbone MAN/WAN. Within the router, SAN traffic is mapped to and from IP addresses and formats via FCIP.

An optical router at the edge between the data center and the optical backbone provides more than high-speed connectivity. It also allows significant simplification in the internal data center network and MAN/WAN, with attendant reductions in cost.

Typical access networks involve multiple layers of carrier equipment including ATM switches, routers, concentrators and SONET add/drop multiplexers.

Customers increasingly demand bandwidth-intensive media services. Servers supporting rich media experiences, and a range of specialty servers potentially can fill very high bandwidth pipes. Given that gigabit and higher server speeds may represent higher bandwidth than current WAN access for an entire data center, it may be time to deploy optics all the way to the server.

Direct optical connectivity between servers and backbone network routers offers a way for data centers to support the traffic demands of the future.

Today’s data centers are straining to keep up with client demands that will grow by orders of magnitude. Now, for the first time, deploying an optically enabled data center offers a solution.

Rob Preece is senior product manager with Lucent Technologies Inc. (www.lucent.com). He can be reached at robpreece@lucent.com.