Considerations for ISLs

Basic MetroCluster ISL requirements

The following requirements must be met:

  • A native-speed ISL switch port must connect to a native-speed ISL switch port.

    For example, a 40 Gbps port connects to a 40 Gbps port.

  • A 10 Gbps port that is in native mode (i.e., not using a breakout cable) can connect to a 10 Gbps port that is in native mode.
  • The ISLs between the MetroCluster IP switches and the customer network, as well as the ISLs between the intermediate switches, follow the same rules in terms of speed.
  • The number of ISLs that are between the MetroCluster switches and the customer network switches, and the number of ISLs that are between the customer network switches, do not need to match.

    For example, the MetroCluster switches can connect using two ISLs to the intermediate switches, and the intermediate switches can connect to each other using 10 ISLs.

  • The speed of ISLs that are between the MetroCluster switches and the customer network switches, and the speed of ISLs that are between the customer network switches, do not need to match.

    For example, the MetroCluster switches can connect using a 40-Gbps ISL to the intermediate switches, and the intermediate switches can connect to each other using 100-Gbps ISLs.

  • The number of and speed of ISLs connecting each MetroCluster switch to the intermediate switch must be the same on both MetroCluster sites.