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This dierence is even more pronounced with 802.11n which makes heavy use o multiple

streams (MIMO) and advanced signal processing techniques to boost perormance.

Trying to iner high rate data perormance or multiple 802.11n data streams rom a

single stream, low rate encoded signal is simply not viable. As Craig Mathias, Principal at

Farpoint Group asserts, With the high degree o instantaneous variability in propagation

inherent in 802.11n, site surveys really are close to nonsense today. 1(Phier, 2010)

Measuring the signal strength alone also bypasses signifcant inrastructure unctions such

as the DHCP and authentication servers, backhaul links, and wireless controllers. APs willcontinue to advertise their presence, even i they cannot accept more users or eectively

route user trafc to the Internet due to limited backhaul bandwidth, a broken backhaul

connection, or misconfgured equipment.

Clearly, the ability to detect a signal rom the AP is necessary in order or users to be able

to access the Wi-Fi network. However, the mere act that an AP is present and advertising

itsel is not sufcient to ensure that a user will achieve reasonable perormance and have

a satisactory experience. A much better criterion to use to sign o a network is whether or

not users would be satisfed with the application perormance that the network can deliver

when the venue is ully populated.

Optimizing or Coverage and not CapacityThe business and technical requirements o cellular ooad are completely juxtaposed to

those o traditional Wi-Fi. Traditionally, Wi-Fi access was a nice-to-have and the network

typically received relatively light use. Under those conditions, it does make some sense to

optimize the network or coverage rather than capacity. In modern ooad networks, the

802.11 usage scenario is defned by congregations o people carrying Wi-Fi-enabled

smart phones. The requirements to serve these customers demand that the network deliver

a satisactory experience to many concurrent users in a high density, heavily used location.

The Wi-Fi access network in this scenario is a critical inrastructure element o the cellular

network.

In large public venues such as stadiums, concerts, conerences, and airs, the number o

smart phones packed into a given area creates some o the most demanding scenarios

or 802.11 deployments. With nearly 50 percent o the population carrying and using

smart phones in modern cultures, and growing, these networks need a lot o capacity. The

challenge with a network designed primarily or coverage is that it uses relatively ew APs

to service large areas and will thereore have a large number o clients attempting to share

any given AP. In these environments, these networks quickly become congested and result

in requent user complaints that they see the network fne, but that it just doesnt work.

Another signifcant concern in large public venue deployments is the capabilities o the

wired inrastructure elements. With thousands o local users, multiple controllers, switches,

and servers must all be confgured and working properly in order to deliver a qualityexperience to all customers. Downloading a web page occasionally rom a single client

will oten work when the network is lightly loaded. When the network is ully loaded and

people are simultaneously trying to upload pictures, download web pages, stream video or

Skype with riends, the aggregate customer experience under scale is oten very dierent

rom the user experience o downloading a web page in an unloaded network.1 Phier, L. (2010, May 18). IxVeriWaves WaveDeploy Raises the Bar on WLAN Assessment. RetrievedFeb 24, 2011, rom Wi-Fi Planet: http://www.wi-fplanet.com/news/article.php/3882671/VeriWaves-WaveDe-ploy-Raises-the-Bar-on-WLAN-Assessment.htm

In large publicvenues such asstadiums, concerts,conerences, and

airs, the numbero smart phonespacked into a givenarea creates some othe most demandingscenarios or 802.11deployments.


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Sometimes the results are manually recorded. Most times it is simply assumed that the

technician verifed the deployment and no data is recorded.

The biggest issue with this approach is that it is human nature to see the result that you

want. I the network seems a little slow in a given spot or a download ails, it is easy

enough to retake the data a couple o times until you get the answer that you want and

convince yoursel that the network is probably fne. I it is late in the day and people are

anxious to go home then they will be more likely to obtain the desired result.

The obvious consequence o each o these problems is that they will ultimately result inservice calls or deection o mobile smart phone customers i they persist. For the proactive

operator, aggressively addressing these challenges and improving the quality o their

solution during deployment represents an opportunity to attract customers rom slow-moving

competitors and retain existing customers via higher renewal rates.

Core Technical Principles o NextGeneration Best PracticesThe defning principles o the next generation o best practices are:

Use application trafc in addition to just signal strength as measurement sources

Report customer satisaction metrics

Use the same high-value client devices that networks users will have

Be able to test network scalability prior to heavy usage at events

Be able to isolate client behavior rom network behavior

In essence, it involves moving beyond site survey and into site assessment. Site assessments

can be run in a similar amount o time as a site survey, but provide a much more

comprehensive view o networks ability deliver customer satisaction, and a more powerul

set o metrics as the deployment sign-o criteria.

The major principle o site assessment is to use application trafc and measure

the customer experience directly rather than iner it rom signal strength as is done

with site survey. This approach detects a much broader range o deployment issues

including misconfgurations o network elements, improperly installed APs with marginal

perormance, network problems caused by client behaviors, and noise. In short, any issue

that degrades customer experience can be detected by measuring the actual customer

experience.

The ability to scale the network allows network deployment to be properly stress-tested

prior to key events and can eliminate or greatly mitigate the normal scrambling that occurson the frst day or two o a large, public event.

The major principleo site assessmentis to use applicationtrafc and measurethe customerexperience directlyrather than iner itrom signal strengthas is done with sitesurvey.


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Equally important to the measurement technique is the ability to isolate the source o

identifed issues to the client or to the network. Service providers are able to easily

address network-related issues once they are identifed using existing practices. Somewhat

surprisingly, it is also true that some signifcant client issues can also be addressed

through alternative network confgurations This ability to take action is the reason why it

is important to know which client devices matter most to your business and to understand

which specifc client behaviors are leading to a degraded user experience. Once known,

alternative confgurations can be tested to deliver optimized perormance to the most

valuable users.

New Product Solutions Supporting New Best Practices

The remainder o this document examines how to apply the best practices in live

engagements. The key enabling technology is the WaveDeploy product amily rom

IxVeriWave. WaveDeploy is the only site assessment solution available today.

The majority o the best practices in this document will require WaveDeploy Pro or Expert.

The reader is encouraged to learn more about WaveDeploy at www.wavedeploy.com or

contact IxVeriWave at +1-503-473-8350 to discuss upcoming projects.

Although the main ocus o this best practices guide is the Wi-Fi network, WaveDeploy willalso work with other IP networking technologies including 3G, 4G, Ethernet, and Home

Networking technologies. This inormation can be extremely valuable to developing a

holistic view o a sites perormance, and it is readily gathered using the same techniques

described in this document.

When conducting feld testing use WaveDeploy to measure real end-user QoE o actual

application trafc, such as web download, Voice over IP (VoIP) calls, and streaming video.

