Setup Guide

• BMP uses untagged dynamic host conguration protocol (DHCP) packets to communicate with the DHCP server.
• o disable this feature on VLT and port channels, use no lacp ungroup member-independent {vlt | port-channel}
command under the conguration mode.
• When you enable IGMP snooping on the VLT peers, ensure the value of the delay-restore command is not less than the query
interval.
• When you enable Layer 3 routing protocols on VLT peers, make sure the delay-restore timer is set to a value that allows sucient time
for all routes to establish adjacency and exchange all the L3 routes between the VLT peers before you enable the VLT ports.
•
Only use the lacp ungroup member-independent command if the system connects to nodes using bare metal provisioning
(BMP) to upgrade or boot from the network.
• Ensure that you congure all port channels where LACP ungroup is applicable as hybrid ports and as untagged members of a VLAN.
BMP uses untagged dynamic host conguration protocol (DHCP) packets to communicate with the DHCP server.
• If the DHCP server is located on the ToR and the VLTi (ICL) is down due to a failed link when a VLT node is rebooted in BMP mode, it is
not able to reach the DHCP server, resulting in BMP failure.
• If the source is connected to an orphan (non-spanned, non-VLT) port in a VLT peer, the receiver is connected to a VLT (spanned) port-
channel, and the VLT port-channel link between the VLT peer connected to the source and ToR is down, trac is duplicated due to
route inconsistency between peers. To avoid this scenario, Dell EMC Networking recommends conguring both the source and the
receiver on a spanned VLT VLAN.
• 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 you enable static ARP on only one VLT peer, entries may be overwritten during bulk sync.
Conguration Notes
When you congure 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 device in the VLT domain is assigned a primary role; the other device 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 congure the primary role manually.
– In a VLT domain, the peer switches must run the same Dell EMC Networking OS software version.
– Separately congure 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 nd 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
dierent 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 can consist of 10G or 40G ports. A maximum of eight ports are supported. A combination of 10G and 40G
ports is not supported.
916
Virtual Link Trunking (VLT)