Dell EMC Configuration Guide for the S4048T–ON System 9.14.2.4

Because VLT ports are Layer 2 ports and not IP interfaces, VLT Unicast and VLT Multicast routing protocols do not operate directly on VLT ports. You must add the VLT ports as a member of one or more VLANs and assign IP addresses to these VLANs. VLT Unicast and VLT Multicast routing protocols require VLAN IP interfaces for operation. Protocols such as BGP, ISIS, OSPF, and PIM are compatible with VLT Unicast Routing and VLT Multicast Routing.

Layer 2 protocols from the ToR devices to the server are intra-rack and inter-rack. Although no spanning tree is required, interoperability with spanning trees at the aggregation layer is supported to prevent switching loops from forming due to any incorrect configuration. . Communication between devices is active-active, with no blocked links. MAC tables are synchronized between VLT nodes for bridging and you can enable IGMP snooping.

Spanned VLANs

Any VLAN configured on both VLT peer nodes is referred to as a Spanned VLAN. The VLT Interconnect (VLTi) port is automatically added as a member of the Spanned VLAN. As a result, any adjacent router connected to at least one VLT node on a Spanned VLAN subnet is directly reachable from both VLT peer nodes at the routing level.