Connectivity Guide

In the above scenario, LACP fallback works as follows:
1 The ToR/server boots up.
2 The switch detects the link that is up and checks fallback enabled status. If fallback is enabled, the device waits for the time-out
period for any LACP BPDUs. If there are no LACP BPDUs received within the time period, then the LAG enters into fallback mode and
adds the rst operationally UP port to the port-channel instead of placing it in an inactive state.
3 Now the ToR/server has one port up and active. The active port sends packets to the DHCP/PXE server.
4 After receiving response from the DHCP server, the ToR/server proceeds to boot from the TFTP/NFS server.
5 When the ToR/server is fully loaded with the boot image and congurations, the server starts sending LACP PDUs.
6 When the switch receives LACP PDUs from ToR/server, the device comes out of the fallback mode and activates the LAG through
normal LACP process.
LACP fallback in VLT domain
In a VLT domain, LACP fallback enables rebooting of ToR or server connected to VLT nodes through VLT port-channel. The other end of
the VLT nodes are connected to a DHCP/PXE server, as shown in the following illustration:
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Layer 2