For example, voice quality can only be conclusively assessed by measuring the Mean

Opinion Score (MOS) while web surfng quality can be assessed by measuring eective

web download speeds. Since actual client devices are a main contributor to end-user QoE,

site assessment needs to be conducted with the actual end-user devices. WaveDeploy testsare conducted using the actual devices, without the need to install proprietary or special-

purpose WLAN adapters in them. Actual user devices include laptops, netbooks, smart-

phones, PDAs, scanners, and a variety o other WLAN enabled clients. WaveDeploy tests

oer the unique Single Pass Site Survey allowing the tester to conduct a single pass through

the assessed acility with all client types being tested.

Conducting a site assessment in ideal network conditions with little, or low, load provides

a baseline o the network and indicates undamental dierences between various client

types and the expected end-user experience. Since real networks are rarely lightly loaded,

WaveDeploy adds the ability to measure end-user QoE in the presence o pre-defned,

vertical market specifc, load.

Since real networksare rarely lightlyloaded, WaveDeployadds the ability to

measure end-userQoE in the presenceo pre-defned,vertical marketspecifc, load.


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EF101 acting asSationary Server

Mobile Clients runningWaveAgent

(laptops,netbooks,smart-phones, etc.)

WaveDeploy runs on laptopalso running WaveAgent

Figure 1. Site Assessment in ideal or lightly loaded network conditions

Conducting a site assessment in realistic network conditions may be impractical or

impossible. For example, when a WLAN is deployed and users have not yet moved into

the acility, it is impossible to create the entire planned trafc load one would expect. By

utilizing WaveDeploy Expert and the WF1101 Trafc Generator, the network can be

loaded with trafc rom hundreds o golden clients that emulate the trafc loads users will

place on the network when they start using it. Not only does this expedite testing, it allows

the tester to detect any defciencies in the network or in mobile-client interaction beore

actual users move in and experience difculties.

EF1101 acting asStationary Server

Mobile Clients runningWaveAgent

(laptops,netbooks,smart-phones, etc.)

WF1101 creates pre-defined,vertical market specific,

load conditions (healthcare, retail,corporate, education, hospitality, etc.)

WaveDeploy runs on laptalso running WaveAgent

Network Under Test

Figure 2. Conducting Site Assessment in planned, realistic, loaded, network conditions

[WaveDeploy]allows the testerto detect anydefciencies in

the network orin mobile-clientinteraction beoreactual users movein and experiencedifculties.


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It is highly recommended that any proposed SLAs be tested in the lab environment using

the WaveTest system rom IxVeriWave. The WaveTest solution is a powerul chassis-

based system that allows users to create thousands o users in a lab environment beore a

deployment is conducted. Using this equipment enables carriers to perorm the ollowing

tasks prior to deployment:

Perorm bakeo testing between competing equipment providers prior to purchase

Determine the application-level SLAs that the AP is capable o delivering prior to

deployment

Scale a solution to thousands o users to determine i there are any breakdowns in

system perormance (APs, controllers, servers, etc.) as the solution is scaled

Test alternative deployment confgurations or easibility

Ater equipment has been deployed into a live production network, the WaveTest is useul

or:

Recreating feld-detected issues in the lab so that they can be addressed and verifed

fxed

Regression testing new releases o inrastructure equipment prior to deployment in the

live network

Interoperability testing new client devices or upgrades to existing devices to identiy

any potential issues

Determine i new overlay services can realistically be supported by the network prior to

live deployment

The combination o WaveTest and WaveDeploy is powerul to service providers because

the solutions share a common set o measurement technologies that allow measurements

made in the lab and feld to be very strongly correlated. For large, high value

deployments, this combination o solutions enables the engineering team to work hand-in-

hand with the feld team to ensure the best possible solution.

A comprehensive discussion o the WaveTest solution is beyond the scope o this document.

The reader is encouraged to go to www.VeriWave.com or to contact IxVeriWave at

+1-503-473-8350 or more inormation.

New Site Deployment StratagiesFor simplicity, this best practices guide will discuss the best practices in the context o

a stadium deployment. The same principles can be applied equally well to the other

potential large, public venues. However, or clarity o communication, the remainder o thedocument is ramed within the stadium context.

In addition to adopting the new assessment capabilities, it is necessary or organizations

to modiy their business practices to more eectively address the goals o cellular ooad.

Previous practices assume too much accuracy o the paper design. The corresponding

deployment process is to install an entire acility and then test to make sure that coverage

goals are met.

The WaveTestsolution is apowerul chassis-based system thatallows users tocreate thousandso users in a labenvironment beorea deployment isconducted.


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As we have been engaged by customers to evaluate these previous deployments, we fnd

that the installations all ar short o the expected capacity, despite generally meeting the

coverage goals. Most o the root causes o the identifed issues have been associated with

site-specifc causes such as construction materials, AP density, and intererence to name a

ew.

For example, concrete poured at dierent times is made o dierent amounts and

types o materials and contains dierent amounts o steel rebar. These items can have

a substantially negative impact on Wi-Fi signal propagation in some cases, and benegligible in others. Ironically, newer concrete tends to be more problematic because it

usually contains more rebar than older concrete.

Another example is when management trafc crowds out user data trafc. The amount o

channel bandwidth consumed by management trafc is directly related to the number o

APs that can be heard on a given channel. In many deployments, the radios are set at their

maximum transmit power, and the overall channel utilization becomes dominated by the

low rate beacon rames rom all o the APs leaving little room or client data trafc.

Since the emerging best practices need to ocus on the quality o experience or client data

trafc, it is important to identiy and address as many o these issues as possible beore

a broad scale deployment. Sending and measuring data trafc is the only way to detectmany o these issues. It is yet another example where work done up ront can pay or itsel

many times over through rework avoidance and retained and attracted customers.

The new best practices dictate that the equipment installation should be installed and

powered up in stages or sections. The frst section installed will also be the most heavily

tested. The goal o that testing will be to make sure that the equipment placement is correct,

the confguration optimized, and that the SLAs can be met at the target capacity. This is

eectively a prototype o the design at the site. Any modifcations to the design at this point

should be incorporated into the rest o the network build out.

During the testing o the frst section, any additional access points in the deployment that

are not within the section under test should be powered o. Again, the best practice is notto install them at all. The goal o this frst section o testing is to identiy what is required to

get the section to unction at the target levels without the issues o cochannel intererence

rom other APs within the deployment.

I a second section can be installed and tested without the need to assign two APs to the

same channel then that is the next reasonable step. The second section should be adjacent

to the frst and the placement o the APs and network confguration should be based on the

design ater it has been updated with the changes resulting rom the installation o the frst

section. This testing is much aster to complete because it will most oten track the results o

the frst section. In cases where there are dierences, the dierences are usually the result

o a single issue and are thereore easily remediated.

