Alidian adds Ethernet service intelligence to metro DWDM systems

Oct. 12, 2001
Oct. 12, 2001--Alidian Networks has introduced a combination of new hardware and software that will enable its Optical Service Node (OSN) family of optical add/drop multiplexer systems to bring to metro-area carrier networks the quality-of-service and transport efficiencies typically associated with access data networks.

Alidian Networks has introduced a combination of new hardware and software that will enable its Optical Service Node (OSN) family of optical add/drop multiplexer systems to bring to metro-area carrier networks the quality-of-service and transport efficiencies typically associated with access data networks.

Alidian's new Ethernet Service Intelligence (ESI) software will allow the OSN family (the OSN 4200, 4400 and 4800, which support 10, 2O and 40 gigabits per second of service-bearing capacity, respectively) to perform service aggregation, rate control and QoS functions -- via standard Ethernet parameters such as IEEE 802.1Q/p, IP ToS and DiffServ. The software requires either Alidian's new four-port gigabit Ethernet service interface module, also being introduced, or one of five existing lower-density Ethernet modules.

The new Alidian ESI software combines attributes of the SONET and data worlds. It takes advantage of Alidian's WavePack technology, which transports multiple traffic types in their native mode on a single SONET-framed wavelength. It then adds the standards-based QoS, rate control and service aggregation capabilities, all performed on either a per-port or per-flow basis. The result is a metro network that is as efficient at transporting data as a typical enterprise network, while still providing carrier-class, multi-service functionality.

The Ethernet Service Intelligence software performs service aggregation and rate control using the IEEE 802.1Q standard that identifies a frame as belonging to a particular virtual LAN (VLAN).

Service aggregation, which allows the grooming of Ethernet services (e.g., high-speed Internet access, transparent LAN) from multiple customers to a single central site, is critical for transport efficiency because it reduces port counts on central-site switches and routers as well as transport gear. Rather than providing bulk transport via inefficient SONET payloads or wavelengths, the ESI software reads individual Ethernet frames and groups VLAN flows for transport and delivery. In multi-node networks, tag translation is applied to ensure that flows are aggregated to the correct VLANs and to ease management operations.

Because many users do not need a full gigabit of bandwidth, rate control is key to letting a provider offer a gigabit Ethernet physical port but charge for only a fraction of its capacity. With the ESI software, a gigabit Ethernet interface can be provisioned in 10-Mbps (one percent) increments. Since only the provisioned bandwidth enters the transport ring, dozens of rate-controlled interfaces can fit on a single OC-48 wavelength, maximizing ring efficiency. Rate control eliminates the need for multi-box solutions (e.g., a multi-connection Ethernet switch plus a SONET or DWDM box) and can be applied on a per-VLAN basis.

With the ESI software's QoS support, services can be differentiated based on application needs, allowing providers to offer more varied services and use their transport networks more effectively. The software reads the Ethernet flow's traffic classification field -- IEEE 802.1p, IP ToS (Type of Service) or DiffServ (differentiated service) -- and maps it to one of four priority levels for transport.

Support for oversubscription is also provided in the ESI software, which uses the QoS features to transport priority traffic first on an oversubscribed ring or port.

All aggregation, rate control and QoS features can be applied on a per-flow as well as a per-port basis, allowing for application differentiation and reducing the number of ports required at the customer site. For example, a gigabit Ethernet connection can be rate-controlled to 300 Mbps: 100 Mbps each for Internet access, transparent LAN service between branch offices, and transparent LAN service between national and regional headquarters sites. The traffic flows are differentiated using VLAN identifiers, each with a different QoS priority, and then are aggregated by VLAN.

Alidian's new four-port SFP (small form factor pluggable) Gigabit Ethernet service interface module doubles the OSN systems' earlier density, and supports both short- and long-reach optical transport. Previously available Ethernet interfaces for the OSN family include one- and two-port Gigabit Ethernet modules (each available in short- and long-reach versions) and an eight-port Fast Ethernet module.

Alidian's Ethernet Service Intelligence software is priced at $7,495 per OSN system. The new four-port SFP Gigabit Ethernet module is priced at $16,995 (U.S. list prices). Both products run on all OSN models and will be available in November.

About Alidian:

Formed in August 1998, Alidian has developed the Optical Service Network (OSN) family, which combines electronics and photonics to permit comprehensive service delivery, breadth and awareness within a single highly scalable architecture for the dynamic metropolitan-area network (MAN) environment. For more information, visit

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