Reference Guide

In the above scenario, LACP fallback works as follows:
1. The ToR/server boots up.
2. One of the VLT peers takes care of controlling the LACP fallback mode. All events are sent to the controlling VLT peer for
deciding the port that should be brought up and then the decision is passed on to peer devices.
3. The controlling VLT peer can decide to bring up one of the ports in either the local port-channel or in the peer VLT
port-channel.
4. One of the ports, local or peer, becomes active based on the decision of the controlling VLT peer.
5. Now the ToR/server has one port up and active. The active port sends packets to the DHCP/PXE server.
6. After receiving response from the DHCP server, the ToR/server proceeds to boot from the TFTP/NFS server.
7. When the ToR/server is fully loaded with the boot image and configurations, the server starts sending LACP PDUs.
8. When the switch receives LACP PDUs from ToR/server, the controlling VLT peer makes the LACP port to come out of the
fallback mode and to resume the normal functionality.
LACP commands
channel-group
Assigns and configures a physical interface to a port-channel group.
Syntax
channel-group number mode {active | on | passive}
Parameters
● number — Enter the port-channel group number (1 to 128). The maximum number of port-channels is
128. The maximum physical port/maximum NPU is supported.
● mode — Enter the interface port-channel mode.
● active — Enter to enable the LACP interface. The interface is in the Active Negotiating state when
the port starts negotiations with other ports by sending LACP packets.
● on — Enter so that the interface is not part of a dynamic LAG but acts as a static LAG member.
● passive — Enter to only enable LACP if it detects a device. The interface is in the Passive
Negotiation state when the port responds to the LACP packets that it receives but does not initiate
negotiation until it detects a device.
Default Not configured
Command Mode INTERFACE
Layer 2 163