PAgP LACP Etherchannel


For this lab you need REAL hardware. You can’t use switches in GNS3!

You need at least Catalyst 2950 switches for this lab.

You are a master of spanning tree and specialized in migration scenarios. Corkscrew inc. is one of your customers and they are having issues with their switches. There are many VLANs in the network and you would like to reduce the number of spanning tree calculations. As a result you decide to implement MST (Multiple Spanning Tree) for them.


  • Configure PAgP between SW1 and SW2. SW1 should actively try to form an Etherchannel and SW2 should only respond to requests.
  • Configure LACP between SW1 and SW3. SW1 should actively try to form an Etherchannel and SW3 should only respond to requests.
  • Configure an Etherchannel between SW2 and SW3. You are not allowed to use any protocol for negotiation.
  • Configure the etherchannel between SW1 and SW2 to use destination MAC address load-balancing.

It took me 1000s of hours reading books and doing labs, making mistakes over and over again until I mastered all the switch protocols for CCNP.

Would you like to be a master of switching too? In a short time without having to read 900 page books or google the answers to your questions and browsing through forums?

I collected all my knowledge and created a single ebook for you that has everything you need to know to become a master of switching.

You will learn all the secrets about PaGP, LACP, Etherchannels, link aggregation and more.

Does this sound interesting to you?

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Basic IOS for the switches should be sufficient. No special features needed.


Etherchannel Network Topology

Video Solution:

Configuration Files

You need to register to download the GNS3 topology file. (Registration is free!)

Once you are logged in you will find the configuration files right here.

Here are the configuration files:

PAgp LACP Etherchannel – Final Configuration

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The How to Master series helps you to understand complex topics like spanning-tree, VLANs, trunks, OSPF, EIGRP, BGP and more.

Written by René Molenaar - CCIE #41726


  1. Profile photo of ciscotuupje says

    Hi Rene, I have 3 2950’s and 1 3550 switches. Next to that I have 3 extra network interfaces in my desktop. I really would like to see a tutorial of labs to combine GNS3 with real switches via the cloud functionally in GNS3. To do something like intervlan-routing etc. Redirect my if there is already a tread about this topic.
    Thank you!

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    • Profile photo of Rene Molenaar says

      Hi Ciscotuupje,

      I don’t have a tutorial for this at the moment but it’s really easy to connect your switches to your GNS3 router, here’s what you do:

      1. Click and drag a router to your GNS3 topology.
      2. Click and drag a "cloud" to your GNS3 topology.
      3. Open the preferences of your "cloud" (right mouse click) and connect it to one of your NICs.
      4. Connect your real switch to that NIC.

      That’s it… they are connected.

    • Profile photo of Rene Molenaar says

      That’s good to hear. Seems packettracer does support PAGP/LACP. Will be helpful for people studying CCNA. It doesn’t include some of the CCNP commands for switches though..

      thanks for your comment!

  2. Profile photo of aungbobo says

    Hi Rene,
    let me say sorry in advance if my question was funny . I heard can use real iOS in GNS3. If so we can use same commands and functions as real devices. I’m confusing why GNS3 can’t use switching labs. Is that mean we must have real devices for testing?

    Best Regards

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    • Profile photo of Rene Molenaar says

      Hi Aungbobo,

      No worries :) GNS3 can run the real IOS image but only for routers. Switches use ASICS (Application Specific Integrated Circuit) and there are currently no emulators that can run the Switch IOS.

      If you want to practice switching you have 4 options right now:

      – Use real hardware, buy the switches yourself.
      – Use a rack rental (check they have a free lab).
      – Use packet tracer (simulator).
      – Use IOU (IOS on Unix). This is the Cisco emulator but it’s not available to the public and I think it’ll take some time to get it working.

    • Adam says

      Jacky the switches view the port-channel as one logical link and will participate in your STP deployment as such; one link. So if you have two switches connected via 8 ports in one port-channel STP will only see one link. If you create more port-channels they will be used in your STP deployment as additional links :)

  3. Fizzy says

    Hi Rene,

    I am on page 146 on CCNA Book, I have 3 2950’s switches – I am not getting the LACP to work it does not show the same output, can these switches achieve LCAP?

  4. Profile photo of Mr.Kd says

    Hi All

    Now we can create this lab using new GNS3 with IOU features.

    IOU3(config-if)#channel-group 10 mode ?
    active Enable LACP unconditionally
    auto Enable PAgP only if a PAgP device is detecte
    desirable Enable PAgP unconditionally
    on Enable Etherchannel only
    passive Enable LACP only if a LACP device is detecte

    Happy Switching

    KaDer :)

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  5. Profile photo of luqmaanki says

    Hello everyone,
    I have a question about connecting real switches to the GNS3. I did as Rene described through the cloud in GNS3, but its only 1 interface. How can I use switch for multiple devices or what kind of topology I can implement with having one switch connected to the router via cloud? Thanks

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