[cisco-voip] Hosted E911 over SIP

Fri Oct 7 13:33:27 EDT 2011

The reason you need to deal with off premise providers all has to do with
the way 911 calls are currently routed in the carrier network. When you dial
911 in a traditional environment, your call is processed through what is
called a Selective Router. Your caller ID is passed to that Selective Router
which takes your phone number and validates that number against the MSAG
(Master Street Address Guide). The MSAG returns an address for your phone
number and the SR can then deliver your call to the appropriate PSAP (Public
Safety Answering Point) for your location.

All this works great right now in the enterprise environment for callers
that are physically located in the place where the call server is located.
When you have remote workers, say a branch office in another town or state,
if all the calls are processed at my host call server, then you can't get
that 911 call to the proper SR for processing. So, if I am in my Atlanta
office, but using a SIP phone attached to my California pbx, the call will
naturally want to go out over my SIP or PRI lines in California, hitting the
California SR's, and not able to get my call to the Atlanta PSAP where I am
located.

The way to overcome that is to have local trunking in the branch offices to
be used in the event 911 is called. So I could have a gateway, like
Audiocodes as example in my Atlanta office. I'm still placing my calls
through my VPN access to my California office, but my pbx is programmed to
send that call back to my gateway in Atlanta and use the local trunking
attached to send the call out in the event I dial 911 only, thereby getting
me to the SR for my state and getting me to the proper PSAP.

If there is no local trunking, or if I was just working out of my basement
or something, then that is when you really have no alternative but to send
all your 911 calls for the remote locations out a SIP trunk and send to a
provider like 911 Enable, RedSky, or my favorite company for that purpose,
911ETC. The 911 calls then land in what is called a Voice Positioning
Center, which takes the 911 call and then routes it to the proper PSAP from
there. Now, there is a much deeper discussion we could get into that
describes that whole process, and different vendors use different
procedures, but not doing that right now. There are tools you can force your
at home workers to input their location data before they launch their soft
client, etc., but that is not always effective because people are inherently
lazy and may not actually fill it out or update it if they change locations.
You get charged I believe $75 for each 911 call they process.

I have presenters and presentations that go deeper into this stuff if anyone
wants to go deep. My company develops applications for 911 to include
discovery for VoIP clients in a customer network and on site notification
for 911 calls. This is stuff you need to really pay attention to as there
are laws now in 17 states that dictate how you must handle 911 calls from
your enterprise environment and to what level of granularity you need to
pinpoint where that caller is located. 

Specifically speaking to Microsoft Lync, their default answer for 911 is to
send all your 911 calls to 911 Enable and you must purchase the 911 Enable
appliance to manage all that. 

In the future with NG911, these type of problems go away. As the PSAP's
become NG911 enabled and can accept SIP calls directly without converting
SIP to CAMA trunks, you will be able to insert all the location details in
the SIP header of the call. Your SIP carrier will be able to route the call
to the appropriate ESRP (Emergency Services Routing Proxy) and through what
is called ESI Net in the 911 field, be able to route your call to the proper
PSAP based upon the information in the SIP header, effectively putting those
guys and the VPC's out of business. The roadblock to all this of course is
bureaucracy and money.

Tim

Tim Kenyon

President

Conveyant Systems, Inc.

Tel: +1.770.339.1085

Fax: +1.770.339.1462

www.conveyant.com

tim at conveyant.com

Ask us about Conveyant's all new E911 offerings!

"Vision, without execution, is hallucination".

Thomas Edison

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Norton, Mike
Sent: Friday, October 07, 2011 12:58 PM
To: Matt Slaga (AM); Scott Voll; Rick Gilliam
Cc: cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] Hosted E911 over SIP

Yes, it is interesting that you bring that up. Do you have any info/links on
that? A potential Lync pilot project on the horizon is actually part of the
reason I'm looking for an E911 solution. I thought it just had to be to a
SIP trunk, not necessarily to an off-premise provider. I.e., a SIP trunk to
an on-premise CER-like product would still work... at least, that was my
thinking.

-- 

Mike Norton

I.T. Support

Peace Wapiti School Division No. 76

Helpdesk: 780-831-3080

Direct: 780-831-3076

From: Matt Slaga (AM) [mailto:matt.slaga at dimensiondata.com] 
Sent: October-07-11 6:53 AM
To: Norton, Mike; Scott Voll; Rick Gilliam
Cc: cisco-voip at puck.nether.net
Subject: RE: [cisco-voip] Hosted E911 over SIP

Just for FYI, with Microsoft Lync, hosted E911 service is the only supported
solution.  Thought that would be interesting to bring up.

From: cisco-voip-bounces at puck.nether.net
[mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Norton, Mike
Sent: Thursday, October 06, 2011 6:58 PM
To: Scott Voll; Rick Gilliam
Cc: cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] Hosted E911 over SIP

Yeah, I guess it would be a little less "dirty" feeling in cases where the
whole phone is already across the Internet anyway. Hadn't really thought of
that scenario.

My inclination is to look for a product that does it like CER does, but all
the vendors' material that I've looked at makes it seem like hosted is the
way to go, even though most of them do offer something for both methods.
Thanks for the feedback; helps to confirm my thinking isn't way out to
lunch.

-- 

Mike Norton

I.T. Support

Peace Wapiti School Division No. 76

Helpdesk: 780-831-3080

Direct: 780-831-3076

From: Scott Voll [mailto:svoll.voip at gmail.com] 
Sent: October-06-11 11:59 AM
To: Rick Gilliam
Cc: Norton, Mike; cisco-voip at puck.nether.net
Subject: Re: [cisco-voip] Hosted E911 over SIP

I'm there too......   But i Know 911 enable does have an on site appliance
so we can do the same as CER.  

But where I think the "dirty feeling SIP" does come into place is with lots
of telecommuters.  I know of a very large company that has hundreds if not
thousands of telecommuters that have soft and hard phones at home.  They
(the company) feels that they should provide 911 service to there
telecommuters.  Since each telecommuter does not have a VGW they use a E911
SIP provider to route the call to the correct PSAP.  Now if you don't have
any VGWs in a city that a telecommuter might be in.... I can see it.

But for a normal environment...... I do understand the "dirty" feeling.

Scott

On Thu, Oct 6, 2011 at 10:19 AM, Rick Gilliam <rdg7656 at yahoo.com> wrote:

Very well said Mike and I for one totally agree with your "Dirty and  just
wrong " of 911 traffic over the Net.

Most customer's I have met also say: it just sounds wrong no matter how much
$$$ we save. these types of mission critical calls should be forced out over
conventional media.

Rick G

From: "Norton, Mike" <mikenorton at pwsd76.ab.ca>
To: "cisco-voip at puck.nether.net" <cisco-voip at puck.nether.net>
Sent: Thursday, October 6, 2011 1:04 PM
Subject: [cisco-voip] Hosted E911 over SIP

Does anyone use any of those "hosted" E911 services (e.g. 911 Enable, Red
Sky, etc.) where you send them the 911 calls over the Internet using SIP?

In my mind, sending calls over the Internet feels dirty and wrong, and
sending emergency calls that way feels just plain stupid. How do you deal
with lack of QoS and having basically no control over availability or
capacity? For regular calls, I could understand just living with it (in some
applications) - but for 911? Seriously?

Is hosted E911 one of those services that looks pretty in a marketing PDF
but nobody actually uses in real life?

-- 

Mike Norton

I.T. Support

Peace Wapiti School Division No. 76

Helpdesk: 780-831-3080

Direct: 780-831-3076

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