Usually at the third section, the realities o Wi-Fi in the 2.4 GHz band assert themselves

and it is necessary to begin confguring APs that reuse existing channels. This testing is

much more like the testing o the frst section in that it requires a bit more data to be taken.

The primary concern with this third section is that cochannel intererence rom the APs will

become a major concern and impact the SLA compliance.

In manydeployments, theradios are set attheir maximumtransmit power, and

the overall channelutilization becomesdominated by thelow rate beaconrames rom all othe APs leaving littleroom or client data

trafc.


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Once the testing o the third section is complete, it is oten useul to have a ollow up

meeting with the non-technical parties involved in the project. This is the ideal point to

confrm SLA metrics or discuss any tradeos that need to be made beore doing the ull

deployment.

With everyone knowing what to expect and with the design well-vetted, it is generally fne

to go orward with the remainder o the build out. Each new section should be tested or

capacity, SLA compliance, and coverage, but this testing is now very quick to complete.

Note that at each step along the way, it is possible to obtain a report as well as all o thedetailed data associated with the testing. These reports are critical to knowing that the

installation work was done correctly and completely. At the risk o belaboring the point, a

test should be run ater each incremental change during the design and a report generated

or saved to document the results. I issues later come up ater the deployment, these reports

serve as a powerul baseline or determining what has changed.

Upon completion o this process, you will know the level o perormance that can be

oered to your customers and delivered with confdence. It is easy enough to monitor the

trends at the sites over time to determine when the usage patterns exceed the design points

and know that it is time to upgrade the network beore your customers start to complain

too. This process allows service providers to leverage the high perormance and low costo Wi-Fi to deliver an outstanding customer experience to their highest margin mobile

customers.

Preparing to go OnsiteThere is no better message when it comes to these engagements than the Boy Scout motto

o Be Prepared. There are a number o details that can be easily addressed prior to going

onsite, and there are a number o potential directions that a deployment test can take i

the results are unexpected. It is best to eliminate as many potential problems beore going

onsite and plan or things to go wrong when you get there. It can be extremely rustrating

to arrive onsite and realize that the critical personnel are unavailable to confgure thenetwork, that you do not know the security settings, or that you orgot to charge the battery

beore you let since you assumed that wall power would be readily available. Planning

or these items ahead o time, and communicating the necessary support to others in the

project, is critical to minimizing the cost and time involved with the deployment testing.

Start by obtaining the necessary background inormation o the network and acility. Make

sure you obtain image fles or the site that will be tested and be clear with everyone

regarding where the frst section to be tested is located. Make sure you have access to get

onsite so that the security guard does not turn your team away when you show up.

Then make sure you have the inormation about the network itsel. Make sure the team

knows the SSID o the network that will be tested, the security settings, and the securitycredentials such as certifcates or passwords that may be required. Note the intended

install location o the APs, their associated BSSIDs and channels on one o the maps.

Distribute this map to everyone on the team and especially the installers!


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It is oten necessary or service providers to deploy in an environment where customers

are active so some consideration should be given to restrict the network access to only

those involved in testing. Hidden SSIDs or security are oten used to restrict access. MAC

address fltering can also be used, but is generally not advised when testing at scale

using the WF1101 appliance due to the large number o MAC addresses involved. Some

client devices do not unction well with hidden SSIDs. Some client and network devices

perorm worse with security enabled than when they are open with no encryption. The best

approach to address this issue is veriy proper operation ahead o time in the lab using the

same equipment as will be used in the assessment.

Install all o the necessary WaveDeploy and WaveAgent resources on the target

devices beore going onsite. Make sure you have the latest version o the application

by downloading it rom http://www.wavedeploy.com. The WaveAgents or all o the

platorms except Apple iDevices are included in the installer and can be ound in the Start

menu. The iDevice versions o WaveAgent must be downloaded rom the Apple App Store

to the iDevice using iTunes. Make sure you activate the WaveDeploy application licenses,

including the support license i purchased. Make sure that you can run a Pro Assessment

by ollowing the example in the help fle and veriy that you know how to include all

components. Clariy the dierence between a speed test and concurrent trafc.

Note that it also helps to become amiliar with the smart phone behaviors. Many othese devices will sleep very quickly to conserve power, roam aggressively to maximize

perormance, or conversely roam very little to minimize risk o roaming ailures and service

interruption, and have limited data handling capabilities. Understanding the behavior

o these devices beore going onsite enables the tester to much more quickly pinpoint

abnormal operation and fnd workarounds or unwanted device behaviors.

I you will be using the WaveDeploy Expert solution then make sure you have updated

the frmware and know how to connect the device to the network under test and run an

assessment. Make sure that you are amiliar with how to confgure the WF1101 beore

going onsite. Make sure you know how to run an ecosystem test, view results, and

download and view a capture fle rom both the WF1101 and the EF1101 appliances.

The fnal equipment preparation involves making sure you have all o the necessary

cabling, antennas, chargers, batteries, etc. to conduct the test. Charge the batteries beore

you go as power is not always readily available.

Locating the WaveDeploy Stationary Server orEF1101 Appliance

The fnal steps in site preparation involve determining where the Stationary Server will be

located and getting its network resources provisioned. The Stationary Server can be a high

perormance server, laptop, or desktop provided by the customer running the WaveAgent

sotware or, preerably an EF1101 appliance. The Stationary Server terminates all o the

trafc in the network inrastructure by acting as a web server, VoIP endpoint, video server,

etc.

The location o the Stationary Server requires careul consideration because it needs to

be reachable by all clients involved in the assessment. WaveDeploy supports a variety o

approaches that can be utilized depending on the requirements o the service provider and

available resources at the deployment site.

Understanding thebehavior o thesedevices beoregoing onsite enablesthe tester to muchmore quicklypinpoint abnormal

operation and fndworkarounds orunwanted devicebehaviors.


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Mobile Agent

Installed Software:

WaveDeploy, WaveAgent

WLAN Controller

Internet

Hot Spot ManagementWeb Authentication

Billing

Access Point

Access Point

Ethernet Switch

Figure 3.

Figure 3 shows a typical controller-based hot spot deployment. There are two specifc

unctions that commonly play into the choice o what equipment, topology, and

confguration to use:

Web authentication

Firewall settings

Web authentication reers to the mechanism whereby a user must open his browser,

and is presented with a page where billing inormation can be provided and terms and

conditions are presented that must be accepted prior to using the network. There is a

specifc challenge with web authentication because there is no supporting standard. Each

vendor implements web authentication dierently, and the implementations can vary

between products rom the same manuacturer or even between releases in the same

product amily.

