How does the WAN Conectivity Check work?

Zyxel_Jason

WAN Connectivity Check is one of new features on NCC Phase 4.

Motivation of this feature:
Scenario:
NSG has dual active WAN interface that makes traffic potentially route across an interface with no Internet connection because of load sharing.

For example, NSG has WAN 1 and WAN 2 connection to perform load sharing.
However, when there is a remote routing failure on WAN 1, NSG can't detect it.
WAN Connectivity Check will let NSG detect the remote routing failure on WAN 1 and has event logs about it.

How it works:
1. NSG will send ICMP request to target domain name or IP address when enable this feature.
    The following is the mechanism of this feature:
    (1) Check Interval: 10 seconds
    (2) Check timeout: 5 seconds
    (3) Check Fail Tolerance: 3 times
    (4) Maximum time to detect failures: 45 seconds
2. Disables routing across WAN interface if connectivity check fails on that interface.

Where to configure:
You may find it on "GATEWAY > Configure > Interface addressing" to enable.