RSVP Extensions for Emergency Services
An Emergency Telecommunications Service (ETS) requires the ability to provide an elevated probability of call completion to an authorized user in times of network congestion (typically, during a crisis). When supported over the Internet Protocol suite, this may be achieved through an admission control solution which supports admission priority capabilities and possibly session preemption capabilities (depending on policies and deployed implementations). Admission priority involves setting aside some resources (e.g. bandwidth) out of the engineered capacity limits for the emergency services only, or alternatively involves allowing the emergency sessions to seize additional resources beyond the engineered capacity limits applied to normal calls. This document specifies RSVP extensions necessary for supporting such admission priority capabilities.