Wired Intelligent Edge (Campus Switching and Routing)

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Occasional Contributor II

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

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!


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MVP Expert

Re: Difference between "dt-trunk" vs. "dt-lacp"

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.



Matt Fern
Senior Technical Marketing Engineer, Aruba Switching

Aruba, a Hewlett Packard Enterprise company

8000 FOOTHILLS BLVD  |  ROSEVILLE, CA 95747
T: 916.540.1759  |  E: mfern@hpe.com   |   Matt @ Twitter

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MVP Guru

Re: Difference between "dt-trunk" vs. "dt-lacp"

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.

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Occasional Contributor I

Re: Difference between "dt-trunk" vs. "dt-lacp"

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.

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MVP Guru

Re: Difference between "dt-trunk" vs. "dt-lacp"


@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.

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MVP Expert

Re: Difference between "dt-trunk" vs. "dt-lacp"

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.



Matt Fern
Senior Technical Marketing Engineer, Aruba Switching

Aruba, a Hewlett Packard Enterprise company

8000 FOOTHILLS BLVD  |  ROSEVILLE, CA 95747
T: 916.540.1759  |  E: mfern@hpe.com   |   Matt @ Twitter

View solution in original post

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Occasional Contributor I

Re: Difference between "dt-trunk" vs. "dt-lacp"

Thanks Parnassus.

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Occasional Contributor I

Re: Difference between "dt-trunk" vs. "dt-lacp"

Thanks Matthew_Fern.