E911 for Static VoIP integration & testing guide

Larry Reeder

Updated

Configuring your 911 services

Session Border Controllers (SBCs)

Bandwidth has two geographically redundant SBCs to send 911 calls to. Routing should be set up as primary/secondary or round-robin. Please reach out to your Implementation Specialist to obtain the specific IPs or open a ticket with your Bandwidth Support Team.

SIP peers

Bandwidth supports the provisioning of IP addresses for 911 routing. Ranges must be separated out, and DNS entries are not supported. By default, Bandwidth allows up to 10 IPs for sending 911 traffic. Additional IPs beyond that are subject to approval and additional charges.

Note: To add new IPs, please reach out to your Implementation Specialist, if you're currently working with one. If not, please open a ticket with your Bandwidth Support Team.

Supported codecs

Bandwidth only supports the G.711 u-law codec for 911. While a call may still traverse the Bandwidth SBC with a different codec, there is no guarantee that a codec other than G.711 u-law will be established properly, potentially causing the call to fail.

Supported privacy types

SIP peers can be configured with the following privacy types:

  • P-Asserted-Identity
  • Remote-Party-ID
  • P-Charge-Info

Bandwidth will automatically search the Remote-Party-ID and From headers. If the P-Asserted-Identity option is set on the trunk group, Bandwidth will also search that header. Headers are preferred in this order:

  1. P-Asserted-Identity (if P-Asserted-Identity option is set on the trunk group)
  2. Remote-Party-ID
  3. From

Bandwidth only supports one P-Asserted-Identity header, which must have a sip URI, not a tel URI.

Bandwidth also supports P-Charge-Info as a caller-identifying header. You must notify your Implementation Specialist if want Bandwidth to use P-Charge-Info. If P-Charge-Info is enabled, the caller identifier will be pulled from SIP headers in the following order:

  1. P-Charge-Info
  2. P-Asserted-Identity (if P-Asserted-Identity option is set on the trunk group)
  3. Remote-Party-ID
  4. From

If no information is populated in any of the above fields, the call will receive a generic callback number and will be passed to the Emergency Call Center (ECC) for processing, unless you have requested that unprovisioned calls be denied.

Populating values in all privacy headers (P-Asserted-Identity, Remote-Party-ID, and P-Charge-Info) is not recommended.

Media/audio

Ports 1024-64000 UDP should be open for RTP Media. If you require the Media IPs, please reach out to your Implementation Specialist.

Other SIP configurations and supported methods

  • SIP REFER is not supported; please use SIP REINVITE.
  • SIP registration should be turned off.
  • SIP authentication (username/password) should be disabled as it's not required
    and may hinder functionality.
  • OPTIONS messages are supported, but should not be sent more than once in a 60
    second period.

Testing your Bandwidth 911 configuration

Once you’ve completed your Bandwidth 911 configuration, it’s time to test it. The steps below are all you need to properly test your setup and make sure you can successfully support 911 calls.

Interoperability testing steps

Once all the technical requirements and setup are completed, testing for 911 functionality is an easy 3-step process. Please review the 3-step process and sample invites below before moving forward with sending Bandwidth production traffic.

1. Provision a 911 endpoint

Provision the endpoint with a valid address in the 911 Access Portal.  

2. Make a 933 call

Bandwidth provides a text-to-speech service for partial 911 testing. You may need to add 933 to your dial plan in order for the call to be made. This service, when called, will read back the telephone number and address that is provisioned in the 911 Access Portal.

The 933 test will perform the following validation checks:

  • The endpoint is properly provisioned
  • Basic interop to the Bandwidth SBC chosen
  • One-way audio

To call the 933 service, just send the SIP INVITE to 933 instead of 911.

3. Complete live 911 testing

Before completing, please confirm that you’re able to do the following:

  • Send a SIP INVITE to 933 and receive the automated recording that reads back the provisioned address.
  • Initiate a 911 call from a specific ANI. This ANI should be set in the From or P-Asserted-Identity fields in the SIP INVITE.
  • Failover to an alternate data center when you receive a SIP 410 response from a 911 SIP INVITE.

Simulated failover testing

This test will validate your system’s ability to successfully redirect failed calls to your secondary route.

During this test, we'll simulate a scenario in which your 911 call is sent to your primary route and will then fail with a SIP 410 response. When you receive a 410 response, you should send the SIP INVITE to the opposite data center.

To complete testing, simply make a call from the following ANIs:

  • If ATL is the primary, 15555558888
  • If DFW is the primary, 15555559999

Once you’re set up to do these things, you’re ready to migrate traffic. Please notify us if you require any assistance with the migration of services.  

Note: If the 933 call isn't successful, please halt testing and open a ticket with your Bandwidth Support Team.

Handling SBC failures

In the event of a live SBC failure, the Bandwidth SBC may respond with a 4xx, 5xx, or 6xx SIP status, or won't respond at all (in the case of a hard-down situation). The non-response or the error message must be handled appropriately on the customer side to fail over to the other functioning SBC.

