Vlt And Stacking; Vlt And Igmp Snooping; Vlt Ipv6; Vlt Port Delayed Restoration - Dell S4820T Configuration Manual

When the bandwidth usage drops below the 80% threshold, the system generates another syslog
message (shown in the following message) and an SNMP trap.
%STKUNIT0-M:CP %VLTMGR-6-VLT-LAG-ICL: Overall Bandwidth utilization of VLT-ICL-
LAG (port-channel 25)
reaches below threshold. Bandwidth usage (74 )VLT show remote port channel
status

VLT and Stacking

You cannot enable stacking on S4820T units with VLT.
If you enable stacking on a unit on which you want to enable VLT, you must first remove the unit from
the existing stack. For information about how to remove a unit from a stack, refer to
from an S-Series Stack. After you remove the unit, you can configure VLT on the unit.

VLT and IGMP Snooping

When configuring IGMP Snooping with VLT, ensure the configurations on both sides of the VLT trunk are
identical to get the same behavior on both sides of the trunk.
When you configure IGMP snooping on a VLT node, the dynamically learned groups and multicast router
ports are automatically learned on the VLT peer node.

VLT IPv6

The following features have been enhanced to support IPv6:
• VLT Sync — Entries learned on the VLT interface are synced on both VLT peers.
• Non-VLT Sync — Entries learned on non-VLT interfaces are synced on both VLT peers.
• Tunneling — Control information is associated with tunnel traffic so that the appropriate VLT peer can
mirror the ingress port as the VLT interface rather than pointing to the VLT peer's VLTi link.
• Statistics and Counters — Statistical and counter information displays IPv6 information when
applicable.
• Heartbeat — You can configure an IPv4 or IPv6 address as a backup link destination. You cannot use
an IPv4 and an IPv6 address simultaneously.

VLT Port Delayed Restoration

When a VLT node boots up, if the VLT ports have been previously saved in the start-up configuration,
they are not immediately enabled.
To ensure MAC and ARP entries from the VLT per node are downloaded to the newly enabled VLT node,
the system allows time for the VLT ports on the new node to be enabled and begin receiving traffic.
The delay-restore feature waits for all saved configurations to be applied, then starts a configurable
timer. After the timer expires, the VLT ports are enabled one-by-one in a controlled manner. The delay
between bringing up each VLT port-channel is proportional to the number of physical members in the
port-channel. The default is 90 seconds.
To change the duration of the configurable timer, use the delay-restore command.
If you enable IGMP snooping, IGMP queries are also sent out on the VLT ports at this time allowing any
receivers to respond to the queries and update the multicast table on the new node.
996
Removing a Unit
Virtual Link Trunking (VLT)