designing and deploying wireless ip communications systems

1© 2005 Cisco Systems, Inc. All rights reserved.Session NumberPresentation_ID

Designing and Deploying Wireless IP Communications Systems

Mike CoffinTME IPCBU/VTG


Enterprise Mobility - Market Overview

• Enterprise Customer Demand:

IPC mobility is becoming enterprise requirement to meet increasing number of mobile workers needs

IPC mobility is an integrated call control and voice application solution that customers wish to purchase directly from IPT vendor

• Enterprise IPC Mobility solution categories:

1) Single mode solutions (i.e. 7920s for wireless enterprise voice)

2) Single number reachability (i.e. IP PBX extension to cellular application)

3) Dual mode solutions (i.e. two line DM, call hand-off, etc.)


Voice over WLAN How to Justify

Employee Productivity • Reduced call backs, fewer call attempts • Single mailbox, fewer duplicate messages• Flexibility: choice of device and location for calls• End-to-end IP telephony

Customer Satisfaction • Increases speed of response• Flexible communication flow with media choices• Personalized service • Location and Identification services

OPEX Reductions• Predictable/controllable cellular expenses• Least cost routing/Intelligent on corporate network• Better visibility, better control

Device consolidation


Worldwide Wi-Fi Handset Unit Breakdown

94%

48%49%

29%

16%

9%

71%

51%52%

6%

91%

84%

0%

25%

50%

75%

100%

CY04 CY05 CY06 CY07 CY08 CY09

Calendar Year

Reve

nue S

hare

(%)

Wi-Fi VoIP

Dual-modeWi-Fi/cellular

VoWLAN Market Figures

Source: Infonetics 2005

• IPC (wired/wireless) is growing at 19% CAGR

• ~6% of WLANs are currently running VoWLAN (SMB-Ent)increasing to ~20% in 2007

• 36% of IPC customers view mobility as the driving app todayincreasing to 47% by 2007

• Of the VoWLAN deployments, 50% are using a single mode phone

• Singlemode share is expect to decrease to 38% by 2007

• Dualmode share is expect to increase to 37% by 2007


• Deployment guidance• WLAN/Network

readiness assesment

Deployment Success

• Mobility a driver for convergence

• Costs savings +productivity increase

Extend IPC investmentsthrough mobility

Thought Leadership in key areas• MFP• Location Awareness (LBAC and IDS)• NAC, NIC, Multi-Layer IDS

Re-seize the security high groundThought Leadership in key areas• Advanced QoS/CAC• Wide support for handsets• Enabling technologies – HD/Mesh/e911

Wireless Voice Strategy

Innovation

Unification & InvestmentProtection

Messaging


A Business Class Wireless Experience

Unified built-in support of leading edge applications - not an after thought. Cisco Wireless Location Appliance, Wi-Fi phones, and Guest Access

Advanced Mobility Services

World Class NMS that visualizes and helps secure your air space. Cisco Wireless Control System (WCS)

World-Class Network Management

Cisco Self-Defending Network

Seamless network infrastructure across a range of platforms. Cisco 4400, 2000 Wireless LAN Controllers. Cisco Catalyst 6500 Series WiSM, ISR and 3750 integration.

Network Unification

Mobility Platform APs dynamically configured and managed through LWAPP. Cisco Aironet Access Points: 1500, 1300, 1240AG, 1230AG, 1130AG, and 1000. Bridges: 1400 and 1300.

Secure clients that work out of the box

Client Devices

What's in Business Class Wireless?

Future


Headquarters – New York

PSTN

Cisco ISR• Security Services (FW, IDS, etc.)• VoIP Gateway• SRST

T1

Branch Office – Newark, NJ

DSLBranch Office – Austin, TX

WAN

Internet

SiSi SiSi

IPC Infrastructure• CallManager• Unity• Conferencing Media Gateways•MeetingPlace

Cisco Integrated Services Router (ISR) Pair• WAN Access• Security Services (FW, IDS, CSA, VSM etc.)• VoIP Gateway• HSRP

Integrated Wired and Wireless Network •WLSM for Fast Secure L3 Roaming •Aironet WLAN Infrastructure with WLSE Mgt/Control

