Nexus 2K to Cisco 2960 IOS Switch

[rthakker]

Hi,

I am trying to connect Nexus 2K FEX to Cisco 2960 IOS Switch (Trunk config) and causing spanning tree loop having issues. I am aware that I should't be connecting non host port to 2K FEX but it's corner case. I have done similar setup with Access Port configuration and didn't faced any issues.

Nexus 5K config Config 

interface Ethernet107/1/47
  switchport mode trunk
  switchport trunk allowed vlan 500-501
  spanning-tree guard root
  spanning-tree bpdufilter enable 

interface Ethernet108/1/47
  switchport mode trunk
  switchport trunk allowed vlan 500-501
  spanning-tree guard root
  spanning-tree bpdufilter enable 

2960-Config 

interface GigabitEthernet1/0/47
  switchport mode trunk
  switchport trunk allowed vlan 500-501
 spanning-tree bpdufilter enable

interface GigabitEthernet1/0/48
  switchport mode trunk
  switchport trunk allowed vlan 500-501
 spanning-tree bpdufilter enable

Error Log

%FWM-2-STM_LOOP_DETECT: Loops detected in the network for mac 001b.1700.0130 among ports Eth107/1/47
Eth108/1/47 vlan 500 - Disabling dynamic learn notifications for 180 seconds 

Should I configure port as "spanning-tree port type network" and create VPC and "storm-control broadcast level" to stop future occurrence?  OR Do i have to configure anything else to prevent spanning-tree loops? 

Thanks for your help

Ritesh

[Reza Sharifi · Accepted solution]

Hi,

spanning-tree port type network is used for VPC peer-link.  Try creating a new VPC and add ports 107/1/47 and 108/1/47 to it and a Portchannel on the 2960 and test.

HTH

[rthakker]

Hi thanks for your help. 

Ritesh