1. Emergency call assurance

2. Highest-level goals Protect PSAP resources –network resources –call takers Protect first-responder resources –unnecessary dispatch No worse than today –local attack vs. non-local –discourage abuse

3. Threats (D) DDOS (bots) –(L) from within local service area –(R) outside local area (C) Hoax/crank calls (humans) –(L) at correct location –(R) at another (fake) location

4. Discouragement Distinguish bots from humans –including silent calls Catch likely remote (bogus) calls Catch perpetrators after the call –discourages crank calls

5. Tools and impact Coarse-grained location assertion –e.g., IP address, provider POP, DSLAM,... –addresses D/R Fine-grained location –e.g., geo, street address –can be by value (“signing”) or reference –address C/L Coarse-grained identity –provider (VSP) –addresses C/R? Fine-grained identity –responsible party (caller) name & address –may not be useful if outside jurisdiction –addresses D/L, C/L, C/R (some) can be signature or transitive trust (reference)

6. Nothing is perfect Unlikely that every legitimate call will have the “good” bits set (signed, recognizable signer, trusted reference,...) Realistic goal is that “almost all” good calls are verifiable –rest is treated as suspicious when call taker resources are available similar to payphone calls today –and will be lower priority during overload (“ranking”) Thus, don’t need perfection in any single technique –combination of techniques likely works better –choose easiest-to-deploy –every call should have one at least one “is good” indicator

7. Deployment scenarios, from easy to hard ISP = VSP –includes large enterprise well-known (to PSAP) VSP, well-known ISP well-known VSP with strong customer authentication –e.g., credit card address (“can sue”) –could be emergency-only VSP well-known ISP with authentication well-known ISP without authentication –“unauthenticated network access” –e.g., guest on corporate or home hot spot or public WiFi unknown ISP/VSP –e.g., out of area (“Sierra Leonian VSP”)

8. Concerns: Delegation identity assurance: subscriber identity within service provider –SIP identity, PAI location signing: within enterprise (room/building level) –ISP customers gets signed LO includes in calls –or private key to sign own LOs? enterprise as trusted CA?

9. Questions: Value or Reference? sign LO –fine-grained or get LO from trusted/verifiable source via TLS? –e.g., corporate LIS