This topic describes the limits that have been applied by Alibaba Cloud to Cloud Enterprise Network (CEN) since August 1st 2018. Note that CEN does not support the original AS-PATH when distributing BGP route to a leased line (IDC). Therefore, routing loops may occur in some complex network topology scenarios. As such, Alibaba Cloud has applied the following limits to CEN:
  • By default, route learning and intercommunication are not allowed between VBRs that are newly attached to a CEN instance. For example, VPC1, VPC2, VBR1 and VBR2 are attached to a CEN instance. Before this change, VPC1, VPC2, VBR1, and VBR2 can communicate with each other; while after the change, VBR1/VBR2 and VPC1/VPC2 can be interconnected, but there is no communication between VBR1 and VBR2. If you need to connect two VBRs, open a ticket. Alibaba Cloud technical support will evaluate the network topology with you and perform background processing.
  • By default, the VBR of a certain VSwitch model on the Alibaba Cloud side cannot be attached to the CEN (the VSwitch model do not support the distribution of the original AS-PATH). If you encounter an error when attaching a VBR that is using the VSwitch model to CEN, open a ticket. Alibaba Cloud technical support assist you by developing a migration plan for you or allow you to continue using the VSwitch.

    The above changes only apply to the VBRs that were attached to CEN instances after the effective date of this announcement, and do not affect the VBRs that were previously attached to CEN instances.