january 23-26, 2007 ft. lauderdale, florida deployment challenges of wi-fi telephony john digiovanni...
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January 23-26, 2007• Ft. Lauderdale, Florida
Deployment Challenges of Wi-Fi Telephony
John DiGiovanniDirector of MarketingStaff [email protected]
January 23-26, 2007• Ft. Lauderdale, Florida
Voice over Wi-Fi – It’s Coming!
January 23-26, 2007• Ft. Lauderdale, Florida
802.11 Standards Review
• 802.11b– Ratified 1999 – Up to 11Mbps in the 2.4GHz Band
• 802.11a– Ratified 1999 – Up to 54Mbps in the 5GHz Band– Not backward compatible to 802.11b
• 802.11g – Backward Compatible to 802.11b– Ratified 2001 – Up to 54Mbps in the 2.4GHz Band– Backward compatible to 802.11b
• 802.11n – Ratified Standard Expected 2008
January 23-26, 2007• Ft. Lauderdale, Florida
Voice over Wi-Fi Challenges
• Shared Medium, Collision Avoidance & Limited Bandwidth
• Channel Allocation, Planning & Usage
• Quality of Service – 802.11e available for voice– Mapping QoS priorities through the wired network
• Wi-Fi Architecture Choices
January 23-26, 2007• Ft. Lauderdale, Florida
Channels & Capacity – 802.11b/g
Only 3 Channels are Non-overlapping
33Mbps in 802.11b of Total Capacity
162Mbps in 802.11g of Total Capacity
Voice Calls Proportional to Channel Usage
Ch# 1 2 3 4 5 6 7 8 9 10 11
2.4GHz ISM Band
Ch# 1 6 11
January 23-26, 2007• Ft. Lauderdale, Florida
Channels & Capacity – 802.11a
• 12 channels for 802.11a
• Use as many Channels as possible• Reuse them as often as possible
FCC has approved 11 more channels
Up to 1.24Gbps of Total Capacity
5GHz UNI Band
Ch# 36 40 44 48 52 56 60 64 161149 153 157
Ch# 100 104 108 112116 120 124 128 132 136 140
January 23-26, 2007• Ft. Lauderdale, Florida
Quality of Service
• 802.11e (Over the Air)– Packet prioritization for downstream traffic
• Wired Class of Service is mapped to wireless TCID settings
January 23-26, 2007• Ft. Lauderdale, Florida
Architecture Choices
1st Generation: Independent APs
• 108Mbps per Cell (2 channels)
• Individually Managed
2nd Generation: Controller + APs
• 108Mbps per Cell (2 channels)
• Centrally Managed
3rd Generation: Controller + Ultra Thin APs
• 108Mbps per Area (2 channels)
• Good for Roaming
January 23-26, 2007• Ft. Lauderdale, Florida
Architecture Choices
Wi-Fi Array• Up to 864Mbps of
Bandwidth per cell• Up to 16 channels per cell• Sector Antenna System• Long Range• Very high client capacity• Very high voice capacity
January 23-26, 2007• Ft. Lauderdale, Florida
Take Aways
• Design for Performance – Not Just Coverage– Over provision for wireless (same as for wired)– Use all available 802.11a/b/g channels simultaneously– Reuse channels as often as possible
• Designed for Voice– More users at higher data rates = less contention/latency– Insist on standards-based QoS (802.11e / scheduled
access)– Map QoS through the wired network
January 23-26, 2007• Ft. Lauderdale, Florida
Thank YouJohn DiGiovanniDirector of MarketingStaff [email protected]