Subject: [Ecrit] i2 NOmadic 911 using TDM interconnect

From: "Karihaloo, Ujjval" <[email-masked]>
Date: Thu, 17 May 2007 15:54:50 -0600

Hi All,

     Is there any guidance on how to do an SS7 handoff to a Carrier for
a Nomadic 911 Call flow? I understand i2 call flow requires an ESRN and
ESQK to be carried as called and calling numbers, where do we actually
populate the Actual ANI in the IAM message whilst handing the 911 Call
off to a Carrier (who then hands it off to a PSAP)?

Ujjval Karihaloo

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From: "Brian Rosen" <[email-masked]>
Date: Thu, 17 May 2007 18:23:04 -0400

This is DEFINITELY not the list to ask such a question.  For i2 information,
you need to go over to NENA and ask there.

I'll answer it though :-)

Let's start with some basics:

i2 is for VoIP 9-1-1 calls.  Calls start as VoIP.

i2 uses a service (Level(3) is one of the vendors that offer this service)
it's called an "Emergency Services Gateway" network.  The ESGW takes a SIP
call on the IP side and puts it into a Selective Router, usually via SS7.

The SS7 connection from the ESGW almost always goes directly to an SR, or
goes through a switch to an SR.  I'm not aware of any ESGW network that
hands the call off to another network.

The actual TN of the caller does not make it to the PSAP via any PSTN
signaling in the current i2 spec.  All the PSAP gets is the ESQK, and it
gets that as ANI.  The actual TN of the caller is sent to the PSAP via its
ALI dip.

The gateway maps the P-Asserted-Identity, which should be the ESQK to the
Calling Party Number and/or Charge Number in the IAM.  The called party
number is 9-1-1.  The SR routes based on ANI to the right PSAP.  ANI in this
case is the ESQK.  See:

http://www.nena.org/media/files/03-503_20051020.pdf

In there you can find section 4.1.3 that tells you how to populate the
fields.

Just for completeness however, there are some changes coming in i2.5, which
the above document anticipates, which provides a mechanism to deliver the
actual TN of the caller (the "Call Back Number") in the IAM.  See section
4.1.4.  It uses the GDP field for the ESQK and the CPN/CHGN for the Call
Back Number.

Brian

  _____  

From: Karihaloo, Ujjval [mailto:[email-masked]] 
Sent: Thursday, May 17, 2007 5:55 PM
To: [email-masked]
Subject: [Ecrit] i2 NOmadic 911 using TDM interconnect

Hi All,

     Is there any guidance on how to do an SS7 handoff to a Carrier for a
Nomadic 911 Call flow? I understand i2 call flow requires an ESRN and ESQK
to be carried as called and calling numbers, where do we actually populate
the Actual ANI in the IAM message whilst handing the 911 Call off to a
Carrier (who then hands it off to a PSAP)?

Ujjval Karihaloo

---

From: "Winterbottom, James" <[email-masked]>
Date: Thu, 17 May 2007 18:12:10 -0500

Hi Ujjal,

I haven't looked at this for a while, but as far as I recall, the ESRN
is oly used by the ESGW to select the trunk-group and trunk to the
Selective Router, and doesn't need to populated into the IAM at all. The
ESQK, is very similar to the ESRK use din cellular, and is populated
into the calling-party number, while the called-number is set to 911.
The selective-router normally takes the calling-party number and
populates this into the ANI or P-ANI and sends this to the PSAP.

Cheers

James

________________________________

From: Karihaloo, Ujjval [mailto:[email-masked]] 
Sent: Friday, 18 May 2007 7:55 AM
To: [email-masked]
Subject: [Ecrit] i2 NOmadic 911 using TDM interconnect

Hi All,

 

Ujjval Karihaloo

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