It is easy or people to interpret these screens and decide what inormation to provide and

where they should click. It is a much more difcult task to automate this process. I possible,

it is best to choose a confguration that circumvents the web authentication mechanism.

I web authentication must be used then one can always use WaveDeploy Pro which

allows up to 10 client devices in the test. The tester would navigate the web authentication

procedure prior to initiating testing.

Firewalls can also be a challenge to testing. WaveDeploy utilizes a distributed protocol

that communicates using UDP on port 18100 by deault. I a frewall is in use then a rule

must be created to allow this trafc to ow.

In practice, we have ound that the most ideal situation is when the Stationary Server

can be connected to an available port on the Ethernet switch as show in fgure 4. In this

confguration, the clients do not need to complete a web authentication in order to be

able to send trafc between the clients and the server, making this confguration ideal or

conducting a scalability assessment o the Wi-Fi network. Furthermore, this arrangement

provides the most direct measure o the wireless networks perormance because it

minimizes the number o devices in the ow between client and server.

Web authenticationreers to themechanism whereby

a user must openhis browser, and ispresented with apage where billinginormation can beprovided and termsand conditions are

presented that mustbe accepted prior tousing the network.


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Mobile Agent

Installed Software:WaveDeploy, WaveAgent

WLAN Controller

Internet


Billing

Access Point

Access Point

Ethernet Switch

EF1101 or Stationary Server

Figure 4

There may be situations where it is not possible to access the Ethernet inrastructure,

commonly an issue in a small hot spot deployment, or where the service provider wishes to

include the eects o the web authentication device. In this case, one is generally advisedto use WaveDeploy Pro and manually navigate the web authentication unction. An

Stationary Server is placed onto the Internet, oten in the Service Provider data center, that

can be used by the technicians as shown in fgure 5.

Mobile Agent

Installed Software:WaveDeploy, WaveAgent

WLAN Controller

Internet


Billing

Access Point

Access Point

Ethernet Switch

EF1101 or Stationary Server

Figure 5

Once you have your topology selected, there are still a ew more tasks that can be

completed beore you go onsite. First, make sure that the Ethernet ports are provisioned

or your use prior to arrival and be sure to understand how you will know which ports to

use and how to access them. Secondly, provision IP addresses or any devices that will

be statically confgured with IP inormation. Finally, have any onsite resources run a quick

connectivity check between the two locations where the Wi-Fi client and the Stationary

Server are located (or as close to that confguration as you can reasonably get). There are

sometimes issues in larger deployments with controller-to-controller trafc or segmentation

o the Ethernet network.


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Defning Loads and Service Level Agreements

WaveDeploy applies a service level agreement to each measurement o every client.

It is critical that each service provider consider the intended SLAs prior to conducting

assessments. Generally speaking, most service providers have existing SLAs that they

aspire to provide, generally specifed in terms o a download speed in Mbps.

This requirement serves as a great starting point, but the SLA is rarely specifed in enough

detail to be used directly in an assessment because the conditions under which that SLA

should hold are not well understood. Traditionally, this lack o clarity has not been a big

problem because the access points were so lightly loaded that they do have the raw

ability to provide the SLA (although deployment issues still severely limited connectivity

and perormance). Large public venues, however, represent the perect storm o high

user density, high network loads, high user expectations, and high visibility. In these

environments, it is critical to careully consider and defne the conditions under which the

SLA should be met.

Items that are oten omitted, but that must be clearly understood as part o the SLA

defnition include:

How many total clients will be connected to the each AP?

How many o the clients will be inactive? An inactive client connects with the AP, but

does not send a signifcant amount o trafc. An example would be a smart phone in a

users pocket.

What are the highest value client types?

For each high value client...

How many clients will be actively connected?

What types o trafc will each client generate or consume and at what rates?

Remember that dierent client devices will have dierent profles. An 802.11g smart phone

would typically expect to achieve a lower level o perormance than a 3x3 802.11n laptop

operating with 40 MHz o bandwidth. It is important to clariy i the goal is to provide the

same level o service to everyone or i dierent classes o devices should experience the

network dierently.

Once calculated, these numbers can and should be verifed or validity via lab testing by

the engineers o the service provider beore doing a ull installation. We have seen in a

number o installations where the requirements being asked o the network ar exceeded its

capabilities. This error, o course, is one o the primary contributors to the degraded Wi-Fi

perormance that ultimately leads to an erosion o the customer base. I detected during

the design phase, this issue can be addressed by modiying the installation plans or bylowering the SLAs to a more reasonable level or the venue and ensuring that every user is

able to achieve a consistent, albeit degraded experience.


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SLA Example Calculation

The ollowing is an example o how to determine SLAs or a stadium deployment.

Stadium deployments certainly qualiy as some o the most challenging Wi-Fi deployment

environments because o the smart phone density, high user expectations, high trafc

load, and challenging RF environment. It is a convenient example to use because it is

easy or most readers to visualize. Nevertheless, it is important to recognize that the same

techniques described in this section will also work or other venues such as concerts, airs,

and conerences.

We will start with the assumption that the business team has indicated that 50% o the

attendees to a given event will have Wi-Fi- enabled smart phones. Base on previous events,

it is assumed that 80% o the devices will be inactive, which means that they will be

connected to the network, but transmitting only a tiny amount o data. The expectation is

that 25% o the active users will be using voice. All o the active users will be transmitting

and receiving web data at 750 kbps in each direction. This assumption is because the

event coordinators noticed that a large number o people are uploading pictures and

downloading a variety o material during the event.

The network being designed is an 802.11g network to maximize compatibility with

existing smart phones. An 802.11g access point has a maximum PHY rate o 54 Mbps,which corresponds to a maximum o about 30 Mbps o application trafc once protocol

overhead is accounted or. The design team decides to target 15 Mbps o worst-case

application load per each AP to provide some perormance tolerance to account or likely

deployment conditions such as a lower actual PHY rate, some intererence, and smaller

rame sizes.

