Frame processors squeeze more out of networks

The highly integrated Harrier family of frame processors provides programmable, intelligent oversubscription to optimise existing network infrastructure.

The highly integrated Harrier family of frame processors provides programmable, intelligent oversubscription to optimise existing network infrastructure and reduce the number of components required to enable a high-density Ethernet solution.

The Harrier family consists of three aggregation devices: Harrier-24 with 24 10/100/1000 Ethernet ports; Harrier-12 with 12 10/100/1000 Ethernet ports; and Harrier-24LS with 24 10/100 ports.

Each device interoperates with off-the-shelf Ethernet physical layer devices via standard RMII/RGMII interfaces and with off-the-shelf network processor units (NPUs) or Sonet mappers via a standard SPI-4.2 interface.

"By the end of 2003, nearly all desktop and server systems will be shipped with gigabit network interfaces.

However, typical user applications demand less than 25% of this available capacity even in peak times, leaving the bandwidth provided by these interfaces significantly underutilised", said Mark Fabbi, vice president Gartner.

"At the same time, enterprise switches and routers are designed for 100% bandwidth utilisation on all interfaces, resulting in an unnecessarily high networking equipment cost.

The solution is to design systems optimised for efficient bandwidth utilisation via intelligent oversubscription".

To enable full utilisation of shared hardware, including NPUs, backplanes and switch fabrics, Harrier's intelligent oversubscription logic optimises existing network infrastructure by eliminating unused bandwidth at the media access controller (MAC) layer.

In a typical Gigabit Ethernet enterprise network system for example, system cost per port can be reduced from about $50 to about $30.

"Increased density means increased profitability", said Scott Clavenna, President of Point East Research.

"Implementing intelligent Ethernet oversubscription means more customers can be served in the same amount of space by maximising bandwidth utilisation".

Harrier implements 2:1 intelligent hardware oversubscription by aggregating 24 incoming Gigabit Ethernet ports to a single 10Gbit/s NPU.

Implementing this hardware-based oversubscription in the router or switch reduces system cost per user by up to 40% without affecting network performance.

Taking oversubscription to a higher level, such as 4:1 or 8:1, enables further network cost reductions.

To ensure quality of service and bandwidth availability to all users, Harrier supports multiple priority queues per port and implements oversubscription algorithms based on weighted random early discard (WRED), modified deficit round robin (MDRR) and in-band pause frame generation for flow control.

To simplify design complexity and reduce system cost, the device includes on chip memory and uses a dynamic memory management system which supplies each port with a cache of virtual RAM efficiently allocating memory to users on an as needed basis.

"The ability to continuously reduce system cost while at the same time providing customers with reliable connections is the challenge faced by system vendors", said Michael Laudon, Director of Hardware Engineering for Force10 Networks".

Ample Communications has covered all the bases with its Harrier product family that cost-effectively supports both oversubscribed and full-rate Ethernet applications".

The primary application for Harrier is in modular, high-density IP-based Ethernet LAN switch and router systems.

As traffic enters the Harrier-based line card on a switch/router, it is preprocessed and rate-limited so that the NPU and switch fabric can be fully used.

In this implementation, 24 incoming Gigabit Ethernet ports can be processed by a single 10Gbit/s NPU.

Harrier will dynamically handle bursts of traffic across these 24 ports and map the traffic onto a 10Gbit/s interface.

This allows a single 10Gbit/s NPU to handle 24Gbit/s of traffic, which results in more than a two-fold reduction in NPU and switching hardware requirements.

For metropolitan network applications, Harrier provides high-density, ultra-efficient Ethernet over Sonet aggregation.

In this application, Harrier is connected to a virtual concatenation Sonet mapper with GFP support.

Virtual Concatenation and GFP mapping have been developed to efficiently transport Ethernet over Sonet metropolitan networks.

Sonet payload envelopes can be efficiently sized to match Ethernet services transports at 10/100/1000Mbit/s increments.

By introducing intelligent oversubscription, operating in conjunction with virtual concatenation, carriers can take this mapping efficiency even further.

With Harrier, Sonet payload envelopes can be sized to match the actual bandwidth utilised within standard Ethernet links, supporting more customers at a lower cost per customer.

"The addition of the Harrier device rounds out our line of frame processors", said Marek Tlalka, Vice President of Marketing for Ample Communications.

"Our focus continues to be on providing merchant silicon that facilitates the use of existing infrastructure to maximise both capex and opex for carrier and enterprise customers, whether their system solutions are Ethernet- or Sonet-based".

Each member of the Harrier product family is a low-power 31mm x 31mm flip chip BGA device, making it extremely attractive for high-density network line card development where space and power availability are at a premium.

Its virtual on-chip RAM eliminates the need for external components, further reducing system cost, space and power requirements.

The Harrier devices come with a comprehensive, portable API that provides high-level access to internal registers and simplifies software development, and support extensive statistics for performance monitoring and billing.

The Harrier-24 device (part number A2510) is priced at $250 per unit in 10,000-unit volume; the Harrier-12 (part number A2511) and Harrier-24LS (part number A2512) are priced at $195 per unit in 10,000-unit volume.

Back to top