Overture Networks bridges the TDM-to-IP edge gap

Telecommunications Americas, March, 2004

www.overturenetworks.com

The advantages of metro Ethernet service are well documented. A recent Metro Ethernet Forum study, for example, revealed a 23-percent reduction in opex over traditional private line, frame relay and ATM. But for existing operators, the challenge is a four-dimensional balancing act between extending and supporting existing infrastructure and services, while offering a new revenue stream with a next-generation IP migration path.

While other vendors have built multi-service platforms, Overture Networks argues it fills that missing link with its ISG 2200 metro edge platform. As a packet-based MSPP that resides on the customer's edge, the ISG 2200 can be used to deliver Ethernet and TDM-based applications as either a standalone product for a single customer or in conjunction with its flagship ISG 5000 product for sub-tending configurations.

Leveraging the same processor and software as its predecessor, the ISG 2200 is ideal for customer locations requiring only a few Ethernet and TDM ports. The product offers an expandable interface slot supporting the same plug-in modules, including GigE, OC-12c/STM-4c/STM-1, DS3, T1/E1, 10/100 Base-T and 100 Base-FX. Through a combination of fixed ports and an expandable interface module, the product enables service providers to support initial requirements with a pay-as-you-grow support path.

Running over any network configuration (SONET/SDH, optical Ethernet, CWDM/DWDM or RPR) the ISG 2200 can deliver Ethernet and TDM-based services to both on-net and off-net customers. Specifically, the product can support such services as Ethernet-based private line, off-net extension via leased lines, high-speed Internet access, VPLS (virtual private line service) and legacy T1/E1 services.

"They figured out how to use Ethernet and bring TDM across the carrier's metro network, but not many people are focused on the endpoint," said Michael Howard, principal analyst at Infonetics. "Carriers have a vision, whether they publicly promote it or not, that they will have an IP-over-glass metro Ethernet network, where all of today's services will run on that Ethernet network. Overture had that vision, and with their small crew developed a potent product."

Claiming to be a cost-effective alternative to RPR, Overture's ISG 2200 incorporates PSR (protected switched ring) technology to provide GigE over dark fiber or extending existing backbone rings. Built using standard Ethernet technology and methodology, PSR enables carriers to run Ethernet with ring-like 50-msec recovery to support both TDM (PBX and ISDN) and packet-based services. Activated via a software upgrade to the ISG, PSRs can interoperate with existing standard Layer 2 switches and backbone DWDM, RPR or SONET/SDH transport systems. To the carrier, the PSR operates much like a standard SONET/SDH UPSR (unidirectional protected switched ring) configuration. While the PSR capabilities are optimized for GigE, PSR interfaces can be applied to 10/100 Ethernet, 100FX Ethernet, DS-3, and OC-n/STM-n.

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Unlike other edge solutions that require multiple devices to manage, the ISG provides a single vantage point that extends management visibility to the remote customer edge, whether they are on or off the metro network. Carriers can manage the ISG either in-band via management VLAN or out-of-band via Ethernet or serial management port. An optional management VLAN can be established on all remote ISG platforms for security from other users. Accessed via CLI or SNMP over any IP connection, the ISG's open design can work with third-party management platforms such as NetCool and HP OpenView.

This approach was music to the ears of Raymond Winkler, vice president of operations at PPL Telcom, a mid-Atlantic metro provider.

"From a maintenance and monitoring standpoint, Overture made sure the MIBs matched up with our standard network monitoring software," said Winkler. "Nothing unusual there other than you can drill down into the device, which is very important when you have a network that's spread out along the East Coast. From a capital standpoint, anytime you can get better use of a network node, that's critical."

Overture has over 10 customers and has garnered OEM partnerships with Movaz Networks and, even more impressive, NEC. Available now, the ISG 2200 is being evaluated by UFO Communications and PPL Telcom, in addition to other unannounced carriers.