Connectivity Guide

Verify LAG membership
OS10# show lacp interface ethernet 1/1/29
Interface ethernet1/1/29 is up
Channel group is 1 port channel is po1
PDUS sent: 17
PDUS rcvd: 11
Marker sent: 0
Marker rcvd: 0
Marker response sent: 0
Marker response rcvd: 0
Unknown packetse rcvd: 0
Illegal packetse rcvd: 0
Local Port: MAC Address=74:e6:e2:f5:b5:80
System Identifier=32768,32768
Port Identifier=32768,32768
Operational key=1
LACP_Activity=passive
LACP_Timeout=Long Timeout(30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner information refresh timeout=Long Timeout(90s)
Actor Admin State=BCFHJKNO
Actor Oper State=BDEGIKNO
Neighbor: 276
MAC Address=00:00:00:00:00:00
System Identifier=,00:00:00:00:00:00
Port Identifier=0,14:18:77:7a:2d:00
Operational key=1
LACP_Activity=passive
LACP_Timeout=Long Timeout(30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner Admin State=BCEGIKNP
Partner Oper State=BDEGIKNO
LACP fallback
LACP fallback allows downstream devices, like Servers, connected to ports of a switch configured as LACP to establish a link
when the system is not able to finalize the LACP handshake.
For example, when servers boot in PXE mode, the server cannot exchange LACP PDUs and the switch does not enable the
ports.
Whenever a PXE server reboots, both the port-channel and ports go down. While rebooting, the ports come up, but not the
port-channel. LACP fallback enables the port-channel to be up and keeps sending packets to the PXE server.
When you enable LACP fallback, the switch starts a timer. If the timer expires before LACP completes, then the switch selects
one port of the port group and makes it operational.
You can set the timer using the lacp fallback timeout timer-value command.
The LACP fallback feature adds a member port to LACP port-channel if it does not receive LACP PDUs from the peer for a
particular period of time.
The server uses the fallback port to finalize the PXE-boot process. When the server starts with the OS, the process completes
the LACP handshake and the fallback port re-unites the other members. The member port becomes active and sends packets to
the PXE server.
When the switch starts receiving LACP PDU, OS10 ungroups the statically added member port from LACP port-channel and
resumes with normal LACP functionality..
When you enable LACP fallback, the port that comes up is selected based on the following:
● LACP port priority configuration allows deterministic port allocation. The port with the least priority is placed in the active
state when a port-channel is in LACP fallback mode.
Layer 2
267