The Big Promise Of Gig-E

By eweek  |  Posted 2001-09-10

The Big Promise Of Gig-E

Gigabit Ethernet. The very name rolls sweetly off the tongue, implying lightning speeds in a protocol as simple and familiar as the plug-and-play ports in the back of your laptop and printer. Its the hottest play in the metro area because it can carry heavy traffic from office to branch office and onto the public network - and do so at a tenth of the cost of the Synchronous Optical Network infrastructure traditionally used in metro rings. So its no wonder that while much of the technology and telecommunications sectors are weathering prolonged slumps, Gig-E is hot and threatening to streamroll other technologies.

"We never approach a customer these days that knows IP at all that doesnt ask for Gigabit Ethernet," said Martin Capurro, who heads Qwest Communications Internationals Dedicated Internet Access division.

Why? Because Gig-E promises to move Ethernet technology beyond the walls of the office to campus environments and across cities to deliver a cornucopia of services to the enterprise:

  • Bandwidth-on-demand, which lets I-managers throttle up the bandwidth for a few hours per week, and then ease it back down, so theyre only using - and paying for - what they need.
  • Quality of service, the ability to sort and prioritize traffic with Multilabel Packet Switching, so service providers can guarantee performance and charge extra for premium service.
  • Carrier-class reliability, resiliency and latency will be added, when a standard is hammered out delineating how to carry Ethernet frames over a resilient ring topography.

Despite the big promises, though, the availability of Gig-E and its even faster sibling - 10 Gigabit Ethernet - remains limited. And the broader question looms: Will it prove as robust and resilient across and beyond the metro area as it did in the University of New Hampshire labs, where vendors tested their products interoperability?

After all, that which is simple in the local office can grow exponentially complex when Ethernet tries to cross the metro area, its mesh-style architecture sprouting lines like a Rube Goldberg spaghetti machine.

"There are some gotchas that some Gigabit Ethernet people havent come clean about," said analyst Mark Main, of market research firm Ovum. For example, he said, an Ethernet mesh architecture gets more complicated with more connection points: Connecting three devices to each other requires three lines; four require six lines; five require 10 lines; six require 15 lines; and 20 require 190 lines. "When they scale up, it can get very difficult to manage. The jury is still out on whether they are as easy as they claim. You can get unforeseen things that dont show up in the lab," Main said.

At its core, Gigabit Ethernet is a set of rules dictating how traffic is to be carried in Ethernet frames at speeds of 1 gigabit per second. And now some companies have also begun rolling out 10 Gig-E, letting local packet-based networks scale from 10 megabits per second to 10 Gbps. Combined, Gig-E and 10 Gig-E offer the possibility of moving the familiar protocol past the metro and onto the long-haul network.

This week, 18 vendors are scheduled to demonstrate interoperability of 10-Gbps products at the NetWorld+Interop show in Atlanta in competition with Foundry Networks, which unveiled its 10-Gbps switch at the last N+I show in Las Vegas in May.

The competition for margins in one of the few growing network markets is fierce. During the second quarter, revenue from Layer 3 modular gigabit switchers rose 4 percent, and sales of ultra-high-end routers - which are capable of 10 Gbps and are rapidly becoming compatible with 10 Gig-E - rose 16 percent, to $286 million.

The overall metro network market for Gig-E, the Synchronous Optical Network and wavelength services is expected to grow from $6.3 billion last year to $17.2 billion in 2003.

Probe Research expects Intelligent Optical Networking, in which Gig-E plays a role, to grow seven times faster than SONET through 2005, when ION, at $38.2 billion in sales, will surpass SONET.

But that doesnt mean SONET is going away. The smart money says SONET - an expensive optical standard with the flexibility to transport many digital signals of different capacities from different vendors - will be very much alive for a long time.

Ethernet History

When Xerox researcher Bob Metcalfe coined the term "Ethernet" 30 years ago to describe a way to push e-mail from one device to a multitude of others across short distances, he had in mind 1 Mbps traveling perhaps a mile. But as modulators blinked the laser light faster and faster, as fiber became more perfectly cylindrical, as algorithms corrected errors in colliding packets and copper wire was fed steroids, the speeds hopped to 10 Mbps, then 100 Mbps and faster.

At those speeds, why not stretch the plug-and-play advantages of Ethernet beyond the local office, engineers pondered, connecting across campuses and metro areas?

The problem is that, with Ethernet, every device sees every frame or packet - so what the protocol gains in familiarity, it can lose in traffic congestion.

