Layer 2 EtherChannel with PAgP

Hi

I was doing lab on RS5 Layer 2 EtherChannel with PAgP and in the workbook it says configure the po12,13,14 with switchport trunk encapsulation dot1q and switchport mode dynamic desirable and other side as mode auto. I am suspecting something is wrong because when use pagp why we need to use dot1q. This scenario dosn't work with do1q enabled bot works fine without dot1q. Here is the sample, I  might be wrong

Po13 with dot1q enabled for pagp

Mar  1 05:35:40.074: %EC-5-CANNOT_BUNDLE2: Fa0/20 is not compatible with Po13 and will be suspended (trunk encap of Fa0/20 is auto, Po13 is dot1q)

po12 works fine after doing no dot1q

sw1#sh eth summ

Flags:  D - down        P - bundled in port-channel

        I - stand-alone s - suspended

        H - Hot-standby (LACP only)

        R - Layer3      S - Layer2

        U - in use      f - failed to allocate aggregator

 

        M - not in use, minimum links not met

        u - unsuitable for bundling

        w - waiting to be aggregated

        d - default port

 

 

Number of channel-groups in use: 3

Number of aggregators:           3

 

Group  Port-channel  Protocol    Ports

------+-------------+-----------+-----------------------------------------------

12     Po12(SU)        PAgP      Fa0/23(P)   Fa0/24(P)   

13     Po13(SD)        PAgP      Fa0/19(s)   Fa0/20(s)   

14     Po14(SD)        PAgP      Fa0/21(s)   Fa0/22(s)  

 

Thanks

Dwarak

Comments

  • Correction:

    instead of why we need to use dot1q, why it is not working with dot1q for pagp which is desirable and auto.

     

    Thanks

    Dwarak

  • Dot1q/ISL and PAgP/LACP are unrelated.  You can run them in any combination.  You have an order of operations issue in your config, that’s what the error message means.  Something between the member ports and the port channel doesn’t agree.

     

    Brian McGahan, 4 x CCIE #8593 (R&S/SP/SC/DC), CCDE #2013::13

    [email protected]

     

    Internetwork Expert, Inc.

    http://www.INE.com

     

    From: [email protected] [mailto:[email protected]] On Behalf Of dwarakrg
    Sent: Wednesday, July 16, 2014 10:14 PM
    To: Brian McGahan
    Subject: Re: [CCIE R&S] Layer 2 EtherChannel with PAgP

     

    Correction:

    instead of why we need to use dot1q, why it is not working with dot1q for pagp which is desirable and auto.

     

    Thanks

    Dwarak




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  • Thanks Brain,

    However it is working when I made other side interfaces as dot1q it formed pagp channel.

     

    Thanks

    Dwarak

  • Start out by building the interfaces first. Or, in the case of using all L2 etherchannels, leave the configurations default and just assign them on the Port-Channel interface AFTER you put the physical interfaces in the channel-group.

    I teach a CCNP related course in the Air Force and my students have the issue like this all the time. My favorite command to teach them is the default interface x/x command. Makes it easy to configure the etherchannels.

    If you can recreate the issue and post the show etherchannel summary again, that would be beneficial as well.

    Eric

  • Furthermore...make it habit to just shut down the physical ports and then turn them up once the channel-group configs are there.  

  •  CCNP related course in the Air Force and my students have the issue like this all the time. My favorite command to teach them is the default interface x/x command. Makes it easy to configure the etherchannels.

    I have always followed this process.  You avoid a lot of headaches this way, but you just have to be very careful with what interfaces you target!

  • Thanks guys for valuable information!!!

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