A Comprehensive VoWLAN Solution

Wireless Voice Clients•Cisco 7920 •CCX clients •Partner Clients •Cisco IPC Client

Integrated Wired & Wireless Network •Wireless AP’s •WLSE Express Management

Wireless Voice Clients

Cisco ISR• Security Services (FW, IDS, etc.)• VoIP Gateway• SRSTIntegrated Wired & Wireless Network •Wireless AP’s •WLSE Express Management

Wireless Voice Clients


• Lightweight solution

Lightweight AP + WLAN controller + Cisco WCS

• Features

High-accuracy location

Downstream WLAN QoS

APIs for software integration

• Benefits

Ease of use and simplified deployment

Protection from unauthorized access and WLAN attacks

Scalability with controller clustering

Reliability N:1 automated failover

Location aware

• Leadership

Dual Band AP deployment with simultaneous support of 802.11a and 802.11g

Estimated 14 simultaneous calls per AP for .a and 7 simultaneous calls per AP .g

Cisco has proven experience deploying VoWLAN in the enterprise

White Papers, Deployment Guides, Presentations, Training, etc.

Leverage Cisco Advanced Services to accelerate voice over WLAN expertise

Cisco WCS

Cisco WLAN Office Controller

Cisco WLAN Remote Office

Controller

Cisco Lightweight

APs

Cisco Lightweight

APs

Unified Wireless Network


What Does an Enterprise WLAN Needfor Wireless Voice ?

• Good Voice Quality

• Security

• Fast Roaming

• Ubiquitous Coverage

• Scalability

• Long Battery Life

• Troubleshooting Tools

• Managed RF Environment

WirelessAccessPoints

AP1200 AP1130

Cisco-brand &Cisco-CompatibleClients

Controllers & Switches

Controllers Cat 6500 Series

BR1300

Cisco Wired + Wireless Infrastructure Centralized Management


Innovating in VoWLAN with

CCX v2CCX v2

• Client Tx sync

• AP neighbor list

• Fast Roaming/CCKM (LEAP)

CCX v3CCX v3

• WME compliance

• Fast Roaming/CCKM (FAST)

CCX v4CCX v4

• Fast Roaming/CCKM (PEAP/TLS/TTLS)

• QBSS Load IE

• CAC (TSPEC)

• U-APSD

• Traffic stream metrics

• GPR handling

• Roaming element

• Voice metricsCCX v5CCX v5CCX Version 4 is what we

need clients to be at for dense deployments


Benefits of Cisco’s VoWLAN Solution

• Enterprise-class SecurityWPA encryption + 802.1X authentication

• Secure, Low-Latency Roaming between AP’s and SubnetsUsing standards-based security (WPA + 802.1X)

• Improved Battery LifeProxy ARP allows phone to skip broadcast/multicast beacons, so device can wakeup/go-to-sleep more quickly and stay in doze mode for longer periods of timeSubstantial improvement in standby time

Savings depends on the amount of broadcast/multicast traffic on the networkTransmit Power Sync reduces transmit power, resulting in improved talktime

• QoS for prioritization of voice traffic over data trafficSupports converged voice + data WLAN networksFully compatible with installed base of 802.11 clientsWi-Fi Standard WMM-based QoS now available on Cisco AP’s


Why New Site Surveys?

• Increased roaming with VoWLAN

• Coverage must be seamless with adequate overlap for smooth roaming handoffs

• Old site surveys need to be revisited to ensure the WLAN meets the VoWLAN requirements


Typical WLAN Data Topologies

Wireless Clients

LAN Backbone

Channel 1

Access Point

Wireless “Cell”

Access Point

Wireless “Cell”

Channel 6

Wireless Clients

Ove

rlap

pin

g

10-1

5%


Ch 1Ch 6

Ch 11

Ch 6

Ch 6 Ch 11Ch 1

Greater Overlap Needed

Single Floor Site Survey for Voice: 802.11b

Dana Tagliafico (dtagliaf)

we've found a way to get around the problem with gradient fills when converting to pdf. We copy/paste special (png or jpg) and we left the original image behind a white block in case you need to alter it in any way. If you have questions, pls email dtagliaf


