A VxRail cluster depends on adjacent Ethernet switches, commonly referred to as ‘top-of-rack’ switches, to support cluster operations. VxRail is broadly compatible with most Ethernet switches on the market. For best results, select a switch platform that meets the operational and performance criteria for your planned use cases.
The VxRail product does not have a backplane, so the adjacent ‘top-of-rack’ switch enables all connectivity between the nodes that comprise a VxRail cluster. All of the networks (management, storage, virtual machine movement, guest networks) configured within the VxRail cluster depend on the ‘top-of-rack’ switches for physical network transport between the nodes, and upstream to data center services and end-users.
The network traffic configured in a VxRail cluster is Layer 2. VxRail is architected to enable efficiency with the physical ‘top-of-rack’ switches through the assignment of virtual LANs (VLANs) to individual VxRail Layer 2 networks in the cluster. This functionality will ease network administration and integration with the upstream network.
One specific network, known as the ‘VxRail internal management network’, depends on multicasting services on the ‘top-of-rack’ switches for node discovery and cluster deployment purposes. Through the VLAN assignment, the flooding of Layer 2 multicast traffic is limited only to the interfaces that belong to that VLAN, with the exception of the interface that is the source of the multicast traffic.
A common Ethernet switch feature, Multicast Listener Discovery (MLD) snooping and querier, is designed to constrain the flooding of multicast traffic by examining MLD messages and then forwarding multicast traffic only to interested interfaces. Since the traffic on this node discovery network is already constrained through the configuration of this VLAN on the ports supporting the VxRail cluster, this setting may provide some incremental efficiency benefits, but does not negatively impact network efficiency.
In certain instances, additional switch features and functionality are necessary to support specific use cases or requirements.