2 Replies Latest reply: Jan 16, 2019 10:38 PM by Timothy RSS

    VTP Pruning and Etherchannel question


      Hi, my question for VTP Pruning is say you have a switch A (has access ports in Vlan 1,2,3,4) , connected to Switch B (has access ports in Vlan 123) and switch B connects to Switch C. What would happen if a host on Switch A sent a frame from VLAN 4 with VTP Pruning enabled to Switch C?

      From my understanding, pruning will have Switch B tell Switch A it has no access ports in Vlan 4 and will want to prune it and not receive broadcasts from Vlan 4 and thus the traffic would never reach Switch C. Am I missing something or is there more config behind VTP Pruning?



      Second question for Ether Channel is if 1 port is configured with Speed 10 and other end is auto, while 2nd port in channel is auto to auto, what would be status of the Etherchannel? From my understanding , Etherchannel requires all ports to be the same duplex, allowed vlans, native vlan, operational mode, and speed. My question is, what would be the status in "Show etherchannel summary" if any of these are mismatched? I tried doing this in packet tracer but it shows normal status of (in use and P for ports)



      Any help is greatly appreciated

        • 1. Re: VTP Pruning and Etherchannel question
          Sourabh Saboo

          Hello Subby,


          For your first question, I will say that please make it clear.

          This is not the way VTP Pruning works.


          For the second question, Ether-channel to work between two different switches the speed and duplex should match.

          Not only this there are some more important things to match for layer2 or layer3 ports.

          If anything would be miss-match then the port will show legend S means Suspended mode.



          • 2. Re: VTP Pruning and Etherchannel question

            1. If you are manually pruning, the frames will not be allowed to go through the trunk.

            2. For EtherChannel to work correctly the speed and duplex should match for all the physical ports on both ends. Have you tried on real equipment, that can really help in solving this question. EtherChannel can be a pain on a real device too. If you can, please try the same using real devices.

            3. It is possible to have an EtherChannel without trunking. You mentioned native vlans and allowed vlans. Are you configuring a trunk between the switches too?


            All the best,