Ease of provisioning, any-to-any connectivity, quality-of-service based tiering and seamless integration of Ethernet flows into the legacy infrastructure are what it takes to put Ethernet on par with the TDM, frame relay, ATM and other mainstays of telecom operators. That's exactly what the close coupling of Layer 2, Layer 3 and even higher layers of the protocol stack in a new generation of switches and related components accomplishes.
If everything works as billed, the implications for carrier strategies are profound, especially for ILECs, that find themselves in a position to challenge Ethernet-based competitors like never before if they're willing to turn a whole lot of their legacy business on its ear.
For leading suppliers of Ethernet core and edge routers and switches for the service provider sector, the emergence of a more ILEC-centric market has required significant adjustments in product strategies. "The reality is the whole market is changing as a result of the cuts in capital spending, collapse of some of the greenfield startups and shifts in market demand," says Ashok Madanahalli, marketing manager for service provider solutions at Extreme Networks Inc. "A year ago the top service requirement was support for flexible bandwidth, but now we're starting to see many other applications, including disaster recovery protection for data centers and convergence of voice onto Ethernet LANs that requires us to be able to separate voice from other traffic at our switches."
These changing market conditions are a plus for companies like Extreme, which have focused on building Layer 3 switches that have the power to "sniff" into the higher layers of the IP protocol stack. But the changes also have required adjustments to accommodate the Layer 2 architecture needs of major carriers. Extreme, for example, has introduced software enhancements into its Black Diamond core switch to address the protection requirements of Layer 2 operations.
Foundry Networks Inc. is another supplier that is adjusting to the new realities. "We see the Bell companies as our biggest opportunity in the service provider sector," says Chandra Kopparapu, director of product marketing for service providers at Foundry. "But they're not going to move in this direction overnight. There's a lot of testing and exchanging of information going on, with people saying it could be anywhere from six to 24 months before we see them rolling out this type of service."
All the RBOCs but one, Qwest Communications International Inc., acknowledge they are moving to greater flexibility in Ethernet offerings, with initial product rollouts already under way (see February xchange article "RBOCs Move to Make gigE Widely Available," page 14). Verizon Communications Inc. and BellSouth Corp. have implemented Ethernet switches to make point-to-point transparent LAN services easier to implement, and SBC is using wavelengths rather than dedicated fiber for delivery of gigE services over its metro networks. As the ILECs move beyond these applications, one of the first things they want to be able to do is support outsourced managed services, where they can deliver network-based security, storage and other hosted applications seamlessly over Ethernet connections to multiple users.
The trick is to avoid for as long as possible turning such capabilities into a regulated switched service, where the floodgates would be opened to ubiquitous offerings that could cannibalize quickly the existing service base. "The majority of the edge switched Ethernet applications that we're seeing are coming from the unregulated side of the RBOCs," notes David Boulos, vice president of product marketing at Telco Systems. "Some are setting up (the switching platform) as a test-bed project where the unregulated side can go out and leverage the technology to get a discount on bandwidth."
Such ploys can't last long, of course. Sooner or later the Bells will have to bite the bullet and take full advantage of the technology if they're going to meet market demand for advanced services. "We're seeing a real pushback from the enterprise sector where more and more companies with transparent LANs are looking for carrier support for turning those into managed LANs and threatening to do it themselves or go elsewhere if their traditional providers won't cooperate," says Moshiko Levhar, director of IP product line management at Telco Systems.
That's why Telco Systems and many other companies have chosen to bring out products that, until recently, would not have gotten the time of day from the RBOCs. In Telco Systems' case, the latest move in that direction involves adding a gigE converter and copper uplink to its edge routing switches and, shortly, a very high speed DSL interface that will allow the switches to support DSLAM-like applications over twisted pair while supplying 10BaseT or higher speed connectivity over fiber and Cat5 wire connections from the same terminal.
Combining Ethernet switching with VDSL also opens a path to residential "triple play" service where carriers can avoid the costs of using ATM as the transport mode for consumer services, Boulos notes. "We're in the labs of some carriers who are looking at doing this," he says.
The company's T5 routing switch supports up to 64 Fast Ethernet (100mbps) or 8 gigE ports with a switching backplane that operates at 30gbps, Levhar says, noting the module can operate as a Layer 3 router and a Layer 2 switch. The Layer 3 functionality gives carrier networks the ability to read packet headers, giving the switch the power to control traffic in accord with QoS priorities. "We can go in with a Layer 2 configuration supporting LAN services at very competitive price points and, through use of software, turn on the system to support very granular levels of service as carriers introduce voice over IP, video and other things," Boulos says.
