VDX 6740 vcs and spanning tree

  • 4 April 2019
  • 1 reply

Hi all, I have 4 vdx6740 switches configured in a logical chassis mode. I have to connect the via a distribuited lacp port channel (only with 2 switches because other ports are busy) to 2 nexsus switches in order to have access to some L2 Vlan configured on the 2 nexsus. These 2 nexsus are the cores of entire network and I connect to them via a vpc (like my port channel distribuited on my 2 of 4switches). Based on your experience have I to setup stp in order to prevent a loop? I think is not necessary because I have a vcs logical chassis and it acts as a single switch, and the nexsus expone a vpc, like a single interface. Any help is appreciated.

Thanks and regards

1 reply

Userlevel 1
Hello Ddevis,
You are correct that you do not have to configure STP since the VCS fabric and the Nexus switches will only see a single link between them,
That said, a number of customers still configure either STP or some other loop detection protocol, so that if a loop is created (accidentally) it does not cause trouble. Whether you wish to go down this path, probably depends on the likelihood of this happening and size of the network.
Within VCS, you have a number of options for loop detection, including STP, Edge loop detection (ELD) and MAC move detection. Which you would use depends on the version of NOS you are running and probably the size of the network.