Verification Involving PSTN Reachability: Requirements and Architecture Overview

Document Type Expired Internet-Draft (individual)
Authors Mary Barnes  , Cullen Jennings  , Jonathan Rosenberg  , Marc Petit-Huguenin 
Last updated 2014-06-12 (latest revision 2013-12-09)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The Session Initiation Protocol (SIP) has seen widespread deployment within individual domains, typically supporting voice and video communications. Though it was designed from the outset to support inter-domain federation over the public Internet, such federation has not materialized. The primary reasons for this are the complexities of inter-domain phone number routing and concerns over security. This document reviews this problem space, outlines requirements, and then describes a model and technique for inter-domain federation with SIP involving the Public Switched Telephone Network (PSTN), called Verification Involving PSTN Reachability (VIPR). VIPR addresses the problems that have prevented inter-domain federation over the Internet. It provides fully distributed inter-domain routing for phone numbers, authorized mappings from phone numbers to domains, a new technique for automated SIP anti-spam, and privacy of number ownership, all while preserving the trapezoidal model of SIP.


Mary Barnes (
Cullen Jennings (
Jonathan Rosenberg (
Marc Petit-Huguenin (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)