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5400R zl2 VSF and Distributed Trunking

 
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parnassus
Honored Contributor

5400R zl2 VSF and Distributed Trunking

Does the VSF (Virtual Switching Framework) supports Distributed Trunking (DT) "Server-to-Switch" (originating from Server)?

As far as I can understand VSF implementation, it seems that DT "Switch-to-Switch" is not supported by the VSF...but there are some diagrams where a VSF Domain formed by 5400R zl2 Switches is set - as example - as the core for various edge (backplane stacked) Switches like the Aruba 2920 or Aruba 3810 and these ones are then connected to the VSF core via DT(s) (the DT origin is thus the stack of Aruba 2920 or 3810).

Example here.

So the question: Does the VSF accept DT(s) coming from Servers and/or (Backplane Stacked / Non-Stacked) Switches although it doesn't support to originate DT(s) destined to other VSF Domains, other logical type of Switches (e.g. IRF/ISC) and Servers?

8 REPLIES 8
Marcus J
Frequent Advisor

Re: 5400R zl2 VSF and Distributed Trunking

Hi,

 

I havent tried the VSF functionality myself, but to my understanding you can connect any device to a VSF "domain" via link aggregation using hp trunking or lacp.

/Marcus

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parnassus
Honored Contributor

Re: 5400R zl2 VSF and Distributed Trunking

Yep, VSF originating a DT is a matter (and this, AFAIK, is not supported), another is the VSF being the destination for a DT generated from other Switches (backplane stacked or not) or from Servers...in this case DT's member links will terminate into both VSF members concurrently...let's say - supposing a 2 links only DT - one DT's link will terminate on the VSF Commander member, the other link will terminate on the VSF Standby member.

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Vince-Whirlwind
Honored Contributor

Re: 5400R zl2 VSF and Distributed Trunking

You don't need to use distributed trunking because it's a VSF, you just use normal 802.3ad for link aggregation.

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parnassus
Honored Contributor

Re: 5400R zl2 VSF and Distributed Trunking

As far as I know IEEE 802.3ad (LACP) Trunks must be co-terminus (they must terminate their originating members' links against the same physical Switch)...so Distributed Trunking was introduced to overcome that protocol limitation:

"The IEEE standard 802.3ad requires that all links in a trunk group originate from the same switch. Distributed trunking uses a proprietary protocol that allows two or more port trunk links distributed across two switches to create a trunk group. The grouped links appear to the downstream device as if they are from a single device. This allows third party devices such as switches, servers, or any other networking device that supports trunking to interoperate with the distributed trunking switches (DTSs) seamlessly. Distributed trunking provides device-level redundancy in addition to link failure protection."

So I asked about DT and VSF, especially from the point of view of edge Switches or Servers (redundantly) connected to the VSF.

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Vince-Whirlwind
Honored Contributor

Re: 5400R zl2 VSF and Distributed Trunking

No, it doesn't have to be the same physical switch, eg, it can be a stack of Cisco 3750s, an IRF stack of H3C 5900s, or in this case the VSF, which is one fabric comprising two physical switches.

DT is for when you do not have a single stack/fabric to connect the redundant connections.

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TG-IT
Occasional Visitor

Re: 5400R zl2 VSF and Distributed Trunking

Hello,

it is an older post, but I have now the same situation.

We use 2x5406 with DT connected to a single 5412. Now I want to replace the 5412 with two 5406R and VSF. From my understanding this should work because the two 5406R with VSF is the "target" for the two 5406 with DT.

Do you have successfully tested this ?

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C0LdWir3
Advisor

Re: 5400R zl2 VSF and Distributed Trunking

Hi.

VSF is a stacking technology so 2x 5400R stacked with VSF will act as a single switch.

No need for DT config

You can do a single LAG connected to both switches from another switch.

 

Best Regards
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parnassus
Honored Contributor

Re: 5400R zl2 VSF and Distributed Trunking

Well, the latest reply to the original post is at least two Years old...but, no matter.

The point is that VSF hides behind a logical switch two (or more) physical switches...so, from the DT pair standpoint, terminating the DT-LACP into one physical switch or terminating the same DT-LACP into one logical switch (with each DT-LACP Port Trunking leg into each VSF Member for resiliency) it the same thing. It works and, if IIRC, Aruba Support evaluated positively this scenario (look for a thread on Aruba Airheads Community).