Ethernet's simplicity, widespread adoption in the LAN and related equipment economies of scale has led many public network operators to embrace the technology. However, despite the excitement around gigabit Ethernet fueled by such next-generation carriers as Yipes Communications Inc. (www.yipes.com), some say Ethernet still is not considered a carrier-class solution because it doesn't offer SONET-like resiliency, doesn't support voice and allows companies like Yipes to offer only single-protocol services.
As a result, vendors are coming from different directions to expand the capabilities of Ethernet--making it more resilient and enabling network operators to offer bandwidth guarantees and SLAs so carriers can offer support for sensitive traffic, such as voice and video, as well as mission-critical applications.
Cisco Systems Inc. (www.cisco.com), Luminous Networks Inc. (www.luminous.com), Nortel Networks (www.nortelnetworks.com) and Riverstone Networks Inc. (www.riverstonenetworks. com) are using resilient packet ring technology--or precursors to RPR--to bring SONET-like functionality to Ethernet in access networks. Meanwhile, some Ethernet vendors are adding MPLS to their products. At the same time, Yipes, considered the leading Ethernet service provider, says it plans on adding voice to its palette of services and has been testing application-aware technology for months.
So, as Ethernet scales from 10mbps to 100mbps to 1gbps and soon to 10gbps speeds, the technology is also gaining "speed" in its reliability and ability to support additional services.
Resiliency
"We believe Ethernet itself is not a carrier-class protocol," says Jay Shuler, vice president of marketing and business development at Luminous. "So we've examined what it is to be carrier class,"
Being carrier class goes well beyond Network Equipment Building Standards (NEBS) compliance. NEBS is an environmental certification created under the former R&D arm of the Bell companies that describes how telephone equipment should stand up under harsh conditions such as fire, humidity, physical impact and the like.
To be carrier class means that it has attributes associated with SONET, such as the ability to deliver a 50-millisecond survivable ring, to carry multiple protocols, to carry TDM services with a SONET-like timetable and to manage it all using fault configuration accounting performance security (FCAPS), an ITU standard, Shuler says.
A group of vendors formed the Resilient Packet Ring Alliance to develop RPR, or a standards-based solution that offers optical Ethernet with carrier-class SONET-like functionality. But a handful of vendors already has come out with recursors to RPR.
The Luminous PacketWave product family is based on Resilient Packet Transport (RPT). In December, the company began shipping its PacketWave M Series, a metro product, based on RPT.
"We've developed resilient packet transport because it works in configurations other than rings," Shuler says. "Only three companies--Cisco with its DPT [dynamic packet transport], Nortel with its IPT [interWAN Packet Transport] and us--have a precursor to RPR. The goal is to create a layer 2 protocol that offers resiliency."
One reason Ethernet is not considered a carrier-class technology is because of its spanning tree function, says Shuler. Spanning tree chooses a span in network, therefore Ethernet cannot complete a ring.
Spanning tree also takes tens of seconds to survive a break in the network. "It's the difference between 50 seconds and 50 milliseconds, which is pretty substantial when you're talking what could be bank traffic or what could be a T1 or DS3," Shuler says.
"We have T1/E1 interfaces on the box and can offer T1/E1 that is indistinguishable from SONET T1," he adds. "And we use a stratum clock, as does SONET. That's meaningful because it keeps you from losing frames on the circuit."
Introducing MPLS
MPLS is another technology vendors are working to introduce into gigabit Ethernet networks.
For example, Riverstone had expected to begin shipping its MPLS products at the end of May. "We have an end-to-end metro solution in our metro optical access router [RS 3000], our mid-sized metro aggregation [S 8000/8600] and metro core router [RS 38000]," says Andrew Feldman, vice president of marketing at Riverstone.
The company also was expected to announce last month a gigabit Ethernet aggregation router that offers 60 gigabits of ports in a five-rack unit.
Meanwhile, Extreme Networks (www. extremenetworks.com) was expected to begin shipping last month an MPLS-based Ethernet metro network solution that consists of an extensible network processor and software-based module integrated with Extreme Networks' BlackDiamond core-switching solution.
"BlackDiamond is now in metro area networks, which are in ring architectures and offer Ethernet services like VPNs and transparent LANs," explains Sam Halabi, director of the MPLS forum and vice president of IP Carrier marketing and business development for Extreme Networks. "MPLS extends those services across wide area networks that are enabled by MPLS. It extends the reach of the service."
For the last 18 months, Extreme has led the deployment of gigabit Ethernet in MANs with customers such as Telia in Sweden (www.telia.com), WIND in Italy (www.wind.it), Telstra in Australia (www.telstra. com), China Telecom (www.chinatelecom. com.cn) and Yipes, Halabi says.
Today, gigabit Ethernet in metropolitan areas is a combination of point-to-point and point-to-multipoint VPN, and transparent LAN. So it connects multiple branches of a corporation in a metropolitan area, or for carrier-to-carrier services, it can offer virtual collocation via managed Ethernet, Halabi says.
"This has been going on for awhile now," he adds. "What's new here is that the service always has been local to the metro itself. To get from one metro area to another, you have to go across the WAN, and the WAN is a combination of services. MPLS is now becoming the conversion player among multiple technologies for control and forwarding. It becomes like a repeater/regenerator of services."
It works like this: At the edge of the WAN, the BlackDiamond acts as a label edge router that provisions label-switched paths across the WAN backbone. MPLS offers the ability to traffic engineer label-switched paths. "LSP for WAN is akin to a PVC in the metro," Halabi says. "So now we've created a virtual packet leased line, compared to your physical leased line."
Foundry Networks Inc. (www. foundrynetworks.com) also is adding MPLS support to its products. The company announced its plans a year ago and as of late April was in beta trials and had expected to make its MPLS products generally available in June or early August, says Chandra Kopparapu, Foundry's product marketing manager.
More Dynamic Bandwidth
Meanwhile, gigabit Ethernet players are preparing to introduce even higher bandwidth and, potentially, services that can be provisioned based on an individual user or application.
"What's next is 10gig and then 40gig," says Ron Young, co-founder and chief marketing officer at Yipes. "We've been outed with 8gig deployments and WDM stuff." And the company expects to adopt 10gbps by the end of the year.
Yipes, which is in 21 U.S. markets, already offers quickly available bandwidth in virtually any increment. "Customers use what they want, which is never 155mbps or 45megs or 1.5 megs," Young says, referring to the increments offered by SONET networks. "What our customers really love is that they can get what they want. A teaspoon of water, a glass of water or whatever--it's not a drop or a fire hose."
In an attempt to add to its flexible bandwidth services, Yipes has been testing an application-aware network for months, Young says. The company refers to this application-aware concept as Emerald City. It encompasses the move to 10gpbs; DWDM technology; lambda services; the support of multiple services including voice, data and video by using 802.1p and 802.1q tagging, DiffServ and MPLS; and web-based operations support systems for management, provisioning and other functions.
"All these features we've been discussing have a purpose, and this is it," Young says. "You can't do this with ATM or SONET."
By 2005, more than 30 percent of high-speed WAN data services will be carried over Ethernet networks, according to predictions in "Look Out WAN--The Ethernet Roadkill Machine is Coming," by Gartner (www.gartner.com). While many metro providers are postponing funding rounds and expansion plans, gigabit Ethernet providers have secured significant funding in the early months of 2001, says The Yankee Group's (www.yankeegroup.com) report, "Metro GigE Providers: Opening the Funding Floodgates." |
