Dell PowerSwitch S4112F-ON EMC SmartFabric OS10 User Guide Release 10.5.0 - Page 1229

Optimized forwarding with VRRP Spanning-Tree Protocol Multicast To ensure the same behavior on both sides of the VLT nodes, VRRP requires state information coordination. VRRP Active-Active mode optimizes L3 forwarding over VLT. By default, VRRP Active-Active mode is enabled on all the VLAN interfaces. VRRP Active-Active mode enables each peer to locally forward L3 packets, resulting in reduced traffic flow between peers over the VLTi link. VLT ports support RSTP, RPVST+, and MSTP. IGMP snooping and MLD snooping are supported on VLT ports. NOTE: 802.1x and DHCP snooping are not supported on VLT ports. Terminology VLT domain VLT interconnect (VLTi) VLT peer device Discovery interface VLT MAC address VLT node priority VLT port channel VLT port channel ID Orphan ports The domain includes VLT peer devices, VLT interconnects, and all port channels in the VLT connected to the attached devices. It is also the configuration mode that you must use to assign VLT global parameters. The link between VLT peer switches used to synchronize operating states. A pair of devices connected using a dedicated port channel-the VLTi. You must configure VLT peers separately. Interfaces on VLT peers in the VLT interconnect (VLTi) link. Unique MAC address that you assign to the VLT domain. A VLT MAC address is a common address in both VLT peers. If you do not configure a VLT MAC address, the MAC address of the primary peer is used as the VLT MAC address across both peers. The priority based on which the primary and secondary VLT nodes are determined. If priority is not configured, the VLT node with the lowest MAC address is elected as the primary VLT node. A combined port channel between an attached device and VLT peer switches. Groups port channel interfaces on VLT peers into a single virtual-link trunk connected to an attached device. Assign the same port channel ID to port channel interfaces on both peers that you bundle together. Ports that are not part of the VLT port channel but members of the spanned VLANs. The term spanned VLAN refers to a VLAN that is configured on both the VLT peers. VLT domain A VLT domain includes the VLT peer devices, VLTi, and all VLT port channels that connect to the attached devices. It is also the configuration mode that you must use to assign VLT global parameters. NOTE: OS10 switches that belong to the same group and have the same port media type can be part of the same VLT domain. For example, you can have S5224F-ON and S5248F-ON as part of the same domain. However, switches that belong to the same group with different port media types cannot be part of the same VLT domain. For example, S4148FON and S4148T-ON cannot be part of the same domain. • Each VLT domain must have a unique MAC address that you create or that VLT creates automatically. • VLAN ID 4094 is reserved as an internal control VLAN for the VLT domain. IPv6 addressing is used on this control VLAN for VLT peer- to-peer communication. • ARP, IPv6 neighbors, and MAC tables synchronize between the VLT peer nodes. • VLT peer devices operate as separate nodes with independent control and data planes for devices that attach to non-VLT ports. • One node in the VLT domain takes a primary role, and the other node takes the secondary role. In a VLT domain with two nodes, the VLT assigns the primary node role to the node with the lowest MAC address by default. You can override the default primary election mechanism by assigning priorities to each node using the primary-priority command. • If the primary peer fails, the secondary peer takes the primary role. If the primary peer (with the lower priority) later comes back online, it is assigned the secondary role (there is no preemption). • In a VLT domain, the peer network devices must run the same OS10 software version. NOTE: A temporary exception is allowed during the upgrade process. See the Dell EMC SmartFabric OS 10.5.0.x Release Notes for more information. • Configure the same VLT domain ID on peer devices. If a VLT domain ID mismatch occurs on VLT peers, the VLTi does not activate. Virtual Link Trunking 1229