We can now write an equation or the total trafc load as:

Total Load = TC x 0.8 x BL + TC x 0.2 x WL + TC x 0.2 x 0.25 x VL

Where:

TC = Total number o client devices

BL = Background load per inactive client

WL = Web load per client

VL = Voice load per client

For our examples, we can substitute the ollowing rates in Mbps:

BL = 0.01 (10 kbps)

WL = 1.5 (750 kbps + 750 kbps)

VL = 0.16 (160 kbps fxed by WaveDeploy or G711 encoded voice trafc)

Total Load = 15


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I we substitute the variables and solve or Total Clients we get:

15 = TC x 0.8 x 0.01 + TC x 0.2 x 1.5 + TC x 0.2 x 0.25 x 0.16

15 = TC x 0.008 + TC x 0.3 + TC x 0.08

15 = TC (0.008 + 0.3 + 0.08)

15 = 0.388 x TC o TC = 39 clients per AP

I we then use our ormulas to derive our client counts again, we get: 31 Inactive Clients generating 10 kbps o background load each

6 Active Clients generating 750 kbps upload and 750 kbps download web trafc

2 Active Clients generating 750 kbps upload, 750 kbps download web and 160kbps o voice

Because it is assumed that 50% o the stadium attendees have smart phones, one can then

calculate that the expectation is that a single AP will serve 39 x 2 = 78 people.

As a check, consider the required AP density or a small ootball stadium that holds

30,000 people. Note that 30,000 people would be considered a very small stadium

and that many important venues are considerably larger (Wikipedia).2 According to theabove calculations, it would be necessary to deploy a minimum o 30,000 / 78 = 384

APs to provide the necessary capacity to deliver on the above SLAs. This number is critical

or testing the validity o the SLAs rom a business sense. I the required number o APs is

too high to justiy economically then the defnition o the project or the SLAs will need to

change accordingly. This defnitional work should be done prior to any deployment.

I the SLAs are acceptable, it would be wise to ensure that the proposed solution can

deliver the requested level o unctionality in the lab prior to deploying hundreds o APs.

It is preerable to use the WaveTest solution to perorm this testing because it oers higher

scalability and more exibility o test confguration than the WaveDeploy solution.

Once the lab testing is complete, the WaveDeploy SLAs can be confgured in accordance

with the inormation above. The target client should be confgured with the maximum

number o applications that people are expected to use. In our example, this would mean

upstream HTTP, downstream HTTP, and voice trafc. The remainder o the clients will be

created in the IxVeriWave hardware in the loaded network condition.

Testing the Initial SectionOnce the lab testing is complete and the SLAs are proven viable in a lab environment, it is

time to start testing the frst deployed section at the site. The goal o the prototype testing

is to prove out that the SLAs established in the lab can be supported in a representative

deployment. New issues can arise at the site that would not normally be present in the labtesting such as:

AP placement considerations: it is not always possible to place an AP in the ideal

technical location. For example, aesthetic considerations may prevent placing in

certain desired locations and a lack o accessible wiring may rule out other locations.

2 Wikipedia. (n.d.). List o American Football Stadiums by Capacity. Retrieved Feb. 15, 2011, romWikipedia: http://en.wikipedia.org/wiki/List_o_American_ootball_stadiums_by_capacity

The goal o theprototype testingis to prove outthat the SLAsestablished in thelab can be supportedin a representativedeployment.


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Intererence: numerous potential intererence sources exist onsite that are not present in

the lab.

Network topology considerations: it isnt always possible to get the wired inrastructure

confguration that is anticipated in the lab testing.

The goal o this initial testing is to optimize the deployment model to ft the realities o the

environment. Once the design is optimized or this one section, it can be repeated multiple

times with much less testing to fll out the remainder o the site. We have seen this step

skipped oten and the most common result is an expensive rework o the entire deployment,usually ater the embarrassment o a ailure under customer trafc at a large event.

It is important to remember to turn o all other APs that are part o the same network but

outside the section under test. At this point in time, the goal is to minimize the intererence

created by other APs in the same deployment. It is usually not possible to disable other

interering networks, in other words access points advertising network names (SSIDs)

dierent rom your target networks SSID, serving the same area. I you can disable them,

it is useul to do so as well in order to eliminate them as a possible intererence source too.

Once initial baseline testing is complete, the interering APs can be enabled and testing

can commence with the presence o intererence. I you cannot disable these interering

APs then just be aware o their potential impact on your results and assign APs to channelsthat have low utilization.

Veriy AP Placement and Confguration

The very frst test to be run is to simply walk through the target area and measure the

signal strength o every AP serving the location. Using a Windows laptop, run this test

with WaveDeploy in the Wi-Fi Scan Only mode. Walk through the target area, mark

your location on the map, and wait or the measurement to complete. Then simply move

to the next location and repeat. While you are walking, pay particular attention to where

the APs are physically mounted. Otentimes the locations are incorrect and do not match

the installation plan. Make a note o any unexpected placements. When the entire area is

covered, stop the test and view the results.

One the results screen, you will see all o the networks and APs that were detected and

their signal strength at each measurement location. Combining this inormation with your

notes enables you to veriy the location and confguration o all o the APs serving the frst

section. Record this inormation onto an updated image map. Unortunately, it is oten the

case that the APs are placed in the wrong physical location, specifc APs are swapped

by mistake and so are not where they should be according to the plan, the APs are on a

dierent channel than planned, or one or more o the APs is inoperable.

Experience dictates that the 30 minutes spent in this initial step is saves hours urther into

the process. Installers oten misread the plans, provide their own solutions to physicalmounting issues (such as placing an AP inside a steal I-Beam so that it mounts securely and

doesnt look bad!), or simply do a poor job o paying attention to details. By perorming

this initial assessment, you will know where every AP is located in the section and be able

to determine i your target device is connecting to one o the best available APs rom a

given location or not.

Experience dictatesthat the 30 minutesspent in this initialstep is saves hoursurther into theprocess.


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One other valuable data point that comes rom this assessment is a view into where the

interering networks are located, their channels o operations, and the potential strength o

their intererence. Armed with this inormation, it is worth considering i it makes sense to

reassign channels on the APs under your control to avoid these potential intererers.

Speed Test the Network Using a Single ClientAssessment

The next step is to perorm a single client assessment using a high perormance clientdevice. The goal o this testing is to determine i the network is able to cleanly deliver a

signifcant trafc load. The primary issue in this stage o testing is that the AP placement

can be allowing the network to unction, but only poorly so that it is able to orward some

trafc, but is still unable to support the load necessary or cellular ooad in a large public

venue.

The best way to perorm this test is to use a laptop and limit it to the 802.11 avors that

you target client will be using. For example, i the target client only supports 802.11g

and the laptop is an 802.11n capable laptop then disable the 802.11n unctionality on

the laptop so it will not use rates that are not supported by the target client. I the laptop

driver also support confguration o stickiness or roaming aggressiveness then set the client

to the most aggressive roaming / least sticky mode o operation. The goal is to measure

the best network perormance available at each location. By allowing the laptop to roam

aggressively, it will tend to move to the highest power APs sooner and thereore track the

network topology better.

