Need some help with Nexus VPC Switching

[andy-cisco]

Hi,

I'm having a strange issue an I'm not the best with understanding VPC so I was hoping someone might be able to help me out here.

I have two SDWAN devices that are connected to their respective core device (sdwan-a to core a and sdwan-b to core-b) but I would like each sdwan to talk BGP to both core-a and core-b.  The issue I'm having is I don't have enough ports on the sdwan to make a physical connection to both so I tried to create a trunk form each sdwan and run two vlan's over the trunk.  I'm able to get the sdwan-b unit working as expected but sdwan-a will not pass traffic though the core-a to core-b.

Does anyone have any idea why sdwan-b can talk to both core-a and core-b but sdwan-a can only talk to core-a?

Additional information:

All 4 vlans are /30 ranges

All 4 vlans are create on both core-a and core-b

VPC peer link has all vlans

sdwan trunk ports are just normal trunk ports

core-a has no mac addresses for local svi 

core-b has no mac addresses for local svi

core-a has mac address for both remote sdwan IP's

core-b has mac address for sdwan-b but no mac address for sdwan-a

At this point I'm thinking for some reason that the mac address for sdwan-a on vlan 20 is not getting passed through core-a but I do not know why.

Any help would be great.

Andy

[andy-cisco]

I do not see any setting in the running config picking the type of spanning-tree but when doing a "show spanning-tree", all the vlan's are in rstp.  This appears to be the default spanning-tree mode.

Do you think it would be a good idea to have "spanning-tree port type edge trunk" on the trunk ports going to the SDWAN devices? 

And what about the new trunk between the to nexus switches that only carries vlan 20,30?

And "also" the vlans 10 and 40, should they get a "spanning-tree port type edge"?

Andy

[MHM Cisco World]

I do not see any setting in the running config picking the type of spanning-tree but when doing a "show spanning-tree", all the vlan's are in rstp.  This appears to be the default spanning-tree mode. <<- can you share show spann in both NSK 

Do you think it would be a good idea to have "spanning-tree port type edge trunk" on the trunk ports going to the SDWAN devices?  Sure that will fast STP status if SDWAN dont send any BPDU 

And what about the new trunk between the to nexus switches that only carries vlan 20,30?  <<- this depend one STP mode you run I need to know which mode to share with you some tips 

And "also" the vlans 10 and 40, should they get a "spanning-tree port type edge"? <<- Big NO if these VLAN is vpc VLAN (i.e. run in trunk use as peer-link) THEN this trunk mandatory need to be network type 

MHM