Liveness Checks on Trunk Connections and Vendor Connections


Liveness Checks are optional checks that monitor whether a configured Connection destination is reachable and available. They can be configured for an individual Trunk Connection or Vendor Connection. This is useful for detecting a destination that has become unreachable or is not responding to SIP requests.

The feature checks destination reachability or SIP availability; it does not replace the Connection's destination, authentication, or routing configuration.

Available checks

  • PING - sends ICMP ping checks to the Connection destination to test network reachability.
  • DNS - checks DNS resolution. Enable this when the Destination is configured as a hostname.
  • SIP OPTIONS - sends SIP OPTIONS checks to verify SIP availability at the Connection destination.

Enable the checks that are appropriate for the destination. For example, DNS checks are relevant when a hostname is used, while SIP OPTIONS checks the SIP service rather than only basic network reachability.


How the checks work

The configured checks run at the specified interval. The Interval, sec setting controls how often checks are performed and must be a positive integer.


The Threshold setting is the number of failed checks after which the Connection is treated as unavailable. It must be a positive integer. A lower threshold detects failures sooner but may react more readily to brief interruptions; a higher threshold requires more failures before the Connection is considered unavailable.

If several Checks are enabled, the Interval and Threshold is shared between them.


Failure Action and notifications

For both Vendor and Trunk Connections, Failure Action controls routing for new calls when the Connection is unhealthy:

  • Make Last In Routing - try healthy Connections first; keep this one as a fallback. This is the default.
  • Block - exclude the Connection from routing.
  • Notify Only - leave routing unchanged.


Block/Make Last In Routing is a temporary state, and liveness checks continue running. If the connection becomes healthy, it is unblocked for calls and returned to its original position in the routing order. 


Notify On Status Change emails the Root Customer's primary contact when a check reaches its Threshold and when it recovers—not after every failed attempt. It is off by default and requires a configured contact email address. (SMTP server and Mail From should be configured)



How to set up checks for a Vendor Connection

  1. Create a Vendor Connection or edit an existing one.
  2. In Liveness Checks section enable the required checks: PING, DNS, and/or SIP OPTIONS.
  3. Set the failure Threshold and Interval, sec.
  4. Save the Vendor Connection.

How to set up checks for a Trunk Connection

  1. Create a Trunk Connection or edit an existing one.
  2. Open the Liveness Check tab and enable the required checks: PING, DNS, and/or SIP OPTIONS.
  3. Set the failure Threshold and Interval, sec.
  4. Save the Trunk Connection.

For both Vendor and Trunk Connections, choose what happens when a check fails using Failure Action. Save your changes; they normally take effect within a few minutes.


Related documentation