In this test, trafc will be sent to a laptop running Wi-Fi rom the Stationary Server that you

provisioned earlier. Again, the results are more accurate as the Stationary Server is located

closer to the Wi-Fi network. Confgure the SLA or the Downstream TCP Speed Test so that

the target value is set to the maximum rate at which you want to oer trafc to the network

and the minimum acceptable rate is set to your SLA. For example, i you wanted to oer

trafc at up to 20 Mbps and would accept any actual trafc rate o more than 15 Mbps

as meeting your SLA then you would set your target to 20 Mbps and your minimum to 15Mbps. It is best practices to set your target SLA 20% or more higher than your minimum

SLA. This approach allows the results to account or the transient conditions that aect

perormance in the network.

The WaveDeploy speed tests are run without any other test trafc present in the network.

This means that the results represent the best raw perormance numbers that the client can

achieve in the network. This confguration is the closest to an ideal conditions test that can

be achieved in the feld. It is useul because i perormance is severely degraded in the

speed test then it makes no sense to continue with the additional clients and trafc types as

they will only degrade the network deployment urther.

Once all o the issues are addressed then it is reasonable to proceed to the next step:

concurrent application trafc with the target client as defned in the next section o this

guide. It is most common or perormance to be unacceptable in this initial deployment

speed test. Usually some locations can provide the necessary perormance while others

cannot. When examining the underperorming locations, it is useul to pay special attention

to which o the APs the client used to access the network. Remember that the location o

the APs rom the previous verifcation step. I the client made reasonable choices as to

which AP to use, but perormance was poor in spots then you likely have an installation



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issue relating to that one AP. I the client made poor choices or connected APs then it

necessary to use a WaveDeploy Expert to test perormance rom a given location to the

corresponding optimal AP as described below.

In the case where the client made reasonable connection decisions but still experienced

poor perormance, it makes sense to go back to the problem location and rerun the test

while using the WF1101 rom the WaveDeploy Expert solution to simultaneously capture

the trafc. The WF1101 captures all o the trafc rom all devices and provides additional

metrics that are not available rom a traditional laptop capture. Once the capture fle isopened, the frst thing to check or is low PHY rates and high rates o retransmission. I

PHY rates are consistently low or the AP or client, or example 11 Mbps or lower or an

802.11g network then this generally indicates that there is an RF problem. The most likely

source o problem, since intererence has been minimized or this test, is AP placement.

Retesting the point with dierent AP and client confgurations can be used to converge on

an ideal placement.

In the case where the client made poor connection decisions, the tester has the choice

o retaking the data using a dierent laptop or the WF1101. The WF1101 is capable

o achieving ull rate 802.11 transmission and reception without any loss or buering.

As such, it is a good solution or seeing the best possible perormance the network can

achieve since, unlike most clients, it can outperorm any networking device. The WF1101enables the user to control which AP it uses to make its connection to the network. Thus,

the user can orce the WF1101 to test any specifc AP in the initial deployment. This is a

bit more work or the user because the user must decide which AP to use or each location,

but it provides the user with unmatched control. In addition, the capture unctionality o

the WF1101 is also active while these tests are running. As a result, the user is able to

connect to the intended AP, perorm a measurement, and then examine the capture data as

described above i the perormance is lower than expected.

The speed test allows the user to identiy a whole class o additional issues that were

invisible in the previous testing:

Poor AP location aecting data perormance

Marginal APs APs with bad radios are unable to reliably transmit or receive at rate

Capacity holes Areas where additional APs are required to achieve necessary

perormance

Note that the emphasis at this step is determining coverage via the ability o the network to

deliver the necessary data orwarding perormance. I a confguration cannot be identifed

that delivers the necessary SLA then it is worthwhile to rework the SLA expectations based

upon the measured data. This method identifes issues with AP placement and operation

based on capacity and not radio coverage and thereore is much more closely tied to theactual customer experience.

Concurrent Application Trafc Test with the TargetClient

Once the speed test assessment is complete, the next step is to apply a typical load using

the target client. Concurrent trafc speaks to the multimodal behavior o smart phones

where a user may be accessing voice, video, and data concurrently. These dierent



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applications have dierent demands on delivery rate, jitter, and loss. As a result, the same

network conditions will produce dramatically dierent customer experiences or dierent

classes o trafc.

The client device has a great deal to do with the customers experience with the network

perormance associated with these applications. For example, a client device with an

underpowered transmit radio could result in a lot o missed acknowledgements by the AP.

The AP will then lower its PHY rate and retransmit the rame under the assumption that the

client did not properly receive its previous transmission.In this test, the WaveAgent is loaded onto the target client device, such as a smart phone,

and an assessment is conducted using concurrent trafc and speed tests. It is also very

useul to have the WF1101 running at the same time to capture the transactions. Many

popular phones, most notably iDevices, do not provide inormation regarding which AP

they are using to communicate with the network. The WF1101 can be used to capture this

inormation and make it available should any diagnostic work be required.

The assessment is taken as beore. This assessment will include both the passive test, the

TCP download speed test, and now will include the application trafc at their specifed SLA

levels as determined previously in the SLA calculation.

The results o this testing will usually be acceptable, but i ailures occur there are usually

one o a ew common reasons. I the concurrent application trafc was uniormly poor then

check the speed test to see i the client can even support the intended trafc load under

ideal conditions. I the client cannot achieve the necessary perormance in the speed test

then the SLAs will need to change or this device.

The next most common experience is that the behavior varies widely across the

measurement region, but all application trafc is aected together. This behavior is most

oten caused by poor roaming algorithms in the target client algorithms. I the connection

inormation is not available or the client in the WaveDeploy results, which happens

because the client device does not provide them through a standard programming

interace, then examination o the WF1101 generally will demonstrate i the client isroaming too aggressively or not aggressively enough.

Scaled Ecosystem Test

When conducting the scaled ecosystem test, you are working to ensure that the network

can continue to provide the proper quality o experience as the network is loaded

down with clients and trafc. As more clients are added to the environment the network

components must keep track o state or each one o them. In most networks, this will lead

to degraded perormance. Unortunately or service providers, this situation is the one that

occurs most requently when the high value events occur.

The principle behind the scaled ecosystem test is to use the WF1101 to create dozens o

representative clients that connect to the network and generate the loads. Then external

clients, such as a smart phone are walked through the ecosystem and the resulting

experience is measured by WaveDeploy. This style o testing is predictive o the quality

o experience that customers will receive when the network is under load.Results include

the amount o aggregate bandwidth delivered by the network, the total number o clients



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connected to the network, and the customer experience by application type or each client

in the network.

This test tends to identiy marginal network confgurations. There is a great deal more

statistical signifcance in the results because they represent the experience o dozens o

clients. It is one thing to maintain a connection with a single client, and entirely another

to maintain connections with every client in an ecosystem. Furthermore, the impact o

the environment and the scalability o the system on the external client is also measured.

