AudioCodes Mediant 4000 SBC - Pre-Empting Existing Calls for E9-1-1 Calls; PSAP Callback to Skype for Business Clients for Dropped E9-1-1 Calls

CHAPTER16 Services
Mediant 4000 SBC | User's Manual
a=rtpmap:8 PCMA/8000
a=ptime:20------=_NextPart_000_4A6D_01CAB3D6.7519F890
Content-Type: application/pidf+xml
Content-ID: <voip_911_user1@contoso.com>
<?xml version="1.0" encoding="utf-8"?>
<presence xmlns="urn:ietf:params:xml:ns:pidf"
xmlns:gp="urn:ietf:params:xml:ns:pidf:geopriv10"
xmlns:bp="urn:ietf:params:xml:ns:pidf:geopriv10:basicPolicy"
xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
xmlns:ms="urn:schema:Rtc.LIS.msftE911PidfExtn.2008" entity="sip:voip_911_
user1@contoso.com"><tuple id="0"><status><gp:geopriv><gp:location-
info><ca:civicAddress><ca:country>US</ca:country><ca:A1>WA</ca:A1><ca:A3>Red
mond</ca:A3><ca:RD>163rd</ca:RD><ca:STS>Ave</ca:STS><ca:POD>NE</ca:POD
><ca:HNO>3910</ca:HNO><ca:LOC>40/4451</ca:LOC>
<ca:NAM>1111-222-333; 1234567890 </ca:NAM>
<ca:PC>98052</ca:PC></ca:civicAddress></gp:location-info><gp:usage-
rules><bp:retransmission-allowed>true</bp:retransmission-allowed></gp:usage-
rules></gp:geopriv><ms:msftE911PidfExtn><ms:ConferenceUri>sip:+14255550199@con
toso.com;user=phone</ms:ConferenceUri><ms:ConferenceMode>twoway</ms:Conferen
ceMode><LocationPolicyTagID
xmlns="urn:schema:Rtc.Lis.LocationPolicyTagID.2008">user-tagid</LocationPolicyTagID
></ms:msftE911PidfExtn></status><timestamp>1991-09-
22T13:37:31.03</timestamp></tuple></presence>
------=_NextPart_000_4A6D_01CAB3D6.7519F890--
Pre-empting Existing Calls for E9-1-1 Calls
If the ELIN device receives an E9-1-1 call from the IP network and there are unavailable channels
(for example, all busy), the device immediately terminates one of the non-E9-1-1 calls (arbitrary)
and accepts the E9-1-1 call on the freed channel:
■ SBC application: The preemption is done only on a call pertaining to the same source IP Group
from which the E9-1-1 call is received, or the same destination IP Group (i.e., PSAP Server).
This feature is initiated only if the received SIP INVITE message contains a Priority header set to
"emergency", as shown below:
PRIORITY: emergency
PSAP Callback to Skype for Business Clients for Dropped E9-1-1 Calls
As the E9-1-1 service automatically provides all the contact information of the E9-1-1 caller to the
PSAP, the PSAP operator can call back the E9-1-1 caller. This is especially useful in cases where
the caller disconnects prematurely. However, as the Enterprise sends ELINs to the PSAP for E9-1-
1 calls, a callback can only reach the original E9-1-1 caller using the device to translate the ELIN
number back into the E9-1-1 caller's extension number.
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