This article describes the MLAG basic setup and best practices. This information expands on standard LAGs.

For the actual step-by-step process of setting up an MLAG, see the MLAG: Create an MLAG section on page 73 of the software manual from the download center.
http://downloadcenter.netgear.com/en/product/M7100-24X%20%28XSM7224%29

Multichassis Link Aggregation Groups

MLAG (Multichassis Link Aggregation Groups) overcomes some limitations of the spanning tree.

• Uses all of the link bandwidth
• Introduces hardware redundancy
• Tolerates both link and switch failures
• Provides much faster recovery than STP

Since the MLAG appears as a LAG to the LAG partner, no special configuration is required on the partner.

Supported switches and firmwares

MLAG is available on the M7100 (XSM7224) switch on firmware version 10.1.0.10 or higher.

Topologies

Several common topology layouts fit MLAG well.

MLAG-based aggregation layer

In this topology, you have redundant MLAG connections up to your core and down to your edge switches. One of the aggregation switches can fail and traffic continues to flow.

MLAG-based storage network

In this tolopogy, you have a separate network with just SAN equipment, such as ReadyDATA 5200, and some VM Hosts, such as Xen, HyperV, and VMWare, that are interconnected redundantly. Each device has an MLAG that is connected to a pair of MLAG-capable switches. In this scenario, any one cable or switch can fail and traffic continues to flow.

MLAG-based collapsed core and aggregation with routed VLANs

In this topology, your core and aggregation layer collapse into one set of switches that run the MLAGs. These switches have a redundant MLAG down to your edge switches. One of the switches or links in the MLAG can fail and traffic continues to flow. The routing VLAN interfaces must be configured with VRRP.

MLAG-based core and aggregation layer with routed VLANs

In this advanced topology, you have redundant MLAG connections up to your core and down to your edge switches. The core is redundant in this setup. The routing VLAN interfaces must be configured with VRRP.

Requirements

Redundancy

When connecting equipment to MLAG switches, this connection should be done redundantly. Ideally, non-redundant equipment is connected through a redundantly-connected edge or core switch.

Peer link

The peer link is a crucial link. You must configure a LAG as the peer link and make sure that enough bandwidth exists.  If the peer link is overwhelmed with data, traffic is disrupted.

VRRP

When doing VLAN routing on MLAG interfaces, you must configure VRRP for that VLAN on both switches for the MLAG to work.

Notes and limitations

• Only the primary switch shows full MLAG peer information.
• VLANs cannot be shared between MLAG interfaces and non-MLAG ports.
• You cannot access the M7100's management network IP address through an MLAG. You can connect the M7100's management network interface to an isolated management network or configure the management network interface through the serial port.