Client issues are identifed that usually relate to an inability o the client where they cannotcompete eectively or the bandwidth. Dierent client types in the ecosystem, particularly

802.11b clients, can have a dramatic and adverse impact on the overall system

perormance. O course, scalability issues are also identifed.

Upon successul completion o this testing, one can conclude that the desired SLA can be

met in the initial section without any adjacent sections active.

Testing Adjacent Sections withNon-overlapping ChannelsOnce the initial section is tested and it is known that the SLA can be supported without

intererence, it is appropriate to build out the next section o the deployment and test it. This

section describes how to build out an adjacent section that has no overlapping channels

with the previously installed sections. The primary goal o this installation is to veriy the

lessons learned in the initial deployment.

Process

During the build out phase, it is appropriate to apply the lessons learned rom the previous

section to select better AP installation locations and network confguration.

Once the network is installed and confgured, the testing cycle will be much shorter than

the testing o the initial section. The primary goal o this testing is to veriy that the APsare placed in the correct locations and that there are no signifcant problems with the

placements as they relate to user QoE.

Veriy AP Placement

As with the initial section, the frst order o business is to run a quick passive assessment

to ensure that the APs are located and confgured as expected. It is common to fnd issues

in this step rom section to section as a result o communication issues inherent with a

large number o people. Proper installation cannot be taken or granted because dierent

installers oten work in dierent sections and they do not immediately beneft rom

their peers experiences.

Once again, make sure the AP locations and inormation on the maps is correct and as

expected beore proceeding urther.


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Speed Test the Network Using a Single ClientAssessment

The speed test with a single client laptop is the next step because it allows testers to identiy

marginal networks. One wants to ensure that the AP can deliver trafc well in addition to

simply advertising its presence. The speed test allows the tester to test the overall coverage

area quickly and identiy any grossly ailing nodes.

The most common reason or a low rate in this case is that the AP was installed in aquestionable location that has a great deal o RF impairments (attenuation, reection,

or intererence). The next most common reason or problems is that the network is

misconfgured. Finally, the AP could just be bad and only oer marginal perormance.

Scaled Ecosystem Test

Finally, rerun the scaled ecosystem test using the WF110 and the target external client. This

test will indicate the ability o the network to meet the intended SLA. Failures in this area

also usually relate to installation or confguration problems.

Testing Adjacent Sections withOverlapping ChannelsOnce overlapping channels exist, a condition where two or more APs are serving the same

network on the same channel, the potential or cochannel intererence between network

elements under the same administrative domain must also be considered. Cochannel

intererence can severely damage the overall perormance o a network in a dense build

out.

The best way to reduce the amount o cochannel intererence in the network is to reduce

the transmit power o the APs. This reduction will shrink the service area o each AP

and thereby reduce the amount o sel-intererence within the network. The downside

o reducing transmit power is that intererence sources external to the target network,such as rogue APs or cameras, will now have more potential to corrupt transmissions in

the network. Thus, tuning the power is a balance between minimizing sel- intererence

where less transmission power is better, and minimizing external intererence where more

transmission power is better.

In order to assess the impact o cochannel intererence, the tester must transmit to multiple

APs on the same channel at the same time. Thus, the user should use two WF1101

appliances. The frst WF1101 should be confgured to use one APs worth o the ull

ecosystem in the frst section. A second WF1101 is used to connect to the AP in the current

section. Both WF1101s should be utilizing the same channel. It is now possible to assess

the true impact o cochannel intererence in the environment by running an assessmentusing the external target client in the new section.

I perormance is ound to be degraded in either section or in the external client, then

one o two options exist. The frst corrective action to apply is to attempt to reduce the

transmit power o both APs to attempt to mitigate their interering eects on one another.

The second course o action is to adjust the SLAs so that the supportable SLA levels are

identifed. This data should then be socialized with the business unctions o the service

areas and ewer clients, is a better course o action.



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Once the SLAs are met, this section is complete and now large scale deployment can

commence.

Completing the Build OutThe remainder o the build out can occur in a more traditional manner whereby large

portions o the service area are installed at once, confgured and then tested. Obviously,

the installation locations and confguration o the devices is dictated by the original plan

plus the lessons learned rom testing the frst ew sections. Careul attention should be paid

to areas where the geometry is largely dierent or where the construction was done during

dierent periods. Construction materials and techniques change over time and so it may be

prudent to do more detailed testing in each dierent construction zone to ensure the highest

SLA.

Ater the network installation and confguration is complete, the user should be able to

do a scaled ecosystem test in each new section. The scaled ecosystem test is the most

comprehensive test that can be run and it is reasonable to run this test once the design

has been largely proven. The results o the scaled ecosystem test can confrm proper AP

placement, network confguration, marginal or broken APs, and SLA compliance at scale.

The test can be run in roughly the same time as it takes to do a passive site survey, but the

end quality o the installation is vastly dierent as it can provide much stronger verifcationo customer satisaction.

Non-technical Best PracticeConsiderationsIxVeriWave has completed a number o 3G ooad assessments with carriers and we

have developed a set o non-technical principles that address issues that we commonly

see aecting every deployment. Deploying Wi-Fi or cellular ooad requires a dierent

mindset than deploying or best eort, hospitality, Wi-Fi. The goal o the deployment should

be providing a guaranteed level o service to a population o customers, not simply RF

coverage. In short, the emphasis should be on capacity, not coverage. Numerous exampleso deployments that were insufciently optimized or cellular ooad exist. 3(Goldman,

2011)

To date, most service providers have deployed using the exact opposite philosophy and

have optimized or RF coverage with little consideration given to capacity. It is no surprise

then, that the mindset and business processes need to change along with the technical

requirements. This section summarizes the key points the key non-technical areas where we

have seen service providers struggle with the transition to cellular ooad.

It is Never as Good as You Think

This point was made earlier in the best practices document, but its importance cannot be

overstated. Initially, there is an inherent belie in service providers that the Wi-Fi network

should basically unction under the extreme loads that cellular ooad demands. For

example, many people do not realize that an 802.11g network with a promoted ratescale,

and these networks can rarely deliver more than 10 Mbps o aggregate application

perormance with high customer satisaction. Oten the maximum perormance is in the

3 Goldman, D. (2011, Feb 18). Why Wi-Fi sucked at Mobile World Congress. Retrieved Feb 28, 2011,rom CNNMoney.com: http://money.cnn.com/2011/02/18/technology/mwc_Wi-Fi/index.htm



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5 to 8 Mbps range. This data constantly surprises personnel who have been deploying

these networks or years and expecting much higher levels o perormance. Plan or these

surprises up ront or the frst ew deployments.

