IP Telephony Applications for Handhelds

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IP Telephony Applications for Handhelds

• Keith Weiner
• DiamondWare

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Presentation goals

• Look closely at cellular, cordless phones
• Why computer telephony, why PDA, why now?
• PDA telephony technologies
• Engineering and market issues
• Projections and statistics
• Demo

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PDA telephony is not cellular

• Those are cool Devices!
• Samsung I300, Nokia Communicator, Handspring Treo
• Its a cool Application!
• Combine two functions into 1 device
• But different.

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Cellular advantages

• Nationwide WAN coverage
• Roaming at 90mph
• Low capex
• Free or near-free
• But no advantage within enterprise space

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Cellular cellularness

• Monthly bills
• High latency
• Hello, Over?
• Poor voice quality
• Especially transcoding between carriers
• Doesnt work well in some buildings
• Fabs, dense high-rises

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But everyone uses it

• On the road
• At lunch
• In coworkers offices
• Out of habit, even at their own desks!
• Give out one number the mobile
• Mgmt. losing control and predictability
• PSTN minutes negotiated in bulk

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Cordless phones

• Expensive
• Nortel T7406 525 MSRP
• Trapped by system vendor
• Or live with analog port limitations
• Another extra device
• Forget it when you wander down the hall
• One more gadget on your belt

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Ok, why computer telephony?

• Why IP?
• Converged networks
• LAN, voice, wireless
• Why a software-based telephone?
• More usable
• Presence
• Availability

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We need to do better
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IP telephony for handhelds

• PDA is becoming mission-critical
• With decent CPU, audio chip, wireless NIC
• Leverage it with a softphone
• Inherently cheaper than dedicated phone
• Cheaper to build and to upgrade
• More powerful

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PDA VoIP advantages

• Same as for desktop and laptop
• Features
• Address book
• Recording
• Presence
• Play tunes without worry, ring can interrupt
• Better voice quality (wideband)
• Plus mobility

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Applications

• Workforce communication in factory floors,
  warehouses, campuses
• Walking over to the next office
• Desktop phone replacement
• Take it with you to Starbucks, airports, hotels
  and other hotspots

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Why wireless PDA? I

• PDA deployment is growing
• Wireless IP deployment is growing
• Leverage them
• Network convergence
• Wired LAN
• Telephony
• Wireless

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Why wireless PDA? II

• See list of conference attendees
• Control your availability as seen by others
• Whiteboard, Text (IM)
• N-way calling
• Line is never busy
• Why limit to just 3-way?

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Softphone architecture I

• IP socket support
• Call control protocol
• SIP or H.323
• Realtime audio transport (i.e. RTP)
• Audio is broken into packets

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Softphone architecture II

• Microphone capture
• Process (e.g. echo, AGC)
• Compress (e.g. G.711, G.729)
• Wrap in an RTP header
• Send to remote host

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Softphone architecture III

• Network receive
• Decompress
• Process (e.g. dejitter, echo)
• Send to audio chip

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What does it take?

• Real computer (PocketPC, Zaurus, Webpad), with a
  real audio chip
• Sorry Palm
• Headphones
• Wireless network, typically 802.11b
• 802.11a gets cheaper (under twice 802.11b)
• For PSTN calls, IP-PBX gateway

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802.11 issues I

• Bandwidth Constrained
• 802.11b has only 11 Mbps
• 802.11a has 54 Mbps
• 802.11g has 54 Mbps also, but 2.4GHz
• QoS
• Cannot add segments, like w/wired LANs
• Sto dow..oading so I .c.. ta..k
• No standard yet

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802.11 issues II

• Airwave contention
• NICs hidden from each other
• RTS/CTS
• RF Interference
• 802.11b uses 2.4ghz, not great spectrum
• 802.11a uses 5ghz, better spectrum

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802.11 issues III

• Security
• Encryption (wired equivalent privacy) is a toy
• Warchalking
• MAC address filtering helps, somewhat
• Access controllers
• Built-in authentication
• Connect to auth server (e.g. RADIUS, LDAP)
• Painless subnet roaming

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VoIP issues

• For IP calls to or from the outside
• NAT
• Firewall
• Proxy
• Some solutions
• Server outside the gate (e.g. Ridgeway)
• UPnP NAT

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PocketPC issues

• Speaker and mic coupled
• Headphones reqd
• Mic-less headphones
• 50 lashes with a wet noodle
• Compute-limited for echo cancellation
• Battery life
• Powered down when idle
• But cant receive calls!

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Market issues

• Inside your space, build what you want
• Not many outside hotspots yet
• Roaming problem
• Dynamic routing
• Mesh Networks
• Mass acceptance reqd for business model
• 200 users at airport gateholy QoS, Batman!

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Marketscape

• Existing products
• Avaya, support for their PBX
• VTGO, supports Cisco Call Manager
• SoftJoy Labs, supports H.323 and SIP
• In Development
• DiamondWare, SIP, lowest latency
• Telesym, connects to 3rd party PBXs
• Others

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Resistance is futile!

• (You will be assimilated)
• The PDA is/will be mission-critical
• You will carry it for many reasons
• Why not use it for the voice function?
• No worse off than before
• Within wireless zones, much better

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Necessary next steps

• Ubiquitous Wireless access points
• Outside the enterprise
• Answers on the business side
• 30 free minutes with every cup at Starbucks?
• By the hour at airports?
• 1000 minutes/month like cellular?
• By the day at hotels?

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My projections

• Wideband (16khz) audio will win people
• PDAs will be carried everywhere
• PDAs will be net.connected when possible
• PDAs will be used as phones when net.connected
• SIP makes follow-me easy
• PoE (power over ethernet) icing on cake

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Statistics

• 100 of communications shows Ive attended, past
  12 months
• 5.3M NICs and 1.8M WAPs sold in 20011
• 400/100 avg. cost, enterprise WAP/NIC
• 44 hotspots in Arizona2

1Gartner 280211hotspots.com
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About me

• CEO of DiamondWare
• Developers of low-latency voice software
• mailtokeith_at_dw.com
• cell [phone]
• SIPkeith_at_dw.com (coming soon)

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Wideband Audio

• Your confirmation number is FS5BP3TD
• Try that on a phone
• Worse yet, a cell