Dell S3100 EMC Command Line Reference Guide for the Series 9.14.2.2 - Page 1891

Example 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 portchannel 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 memberindependent 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. 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 Command History VLT DOMAIN (conf-vlt-domain) This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide. Virtual Link Trunking (VLT) 1891