Spanning tree issue with Nexus 6001

[shraddha.pajwani]

We have Nex6K build as dual home. Spanning tree running on it as PVST+. These are new Nexus6k when we try to add in our production network , where Layer2 portion of network is all Netgear switches  Model M5300-52GS3 and M4100  POE, Network goes down and migration never complete.

I am not sure if Nex 6K has spanning-tree compatibility issue with Netgear switch has STP 802.1w enabled. 

Is there any specific config change require for this issue on Nexus side ? or would it be design issue?

[Furose M]

Cisco switches runs PVST/RPVST which wont work with any other vendor switches which runs IEEE version of STP/RSTP.

please use MST in all the switches for interoperatability.

[shraddha.pajwani]

Forose

Thank you so much for update. These Nexus has been setup as Dual home with Fex as shown below. How can I config MST on both of the switches?

wi-core-sw-01# show fex
  FEX         FEX           FEX              FEX              Fex      
Number    Description      State            Model            Serial    
------------------------------------------------------------------------
101        FEX0101                Online    N2K-C2348TQ-10GE   FOC2017R24T
102        FEX0102                Online    N2K-C2348TQ-10GE   FOC2013R3X3

wi-core-sw-02# show fex
  FEX         FEX           FEX              FEX              Fex      
Number    Description      State            Model            Serial    
------------------------------------------------------------------------
101        FEX0101                Online    N2K-C2348TQ-10GE   FOC2017R24T
102        FEX0102                Online    N2K-C2348TQ-10GE   FOC2013R3X3

[Furose M]

FEX is simply a linecard attached to the N6k. so, whatever configure you do on N6k is applicable to FEX too.

[shraddha.pajwani]

That is correct however for MST instances to work on both Nexus , Do I need to create same MST config on both Nexus 6K?

[Furose M]

MST is a strict guy. all the devices in the network should have exactly the same MST config. else, they wont become friends.

The instance to Vlan mapping, conf revision number and name should be exactly same.

[shraddha.pajwani]

Furose

Thank you.

[shraddha.pajwani]

Furose

Hi, Netgear switches has to act as root switch. we can not has Nexus 6K as Master. Changing priority or making in root secondary is not going to help. Any Idea what else should I try?

Thanks

Shraddha

[Furose M]

why not changing priority wont help here?

[shraddha.pajwani]

Furose

Hi, we have only 20 VLANs, If I put all VLANs to MST0 on Cisco side as well as on Netgear side, would it cause any issue? I create MST instance for VLANs, only MST0  read BPDU. Keeping all the VLANs in MST0 is working to get Negear as root switch. 

[Furose M]

it should be fine.

[shraddha.pajwani]

We have our colo site with netgear network and I am not sure if our remote site needs to have all VLANs added on MST0 ? 

Should same VLANs that are learning route via layer 3 to main office and visa versa all can be put on MST0 at main office  or should we create a separate instance for VLAN that are at remote site and learning routes via layer3?

Thanks you 

Shraddha 

[Furose M]

as these FEXes are VPCed to both 6k, please do the change in a MW or use config-sync feature.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus6000/sw/system_management/6x/b_6k_System_Mgmt_Config_6x/b_6k_System_Mgmt_Config_602N11_chapter_010.html