Comparing costs of wireless LAN options

It can be hard to predict costs when planning a large-scale wireless LAN (WLAN). What impact does the new technology have on existing products, policies and procedures? Is there a significant learning curve to implement the new solution? How difficult is the new network to manage? How long will it last?

As with any networking technology, deploying a new WLAN incurs both capital and operational expenses. The features and functionalities of a WLAN solution determine the extent of these costs, which can vary dramatically. However, new WLAN architectures are emerging that reduce capital expenditures and ease operational burdens, helping enterprises to reap the value of wireless with minimal impact on the bottom line.

A Capital Idea

A move to wireless technology requires an investment in new hardware and software. This is unavoidable. To illustrate a specific capital cost comparison between common WLAN architectures, we will use the fictitious enterprise, Untethered Corp.

Building type: Hard (solid) walls & Structural (open) ceilings
Building size:675,000 square feet
Number of wireless users:1,500
Existing LAN:Ethernet w/ Power over Ethernet (PoE) capabilities

Architecture 101: The market currently offers two approaches to deploying WLANs. The traditional WLAN architecture was designed to function as a stand-alone network or to provide isolated wireless access to a network. As such, the traditional WLAN is based on a single device known as a "fat" access point (AP), which contains all the mandatory wireless processing capabilities.

Comparatively, the hierarchical WLAN architecture was designed with flexibility in mind in order to be used for a variety of applications, including mass network coverage. The hierarchical architecture uses a two-tiered hardware approach based on a "lightweight" AP connected directly to a wireless switch or indirectly to a wireless appliance. The lightweight AP delivers radio frequency (RF) functions, while the wireless switch or appliance controls the intelligent wireless processes.

The complete package: Any wireless LAN solution can provide basic RF connectivity. A complete solution, designed for business usage, will go beyond this to support key applications, provide extra security, and make day-to-day management more cost effective. As a result, an enterprise-grade WLAN solution, such as the one required by Untethered Corp., should also provide automated RF management, AP management, seamless mobility, wireless intrusion protection, virtual private network (VPN) concentration and wireless security.

Traditional WLAN architectures provide only a subset of this functionality. To create a complete WLAN solution, enterprises using these products are forced to deploy a variety of different appliances to address these deficiencies, such as a mobility manager, VPN concentrator, intrusion detection systems system, etc. For a company like Untethered, these appliances can easily add over $200,000 in extra equipment costs.[1]

On the other hand, many hierarchical WLAN solutions combine the functionality of several of these distinct products into one tightly integrated platform. As a result, there is no need to purchase numerous separate appliances to handle these capabilities, making the new generation architecture extremely cost effective for Untethered's network environment.

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Putting APs on a diet: Traditional WLAN solutions can be expensive to implement in large-scale enterprise environments. That is because most of the costly intelligence resides in the AP itself, adding to their overall cost. A company like Untethered would require approximately 225 traditional APs to meet their users' wireless requirements.[2] At $1,100 per fat AP [3], this equals $247,500 in equipment costs.

The newer hierarchical WLAN architecture centralizes intelligence within a wireless switch/appliance, while pushing policy information to lightweight APs for execution. As these APs are more cost effective than traditional APs, this architecture dramatically reduces WLAN equipment costs. When factoring in the switch/appliance price, the cost per managed AP is usually 33% lower for a hierarchical WLAN than for a traditional WLAN, representing a cost savings of $82,500 for Untethered. [4]

Unified air traffic control: Most corporations require real-time monitoring of the air space for intrusion protection, RF management, and seamless operations. Newer WLAN architectures can deliver this functionality simultaneously with traffic delivery - i.e. via the same AP. This is dramatically different from rational WLAN solutions that require one set of APs for monitoring and another set for traffic forwarding.

For these solutions to provide a minimal level of effectiveness, one monitoring device is recommended for every three service delivery APs. Assuming Untethered requires 225 multipurpose APs, a competitive solution would require 300 traditional APs. At an average monitoring AP price of $400 [5], newer generation WLAN solutions can save Untethered approximately $30,000.

LAN evolution, not revolution: Wire-line networks have been around for a long time. They work, and corporations have invested significant amounts of time and money into their development. Therefore, WLANs must coexist with existing LAN infrastructures, not replace them.

Hierarchical WLAN appliances enable IT staff to build a wireless network on top of existing Ethernet LANs. Appliances connect to the back end of existing Ethernet switches providing RF management, mobility and security functions to any APs connected to the switches. This eliminates the need to replace existing wire-line switching functionality. In environments without wire-line switching with PoE, hierarchical switches can be used to deliver both wireless and wire-line switching functionality. Additionally, many hierarchical WLANs integrate with existing corporate wire-line schemes including quality of service, virtual LAN and security such as IPsec, 802.1x and RADIUS.

Traditional WLANs also integrate into existing Ethernet LANs, by connecting fat APs directly to an existing LAN switch. However, due to localized processing by fat APs, an IT department requiring centralized network management capabilities is tied to a single wireless vendor. Conversely, hierarchical WLAN products can integrate into existing WLAN deployments. Fat APs can be managed by a hierarchical switch/appliance performing software configuration, mobility management and power output, among other functions.

