vofi standards & deployment models thenu kittappa
TRANSCRIPT
VoFi standards & deployment models
Thenu Kittappa
www.voipdeveloper.comAugust 8-10, 2006
Santa Clara, CaliforniaHyatt Regency Santa Clara
Agenda
• Trends in VoWLAN• VoWLAN standards• What makes a good VoWLAN handset?• Different deployment models for Voice over Wi-Fi,
single-mode & FMC
www.voipdeveloper.comAugust 8-10, 2006
Santa Clara, CaliforniaHyatt Regency Santa Clara
VoWLAN trends 2005-07
Q3 05 Q4 05 Q1 06 Q2 06 Q3 06 Q4 06
FMCA PRD I(UMA)
FMCA PRD II(SIP)
FMCA PRD III(IMS)
FMC Gateway
s
FMC Operator
s
Small SIP PBX
Large SIP PBX
SIP handset
s
WMM handset
sWMM infra
802.11e in CE
SVPQoS
VoIP
FMC
WMM-SA?
Any SIP VoWLAN handset with any SIP
PBX
Fixed-Mobile Systems with handover
Fixed-Mobile Systems Single-number
with no handover
Later Later
FMCAMobileIGNITE
UMAVCC
802.11WFA
SIP (IETF)
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Enterprise VoWLAN interfaces
SIP PBXOr softswitch
Voice Telephony Gateway
WLAN to Handset interface• Fast handover• Good QoS• Call Admissions Control• Good battery life• Public access & emergency
WLAN to PBX interface• Emergency call handling• Location• SLA indications• Troubleshooting tools
WLAN • QoS• Seamless coverage• Interference detection• Management tools• Troubleshooting tools
Handset to PBX interface• SIP• SIP++• Presence• Emergency calls
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Current 802.11 standards
• Standards activity relevant to voice
– .11i (MAC Security Enhancements) / WPA• All phones will become better at authentication, encryption, by implementing
WPA, WPA2…
– .11e (MAC Enhancements, QoS) / WMM• Phases: WMM, APSD, TSpec sig, WMM-SA improve QoS, battery life
– .11k (Radio Resource Measurement)• Assistance for handoff: opportunistic key caching with knowledge of key scope
– .11r (Fast Roaming)• Aimed at improving secure handoff speeds. Not necessary when .11k neighbor
report is used in conjunction with centralized encryption
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1 2 3 4 5Scale of excellence
802.11r
802.11r
How complete is standards support?WMM-SA
802.11k
WMM functionality
802.11k
WMM-SA
Other 802.11 functionality
Centralized architecture & vendor-specific features
QoSJitter
Latency
Packet errors/ drops
(Over wired and wireless)
CAC
HandoverControl/influence decision
Speed of handover
Security of handover
Sleep Control: battery lifeU-APSD
S-APSD
Other featuresCALEA
E911
Coverage
802.11h
802.11h
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What makes a good WLAN phone?Function Good Better Best Notes
Call Admissions Control & QoS
802.11e QBSS load element
Tspec signalling
Uplink QoS WMM (EDCA)
Authentication MAC address 802.1x 802.1x & PMK caching
Encryption Static WEP PSK-TKIP, PSK-AES TKIP, AES Aim for WPA2
Handover 802.11k AP channel report element
802.11e QBSS load element
AP channel report & QBSS load & 802.11k neighbor report & PMK caching
Depends also on algorithms in handset
Transmit power control
802.11h TPC
Bandwidth efficiency
802.11b 802.11a/g .11b reduces the cell throughput
Battery life 802.11 power save U-APSD U-APSD & 802.11h TPC & proprietary
Future developments on loosely-associated state
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Deployment of Voice in the Mobile Network
• VoIP allows a phone to receive corporate dialtone over the Internet• Incoming, outgoing numbers as PBX extension• Wireless VoIP is more secure than wired VoIP• Wireless requires less reprogramming than wired VoIP (no reconfiguration of
AP or handset)
Corporate IP PBX
LAN Internet
Home officeMain location
WAN
Hotel roomBranch office
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Enterprise VoWLAN Deployment Models
SIP PBXOr softswitch
Voice Telephony Gateway
Internet
• PBX Extension Mode: Wireless phone is configured as an extension on the PBX
Pros• Easy to configure on the WLAN and the IP-PBX• SIP support on single-mode VoFi phones and IP-PBX allows best-of-breed mix & match• Phone automatically participates in Enterprise numbering plan (4-, 5-digit) and least-cost routing for long-distance calling
Cons• Existing PBX may need upgrading to support SIP extensions• All configuration falls on the Enteprise IT group (or outsourcer)• Single-mode phones will work on Enterprise Wi-Fi network & home locations, but not outside this coverage• Configuration complexity when users roam between sites (unless already covered by a unified PBX network)
LAN core
LAN edge
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Enterprise VoWLAN Deployment Models
SIP PBXOr softswitch • Hosted Mode: All call control is from the
Internet
Pros• No end-user configuration• Works with VoIP wired and single-mode wireless phones• Easy to upgrade to a fixed-mobile service (upgrade by the SP) • Easily integrated by the SP with long-distance & international VoIP plans
Cons• Survivability (loss of WAN = loss of service)• QoS (may require a guaranteed-QoS Internet/VPN service)• Single-mode phones will work on Enterprise Wi-Fi network & home locations, but not outside this coverage
LAN edge
LAN core
Internet
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Enterprise FMC Deployment ModelsSIP PBXOr softswitch
LAN edge
LAN core
Internet
Cellular Core
FMC Gateway
Cellular Base Station
• Hosted Mode: VoFi side of the phone is homed to the hosted FMC Gateway
– Cellular operator (SP) ‘owns’ the phone number and behaviour
– User experience is closer to cellphone whether in or out of Wi-Fi coverage
Pros• No configuration by the IT group (except for access, see below)• Standards support for this model will ensure good pricing and availability of phones (eventually)• Easy inter-site roaming• Easily extended to commercial hotspots by SP roaming agreemeents
Cons• Configuration of SSIDs, NAT, firewall may be a problem• Access by the SP for troubleshooting may require special firewall, demarc considerations• All calls are seen and possibly charged by the SP
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Enterprise FMC Deployment Models
• PBX Extension Mode: VoFi side of the phone is homed to the PBX
– PBX forwards calls to the cellular number when phone is out of Wi-Fi coverage
– Sometimes works with cellular data channel for presence & signalling when in cellular coverage
– User experience is closer to PBX extension whether inside or outside Wi-Fi coverage
Pros• Can be configured by the IT group• Major PBX vendors are adding this functionality• Integrates with PBX numbering plan & features
Cons• Configuration burden falls on the IT group• All calls are anchored on the PBX • No standards, so phones will need custom code updates• Inter-site roaming needs to be carefully configured
LAN edge
LAN core
Internet
Cellular Core
Cellular Base Station
SIP PBXOr softswitch
Voice Telephony Gateway
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• Thank you