M4300-12X12F - LAG State Admin Mode D-Disable

[xw32]

Hi, I have 2 M4300-12X12F in stack.

After this error "Diagnostically disabling interface lag 8 as rate limit of 15 for 3 consecutive seconds has been exceeded"

I found both ports included in the LAG with admin mode disabled and the LAG State in D-Disabled mode.

I managed to re-enable Admin mode in switching -> ports -> admin mode but LAG State remains in D-Disable. In switching -> LAG i try to change LAG State in Admin Mode enabled but the change is not saved.

How can I reactivate the LAG without restarting the switch?

[Retired_Member]

Hi @xw32 

Welcome to Community!

How about your network topology? Is there loop connect? D-disable status may be casued by spanning-tree detect there is a loop.

Regards,

Eric

[xw32]

Hi, both ports number 3 of the netgear switch went into block were attached in lag towards an HP aruba switch, I am attaching a diagram of how the various switches are connected; the loop was probably generated by a switch3 reset procedure (HP).

thanks for the support

[Retired_Member]

@xw32 

Yes, I see both port 1/0/3 and 2/0/3 connect to switch2, and it will cause loop, Loop Protection will D-disable some port when detect loop. Is it necessary to connect two ports(1/0/3, 2/0/3) to switch2? Is it possible binding two ports as a lag?

And what about other port connection? such as lag1..lag8? 

Could you please command as 'show spanning-tree summary' and 'show spanning-tree mst port summary 0 active', and print the output info here?  I want to check which ports is discarding status.

[xw32]

Hi, ports 3 were part of LAG1 it is correct that they are connected to switch2 to create redundancy in case of failure of one of the 2 netgear switches in stack. Right now they are disconnected I tried to remove them from the LAG to try to reactivate Admin Mode from D-Disable to Enable.

(M4300-12X12F) >show spanning-tree summary

Spanning Tree Admin Mode.......... Enabled
Spanning Tree Version............. IEEE 802.1w
BPDU Guard Mode................... Disabled
BPDU Filter Mode.................. Disabled
Configuration Name................ ****
Configuration Revision Level...... ****
Configuration Digest Key.......... ****
Configuration Format Selector..... 0
No MST instances to display.

(M4300-12X12F) >show spanning-tree mst port summary 0 active

STP STP Port
Interface Mode Type State Role Desc
--------- -------- ------- ----------------- ---------- ----------
1/0/15 Enabled Forwarding Designated
1/0/19 Enabled Forwarding Designated
1/0/23 Enabled Forwarding Designated
1/0/24 Enabled Forwarding Designated
2/0/4 Enabled Forwarding Designated
2/0/15 Enabled Forwarding Designated
2/0/19 Enabled Forwarding Designated
2/0/20 Enabled Forwarding Designated
2/0/23 Enabled Forwarding Designated
2/0/24 Enabled Forwarding Designated
lag 2 Enabled Forwarding Designated
lag 3 Enabled Forwarding Designated
lag 4 Enabled Forwarding Designated
lag 5 Enabled Forwarding Designated
lag 6 Enabled Forwarding Designated
lag 7 Enabled Forwarding Designated

[Retired_Member]

@xw32 

Ok, got it.

I notice you diable STP mode on LAG1, right? It's mean LAG1 not participate spanning-tree caculate, and will casue broadcast stome. The root cause is 'BPDU Storm: An interface/port will go into D-Disable state if number of bpdus exceeds 15 for 3 consecutive seconds.'.

So please enable stp port mode on lag1, and then STP will change port to Discarding status if there is loop in your network.

interface lag 1
description 'trunktolan'
port-channel static
no spanning-tree port mode
vlan participation include 8,25
vlan tagging 8,25
exit

[xw32]

Now STP Mode on LAG1 is enable but Admin mode stay in D-Disable and I can't change it to enable

[Retired_Member]

@xw32 

I'm afraid there is loop in your network, switch will D-disable the port once receive BPDU Storm in an interface/port, could you please double check again? Last topology picture your provide is only show port 1/0/3 and 2/0/3 connection, how about other port connection? I want to check all up ports connction topoloygy.

[xw32]

but the ports 1/0/3 and 2/0/3 are physically disconnected at the moment, can't I set Admin mode Enable in the LAG when nothing is connected?

[Retired_Member]

@xw32 

Yes, it's allowed.

[xw32]

I attach the screenshots of the change that I can't apply

[Retired_Member]

@xw32 

Please check if there is error log while enable the LAG port.

Meanwhile, could you please run command as 'show interfaces status err-disabled', it will display the reason for D-Disable state. BPDU storm would also result in such state

[xw32]

what is the correct syntax?

(M4300-12X12F) >show interfaces status err-disabled
                                         ^
% Invalid input detected at '^' marker.

[Retired_Member]

@xw32 

You need go to en mode first by input 'en', then run this command again.

[xw32]

no result with this command:

(M4300-12X12F) >en

(M4300-12X12F) #show interfaces status err-disabled

(M4300-12X12F) #

I tried to re-enable the LAG in admin mode enable and collect the logs

[Retired_Member]

@xw32 

Yes, please run the command while the issue happen again.