Carriers also want interfaces into legacy ATM, frame relay and SONET links that support transmission of Ethernet without sacrificing bandwidth efficiency. "A year ago packet over SONET or ATM was frowned upon because of the overhead costs you incurred through incompatibilities between the formats," Boulos notes. "But now with chipsets on the market that are fast enough to concatenate Ethernet packets into small timeslots, you get 100mbps of real throughput for 100mbps of bandwidth usage, and that's a big reason carriers are looking seriously at Ethernet."
Other vendors make many of the same points. Foundry has introduced a line of core, edge and premises routers and switches built on its third-generation Jetcore ASIC (application specific integrated circuit) with the ability to support multipoint-to- multipoint virtual LAN services at Layer 2 or Layer 3 implementations. The latter approach is tied to MPLS and a new extension of MPLS known as VPLS (Virtual Private LAN Service). The new ASIC collapses the functionalities of nine ASICs used in second-generation Foundry products, allowing carriers to pack up to 232 gigE ports into a core routing unit that's only 30 inches tall, Kopparapu says.
The product can provision bandwidth in increments as small as 256kbps by tapping into the Layer 3 and Layer 4 packet-reading processes to determine bandwidth priorities for each flow. It also randomly can sample packet flows, allowing service providers to bill by type of application, monitor peering agreements and let customers know whether they need more bandwidth to handle the traffic they're sending. The new routers support up to 2 million MAC (media access control) addresses to augment scaling in Layer 2 applications and to allow carriers to interoperate multiple Layer 2 metro access networks with an MPLS metro core.
"If you're a service provider you want to provide virtual LAN service in both point-to-point and multipoint-to-multipoint modes as the next step beyond today's transparent LAN services," Kopparapu says. "You have the choice of doing this as a Layer 2 architecture or Layer 3 using MPLS." In terms of the type of service offered the two approaches net the same thing, he adds, noting that "in the Layer 2 metro implementation, every virtual LAN is a VPN."
But ILECs are looking for traditional protections that come with Layer 2 architectures, so achieving carrier class service levels with Ethernet using Ethernet switching is essential if this platform is to be offered as a public network service like any other. Foundry has implemented two solutions to make this happen in mesh and ring environments at sub-second rates that are much faster than the guaranteed sub-5-second rate offered by the new Rapid Spanning Tree technology. For the ring topology the vendor employs its own Metro Ring Protocol as a sort of precursor to the emerging Resilient Packet Ring standard. For mesh topologies it employs Virtual Switch Redundancy Protocol, which is a variation on Virtual Router Redundancy Protocol.
Perhaps nothing better underscores the strength of the demand for solutions that will bring Ethernet into the carrier mainstream than the latest product developments at Nortel Networks. The company is rolling out new units and upgrades to existing product lines that will allow unprecedented automation and flexibility in the end-to-end provisioning of Ethernet services across the metro network, says Al Safarikas, vice president of marketing for optical Ethernet at Nortel.
"Every one of the top 100 carriers globally is actually in some stage of an Ethernet RFP process that represents a major change in their approaches to Ethernet service," Safarikas says. "Our goal with this suite of products is to meet these requirements."
If carriers are going to move in this direction, their confidence the investment is going to pay off in driving a vast market base to Ethernet services beyond the legacy enterprise market rests not just on upfront capital expenditure savings but, more importantly, on sustained operations savings, he adds. "Unless they're able to reduce operating costs 25 to 30 percent per year through 2005, there's not going to be an incentive to introduce the disruptive changes that Ethernet services would bring to the marketplace."
Such savings are what Nortel has in mind with its new class of optical Ethernet edge devices and a new Ethernet services switch that are coming to market. At the metro core, the OPTera Metro 8000 Ethernet Services Switch employs standards-based MPLS software to support scaling of Ethernet services to tens of thousands of customers in any given metro region, Safarikas says.
Extending QoS capabilities beyond the core, the new OPTera Metro 1200 edge device allows service providers to provision multiple end users from a single edge device, where the incoming gigE signal is partitioned to deliver separate 10- or 100-megabit Ethernet streams to customers. Service providers will be able to provision any one customer across all endpoints automatically, without having to provision each endpoint individually, Safarikas notes. "The 1200 serves as a demarcation point at the edge, which means service providers can introduce guaranteed quality of service levels all the way to the customer premises," he says.
The Metro 1200 went into commercial delivery in April, and the Metro 8000 is slated for delivery starting in June. This month the company is introducing enhancements to its OPTera Metro 3500 Multiservice Platform, increasing the capacity of Ethernet over Resilient Packet Ring and extending QoS across disparate but interoperable networks, such as Ethernet over DWDM and Ethernet over dark fiber.Â
