Addendum

• Bulk Sync happens only for Global IPv6 Neighbors; Link-local neighbor entries are not synced.
• If all of the following conditions are true, MAC addresses may not be synced correctly:
– VLT peers use VLT interconnect (VLTi)
– Sticky MAC is enabled on an orphan port in the primary or secondary peer
– MACs are currently inactive
If this scenario occurs, use the clear mac-address-table sticky all command on the primary
or secondary peer to correctly sync the MAC addresses.
• If static ARP is enabled on only one VLT peer, entries may be overwritten during bulk sync.
• For multiple VLT LAGs configured on the same VLAN, if a host is learned on one VLT LAG and there is
a station move between LAGs, the link local address redirects to the VLTi link on one of the peers. If
this occurs, clear the link local address that is redirecting to the VLTi link.
Configuration Notes
When you configure VLT, the following conditions apply.
• VLT domain
– A VLT domain supports two chassis members, which appear as a single logical device to network
access devices connected to VLT ports through a port channel.
– A VLT domain consists of the two core chassis, the interconnect trunk, backup link, and the LAG
members connected to attached devices.
– Each VLT domain has a unique MAC address that you create or VLT creates automatically.
– ARP tables are synchronized between the VLT peer nodes.
– VLT peer switches operate as separate chassis with independent control and data planes for
devices attached on non-VLT ports.
– One chassis in the VLT domain is assigned a primary role; the other chassis takes the secondary
role. The primary and secondary roles are required for scenarios when connectivity between the
chassis is lost. VLT assigns the primary chassis role according to the lowest MAC address. You can
configure the primary role.
– In a VLT domain, the peer switches must run the same Dell Networking operating system (FTOS)
software version.
– Separately configure each VLT peer switch with the same VLT domain ID and the VLT version. If
the system detects mismatches between VLT peer switches in the VLT domain ID or VLT version,
the VLT Interconnect (VLTi) does not activate. To find the reason for the VLTi being down, use the
show vlt statistics command to verify that there are mismatch errors, then use the show
vlt brief command on each VLT peer to view the VLT version on the peer switch. If the VLT
version is more than one release different from the current version in use, the VLTi does not
activate.
– The chassis members in a VLT domain support connection to orphan hosts and switches that are
not connected to both switches in the VLT core.
• VLT interconnect (VLTi)
– The VLT interconnect must consist of either 10G or 40G ports. A maximum of eight 10G or four
40G ports is supported. A combination of 10G and 40G ports is not supported.
– A VLT interconnect over 1G ports is not supported.
– The port channel must be in Default mode (not Switchport mode) to have VLTi recognize it.
– The system automatically includes the required VLANs in VLTi. You do not need to manually select
VLANs.
– VLT peer switches operate as separate chassis with independent control and data planes for
devices attached to non-VLT ports.
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Virtual Link Trunking (VLT)