Optical networks get smart
americasnetwork.com
Startups mesh around with existing optical models so carriers can provision service more reliably and cost-effectively.
By Annie Lindstrom
At Supercomm'98, optical network vendors boasted about the brawn of their equipment. This year, they'll be touting brainy gear and broadened product portfolios.
This new equipment comes from the wealth of wavelengths that dense wavelength division multiplexing (DWDM) systems can produce on a single fiber in long-haul and short-haul optical networks. Such innovation has created — or according to some, is poised to create — a ‘spaghetti factory' effect.
The burning issue is not how many wavelengths can be squeezed onto a fiber; rather, it's how carriers can provision reliable bandwidth or provide services using those wavelengths.
Since June 1998, several startup vendors that claim to have anticipated this glut-rut have unveiled solutions that add intelligence to the equipment equation. Just how many of those newcomers' names will bask beneath the booth lights at Supercomm'99 remains to be seen. It's a safe bet that many of them could be snatched up by other vendors before the doors to the Georgia World Congress Center swing open for the last Supercomm of the century.
Ciena (Linthicum, Md.) was one of the first to gobble up an intelligent optical networking newcomer with its recent purchase of Lightera Networks (Cupertino, Calif.), maker of the CoreDirector intelligent optical core switch. The DWDM manufacturer, which itself was almost purchased last summer by Tellabs (Lisle, Ill.), also acquired Omnia Communications Inc. (Marlborough, Mass.), maker of the AXR-500 multiservice distribution switch. Both products will make their debut as part of Ciena's LightWorks platform at Supercomm'99.
Ciena's MultiWave line of DWDM systems provides raw capacity on fiber. The CoreDirector delivers capacity at different locations when and where it is required with different survivability and protection options; and the AXR 500 switch transforms raw capacity into services such as T-1 (1.5 Mbps), transparent local area network (LAN) or Internet access services, says Denny Bilter, director of marketing at Ciena.
The new elements of the LightWorks platform take the place of existing network elements, Bilter says. The AXR 500 provides the functionality of an access router, combined with synchronous optical network (Sonet) add/drop multiplexer (ADM) and integrated narrowband cross-connect system (DACS) functions. The Core Director replaces the optical/electrical cross-connect (OEXC), the broadband digital cross-connect (BDCS) and larger ADMs.
"Even though we are introducing two new products into the network, we are reducing the number of legacy network elements that are needed," Bilter notes.
"If carriers continued to build on the path that they were building on, they would end up with an OEXC, a BDCS and ADMs to create a transport network. Instead they can get all that functionality in the Lightera product as well as other features that we provide through the intelligence we embed in each switch," says Charles Chi, vice president and cofounder of Lightera.
The Core Director, aimed at interexchange carriers, is slated for its first customer shipment in the third quarter and general availability in fourth quarter, Chi says. The new products will display the Ciena brand name (the Lightera name is being retired). The AXR 500 will be commercially available in June.
Topology wars
While ring-based architecture has been the mainstay of existing optical network topologies for years, a change is coming. The pace and fury of competition is opening the door to a new alternative: mesh networks. Many startup companies are out to prove that software, and the intelligence it provides, can give carriers a more cost-efficient way to route and protect traffic than hardware-based ring infrastructures can. Lightera, however, is neutral at this point.
"If they want to do rings, do rings. If they want to do mesh networks, do them. It's important for us to support ring topologies because carriers want to transition technology into a network," Chi says. "The last thing they want to do is a flash cut. We give carriers the choice so they can do mesh or ring architectures concurrently."
On the other side of the fence is Monterey Networks Inc. (Richardson, Texas). Officials at Monterey believe strongly that rings are a waste of perfectly good bandwidth and that mesh networks are the most cost-effective path to the future, according to Joe Bass, president and CEO of Monterey. The company's Wavelength Router is designed to be situated in a backbone network of companies such as the following:
• Long-haul carriers and Internet service providers (ISPs) that want to interconnect Internet protocol (IP) routers and switches across a ‘ringless' optical core; and
• Companies that want to make the most of their fiber infrastructures.
"Because mesh networks provide carriers with more than one way to get to any point on the network, they need only 30%, rather than 100% extra capacity, to provide survivability," Bass says.
According to Monterey, that restoration can be performed on a nationwide mesh network just as quickly as it can be done on Sonet. Using the router's Wavelength Routing Protocol (WaRP), Bass claims Monterey has been able to restore as many as 600 OC-48 (2.5 Gbps) links simultaneously on a "realistic mesh-based national core network," with resting restoration times ranging from 21 to 48 milliseconds (ms) and with 30% to 60% restoration-bandwidth savings over comparable ring topologies.
Monterey's WaveLength Router is not an optical/electrical cross-connect, Bass notes; rather, it's a ‘network-aware' router that understands the resources available in a network to which it is connected (Figure 1). Each WaveLength Router communicates with its counterparts on the network to provision circuits or to re-route traffic in the event of an outage, he explains.
Devices are attached at ‘optical junctions' to multiple DWDM terminals and/or to one or more IP routers, ATM switches, and Sonet ADMs and cross-connects.These groom traffic from DS1 to DS3 (45 Mbps), and OC-3 (155 Mbps) and OC-12 (622 Mbps) flows up to OC-48 and OC-192 (10 Gbps) connections that map to wavelengths. The WaveLength Routers then route the traffic hop-by-hop to its destinations. All traffic is managed at the OC-48 and OC-192 level.
"We think OC-48 is the right lowest common denominator," Bass says. Additional granular management is completed locally by the equipment to which traffic is handed, he explains.
As metro rings are developed, carriers will be able to use the WaveLength Router to transport their traffic across long-haul networks. According to Monterey, the router will enable bandwidth brokers to create wholesale, retail and on-the-spot markets for managed, restorable OC-48/192 bandwidth. Large ISPs will be able to use the device to aggregate routers at IP points of presence (POPs).
