2. January 23-26, 2007 Ft. Lauderdale, Florida Deployment Challenges of Wi-Fi Telephony John DiGiovanni Director of Marketing Staff Technologist john.digiovanni@xirrus.com

3. January 23-26, 2007 Ft. Lauderdale, Florida Voice over Wi-Fi – It’s Coming!

4. 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

5. 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

6. 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

7. 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#3640444852566064161149153157 Ch# 100104108112116120124128132136140

8. 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

9. January 23-26, 2007 Ft. Lauderdale, Florida Architecture Choices 1 st Generation: Independent APs 108Mbps per Cell (2 channels) Individually Managed 2 nd Generation: Controller + APs 108Mbps per Cell (2 channels) Centrally Managed 3 rd Generation: Controller + Ultra Thin APs 108Mbps per Area (2 channels) Good for Roaming

10. 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

11. 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

12. January 23-26, 2007 Ft. Lauderdale, Florida Thank You John DiGiovanni Director of Marketing Staff Technologist john.digiovanni@xirrus.com