ISL cabling requirements

When using shared ISLs in a MetroCluster IP configuration, you must be aware of the requirements for the end-to-end MetroCluster ISL running from controller ports on site A to controller ports on site B.

Note: You must follow the basic ISL requirements: Considerations for ISLs

Number of ISLs and breakout cables in the shared network

The number of ISLs connecting the MetroCluster IP switches to the shared network varies depending on the switch model and port type.

MetroCluster IP switch model Port type Number of ISLs
Broadcom-supported BES-53248 switches Native ports 4 ISLs using 10 or 25-Gbps ports
Cisco 3132Q-V Native ports 6 ISLs using 40-Gbps ports
Breakout cables 16 x 10-Gbps ISLs
Cisco 3232C Native ports 6 ISLs using 40 or 100-Gbps ports
Breakout cables 16 x 10-Gbps ISLs

For optimum performance, you should use at least a 1 x 40 Gbps or multiple 10 Gbps ISLs per network. Using a single 10 Gbps ISL per network for AFF A800 systems is strongly discouraged.

The maximum theoretical throughput of shared ISLs (for example, 240 Gbps with six 40 Gbps ISLs) is a best-case scenario. When using multiple ISLs, statistical load balancing can impact the maximum throughput. Uneven balancing can occur and reduce throughput to that of a single ISL.

Support for WAN ISLs on the Broadcom BES53248 switch

A 40-GbE or 100-GbE WAN ISL requires an RCF file version 1.40 or higher.

Note: Extra licenses are required for additional ports.