Cisco Cisco Aironet 3500i Access Point Weißbuch
Farpoint Group White Paper – April 2010
Spectral Assurance Total Cost of Ownership
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Farpoint Group thus believes that the network optimization and productivity
enhancements of the centralized/infrastructure model are sufficient justification for
implementing a CIM spectral-assurance solution. To introduce the impact on total cost of
ownership, think of the CIM strategy as converting expensive, personnel-centered
operating expense into greater but more efficient capital expense. But it’s also important
to consider that spectral assurance is also a bit like an insurance policy, with an
opportunity cost assigned to not having it at all. So we assume that an SA capability is
essential, and that the fundamental cost analysis is between the WAM and CIM
approaches, not with respect to whether SA is valuable or not. It is, and very.
Building a TCO Model of Centralized Spectral Assurance
Any model of total cost of ownership has two components: capital expense (CapEx), and
operating expense (OpEx). Capital expense includes all required equipment, planning,
installation, functional verification, and related non-recurring engineering charges, which
are most often only a small percentage of the cost of the equipment required. Operating
expense includes all expenditures related to ongoing operations, including network
management, troubleshooting, remediation, user support, maintenance, and many other
functions.
Over time, the OpEx is usually much larger than CapEx, and for a simple reason. While
CapEx largely depends upon the cost of manufactured products, which almost always
declines over time and which benefits from improved price/performance regardless (often
noted in the press as the “faster/better/cheaper” typical of high-tech products), OpEx is
essentially labor-intensive, and costs here demonstrate the opposite property – they
almost always increase over time. The best way, of course, to address rising labor
expense is to improve productivity. The centralized model of spectral assurance can most
certainly do this, as it converts staff-oriented walking around into centralized, continuous,
infrastructure-based monitoring and analysis, along with appropriate automation in
response to detected problems and issues. And, of course, the requirement for direct labor
to do all that walking around is dramatically lessened and even eliminated in many cases.
In a centralized spectral-assurance solution, assuming that the required sensors are
resident in devices that can also function as access points, the bulk of CapEx involved in
greenfield (pervasive) deployments is the differential between the cost of a spectrally-
enabled AP and one that is not. Depending upon model, this might amount to a few
hundred dollars per AP. In augmenting existing deployments, Farpoint Group generally
assumes a 1:4 to 1:6 relationship between spectrally-enabled APs and others. While some
compromise in capability is inherent in a partial deployment, the cost can be quite low. In
addition, it may be necessary to perform functional verification on a client-type basis
against two different APs in the partial case, but these costs should be quite low and are
regardless a function of local policies and procedures. The only other cost is that required
for an appliance to implement location functionality; again, this is quite minimal given
the overall cost of the installation. The incremental cost of adding centralized spectral