does emergency (911) dispatch uses IP ?

Wed Jan 2 22:36:14 UTC 2019

Yes.

Look for NENA (National Emergency Number Association).

20+ years ago, 911 routing required telco connections in each LATA. Some 
legacy (e.g. copper) still uses LATA-based 911 routing, but a lot of 911 
routing (i.e. cell, voip, next-gen voice, etc) has been consolidated to a 
few service providers' data centers connected via IP.

NextGeneration 911 will be essentially 100% IP.

Cost, efficiency, etc.

On Wed, 2 Jan 2019, Mankamana Mishra (mankamis) via NANOG wrote:
> While reading CL network down impacting 911 services, was trying to get more
> information about how does this network looks like. From end user to center,
> I guess VOIP is used. Wondering what is the communication method from
> Emergency service center to end units (Police, Fire or any other services).
> Do they also use IP ? or its Still Radio only ? if it is IP, do they use
> Unicast or multicast or broadcast ?
> 
> 
> Tried googling, but did not get much information. Any insight would be
> appreciated.