In large-scale branch networks where SAG-1000 devices run in one-arm mode, static routes require manual updates each time the topology changes. BGP automates route exchange between your private network and Alibaba Cloud, so traffic follows the current topology without manual reconfiguration.
Prerequisites
Before you begin, ensure that:
Your SAG device model is SAG-1000
You have access to the Smart Access Gateway console
How BGP works
Border Gateway Protocol (BGP) is a standardized exterior gateway protocol that exchanges routing and reachability information between autonomous systems (AS). Each AS uses a designated border router to communicate with peer AS. BGP runs over Transmission Control Protocol (TCP), which provides the reliability and session management that stable inter-AS routing requires.
Configuration has two layers:
Global BGP settings — the AS number, router ID, and session timers that apply to the SAG-1000 device as a whole
Port-level BGP settings — which physical ports run BGP, and the peer IP address and AS number for each
Configure global BGP settings
Log on to the Smart Access Gateway console.
Open the Device Management tab using one of the following methods:
Click the ID of the target SAG instance. On the instance details page, click the Device Management tab.
Find the target SAG instance, then choose
> Device Management in the Actions column.
On the Device Management tab, click Manage Routes.
In the BGP Protocol Settings section, click the Edit icon.
In the Configure BGP Route Protocol dialog box, set the following parameters.
Parameter Description Local AS The AS number assigned to this SAG-1000 device. Valid values: 1–2,147,483,647. Router ID The BGP router ID for this device, expressed as an IPv4 address (for example, 192.168.1.1).Hold Time How long (in seconds) a BGP session stays open without receiving a keepalive or update from the peer. If no message arrives within this period, the session closes. Valid values: 3–65535. Both peers must use the same value. Keep Alive How often (in seconds) the device sends keepalive messages to the peer. Valid values: 0–65535. Both BGP peers must use the same hold time. If the device does not receive a keep-alive or update message from the peer device within the hold time, the connection between the BGP peers is closed.
Enable BGP per port
In the Dynamic Routing Settings section, select Enable BGP Protocol.
Find the target port and click Edit in the Actions column.
In the Modify BGP Dynamic Routing Settings dialog box, select one of the following options, then click OK:
Enable BGP — BGP runs between this port and its peer. Specify the peer IP address and AS number.
Disabled — BGP is disabled for this port.