IDEAL VoWLAN RF ENVIRONMENT

Cisco Unified Wireless IP Phone Cells Should Have Overlap of 15-20%

Redundancy throughout cell

Cisco Unified Wireless IP Phone Cells Should Have Overlap of 15-20%

Redundancy throughout cell

Maintain Proper Separation of Cells

(see deployment guide for recommendations)

Maintain Proper Separation of Cells

(see deployment guide for recommendations)

-67dbm at Edge(see deployment guide for

recommendations)

-67dbm at Edge(see deployment guide for

recommendations)


Flr 1

Flr 2

Flr 3

Flr 4

AP 1

Ch 1

AP 2

Ch 11

AP 4

Ch 1

AP 3

Ch 6

Multi-Floor Site Survey


Ideal Environment

• Reduction of noise

Noise leads to static and choppy voice

More APs / clients will increase the noise levels

• Proper RF overlap

Faster / smoother roaming

Provide a secondary AP if one of the APs is unavailable or congested

Load-Balancing

• Correct data rates

Faster data transmissions, reduction of AP utilization, more calls per AP


Ideal Environment

• Minimum 2 access points on non-overlapping channels at all times with:

RSSI >= 35 (minimum value) -67dBm

CU (QBSS) load < Max Threshold

• Provides for redundancy and load-balancing

Definitions:

RSSI (Received Signal Strength Indicator)

CU (Channel Utilization)

QBSS (QoS Basic Service Set)


Ideal RF Environment

• Non-overlapping cells are 22 MHz apart

1, 6, 11 (North America)

1, 6, 11 or 2, 7, 12, etc. (Europe and Japan)

Do not have to be exactly 5 channels apart (i.e. 1, 7, 13)

1 2 6 113 4 5 7 8 9 12 13 1410

2.402 GHz 2.484 GHz

Channels

22 MHz


Non-Overlapping Channels

• Phone will scan all channels at power up

• Attempts to associate to AP with the highest signal

• Will periodically scan all channels after association giving priority to discovered non-overlapping channels

1

6

11

1

6

11

1

6

11

1


802.11g Radios

• Disable 6, 9, and 12 Mbps for 802.11g

Will reduce throughput if enabled

• Set 802.11g rates as “enable” vs. “required”

• 7920 phones are 802.11b only

• Enable all other 802.11g data rates for data devices


Signal to Noise Ratio (SNR)

• Signal of -67 dBm or higher

• Packet Error Rate (PER) no higher than 1%

• Minimum SNR of 25dB = -92dBm noise level

Time (Seconds)

Noise Level

RSSI / Signal Strength

Power (dBm)

Adding signal does not always increase SNR

Signal to Noise Ratio


Recommended SNR Values

Data Rate(Mbps)

Data Cell WIPT Cell

MinimumSignal

Strength(dBm)

MinimumSNR(dB)

MinimumSignal

Strength(dBm)

Minimum SNR(dB)

54 -71 25 -56 40

36 -73 18 -58 33

24 -77 12 -62 27

11 or 12 -82 10 -67 25

5.5 or 6 -89 8 -74 23

2 -91 6 -76 21

1 -94 4 -79 19


COMPARISON OF 802.11 SPECTRUM– Throughput & Channels

Data Rate (Mbps)

Approximate Throughput

(Mbps)

Non-Overlapping

Channels

802.11b 11 6 3

802.11g (with .11b clients in cell)

54 8 3

802.11g (no .11b clients in cell)

54 22 3

802.11a 54 25 19


Dynamic Transmit Power Control (DTPC)

• Set the same transmit power on the AP and on the phones

If using an AP that supports DTPC, then ensure client power matches the local AP power

(Do not use default setting of Max power)

If the AP does not support DTPC, then need to statically set the phone’s transmit power to match the AP with the highest transmit power in the WLAN (default 7920 setting = 20mW)

• Prevents one-way audio

i.e. RF traffic is only being heard in one direction

100mW 20mW


Multi-Path

• AP antennas need placements that are away from reflective surfaces

• Maximize line of sight

NEVER MOUNT ANTENNAS NEAR METAL OBJECTS or REFLECTIVE SURFACES

P1

P2

P3

TX RX

Ceiling

Obstruction

Floor


Diversity

• Match the antenna types and ensure they cover the same radio pattern

• If using cable extenders, should be the same length and type


Note: These numbers can vary depending on the specific RF environment and the amount of data traffic

