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Poly Phone Line Unregistered Error

Symptom

Line Unregistered displays on Poly phones intermittently with SRTP enabled.

Applies To

  • SRTP-Enabled Poly Phones

Resolution

  1. Verify firewall settings. See Configuring Your Network for VoIP Services.
  2. TCP Time out and TCP Close Wait options need to be set to 660 seconds if applicable in the firewall.
  3. Set the 8x8 GTM on the phones or the phone VLAN. Do not set the GTM on the data network.
    1. GTM 1: 8.28.0.9
    2. GTM 2: 192.84.18.11
  4. Update device firmware to 5.9.4.3247 with, this can be done by creating a case with 8x8 Support.
  5. If the issue persists, disable SRTP on all phones. See Enabling and Disabling SRTP in Admin Console.

Cause

8x8 Work SRTP Service (Secure Real-time Transmission Protocol) encrypts telephone call media on Poly handsets and Work for Desktop and mobile clients*, and de-encrypts the call at the session border controller (SBC) on 8x8's network.
For SRTP encryption to fully function, both parties on an SRTP-encrypted call must use 8x8 Work SRTP and one of the following:
  • Poly VVX handset
  • Poly Soundpoint IP
  • Yealink handset
  • Cisco 7x and 8x Series handset
  • Panasonic DECT wireless handset
  • 8x8 softphone clients
IETF Standard (RFC 3711) which ensures Encryption, Authentication, and Integrity.
8x8 SRTP meets Federal FISMA 140-2 standards.

Common Causes of Registration Issues

TCP Connection

When registration is established between an SRTP-enabled device and the proxy, a TCP connection is established between the endpoint and server. Since TCP is a connection-oriented protocol, if this connection is severed the device will lose registration. The TCP connection needs to maintain a connection with the registration server, whereas the devices using UDP registration (devices with SRTP disabled) do not.

Geo-Routing Issues

This is most commonly identified when devices route intermittently between two data centers and can be identified in the Network Utility under the DNS testing for geo-routing.

Firmware

Poly firmware has been identified as an issue that can cause registration issues with SIP over TLS enabled. It is recommended to update the firmware to mitigate this issue. Registration issues may still occur on this firmware version, however, the registration issues are far less frequent than in previous firmware versions.

TCP Socket Has Been Reset or Closed

SIP over TLS uses TCP traffic for registration. If the TCP socket the device is communicating over has been reset or closed, the device will lose registration. Modifying the TCP Time Out and TCP Close Wait options where applicable on the firewall is recommended to mitigate this potential issue.

Identifying SRTP-Enabled Lines in 8x8 Admin Console

  1. Navigate to a user extension inside of 8x8 Admin Console.
  2. Click "Voice basic settings" on the left sidebar.
  3. The "Enable Secure Real-time Protocol" will be blue if the setting is enabled.

Additional Information 

8x8 does not recommend using Google DNS on the phone network.