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  • 1.  Difference between "dt-trunk" vs. "dt-lacp"

    Posted Aug 01, 2019 08:39 AM

    Hi, maybe somebody can explain the difference between the commands -> trunk a13 Trk1 dt-trunk (= HP Trunk) and trunk a13 Trk1 dt-lacp <- to me?

     

    thank you!



  • 2.  RE: Difference between "dt-trunk" vs. "dt-lacp"

    Posted Aug 01, 2019 05:29 PM

    You are referring to Distributed Trunking (HP/HPE/Aruba aggregation technology well described here): so dt-trunk and dt-lacp options are like, respectively, trunk and lacp options for trunk command (where trunk means aggregate two or more physical links together) BUT those options (dt-trunk and dt-lacp) refer to a Distributed Trunking scenario.

    Do not confuse trunk with the meaning Cisco gave to the word (basically tagging more VLAN IDs on the same interface).

     

    Edit: for the very same reason that dt-trunk option is different by dt-lacp option (exactly like trunk option is not like lacp option) I suspect the Switch 4 (top Access Switch 2520 in the presentation linked above, page 45 of 60) configuration line:

     

    Switch4(config)# trunk 3-4 trk4 lacp

     

    is wrong, it should have been instead:

     

    Switch4(config)# trunk 3-4 trk4 trunk

     

    The example (top Access Switch versus bottom Access Switch, both uplinked to a DT depolyment of two HP 5412zl switches) was provided to highlight the fact you can have Non Protocol Trunks and IEEE 802.3ad (LACP) Trunks that are terminating into the DT deployment.



  • 3.  RE: Difference between "dt-trunk" vs. "dt-lacp"

    Posted Sep 04, 2020 08:07 PM

    Hi Parnassus,

     

    Thanks for this information. I have read the 60-page presentation document. The DT technology makes the 2 DT switches act somewhat similar to VSX-peers. Is this another way of explaining how VSX works? I am just trying to "hammer" the difference between having 2 separate switches running DT to a single/stacked access switch, and having 2 VSX-peer switches running MC-LAG to a single/stacked access switch. In my work environment, I run MC-LAG on 2 ArubaOS 8320CX VSX-peer switches to 2 ports (1/A1, 8/A1) on an 8-stacked ArubaOS 3810M switch (as access switch). These ports (1/A1 & 8/A1) form a trunk group, trk1, running "dt-lacp". 

     

    trunk 1/A1,8/A1 trk1 dt-lacp

     

    I just want to know if I am doing the right thing by running "dt-lacp" on trk1 interface and not just "lacp". Or should I change it to just "lacp" since the VSX best practice guide actually used "lacp" instead of "dt-lacp".

     

    Would appreciate a response.

     

    Thanks.



  • 4.  RE: Difference between "dt-trunk" vs. "dt-lacp"

    Posted Sep 06, 2020 05:59 AM

    @D.I. wrote: The DT technology makes the 2 DT switches act somewhat similar to VSX-peers.

    I think DT and VSX can't be directly compared...eventually they can from standpoints of the peers (and not for sure in a like for like comparison): VSX is, from that regard and as I already wrote time ago, DT with steroids...but also VSX is running on a completely different OS with totally different software engineering history and new features. VSX offers much more than DT (or DT + VRRP).

     


    @D.I. wrote: In my work environment, I run MC-LAG on 2 ArubaOS 8320CX VSX-peer switches to 2 ports (1/A1, 8/A1) on an 8-stacked ArubaOS 3810M switch (as access switch). These ports (1/A1 & 8/A1) form a trunk group, trk1, running "dt-lacp". 

     

    trunk 1/A1,8/A1 trk1 dt-lacp

     

    I just want to know if I am doing the right thing by running "dt-lacp" on trk1 interface and not just "lacp".

    A stack of Aruba 3810M is necessarily deployed by using Hardware stacking modules and stacking cables (isn't it?)...DT is simply not in the picture...because you have a stack (virtual switch)...so the answer to your question above is: use simply Port Trunking (using LACP) on the Aruba 3810 Stack side...and corresponding VSX LAG (using LACP) on VSX side.



  • 5.  RE: Difference between "dt-trunk" vs. "dt-lacp"

    Posted Sep 08, 2020 06:48 PM

    Thanks Parnassus.



  • 6.  RE: Difference between "dt-trunk" vs. "dt-lacp"
    Best Answer

    Posted Sep 08, 2020 02:36 PM

    Greetings!

     

    Distributed trunking on the 5400, 5400R, 3800, and 3810 switch families is similar to VSX on AOS-CX in that you may distribute link aggregation across a pair of switches with separate control planes, with trunk state synchronization and inter-switch traffic forwarding between DT members; in the case of the 3800 and 3810, this can include a pair of switch stacks as well as standalone switches.

     

    If you are only distributing links across members of the same stack, however, you would not use dt-trunk or dt-lacp, but rather the 'normal' trunk or lacp protocols when defining trunks. The dt-trunk and dt-lacp protocols are intended only for distributed trunking setups, where the trunk member ports are distributed across a distributed trunking switch pair.



  • 7.  RE: Difference between "dt-trunk" vs. "dt-lacp"

    Posted Sep 08, 2020 06:49 PM

    Thanks Matthew_Fern.