Dune Networks today introduced a duo of new traffic manager chips that it claims can guarantee end-to-end quality of service for packet networks (see Dune Releases New Traffic Managers).

The new chips, FAP10V and FAP20V, are an integral part of Dune's SAND switch fabric chipset, providing queuing and scheduling of packets with 10 and 20 Gbit/s of throughput, respectively.

The most salient feature of these chips is the distributed traffic management function, meaning the chips can communicate with each other across the fabric to ensure that high-priority traffic gets though.

"This capability of end-to-end rate guarantee can not be emulated with any standalone traffic managers and legacy switch fabric," claims Eyal Dagan, Dune's CEO.

Dune isn't the first vendor to make lofty QOS claims, but it does appear to have made a significant advance, says Simon Stanley, founder and principal consultant of Earlswood Marketing Ltd. "It's fundamentally different to what's been done before," he avers.

Most traffic managers manage the input and output of the switch separately, meaning the packet has to be queued and scheduled twice. That increases the likelihood that it will get held up -- just because a high-priority packet gets the green light on the way into the switch, doesn't mean it won't hit a jam at the output.

In Dune's new chips, packets are buffered at the ingress to the switch. Scheduling is handled by the traffic manager on the egress, which looks at what's going on there, and passes the information back to the chip at the input. The upshot is that the ingress traffic manager can make better scheduling decisions, only sending packets across the fabric when there's capacity available.

It's worth pointing out that this feature isn't completely new. It has previously been designed into the Prestera FX-930, a traffic manager that Dune designed for Marvell Technology Group Ltd. (Nasdaq: MRVL). But the startup didn't publicize this particular functionality in relation to that chip, Stanley notes.

Unlike the product for Marvell, Dune's latest chips will connect with network processors from most other vendors. On the linecard side, they have SPI-4.2 interfaces -- the industry standard for connecting to 10-Gbit/s network processors. FAP10V has a single SPI-4.2 inteface, and FAP20V has two.

Dune's nearest competitor is probably Agere Systems Inc. (NYSE: AGR.A), which offers the Advanced Payload Plus traffic manager. For more detailed analysis of traffic manager chips please see Simon Stanley's recent Light Reading report: Traffic Managers Update.

The FAP10V and FAP20V are available immediately. Pricing was not disclosed.

— Pauline Rigby, Senior Editor, Light Reading