Emergency Calling Services(Calls for police, fire, ambulance, etc.)

SIPPING WGIETF 58

Tom Taylortaylor@nortelnetworks.com

Looking at Emergency Calling Service(Calls to police, fire, ambulance, etc.)

Call Origin

PSTN

SIP Phone

draft-schulzrinne-sipping-sos

Emergency Call Centre Location

PSTN IP Network

Legacy

NOW!

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EMERGING

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Issues Considered

• Identifying emergency calls– SIP phone or network may have to recognize numbers– universal emergency URI a partial solution– have to distinguish between regular and hearing impaired ECCs in

some jurisdictions• Routing from the SIP phone to the target ECC

– depends on caller location• Presenting caller location at the ECC

– calling party number used to determine caller location– PSTN may determine calling party number based on incoming circuit

• Presenting callback number at the ECC– PSTN gateway may have to provide limited-lifetime number, map back

to non-numeric SIP URI• Holding the caller accountable for the call

– tradeoff: user/device authentication vs. importance of handling emergency

Possible Solutions Depend On The Application Scenario

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PSTNGateway

TargetECC

PSTNGateway

ECC

SIP network

Routed as emergency callRouted as ordinary call

SIP Phone:stationary

vs.nomadic

Emerg.Services

DB

DB DB

Looking Forward

• Requirement to carry location info in SIP– confidentiality, integrity – applies to call signalling as a whole

– usable by proxies, PSTN gateways for call routing

– may be inserted by SIP phone or by proxy

– ideally, could be constructed by SIP phone based on manual configuration

• hotel room example

• Potential BCP work for devices• Potential BCP work for network operation