Gig-E, formalized as a standard in 1998, raises the minimum size of a frame from 64 bytes to 512 bytes, giving the transmitting device more time to receive a collision warning when traffic is congested. The maximum size is also increased, from 1,514 bytes to 9 kilobytes, improving the throughput time because the switch doesnt have to read as many headers.

Recent breakthroughs with Multiprotocol Label Switching bring discipline to traffic engineering on a Gig-E IP network by letting routers read just the first packet in a data stream, then slap a short label on that packet and all subsequent ones in the stream. The MPLS tag speeds up switching, determines the best route for the data stream and assigns it a grade of service. That MPLS-driven differentiated service excites the Gig-E crowd, because offering premium service guarantees over an inexpensive network promises real profits.

In addition, the Resilient Packet Ring Alliance is hammering out standards to carry Ethernet frames with the resiliency and low latency of SONET - a crucial threshold if the regional Bells are to embrace the protocol. But both MPLS and RPR are in development, and havent passed muster with the standards bodies. The Metro Ethernet Forum, a new alliance of 51 chipmakers, equipment vendors and service providers, had hoped the MPLS standard could be formalized by next spring, but officials said things are moving more slowly than expected.

Until standards are formally adopted, the future of the early Gig-E players is as elusive as, well, ether.

Hot Gig-E Products And Services

Those risks and uncertainties certainly havent stopped several new vendors and carriers from jumping into the Gig-E and 10 Gig-E markets, though, and they are confident their technologies can take Ethernet to the next level.

In May, Foundry "planted the flag" when it began selling 10-Gbps products, putting pressure on others in the marketplace to do the same, said Marshall Eisenberg, Foundrys director of product marketing. The California startup has a 10 Gig-E switch available now for $45,000, potentially blowing the closest competing technology out of the water. OC-192 - the SONET platform capable of 10-Gbps speeds - is typically priced at $200,000.

Foundry is collaborating with Lucent Technologies to stretch the 10 Gig-E protocol to 40 kilometers across a metro area - Gig-E reaches just 5 kilometers on single-mode optic fiber - but like its competitors, Foundry is still deploying more Gig-E than 10 Gig-E right now. And the company makes sure its boxes are compatible with SONET infrastructure.

Customers using Gig-E now can add 10 Gig-E as easily as adding a blade to their existing chassis, Eisenberg said. "Theyll buy a second set of Gigabit [Ethernet] equipment and deploy it in parallel with existing SONET infrastructure," he said.

Among Foundrys 3,300 customers are EarthLink, Exodus Communications, Microsoft, MindSpring, the U.S. Army, the U.S. Air Force and Verio.

Foundry has also been involved in a groundbreaking project in Sweden. In May, Swedish carrier Utfors used Sycamore Networks ultra-long-haul transport program and switches from Extreme Networks and Foundry to connect Stockholm to Helsinki using the Gig-E protocol. Utfors plans to offer fixed telephony, office-to-office interconnections and virtual private networks across Scandinavia. Its success should quiet critics who say Gig-E cant scale across a metro area or beyond, said Bob Klessig, chairman of the MEFs Technical Committee.

Vendors are also pushing Gig-E technology as a solution for bandwidth-hungry enterprises with optic fiber to their buildings.

Verio uses Foundrys Big Iron Gigabit Ethernet switching services for its Web hosting. Verio customer PreviewPort hosts video and voice chats with authors, and is gearing up for Barbara Walters publicity blitz when her book is released in the fall. For PreviewPort, the ability to crank the bandwidth up and down, and pay only for what it uses, is essential, said Susan Bergman, PreviewPorts CEO and founder.

"If we have something big going on, we need not just a load balancer, but burstable capability," Bergman said. One episode of capacity overload convinced her to find a more flexible, yet inexpensive, approach. "Weve tried to set it up in a totally scalable way, while keeping our bills as low as we can."

RealRead, a Web site-based business that lets people read book excerpts, never knows when a new book will become a sensation that sends a stampede of readers to its Web site. So RealRead turned to Netvein, a service provider that offers quick bandwidth provisioning to its customers. Netvein turned to Qwest, which recently made its Dedicated Internet Access service - based on Gig-E - available in seven major cities.

"Were extremely happy with it," said Eric Allen, Netveins chief operating officer. "I can sleep at night knowing that portion of the business is humming."

Qwest announced its Gig-E offering in May, and plans to be in 25 cities by the years end. Two years from now, most - if not all - links connecting enterprises to broadband will be made through Ethernet, not the venerable OC-3 (155-Mbps), OC-12 (622-Mbps), DS-3 (45-Mbps) connections of the SONET world, Qwests Capurro said. IP services that save the enterprise money and give the service provider or carrier a chance to make a profit on every customer every month will drive Gig-E sales.

