Administrator Guide

Version Description
8.3.12.0 Added port-channel parameter on the S4810.
8.3.8.0 Introduced on the S4810.
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 configuration, the system must be able to reach the DHCP server with the boot
image and configuration image. To receive an offer on static LAGs between switches, only untagged DHCP
requests are sent to the DHCP server. Configure 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 configuration 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 configurations, 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
offer may not be forwarded by the ToR to the correct node. To avoid this issue, configure 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 flap, the links
become independent switch ports and forward the traffic even before LACP is formed on that port.
Ensure that you configure 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 configuration 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 configuration 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, configure 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)
Command History
This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC
Networking OS Command Line Reference Guide.
Version Description
9.10(0.1) Introduced on the S6010-ON and S4048T-ON.
9.10(0.0) Introduced on the S3148.
Virtual Link Trunking (VLT) 1603