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Call identification alternatives
only trust Accept-Contact from same trust domain
see P-Asserted-Identity model (RFC 3325) ? brittle
or use Identity model ? signed by outbound proxy
unfortunately, not covered by
doesn’t help with UA rec/res model!
creating a new header likely to have similar issues
re-do mapping and ensure that URL matches
server can learn list of “legal” URLs after a while
can fail if mapping is dynamic (advertisement changes)
then just replaces URL
forces each outbound proxy to do mapping
check external source that URL is indeed a PSAP
use draft-ietf-sipping-certs for destination URL, but would need to have a role-based cert “this is a bona-fide PSAP”
easy to posit, harder to deploy globally
can incur significant delay
but only needed when there’s service differentiation
new TLD for PSAPs only ?
PPT Version