Dell PowerStore PowerStore T and Q Networking Guide for Storage Services

Direct interconnect using Multi-chassis Link Aggregation (MC-LAG)

It is highly recommended that you deploy PowerStore with an MC-LAG interconnect between the two Top-of-Rack (ToR) switches.

MC-LAG is a switch interconnection technology that joins independent ToR switches into a single virtual chassis. MC-LAG allows the link aggregation (LAG) port groups to span multiple chassis, enabling better resilience of the LAG connection. Also, MC-LAG enables traffic going from switch to switch using the full bandwidth of the available connection, without using spanning tree protocol (STP), which would disable some links to prevent loops.

MC-LAG is a general name for the technology, however certain vendors use their own proprietary terminology to define MC-LAG connectivity.

When the ToR switches are interconnected with MC-LAG the two ports that are used on PowerStore appliance 4-port card, or I/O module (system bond) are configured in an active/active state.

For MC-LAG connectivity it is recommended that:

• A minimum of two connection cables in parallel with a high-speed reliable connection.
• Use of high-speed ports reduces the network traffic congestion between the two switches.
• Verify best practices for MC-LAG from your switch provider documentation.

MC-LAG interconnect with upstream links

Also, in an MC-LAG environment the two switches are treated as one logical switch. This type of interconnect allows you to add all the upstream links from both switches into a single port channel that spans the MC-LAG as demonstrated in the following diagram.

NOTE:Work with your network administrator if you are connecting the ToR switches to upstream switches.