Users Guide

Usage Information
LACP on the VLT ports (on a VLT switch or access device), which are members of the VLT, are not brought up
until the VLT domain is recognized on the access device.
During boot-up in a stacking conguration, the system must be able to reach the DHCP server with the boot
image and conguration image. To receive an oer on static LAGs between switches, only untagged DHCP
requests are sent to the DHCP server. Congure the DHCP server to start in BMP mode.
If the switches are connected using LACP port-channels (for example, the VLT peer and top of rack [ToR]), use
the port-channel option on the ToR-side conguration to allow member ports of an ungrouped LACP port-
channel to inherit VLAN membership of that port channel. This ensures untagged VLT peer device packets reach
the DHCP server on the ToR.
To ungroup the VLT and port-channel congurations, use the no lacp ungroup member independent
command on a VLT port channel.
If you reboot both VLT peers in BMP mode with static VLT LAGs, the DHCP server reply to the DHCP discover
oer may not be forwarded by the ToR to the correct node. To avoid this issue, congure the VLT LAGs to the ToR
and the ToR port channel to the VLT peers with LACP.
If supported by the ToR, enable the lacp-ungroup feature on the ToR using the lacp ungroup member-
independent port-channel command.
If the lacp-ungroup feature is not supported on the ToR, reboot the VLT peers one at a time. After rebooting, verify
that VLTi (ICL) is active before attempting DHCP connectivity.
Use the lacp ungroup member-independent command only if the system connects to nodes using bare
metal provisioning (BMP) to upgrade or boot from the network. Otherwise, when the member links ap, the links
become independent switch ports and forward the trac even before LACP is formed on that port.
Ensure that you congure all port channels as hybrid ports and as untagged members of a VLAN where the LACP
ungroup option is applicable.
BMP uses untagged dynamic host conguration protocol (DHCP) packets to communicate with the DHCP server.
To disable this feature on VLT and port channels, use no lacp ungroup member-independent {vlt |
port-channel} command under the conguration mode.
Example
DellEMC(conf)#lacp ungroup member-independent ?
port-channel LACP port-channel members become switchports
vlt All VLT LACP members become switchports
multicast peer-routing timeout
To retain synced multicast routes or synced multicast outgoing interface (OIF) after a VLT peer node failure, congure the timeout value for
a VLT node.
Syntax
multicast peer-routing timeout value
To restore the default value, use the no multicast peer-routing timeout command.
Parameters
value Enter the timeout value (in seconds). The range is from 1 to 1200. The default is 150.
Command Modes VLT DOMAIN (conf-vlt-domain)
1942 Virtual Link Trunking (VLT)