Two pioneers of the pure Ethernet play in the metro area are Telseon and Yipes Communications. The fact that venture capitalists enthusiastically shower them with money indicates their potential. Both have fiber-optic rings around 20 U.S. cities, offering customers a way to bypass the local exchange carriers altogether.

Yipes brings optics all the way to the end user, and is being very careful about which downtown blocks and suburban office parks have enough potential customers to justify stretching the expensive fiber. In late June, Yipes announced it had optic fiber within 500 feet of 10,000 buildings serving 53,000 tenants in New York. Eight customers and 10 major multitenant units there have signed up for Internet and intercity data services.

Meanwhile, vendors are demonstrating that their equipment is compatible with smaller and larger Gig-E switches.

Avici Systems - which last quarter doubled its share in its battle with Cisco Systems and Juniper Networks for the terabit router market - demonstrated at SuperComm in July its compatibility with Riverstone Networks RS 8000, using Gig-E as the interface. After their interoperability demonstration, Avici and Riverstone won a deal to roll out voice, video, data and DSL services for Chunghwa Telecom, Taiwans largest service provider.

"As data traffic continues to overtake all other traffic in volume, Gigabit Ethernet is able to deliver some pretty tangible economic benefits," said Esmerelda Swartz, Avicis vice president of marketing.

SONETs Not Going Away

Still, SONET will be around for quite a while because Gig-E remains out of reach for most.

There may be a glut of fiber in the long-haul network connecting metro areas, nations and continents, but there is a profound shortage of fiber connecting businesses to metro networks. Perhaps 5 percent of businesses have optic fiber to their buildings, according to market research firm IDC.

"The entire market is limited by availability of fiber to the end customer," said Sterling Perrin, an IDC analyst. "Until they get fiber to them, theyre not going to have Gigabit Ethernet to the network."

Even if copper could handle gigabit speeds over distance - or even if optic fiber wasnt beyond most budgets - most enterprises need nothing like gigabit speeds, Perrin said.

Today, most connections from businesses to the public network are at T1 (1.5-Mbps) speeds. Six years from now, three-quarters of the connections to businesses still will be about one-sixth of a gigabit, according to Ovum.

Enterprises can wait weeks to get bandwidth upgrades from a SONET cloud, and the company that wants just a little more than the 1.5 Mbps it has now can be forced to get - and pay for - 30 times its old capacity.

And yet, SONET endures.

SONET is an optical standard with the flexibility to transport many digital signals of various capacities from different vendors. Developed when voice was the dominant traffic, it features huge rings around metro areas that carry conversations - and data - with high resiliency and very low latency. The very fact that its expensive and durable keeps it from fading away, despite its unsuitability for data and its labor-intensive upgrades.

"The beauty of SONET is that, OK, its old and expensive, but it works, and its ring architecture is simple, even if its inefficient," Ovums Main said. SONET has been proven to handle both voice and data traffic with little latency or jitter, something Gig-E hasnt proven on a metrowide scale in the real world. At $200,000 for one OC-192 SONET-style switch, incumbent carriers such as the former regional Bells wont dismantle their voice-based SONETs until they wear out or until Gig-E proves overwhelming economic superiority.

The wind seems to be blowing in favor of SONET, too.

The MEF is moving toward a standard that would let Ethernet frames be carried over several technologies, such as SONET, dark fiber or Wavelength Division Multiplexing, the MEFs Klessig said. "That would let the regional Bells build networks using Ethernet switches part of the way, while maintaining their SONET infrastructures," he said.

"Its pretty clear a lot of carriers that have that installed [Asynchronous Transfer Mode or SONET] base want to do a gradual migration" to Gig-E, he said. "The thinking is that by having high degrees of interoperability over several infrastructures, all boats will rise in the water."

That leaves the pure Gig-E players such as IntelliSpace, Telseon and Yipes with less of an advantage than they might otherwise have had. But with standards that promote universal interoperability, new and old players can more easily connect to "technology-agnostic" equipment and networks.

That likely would usher in a hybrid world, giving end-to-end elegant Gig-E to a few large enterprises, while the rest enjoy some cost savings and cool new applications from their Gigabit-somewhere-some-of-the-time networks.

Unanswered Questions

Despite the promises and optimism from enthusiastic vendors, physicists are still puzzling over how to carry Ethernet frames to dozens - or hundreds - of devices without the Gig-E network looking like a Rube Goldberg contraption.

One proposed solution, RPR, is a way to carry Ethernet frames in a token ring configuration while allowing many devices to attach to the common ring. It lets a single set of Ethernet switches read all kinds of traffic on a Gig-E network, while providing the 99.999 percent reliability, the quick restart time and the microsecond latency required by carriers moving both data and voice. But the RPR Alliance acknowledged that acceptance of the standard is at least two years away.