Monterey will unveil the WaveLength Router at Supercomm'99; however, commercial availability is not expected until early in 2000.
Connect the dots
Five-month-old Sycamore Networks Inc. (Chelmsford, Mass.) is making equipment that can connect to the switch/routers made by Lightera and Monterey as the need for those types of devices proliferates. In the meantime, the company's first product, the SN 6000 Optical Transport Node, is solving immediate problems. The device enables carriers to introduce OC-48 wavelengths in existing OC-192 DWDM networks.
"All [of] the big carriers have OC-192 systems deployed for DS0-centric services; but now they have to offer high speed OC-48 links to interconnect routers and other private line-type services," says Jeff Kiel, marketing director at Sycamore Networks. "The SN 6000 allows them to put OC-48 services over lightpaths available on existing infrastructures."
Sycamore's first customer is Williams Communications (Tulsa, Okla.), which is using the gear in its Multi-Service Network — spanning 17,000 route miles of lit fiber. Williams' network includes OC-192 gear from Nortel Networks (Brampton, Ont.) and GX 550 ATM switches (featuring OC-48 optical interfaces) from Ascend Communications (Alameda, Calif.). Williams uses Sycamore's products to interconnect ISPs across its backbone and scale its network in the optical domain, rather than the Sonet domain, to accommodate future growth, according to Kiel.
"What we do for Williams is coexist in the optical domain with the existing Sonet system," Kiel says. "When the OC-192 waves travel down the fiber, we take OC-48 waves carrying data services and inject them between the OC-192 waves carrying DS0 services using the available optical spectrum inside the deployed network."
For carriers, "this reduces service provisioning time to six days instead of six months," Kiel adds. "You just slide in a line card and connect the customer."
Sycamore's market directive is to help carriers build their intelligent optical networks gradually and "meet the service needs of carriers today while introducing our product in a low-cost, nondisruptive manner," Kiel says.
Sycamore also has rolled out SN 8000 and 8400 intelligent optical ADMs (OADMs). The SN 8000/8400s deliver networked service over light paths in access, interoffice and regional environments, and provide transport, switching and routing on a single platform. The first release of the product supports up to 44 wavelengths at distances of as far as 500 km without amplification, Kiel says. Because the gear incorporates integrated Sonet/synchronous digital hierarchy (SDH) features, it can be introduced easily into existing network infrastructures, he adds.
Short-haul sighted
As we have reported frequently, DWDM isn't just for long-haul networks any more. Although not much equipment has been deployed, all of the major vendors have introduced plans and, in some cases, products designed specifically for the metropolitan area (Figure 2). Accordingly, expect more metro-focused DWDM equipment from established vendors and still more from startups at this year's Supercomm.
"Now that we have got another piece of equipment that goes out into the access area, you are going to see more people interested in looking at our metro products, because now we can take the raw bandwidth our DWDM systems provide and deliver services from it," Ciena's Bilter says. "The acquisition of Omnia positions us much better to provide solutions and stimulate the metro market."
Optical Networks (San Jose, Calif.) has set afloat its ideas of how optical networking ought to be done in the metro area and, in Atlanta, will show off the equipment portfolio that supports those ideas, according to Rohit Sharma, vice president and chief architect at Optical Networks.
"The requirements of actual end users are very different from what DWDM alone can provide," Sharma says.
Scalability is of particular concern. "Why should Amazon.com have to pay for an OC-48 for 12 months when they just need it for three months of the year?" Sharma notes.
The Optical Networks product portfolio reportedly will enable carriers to provide customers with cost-efficient, protected bandwidth and services they need on a dynamically available basis. "The dynamic environment you are going to see in the metro world — that is driven by end users and their applications — is going to require a whole new set of software," Sharma says.
The portfolio includes the following products:
• The Optix operating system dynamically makes decisions about "who gets what," as far as bandwidth is concerned, Sharma explains.
• The OnLine optical transport platform provides carriers with low first-cost, scalable capacity, and dynamic bandwidth provisioning. It supports ring, mesh or point-to-point topologies; it also features built-in optical protection and initially will support 56 wavelengths.
• The Optical Link Management Protocol (OLMP) allows routers and switches to talk to the transport environment.
Optical Networks and other vendors are working with the Optical Internetworking Forum to develop a standard data-to-transport layer communications protocol. "We have mostly data routers, Cisco [Systems] and Juniper [Networks] boxes working as OC-12 and OC-48 packet-forwarding engines at the edge of the network. The network needs to know the needs of this layer," Sharma says. "Those routers are completely disconnected from what is going on in the transport layer and there is no way of signaling up or reading back any requirement that the data layer may have."
Test balloons
It's simply a matter of time before we'll see which of these newcomers will become subsidiaries of others and which will become tomorrow's optical powerhouses. In the meantime, everyone is sending up test balloons to see which carriers and which additional vendors are interested in which solutions. Sycamore got a ‘bite' from Williams, and Lightera is under Ciena's wing.
"The startups are creating systems that make it easy for competitive local exchange carriers and interexchange carriers to deliver services, not just bandwidth, to customers," says Michael Howard, CEO of Infonetics Research Inc. (San Jose, Calif.).
"You are going to hear a lot about mesh networks and dynamic bandwidth allocation," adds Mark Lutkowitz, president of Trans-Formation Inc. (Birmingham, Ala.). "But ... all the vendors are doing different things and all of their solutions are a little bit different. The startups may play in different portions of the network [and] provide different functionalities and implementations, but they are all playing in the same overall space of trying to deal with the problem of making things more efficient — getting things together, lowering costs and helping carriers become more competitive."
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