This article provides step-by-step guidance to configure link dial backoff settings on Edge Routers to reduce unnecessary retry attempts and log noise when certain Public Edge Routers are unreachable (for example, due to firewall restrictions).
The configuration leverages the built-in exponential backoff mechanism in the router to progressively slow retry attempts after consecutive failures.
When Should This Configuration Be Used?
You should apply this configuration if:
- Some Public Edge Routers are not reachable from your environment
- Certain Public ER domains or ports are not whitelisted in your firewall
- You observe repeated link dial errors or excessive retry logs
- You want to reduce retry frequency while still allowing recovery when connectivity is restored
How Link Dial Backoff Works (Brief)
- When a fabric link dial attempt fails, the router retries after a delay
- The delay increases exponentially after each failure
- The retry interval eventually stabilizes at a maximum value
- Separate backoff policies apply for:
- Healthy routers (connected to the controller)
- Unhealthy routers (considered offline)
This behavior is enabled by default and can be tuned via configuration.
Configuration Steps
Step 1: Locate the Edge Router Configuration File
On the Edge Router host, open the router configuration file ( /opt/netfoundry/ziti/ziti-router/config.yml).
Step 2: Add or Update Link Dial Backoff Settings
Add the following section under the link: configuration.
Example Configuration
link:
dialers:
- binding: transport
healthyDialBackoff:
retryBackoffFactor: 1.5
minRetryInterval: 5s
maxRetryInterval: 24h
unhealthyDialBackoff:
retryBackoffFactor: 10
minRetryInterval: 1m
maxRetryInterval: 1h
Configuration Parameters Explained
Healthy Dial Backoff
Applied when the router being dialed is considered healthy by the controller.
Unhealthy Dial Backoff
Applied when the target router is considered unhealthy.
Defaults are typically sufficient, but they can also be customized if needed.
Recommended Values
| Parameter | Recommended Value | Reason |
|---|---|---|
| minRetryInterval | 5s | Fast recovery if connectivity returns |
| retryBackoffFactor | 1.5 | Gradual exponential increase |
| maxRetryInterval | Up to 24h | Prevents repeated retries when links are permanently blocked |
Note: The maximum supported retry interval is 24 hours.
Important Notes:
The minimum supported network/ziti version for this feature is 7.3.94/0.30.4
A router restart is required after making configuration changes.
The backoff timer resets automatically when:
- A link successfully connects, or
- A connect/disconnect event occurs.
Summary:
Configuring link dial backoff allows Edge Routers to handle unreachable Public ERs efficiently by:
- Reducing unnecessary retries
- Minimizing log noise
- Preserving system resources
- Maintaining stable fabric behavior at scale
This configuration is optional but recommended in environments with restricted network reachability.