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require state information coordinating between the two VLT chassis. IGMP and VLT configurations must be identical on both
sides of the trunk to ensure the same behavior on both sides.
Figure 130. Virtual Link Trunking
Multi-domain VLT
A multi-domain VLT (mVLT) configuration creates a port channel between two VLT domains by allowing two different VLT
domains, using different VLT Domain ID numbers, connected by a standard LACP LAG to form a loop-free Layer 2 topology in
the aggregation layer.
This configuration supports a maximum of four (4) nodes per mVLT domain, increasing the number of available ports and
allowing for dual redundancy of the VLT.
Additionally, a VLT domain that is a member of one mVLT can be used in another mVLT configuration with a different VLT
domain. Routing protocols such as OSPF are not compatible with mVLT; however, VLT domains can be used for routing. A
separate Layer 3 router is not required for inter-VLAN communication.
The following figure shows how the core/aggregation port density in the Layer 2 topology is increased using mVLT. For
inter-VLAN routing and other Layer 3 routing, a separate Layer 3 router is required.
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Virtual Link Trunking (VLT)