"The bigger story here is that de-duplication is a widely-used technology now, and software developers need to take account of that. We are 100 per cent certain of the problem, and any vendor has the same issue, which is that you don't get to look at the data before it gets written to disk."
He adds that it's not just dynamic file formats either - it's any well-meant application change that stops block-level caching from working, including encryption and compression. For example, he claims IBM had to patch Lotus Notes to turn off encryption as it was causing performance problems over the WAN.
However, while other WAN accelerators acknowledge that the issue exists, some of them claim to have solved it already.
"We opened, changed and saved the same file Autodesk used to test Riverbed," says Jeff Aaron, product marketing director at Silver Peak. "We saw around 78 per cent improvement on AutoCAD 2005 and around 70 per cent on AutoCAD 2008. It definitely was harder to de-duplicate, but we still saw significant gains."
Aaron claims Autodesk had its own reasons for formally testing his company's gear - it is a Silver Peak user, with some three dozen of its WAN optimisers around its organisation.
Granulated or lumps?
He argues that it all comes down to how the various WAN accelerators work. In particular, it's their granularity - whether they work at the block level, as Riverbed and others do, or go down to byte level as Silver Peak does.
"This is a de-duplication issue, and it's not the first time it has happened - the onus is on the networking developers, the network needs to be agnostic," he says.
He adds, "The same vendors have had problems with other dynamic file formats. We saw a similar scenario with Microsoft Excel over the WAN, as it breaks up changes and randomly spreads them through the file."
Aaron acknowledges though that when Saldich argues that application developers need to be better aware of how their software will run over a WAN, he has a good point.
"The more the software developers do to address this, the more we all benefit," he says.
We asked Autodesk for its comments, but nearly two weeks later the company had still not found a spokesperson or offered any feedback.
