topic LACP Neighbor Output Inconsistency in Server Networking

LACP Neighbor Output Inconsistency

mfarrenkopf — Thu, 18 Mar 2021 19:08:08 GMT

On Nexus 6001s, running two different NX-OS versions (6.0(2)N2(5), 7.0(8)N1(1)). show lacp neighbor output looks inconsistent. Partner Flags says neighbor is sending fast LACP PDUs, but Partner Port State says 0x3d, which decodes to slow LACP PDUs.

DC1-S1# show lacp nei interf po116
Flags: S - Device is sending Slow LACPDUs F - Device is sending Fast LACPDUs
A - Device is in Active mode P - Device is in Passive mode
port-channel116 neighbors
Partner's information
Partner Partner Partner
Port System ID Port Number Age Flags
Eth1/31 32768,2-a0-98-9f-58-b0 0xa 10467536 FA

LACP Partner Partner Partner
Port Priority Oper Key Port State
32768 0x32 0x3d

show lacp interface correlates to the 0x3d port state:

DC1-S1# show lacp interf e1/31
Interface Ethernet1/31 is up
Channel group is 116 port channel is Po116
PDUs sent: 148671309
PDUs rcvd: 148130434
Markers sent: 0
Markers rcvd: 10
Marker response sent: 10
Marker response rcvd: 0
Unknown packets rcvd: 0
Illegal packets rcvd: 0
Lag Id: [ [(2000, 0-23-4-ee-be-1, 8074, 8000, 11f), (8000, 2-a0-98-9f-58-b0, 32,
8000, a)] ]
Operational as aggregated link since Tue Nov 17 06:58:36 2020

Local Port: Eth1/31 MAC Address= 0-2a-6a-ba-1d-7c
System Identifier=0x8000, Port Identifier=0x8000,0x11f
Operational key=32884
LACP_Activity=active
LACP_Timeout=Short Timeout (1s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner information refresh timeout=Long Timeout (90s)
Actor Admin State=(Ac-1:To-1:Ag-1:Sy-0:Co-0:Di-0:De-0:Ex-0)
Actor Oper State=(Ac-1:To-1:Ag-1:Sy-1:Co-1:Di-1:De-0:Ex-0)
Neighbor: 0xa
MAC Address= 2-a0-98-9f-58-b0
System Identifier=0x8000, Port Identifier=0x8000,0xa
Operational key=50
LACP_Activity=active
LACP_Timeout=Long Timeout (30s)
Synchronization=IN_SYNC
Collecting=true
Distributing=true
Partner Admin State=(Ac-0:To-1:Ag-0:Sy-0:Co-0:Di-0:De-0:Ex-0)
Partner Oper State=(Ac-1:To-0:Ag-1:Sy-1:Co-1:Di-1:De-0:Ex-0)
Aggregate or Individual(True=1)= 1

Output above is from one switch (running the 6.0-series software), but I have another switch for comparison running the 7.0-series software with the same conflicting information.

Is this a bug in the output? Is the connected device really sending fast LACP PDUs, and NX-OS is reporting this, but the end device is lying in its flag status? Connected device is a NetApp of some flavor; I don't know model or OS version.

Thank you kindly for any input on this.

Re: LACP Neighbor Output Inconsistency

balaji.bandi — Thu, 18 Mar 2021 21:14:37 GMT

In general, if this is connected to NetApp bridge, then you should run simple ISL not LACP, Looks other side could be but, we need more information of the configuration of the interface and need to know the exact model of the device other side configured, some config also from another side?

Re: LACP Neighbor Output Inconsistency

mfarrenkopf — Thu, 18 Mar 2021 21:35:04 GMT

Hi Balaji,

I appreciate the reply. However, I'm the network engineer; I don't have access to the NetApp or its configuration. All I can tell you about the NetApp is the CDP data, which says AFF-A700, port e10a, and NetApp version 9.5P16.

I appreciate you want to dig into that side, but really, what I need answered is: why is the Nexus telling me the other side is doing fast LACP, when the LACP flags don't reflect that? Is it showing FA because the Nexus 6001 is seeing LACP PDUs every second? Or is there some unknown reason why the "FA" and the flag bits don't match up?

Edit: to be clear, I configure and maintain the access switch side, the connectivity between the NetApp and the enterprise network. I know the NetApps have internal switches. That is not the configuration I'm maintaining.