Test in the Lab First - Beore a Large Deployment

It is necessary to test your assumptions in the lab beore doing a major build out.

Fortunately, these assumptions are easily tested in the lab, but it requires organizational

awareness and commitment to take this step. Skipping this step will inevitably lead to

major and expensive rework in the feld. Oten, the SLAs that are oered by the business

team stand no chance o being supported in the feld. Aligning these two points prior to

a deployment will dramatically improve the business proposition or the company while

simultaneously speeding the organization toward the end goal o a high quality cellular

ooad.

Apply Process

Another major issue that we see with the shit rom delivering a best eort, hospitality

service to a high availability, constant quality service is that the process or resolving issues

ound during deployment testing in the feld occurs in a very ad hoc manner. Multiple

elements are oten changed at the same time and retesting proceeds in a haphazardmanner. This approach simply does not work because the multiple, simultaneous changes

rarely converge on a viable solution.

It is critical to establish a process whereby the deployment itsel is done incrementally and

any modifcations to the installment or confguration are made one at a time and retested

in order to determine i they provide the intended improvement. Tracking this work and

documenting these changes is critical to identiying opportunities to improve and shorten

uture deployments.

Prepare Beore Going Onsite

Numerous items can and should be addressed prior to going onsite. There are thetechnical details, o course, such as making sure you have all o the equipment necessary

to conduct the assessment. There are a bevy o additional items that are oten overlooked,

but which should be addressed prior to going onsite including:

Get proper security credentials or your personnel

Make sure you know your points o contact email and mobile phone numbers

Make sure everybody knows where and when the team is meeting. The venues are

oten very large and it isnt enough to say that you will meet onsite.

Have the local team provision and test any additional network resources you will need

Make sure the local resources will be available to you, particularly during the initial

testing

Make sure the SLAs are well understood by the team, including the business

personnelGet the image map that shows AP locations and confguration

Bring and manuals you may need



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Activate any sotware licenses as necessary

Have a structured plan or the onsite work

These details and more are spelled out earlier in this document, but they are critical to

achieving timely success. Neglecting to do this work prior to showing up can easily result

in a hal a day to one days time worth o lost productivity during the deployment.

Report the Results

Report on the project at the end o the installation. At a bare minimum, archive the

technical results o the deployment, including modifcations made and their corresponding

impact so that they can be accessed in the uture. When another team needs to go onsite,

access to this inormation will be invaluable or them to see how things may have changed

over time and provide critical clues as to why something may not be working properly.

In the initial deployment, in particular, it is also well worth the time to write a short report

that summarizes the work done and provides a written interpretation o the activities

and results. While the data may hold all o the clues, the written document can be used

to summarize the key points or the entire team and provide a road map to the detailed

reports that the technical resources may need. This document essentially captures the

lessons learned rom the deployment and provides ready odder or process improvement

in uture deployments.

ConclusionCellular ooad onto Wi-Fi requires a new approach to deployments which ocuses on

customer satisaction with their applications in a realistically loaded environment. Adopting

the best practices contained in this document will allow service providers to dramatically

improve the quality o their new deployments, resulting in happier customers. With Wi-Fi

now inexorably tied into cellular contracts and the rapid rise in Wi-Fi-enabled devices,

service providers should be able to improve customer attraction rates and reduce churn

by delivering a satisying customer experience over Wi-Fi. Ultimately, improved Wi-Fi willgenerate more revenue and proft or service providers.

The solution required to deliver this experience exists today. Adopting the IxVeriWave

solutions, including WaveTest or the lab and WaveDeploy or the feld, along with

improving the sign o process enables service providers to signifcantly improve their

wireless oerings.



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Appendix A: Corrective Actions or BestPractices ImplementationThis section summarizes the problem issues that are commonly present in deployments. The

table highlights the problem, and the means by which it is identifed using IxVeriWave.

Problem Identifcation Technique Simple Solution

Non-unctional AP During a passive assessment, the AP does

not show up in the list o detected APs.

Veriy that the AP is properly

confgured

Replace the AP i it still doesnt

work

Marginal AP due to placement During the speed test the AP underperorms.

Examination o the data shows a high level

o 802.11 retransmits and low PHY rates in

the associated trafc. Testing rom a line o

sight to the AP results in high perormance

and improved 802.11 layer unctioning.

Physical examination o the AP may indicate

a poor installation choice.

Change the AP placement, preerably to

line o sight to the service area.

Insufcient coverage During the speed test and the ecosystem

test, the system is unable to deliver

acceptable QoE in locations ar rom

existing APs. This will commonly occur near

the edges o the served area, but may also

occur within a served area where no AP

sufciently services an interior location.

Move the APs as necessary i it

appears that they can serve the

existing coverage area, but are

simply located poorly.

Add more APs i the existing

APs are insufcient to cover the

necessary perormance areas

Improper AP confguration During the testing, it is noticed that they AP

is set to the wrong channel or power level

with respect to the planned installation.

Change the confguration


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Poor Perormance under Load without

Intererence

The speed test reveals that the network

is not delivering as much capacity as

it should in comparison with the lab

testing. Checking the 802.11 PHY

rates and retransmission does not

indicate any issues with the PHY layer.

Examining the trafc using the WF1101in capture mode does not indicate

intererence or excessive management

trafc as a source o the problem.

Rerun the test using the WF1101

to determine i the network o the

client is the source o the problem.

Check the confguration o the

wired network and controllers

i the network is at ault. Test to

dierent locations i possible to

identiy the location o the limit.

Make sure the proper frmware

is loaded onto the devices.

Upgrade frmware as necessary or

appropriate.

I testing to a central site in

the Internet, consider installing

an EF1101 at the local site

and retesting. I the expectedperormance is achieved in the

local network then the problem is

the Wan backhaul.

Trafc levels are met, but the SLA or

certain application types are not met.

In the WaveDeploy ecosystem test, the

application SLAs will show red even

though the aggregate throughput is as

expected.

Consider implementing QoS in the

network i appropriate.

Reduce the number o clients and

trafc served by an AP.

Try a dierent client type to see i

the client has an inherent issue.

These results can and should be

tested in the lab frst and then in

the feld.

For very high value clients, a

separate SSID can be deployed

to provide dedicated resources

or client confguration changes

can be applied. An example o

this type o device would be a

handheld ticket scanner at a largevenus.


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IxIa WorldWIde Headquarters26601 Agoura Rd.Calabasas, CA 91302

(toll Free NortH amerIca)1.877.367.4942

(outsIde NortH amerIca)+1.818.871.1800

(Fax) 818.871.1805www.ixiacom.com

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Cellular Offload[1]

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Transcript of Cellular Offload[1]