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Spanning-tree blocks VPC port-Channel

Kaneki007
Level 1
Level 1

Hello, 

I got an issue with a VPC link after upgrading my two VPC peers to 10.3.5(M) NXOS, below i little demonstration on how my my connections are: 

Kaneki007_0-1721382707797.png

 

My ports configuration is like this: 

N9K1#interface ETH1/9

lacp rate fast
switchport
switchport mode trunk
switchport trunk allowed vlan 4008
spanning-tree port type normal
channel-group 106 mode active
no shutdown

N9K1#int Po106

switchport
switchport mode trunk
switchport trunk allowed vlan 4008
spanning-tree port type normal
vpc 106

======================================

N9K2#

N9K2#interface ETH1/9

lacp rate fast
switchport
switchport mode trunk
switchport trunk allowed vlan 4008
spanning-tree port type normal
channel-group 106 mode active
no shutdown

N9K2#int Po106

switchport
switchport mode trunk
switchport trunk allowed vlan 4008
spanning-tree port type normal
vpc 106

=================================================

 

When i let the two ports UP both of them start flapping and then they go down, but when i shutdown the second port it works, now i working with just the port channel of the N9K1, i tried to understand the issue but i don't find why would spanning three blocks my port-channel since i have vpc he should consider the two nexus as to be one switch

 

this is the result when i let two port-channels UP: 

 

On the N9K1: 

N9K1#Show spanning-tree vlan 4008

VLAN4008
Spanning tree enabled protocol rstp
Root ID Priority 36776
Address 0023.04ee.be65
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 36776 (priority 32768 sys-id-ext 4008)
Address 0023.04ee.be65
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po100 Desg FWD 1 128.4195 (vPC peer-link) Network P2p
Po107 Desg FWD 1 128.4202 (vPC) Edge P2p
Eth1/57 Desg FWD 4 128.225 Edge P2p
Eth1/58 Desg FWD 4 128.229 Edge P2p

N9K1#show port-channel sum | inc 106

106 Po106(SD) Eth LACP Eth1/9(D)

N9K1#show interface po106 brief 

------------------------------------------------------------------------------------------
Port-channel VLAN Type Mode Status Reason Speed Protocol
Interface
------------------------------------------------------------------------------------------
Po106 1 eth trunk down No operational members auto(D) lacp

N9K1#show interface ETH1/9 br

--------------------------------------------------------------------------------
Ethernet VLAN Type Mode Status Reason Speed Port
Interface Ch #
--------------------------------------------------------------------------------
Eth1/9 1 eth trunk down initializing auto(D) 106

======================================================

 

On the N9K2 

N9K2#show spanning-tree vlan 4008

VLAN4008
Spanning tree enabled protocol rstp
Root ID Priority 36776
Address 0023.04ee.be65
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 36776 (priority 32768 sys-id-ext 4008)
Address 0023.04ee.be65
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Po100 Root FWD 1 128.4195 (vPC peer-link) Network P2p
Po107 Desg FWD 1 128.4202 (vPC) Edge P2p
Eth1/57 Desg FWD 4 128.225 Edge P2p
Eth1/58 Desg FWD 4 128.229 Edge P2p

#show int Po106 brief 

------------------------------------------------------------------------------------------
Port-channel VLAN Type Mode Status Reason Speed Protocol
Interface
------------------------------------------------------------------------------------------
Po106 1 eth trunk down No operational members auto(D) lacp

 

show int Eth1/9 brief 

--------------------------------------------------------------------------------
Ethernet VLAN Type Mode Status Reason Speed Port
Interface Ch #
--------------------------------------------------------------------------------
Eth1/9 1 eth trunk down initializing auto(D) 106

 

And then when i shutdown the port on the second switch 

N9K1#show spanning-tree vlan 4008 

Po106 Desg FWD 1 128.4201 (vPC) P2p

I also checked vpc 

show vpc consistency-parameters vpc 106

Legend:
Type 1 : vPC will be suspended in case of mismatch

Name Type Local Value Peer Value
------------- ---- ---------------------- -----------------------
delayed-lacp 1 disabled disabled
lacp suspend disable 1 enabled enabled
mode 1 active active
Switchport Isolated 1 0 0
Interface type 1 port-channel port-channel
LACP Mode 1 on on
Virtual-ethernet-bridge 1 Disabled Disabled
Speed 1 10 Gb/s 10 Gb/s
Duplex 1 full full
MTU 1 1500 1500
Port Mode 1 trunk trunk
Native Vlan 1 1 1
Admin port mode 1 trunk trunk
Port-type External 1 Disabled Disabled
STP Port Guard 1 Default Default
STP Port Type 1 Normal Port Normal Port
STP MST Simulate PVST 1 Default Default
lag-id 1 [(7f9b, [(7f9b,
0-23-4-ee-be-65, 806a, 0-23-4-ee-be-65, 806a,
0, 0), (8000, 0, 0), (8000,
98-d8-8c-94-6c-0, 98-d8-8c-94-6c-0,
43e8, 0, 0)] 43e8, 0, 0)]
Allow-Multi-Tag 1 Disabled Disabled
Vlan xlt mapping 1 Disabled Disabled
L2PT Vxlan Vlans 2
vPC card type 1 N9K TOR N9K TOR
Allowed VLANs - 4008 4008
Local suspended VLANs - - -

 

Can you please help to resolve the issue? Thanks a lot

 

10 Replies 10

Hi @Kaneki007 

 It was working before the upgrade?
  Who is putting the port in block the Nexus or the nortel?