Attenuate interacts with IIS through its ISAPI Filter interface. It makes
no modifications of requests sent to IIS, so will not interfere with normal
operation or with other add-on components. The Attenuate Client loads and
interacts with the same ISAPI Filter DLL. It can load/access all data, via
shared memory, regardless of whether IIS has the filter
loaded.
The Attenuate Client permits easy editing of these constraints either in
offline mode or in online (realtime) mode. Once properly installed, Attenuate
loads its constraints automatically from a file when IIS is invoked. The
Attenuate Client can be used to update this file and make changes to Attenuate
while it is operating.
Once a suitable set of constraints are determined, the Attenuate Client/Editor
need not be used until changes are again required. The data file can be backed
up, or transfered to other Attenuate installations. IIS will load the Attenuate
DLL which, in turn, will read the constraints data file.
Certain ISAPI filter DLL's have been known to cause performance problems
with IIS. Whether this is due to high computational complexity in the particular
DLL, or Microsoft's implementation of the interface is subject to debate.
The calculations performed by Attenuate per packet take much less time than
that required to load a block of data from the disk. Some overhead penalty
might accrue if the string table becomes large. Prospective customers are
encouraged to try Attenuate in their particular situation. A 15 day trial
is free. |
