Branch offices that rely on a single Internet link risk losing connectivity when that link fails. Smart Access Gateway (SAG) addresses this with dual-link high availability (HA): a wired connection (WAN port) as the active link and a 4G wireless connection as the standby link. When the wired link fails, the SAG device automatically switches to 4G.
Prerequisites
Before you begin, make sure that you have:
A functional 4G subscriber identity module (SIM) card purchased from an Internet service provider (ISP) and inserted into the SAG device
Each SAG device ships with a 4G SIM card. That card can only receive configuration data from Alibaba Cloud — it cannot carry user traffic. Purchase a separate SIM card from an ISP to use 4G as a standby data link.
How it works
The SAG device uses the WAN port for the active (wired) connection and 4G for the standby (wireless) connection:
Active link fails: the device automatically fails over to 4G within seconds.
Check the status of both links at any time in the SAG console.
Check HA status
Log on to the Smart Access Gateway console.
In the left-side navigation pane, click Smart Access Gateway.
Find the target SAG instance and click the instance ID.
On the instance details page, click the Configure High Availability tab.
In the HA Configuration section, check the status of the wired and wireless connections.
Green: The network connection is available.
Red: The network connection is unavailable.