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Opinion
Bob O
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Service failure is not an option: Business-critical networks must be reliable. Loss of network connectivity can have a direct impact on profitability.

Newer WLAN solutions address this issue by building fault tolerance directly into the RF domain. Using RF intelligence, the WLAN network detects the loss of a switch/appliance and "herds" users to the best available device via the air space. These systems also detect the loss of an AP, and intelligently adjust the power output and signal strength of adjacent APs to compensate for the loss. Handling fault tolerance via RF intelligence saves approximately 40% [6] of the cabling and hardware costs required by alternative solutions.

Smooth Operations

While capital costs are usually the easiest to quantify, operational costs can have the largest impact on an enterprise. Introducing a new technology into an existing network environment can be costly if handled improperly. Ideal solutions minimize costs by automating the key tasks associated with wireless deployment and operations. This flattens the learning curve for WLANs, and reduces IT burdens by curtailing hands-on management.

Dynamic engine races through deployment: Effective software engines incorporating dynamic RF intelligence save significant time and money during deployment by minimizing the need for site survey tools. With self-configuring software that dynamically adapts to the RF environment, there is limited need to perform site surveys to determine "optimal" radio placement and configuration. The network will take care of itself once deployed. As a full site survey might cost $5,000 for every 20,000 square feet [7], the intelligent software solution could save an enterprise like Untethered $170,000.

Central intelligence can promote dynamic operations: By concentrating intelligence within a switch/appliance, hierarchical solutions provide a centralized view of an entire wireless network. This enables easy policy (QoS, security, VLANs, etc.) creation and enforcement across thousands of APs, without requiring individual AP management.

Some hierarchical software solutions use dynamic RF intelligence to further reduce management costs by adapting WLAN characteristics in real-time to ensure optimal coverage and capacity. By creating a network that self-configures in real-time, network administrators are relieved from the burden of minute-by-minute WLAN monitoring and maintenance.

A WLAN solution delivering dynamic RF intelligence in real-time demands minimal in-house RF expertise, requiring no expensive RF training or new administrative resources for network support. Less intuitive wireless software solutions would require two new full-time staff members to handle Untethered's daily WLAN management. A self-optimizing software solution would require one half of a new resource [8]. The intelligent software platform could save Untethered close to $150,000 in annual salary costs [9], and tens of thousands of dollars in training costs.

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Cancel that order for new trouble tickets: Network troubleshooting can be costly. Responding to reports, isolating faults, and resolving problems takes a significant amount of time and resources. Real-time dynamic RF intelligence solutions reduce troubleshooting costs by ensuring problems are resolved before they impact the end user.

Problems that are unable to be dynamically addressed should be easily diagnosed through a user-friendly management software interface. Optimal solutions provide graphical analysis and trending tools for rapid fault detection, isolation and correction, giving IT staff visibility into the complete RF environment. These tools illustrate WLAN characteristics including traffic load, interference, noise level, signal strength and network topology.

As a single trouble ticket can cost $50 to resolve [10] (includes IT staff time, plus loss of productivity), Untethered's network might generate close to $20,000 annually in troubleshooting costs. The newer self-healing capabilities and advanced monitoring tools of some hierarchical software solutions are estimated to avoid 75% of these costs, saving $15,000 in annual operational expenses.

The options are clear for enterprises looking to deploy business critical wireless networks. I believe a hierarchical WLAN architecture solution with real-time dynamic RF intelligence may offer the highest level of WLAN functionality in the industry with the lowest total cost of ownership.

TCO Summary

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Traditional WLAN Hierarchical WLAN
Investment Costs
Site Survey $170,000 N/A
WLAN Infrastructure (a/b/g) $337,500 $225,000

Point appliances

– RF management

– Mobility

– IDS

– Security
$245,000 N/A
Monitoring APs $30,000 N/A
$782,500 $225,000
Annual Operating Expenses
Salary $200,000 (2 IT staff) $50,000 (1/2 IT staff)
Trouble Ticket costs $20,000 $5,000
$220,000/year $55,000/year

Notes: [1] - From Airespace sampling of average industry prices for various appliance products - November 2003. [2] - WLAN deployment best practices indicates 1 AP required for every 3,000 - 7,000 feet in a typical office environment. [3] - AP pricing taken from numbers in a recent industry publication (Oct. 2, 2003). [4] - Taken from total solution pricing provided to a mock RFP in an industry publication (Oct. 2, 2003). [5] - Taken from average pricing of leading vendor solutions taken from publication reviews and vendor press releases (Q3 2003). [6] - Assumes alternative solutions require dual-homing of all APs. Industry best practices indicates that this accounts for 40% of total cabling costs. [7] - Average price quoted from several VARs offering site survey services. [8] - Average full-time equivalent (FTE) employee required across 20 Airespace WLAN deployments. [9] - One-half FTE saved at $100,000/FTE (industry average salary for a WLAN administrator) = $150,000.

[10] - Based on average costs quoted by Airespace customers.

Copyright © 2004 IDG Communications, Inc.

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