Linkset is a group of interfaces of cluster nodes that belong to the same broadcast domain. In linksets, each node has the information about which interfaces of other nodes are connected to the same broadcast domain.
Linksets are a mandatory configuration in the following scenarios:
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For deployments that require MAC-Based Forwarding (MBF).
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For "-m MAC" mode that is enabled at the virtual server along with MBF mode enabled globally.
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To improve the manageability of ACL and L2 policies involving interfaces. You define a linkset of the interfaces and add ACL and L2 policies based on linksets.
In a cluster setup, the following features use MBF internally.
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Forwarding session
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L2Conn
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MAC mode virtual server
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Transparent monitor
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LLB
Linksets must be configured only through the cluster IP address.
Consider an example with a three node cluster. In the following figure, the interfaces 0/1/2, 1/1/2, and 2/1/2 are in the same broadcast domain and therefore can be configured as linkset (LS/1).
Figure 1. Linksets topology
Figure 2. Traffic distribution flow using linksets