Border Gateway Protocol (BGP) is a dynamic routing protocol based on Transmission Control Protocol (TCP). BGP is used to exchange routing information and network accessibility information among different autonomous systems. When you use an Express Connect circuit to connect to Alibaba Cloud, you can configure BGP to enable private communication between your data center and the associated virtual border router (VBR). This helps you build a hybrid cloud in an efficient, flexible, and reliable way.
Limits
- You can specify only the data center as the BGP peer of a VBR.
- VBRs support only BGP-4.
- You can create at most eight BGP peers for each VBR.
- The Autonomous System Number (ASN) of Alibaba Cloud is 45104. You can specify a 2-byte or 4-byte ASN for the data center.
- Bidirectional Forwarding Detection (BFD) is disabled for VBRs by default. To use this feature, Submit a ticket.
Prerequisites
- A VBR is created. For more information, see Create a VBR.
- BGP routing is configured in the data center so that the BGP routes can be advertised to Alibaba Cloud. You can also configure BFD based on your business requirements. Contact the service provider of your gateway device for the relevant commands.
Step 1: Create a BGP group
BGP groups are used to simplify BGP configurations. You can save time and effort by adding BGP peers that use the same configurations to one BGP group. Before you start, you must create a BGP group with the requested ASN.
Step 2: Create a BGP peer
After you create the BGP group, you can add BGP peers that use the same configurations to the BGP group. This way, you do not need to configure the BGP peers one by one.
Step 3: Advertise the BGP CIDR block
- Log on to the Express Connect console.
- In the top navigation bar, select the region and click Virtual Border Routers (VBRs) in the left-side navigation pane.
- On the Virtual Border Routers (VBRs) page, find the VBR that you want to manage and click its ID.
- Click the Advertise BGP Subnet tab and click Advertised BGP Subnets.
- Enter the CIDR block to be advertised and click OK.
What to do next
View the monitoring events of BGP peers
CloudMonitor manages system events and custom events of Alibaba Cloud services in a centralized manner. You can configure event-triggered alert rules to monitor the BGP peer status and routes. If an exception occurs, you are notified so that you can manage the exception at the earliest opportunity. For more information, see Event monitoring overview.
Manage BGP
Operation | Procedure |
---|---|
Modify a BGP group |
|
Modify a BGP peer |
|
Delete a BGP group |
|
Delete a BGP peer. |
|
Delete the CIDR block advertised by BGP |
|
References
- CreateBgpGroup: creates a BGP group for a VBR.
- CreateBgpPeer: adds a BGP peer to a BGP group.
- AddBgpNetwork: advertises a BGP network.
- ModifyBgpGroupAttribute: modifies the attributes of a BGP group.
- ModifyBgpPeerAttribute: modifies the attributes of a BGP peer.
- DeleteBgpGroup: deletes a BGP group.
- DeleteBgpPeer: deletes a BGP peer.
- DeleteBgpNetwork: deletes an advertised BGP CIDR block.