The one exception is a 487 response, which is a normal response to you sending a CANCEL for the call. If you receive a 487, don't fail over to the alternate SBC. 

Sample invites

The sample invite is for a 911 call. A 933 INVITE is exactly the same, just replace “911” with “933”. See below for a description of the 933 service.

INVITE sip:911@XXX.XX.XXX.XX.10:5060 SIP/2.0 
From: <sip:5553211234@X.X.X.X:5060>;tag=9098.A419
To: <sip:911@XXX.XX.XXX.XX:5060>
Call-ID: 0014.4F26.94FB.4E45.909B.2603 
CSeq: 8573 INVITE 
Max-Forwards: 70 
Via: SIP/2.0/UDP X.X.X.X:5060;branch=z9hG4bK4E45.9098.A4198573 
Contact: <sip:911@XXX.XX.XXX.XX:5060>
Allow:INVITE,BYE,INFO,PRACK,CANCEL,ACK,OPTIONS,SUBSCRIBE,NOTIFY,REGISTER,
REFER,UPDATE 
Supported: timer,100rel 
Content-Type: application/sdp 
Content-Length: 195 

v=0 
o=- 23714 23714 IN IP4 X.X.X.X 
s=- 
c=IN IP4 X.X.X.X 
t=0 0 
m=audio 29740 RTP/AVP 0 101 
a=rtpmap:101 telephone-event/8000 
a=fmtp:101 0-15 
a=ptime:20 
a=sendrecv 

Tips for successful 911 test calls

The PSAP testing instructions listed below are helpful suggestions for placing test calls to a PSAP. Test calls from an unprovisioned phone number are not permitted, unless specifically allowed ahead of time by your Bandwidth Support Team, and may be charged for at the rate specified in the customer contract. 

Do's and don'ts when making 911 test calls

  • It's a best practice to call the 10-digit non-emergency PSAP number that will be utilized in your testing and advise the 911 operator that you'll be conducting 911 test calls in advance of any testing. Many larger PSAPs will request that you schedule testing with them during what are typically less busy hours. The non-emergency number of the PSAP can be obtained in the 911 Access Portal while in the emergency endpoint. If you need assistance with this, please open a ticket with your Bandwidth Support Team.
  • When calling 911, immediately state: “This is NOT an emergency; this is a test. Do you have a few minutes to review my information with me?”
  • If no, say “Thank you, goodbye” and immediately hang up. Try back at a less busy time, or schedule the test call as mentioned previously.
  • If yes, ask your questions quickly, and end the call.
  • Do expect the PSAP operators to be abrupt, as you could be blocking a life-threatening call.
  • Don't call during the busy hour of lunch, or between 4:00 p.m. and 6:00 p.m. in your local time zone or the location for which you're testing.
  • Try to call during off-hours such as 6:00 a.m.

General information regarding a PSAP test call

  • Ensuring that your 911 service testing is successful is extremely important. However, test calls demand the 911 operator’s attention. So, please remember that an actual emergency situation must take precedence over test calls.
  • PSAPs have limited trunking and stations.
  • Generally, PSAP turnover is high, which could result in staffing and training not being adequate.
  • Bandwidth has a comprehensive list of PSAP administrative contacts. If you have trouble with a specific PSAP, feel free to report it by opening a ticket with your Bandwidth Support Team. We'll review the call recording and clarify the situation with a supervisor or appropriate member of the PSAP team. 

Additional information regarding 933 service 

The 933 service is a courtesy text-to-speech service that Bandwidth offers as part of the 911 package. When an end user dials 933, it will play back the phone number and address provisioned in the 911 Access Portal. This service is used as part of the 911 testing performed during the onboarding process, before the live 911 calls, and is used primarily to test connectivity to the emergency IPs for 911 service. Secondarily, it tests to make sure the provisioned address is being broadcast.

As with any text-to-speech service, there may be parts that are not appropriately recognized and therefore skipped in the playback. The point of using the 933 service is to verify that:

  • Calls are reaching the SBCs
  • Some resemblance of the address provided in the 911 Access Portal is represented

For example, if the 911 address entered is “123 N Main St, Ste 400, Denver Colorado 80205”, the 933 service would likely read back “123 Main, Denver Colorado 80205”. This would be considered a successful call. If it read back something entirely different, such as “2963 Stormy Ave, El Paso TX”, this would indicate a problem either with the 933 service or with the address in the 911 Access Portal.

The 933 service may be used at any time (please limit calls to 1 call per minute). However, it's a courtesy service and is not meant to be used as a fully functional address verification service. To verify a full address, it's best to check the provisioned address directly in the 911 Access Portal or via an API call.

Questions? Please reach out to your implementation specialist. You can also open a ticket with your Bandwidth Support Team or hit us up at (855) 864-7776!

Article is closed for comments.