The MEFs Klessig said any vendor implementing its proprietary version of RPR is taking a risk because "it will end up having to be changed, almost for sure." Cisco and Dynarc both have versions of the proposed RPR standard, and may have to retrofit if the standards body moves in another direction.

By contrast, vendors running their own versions of MPLS are probably on safer ground. "Theyre quite close on what a label should look like. Its almost cast in concrete," Klessig said.

Meanwhile, the 10 Gigabit Ethernet Alliance hopes to win ratification of its standard by spring of next year. Last month, the alliance approved higher-density, lower-cost switch chips and optical transceivers that will allow a single chip to support many 10 Gig-E ports.

Sigma Networks offers both SONET and Gig-E to its service provider customers, and hopes to expand into Dallas, Los Angeles and New York by years end. Venture capitalists rewarded the companys business plan - which is based on offering both SONET and Gig-E - with $400 million early this year. Most of Sigmas customers are sticking with SONET traffic, typically asking for 622 Mbps, said Sigma CEO John Peters.

"Our customers are all interested and want to learn more about Ethernet. [They] want to offer it to their enterprise customers," Peters said. "But were not seeing a huge groundswell of energy to deploy those services yet. There are two issues with Gigabit Ethernet - robustness and overall reliability. For many applications, that reliability and robustness still drive a SONET-based solution. That gap will close over time, though.

"Ive been in the communications business for 25 years, and every few years something comes up that is going to be the answer to world hunger. Ethernet isnt that answer. But it is a great protocol for an appropriate set of applications," Peters added.

Ovums Main agreed, saying Ethernets promise to deliver a cornucopia of services is unproven. The early adopters base their optimism on MPLS ability to sort traffic and give a higher priority to, say, voice and video, and a lower priority to e-mail and data.

"MPLS is probably the right way to go, but right now its proprietary," Main said. "Theyre deploying networks based on half-finished implementation of MPLS. Theres an advantage to being first to market, but theres also the risk of getting it wrong, of backing the wrong horse."

Stumbling To A Bright


The MEFs Klessig, however, said that all of Gig-Es inherent weaknesses can be - and are being - overcome by innovative engineers and standards bodies.

The MEF is working to erase doubts about Gig-E services in the metro area. For example, Gig-E doesnt have to connect end-to-end for customers to take advantage of its savings and its ability to deliver premium services, said Klessig, who is also Telseons vice president for product development.

Telseon uses Gig-E to connect to its service provider customers at carrier hotels in metro areas. The service providers, in turn, may use copper wire to reach the last mile to their enterprise customers. Their equipment at the carrier hotels can still deliver enhanced Ethernet services to the end user, even if its trickling at 10 Mbps or 100 Mbps.

And skeptics are wrong if they envision metro Gig-E as a spaghetti mesh connecting every switch to every other switch, proponents say.

"We call it richly connected, " Klessig said. Every switch has at least two other connections to the rest of the network, but not to every switch. In Dallas, for example, Telseon uses 12 fiber pairs for its physical ring. It then breaks into point-to-point rings closer to the end user.

Formed in June, the MEF now has 50 members, including most, but not all, of the biggest players in components (Intel, Texas Instruments, etc.), systems (Cisco, Extreme, Foundry, Lucent, Nortel Networks, ONI Systems, Riverstone, etc.) and carrier traffic (BellSouth, SBC Communications, Telseon, Yipes, etc.).

"There are enough major players from every segment to be tantamount to critical mass," Klessig said.

Ron Young, who co-founded Yipes and is president of the MEF, is sanguine about Gig-Es future.

"Chief information officers need to recognize that help is on the way," Young said. "That huge scalable Ethernet that they love so much inside is going to be their business-to-business connection outside the building."

The consensus: Gig-E will stumble toward a bright future.

"Im a little skeptical when vendors talk about near-term opportunities of voice over this infrastructure," IDCs Perrin said. But long-term, he said, its inevitable that telecommunications will move toward Gig-E and beyond.

Qwests Capurro said Gig-Es great attraction is that CIOs dont have to reserve bandwidth before they know what the month is going to look like. Theyll be able to buy a part of a circuit for the typical months activities, then buy a voice-over-IP offering, manage call services on demand and arrange for videoconference calls with various customers on the fly. "It allows us to bring up virtual networks for events and bring them right down again," he said.

Like much of Gig-E, though, Capurro said, its not quite available - yet. "Were still trying to pluck away at what the dream is and what services are possible," he said.

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