could happen L2 loop between VMware ESXi and cisco switch ??

[Qays]

Hi

I have ESXi server  has 4 NICs, I used 2NICs For ESXi management these NICs connected to two different cisco switches and there is an Trunk between the switches, could this make L2 loop between cisco switches and VMware virtual switches?

the connection as in the screenshot

 

[balaji.bandi]

yes it will be L2 loop - and STP will block on of the side. you can use vlan priorities to differentiate. ( switch between Trunk also allowed VLAN 100 ?)

[Qays]

yes, VLAN 100 is allowed on the trunk.

[balaji.bandi]

In normal case if you deploy it will be expected as loop depeds on how it was configured.

as noted by @Seb Rupik  how you can achieve

Additional reference.

https://kb.vmware.com/s/article/2047822

https://kb.vmware.com/s/article/1004252

[Qays]

Thanks 

[Seb Rupik]

Hi there,

No there will not be a loop. This is why the VMware documentation recommends portfast or portfast trunk be configured on the switch ports connected to the ESXi server.

The vSwitch does no participate in STP and discards BPDUs, it also has the built-in logic to not forward a frame received on one uplink down another.

https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/virtual_networking_concepts.pdf

https://kb.vmware.com/s/article/1004074

cheers,

Seb.

[Qays]

Thanks

[MHM Cisco World]

Uplink is config in which way?
VMware dont depend on STP for loop prevent.
just share the Uplink config and we will check if there is loop or not

[Qays]

Hi

From cisco switches the interfaces in mode access (switchport access vlan 100)

From VMware vSwitch its two Active adapters 

[MHM Cisco World · Accepted solution]

The VMware Uplink receive the packet It never forward it toward the other Uplink so there is no Loop.
route based on original virtual port 
the MAC address will be load depend on VM Mac and hence the Mac address not show flap in cisco SW.