Spanning Tree CST , PVST+ , RSTP and MST

In this video Orhan Ergun explains all the spanning tree modes and compare them from the design point of view. If you need scalability use MST , if you want fast convergence and flexibility use RSTP and so on. If you want me to share more spanning tree videos or explain specific technology please comment below.


5 Replies to “Spanning Tree CST , PVST+ , RSTP and MST”

  1. Hi,

    Would you please explain the difference between PVST+ and RPVST+. Below what I understood kindly correct if i’m wrong.

    in PVST+ we should define the portfast – uplinkfast – and backbone fast, while in PRVST+ is already built in and no need to define it and both of them use multiple vlan instances. (is that the meaning of that RPVST+ combines rapid STP and PVSTP)
    PVST+ defined in the global config
    spanning-tree mode rapid-pvst
    PRVST+ defined per interface
    spanning-tree link-type point-to-point


    1. @MKhalid It is all about scaling and whether you are a Cisco shop.

      Yes Fabricpath is nice , it can give you L2 multi path, it avoids to have multiple pods and you don’t have to connect them through 3 tier topology by using leaf and spine

      but If your datacenter size is enough, go for Multichassis LAG solution. It can be Cisco. Jumper . HP , Avaya anything.

      All of them has MLAG solutions, data plane active on all chassis , control plane may or mayn’t be single device.

      Also don’t forget that if you use Fabricpath you will be locked in to one vendor. It is not good strategy in general.
      Layer 2 multipathing can be supported by many other technologies as well.

      If your requirement is large scale deployment,then still as physical network you can have leaf-spine, 3 -5 Stage Clos, Hypercube, Toredo, Full mesh or whatever and you can use TRILL as an industry standard or Shortest Path Bridging (SPB) just for L2 multpath.

      Also don’t forget that it is not uncommon to use BGP as a control plane in the datacenter for very large scale deployments.

  2. Hi Orhan, this was a very wonderful video about the basics of STP in regards to 802.1d,802.1s and 802.1sw. As an upcoming network design engineer what will be your recommendation or thoughts about spanning tree implementation on a new network. In other questions what will you recommend, should the default configuration be set or make some tweaks on the implementation. Again I will like you to go deeper small about how the various instance are been designed thank you.

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