This topic lists the network requirements on the on-premises data center when you use Express Connect to connect the on-premises data center to Alibaba Cloud.

  • If you use an optical port, you must use one of the following types of single-mode optical modules to connect to the access device of Alibaba Cloud. Make sure that the optical modules on both ends of the connection have consistent parameters configured.
    • 1 GB Ethernet 1000Base-LX single-mode optical module
    • 10 GB Ethernet 10GBase-LR single-mode optical module
    • 40 GB Ethernet 40GBase-LR single-mode optical module
    • 100 GB Ethernet 100GBase-LR single-mode optical module
  • You must disable auto-negotiation for the port. You must manually configure the port speed and use the full-duplex mode.
  • The entire connection, including intermediate devices, must support 802.1Q VLAN encapsulation.
  • The network device in your on-premises data center must support Border Gateway Protocol (BGP) and BGP MD5 authentication, or support static routing.
  • If you use redundant physical connections, ensure that you can set route weights on your network devices.
  • Optional. You can configure Bidirectional Forwarding Detection (BFD) on the network.
  • The physical-layer maximum transmission unit (MTU) is 1,522 bytes, which is the sum of 14-byte Ethernet header, 4-byte VLAN flag, 1,500-byte IP datagram, and 4-byte frame check sequence (FCS).

    Recommended value: 1500.

  • We recommend that you use private IP addresses for the connection between the on-premises data center and Alibaba Cloud. The CIDR blocks used for the connection must not conflict with each other.
  • To avoid conflicts with the IP addresses used by cloud services, the on-premises data center cannot use the CIDR block 100.64.0.0/12.
  • Do not use the CIDR block 100.64.0.0/10 for the connection between the Alibaba Cloud VBR and the gateway of the on-premises data center.
  • The bandwidth limit of the gateway on the premises must be greater than 500 Internet Control Message Protocol (ICMP) echo request packets per second. Otherwise, the detection packets in the health check can be limited by the gateway of the on-premises data center. If this occurs, the health check may fail and cause network jitter.