Ideal Environment

• G.711 - 7 concurrent voice streams

• G.729 - 8 concurrent voice streams

(# of 7920s on call per AP)

• Call numbers are with Voice Activity Detection (VAD) disabled, which is recommended

• Voice quality maintained with standard data traffic on AP


Set Expectations

• Difficult to achieve 99.999% availability with VoWLAN (2.4 Ghz)

• The better the RF environment is controlled the better the quality will be

• Coverage in elevators is challenging

• Recommended to use CCKM when doing 802.1x authentication otherwise voice gaps may exist during roaming


Site Survey Process

Site Survey

• Identify areas in the physical environment where there is non 802.11 RF interference

• Identify and eliminate rogue APs

• Identify key utilization requirements

• Determine proper AP location and transmit power levels

• Proper configuration of APs

• Proper configuration on network and server


• Assists you in the assessment

Type of survey needed

How long it will take

Equipment needed

Introduction to the customer’s facility

• General fact gathering form

Pre-Site Survey Form


Site Survey

• Survey each floor individually then combined to check leakage

• Ensure testing is done with users and wireless network traffic

• Do not assume all channels can be used in every environment

• Try to logically segment subnets based on roaming behavior

• Keep in mind users will talk in locations where they don’t normally use wireless data

Staircases

Quiet locations


Off-hours or Green Site Survey

• No noise during site survey, however will be post deployment

• Measure noise during the day or at other similar deployments

Equivalent number of people and devices

Similar type of RF utilization


Evaluate Key Areas

Break Room (Microwave Ovens - 2450 Mhz)

File / Supply Room

(Large Filing or Metal Cabinets)

Stairwells (Reinforced

Building Area)

Elevator Shafts Test Lab

ConferenceRoom

Office

Cubes VIP (CEO)


Site Maps

Coverage Not Required

Low Capacity Areas

High Capacity Area

Stock Room—Metal ShelvesP

arki

ng

Gar

age

Office

Cubes


Site Survey Report

• Be very specific when describing locations

• Use tape and facility markers

• A picture is worth 1,000 words

• Antenna orientation

Not all installers familiar with the equipment

The more directional an antenna is, the more important the orientation description has to be


Incorrect Placement of APs

• Incorrect placement of APs can lead to coverage or quality issues

Move AP a minimum of 2 feet from metal beam


Incorrect Placement of APs

• Mount a wood board between metal tracks


Incorrect Antenna Orientation

• Antennas are pointing incorrectly

• Point the antennas toward the desired coverage area


Long-Term Site Survey Report

• Site survey report is required for the life of the WLAN deployment

Configurations of the APs

Location of the APs

Channel and transmit power map

Switch port configurations

AP model types

Coverage map per frequency

Antenna type per AP


Tools for VoWLAN Site Surveys

• WLSE assisted site survey tool is currently NOT recommended for voice deployments

(The minimum cell overlap for seamless roaming is not present)

• WLSE is recommended for managing APs post-deployment

• Use tools like Airmagnet Analyzer and Surveyor, Cognio Spectrum Anaylzer

• Finish using end-user devices such as Cisco Unified Wireless IP Phone 7920 and wireless laptops to ensure 100% coverage and quality


Installation and Network Verification

• As important as site survey

• Insures entire system works as designed

• Make actual phone calls to test voice quality

• Phone equipment requirements:

Headsets to monitor RSSI and communicate on Cisco Unified Wireless IP Phone 7920

Call between Cisco Unified Wireless IP Phone 7920 and wired Cisco Unified IP phone

• Wired infrastructure pre-requisite:

Proper wired network must be in place

www.cisco.com/go/srnd


Installation Verification

• Suggested test areas:Primary area of each AP cell (1)

Any location where there might be high call volume (2)

At the fringes of an AP’s coverage area (3)

Areas of where overlap might be questionable (4)

At locations where coverage might be slightly questionable but still need to be certified (i.e. stairwells, bathrooms, etc.)

1

23

4

Conference Room


Wireless Voice Verification Plan (WVV)

• Important every time changes are made to:

Wired network

Wireless network

Physical environment

End user devices

(Voice or data)


Q and A

designing and deploying wireless ip communications systems

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