Do DSP Boards Still Have a Place in Today’s IP Telephony Environment

In recent years we’ve seen a shift from DSP-based telephony boards to software-based Host Media Processing (HMP). The continued advance of multi-core processors allows for ever-higher port density telephony solutions. But before we abandon the DSP telephony board completely, let’s look at some recent successes.

In a recent interview with Alan Pound, CEO of Aculab, a UK-headquartered company, the question was posed as to how far HMP can go in displacing DSPs for media processing. Pound’s response: “If there’s a natural ‘home ground’ for dedicated DSPs, it is certainly in those situations where density is at a premium, and by this I mean both ports per cubic inch, and ports per Watt. Telcos, data centers, and I suppose military applications have big issues with the physical footprint – the cost of floor space, and of heat dissipation. These are really major problems in those applications, and along with critical performance parameters such as timing and jitter, dedicated, ‘designed for purpose’ devices, i.e. DSPs, are simply the best fit for the task – it is what they were designed to do, and as good as HMP becomes, I cannot see it actually overtaking DSPs in terms of performance.”

An excellent example of this “design for purpose” approach is evidenced by the Aculab GroomerII product (based upon the Alliance Systems I-6000R3). According to Ian Colville, Aculab Product Manager, “GroomerII provides connectivity for an extensive range of protocols, including CAS, H.323, ISDN, SIP, and SS7 networks and is a very cost-effective solution for large-scale call centers where high call volumes occur via the PSTN and SS7.”

Aculab’s GroomerII signaling and media gateway received global approval from Siemens by completing interoperability testing at their labs in Munich, Germany. GroomerII was successfully tested in a number of call scenarios involving ETS300, SS7 and SIP protocols using Siemens’ HiPath 8000. Aculab is now an approved Siemens Technology Partner which means that Siemens business units worldwide can confidently specify GroomerII for interconnect solutions in conjunction with their HiPath 8000 product line. GroomerII provides a dependable, compliance-tested solution for interconnecting not only TDM networks, but also for connecting to SIP networks and equipment, such as the HiPath 8000.

Final Score. The advantages of host processor-based IP Telephony solutions can be very compelling. At the same time, the ability to scale up to a very high call count in a reliable manner is still highly dependent upon DSP-based telephony boards technology, and will be for quite some time to come. IT

Jeff Hudgins is VP of Engineering at Alliance Systems (http://www.alliancesystems.com).

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