Creating a failover network using Active and Standy Management Modules - HP 5406R zl2

[bsimpliciano]

Hello,

I would like to implement a failover configration using (4) HP 5406R zl2 switches at each of our utility substations. Our current configuration between switches consists of the following:

- Each switch A-D is connected through fiber, carrying specific VLANs - all trunked through Management Module A on each switch.

- We also have an unplugged Ubiquiti radio that we use to connect Switches A and D. Linking the radio creates an infinite broadcast loop.

We would like to use the B Management Modules of each switch, to connect the switches through the backplane, and allowing us to activate the radio link without creating a loop, and having a failover in case the radio link or fiber link goes down.

i.e if Switch B loses fiber connectivity with Switch C, Switch D will still be able to transmit/receive data from Switch B using the radio link through Switch A.

Anything helps. I've attached a basic scheme of what we are aiming for. Thank you.

P.S I've tried implementing the HP 5406 "mesh" configuration, however, since mesh automatically tags ALL VLANs on a switch, it would not be ideal to send out data that shouldn't be sent out to the other substation switches for security purposes. Also, unless I configured it incorrectly, I don't think Ubiquiti radios work with the mesh configuration of the 5406 switches.  

[parnassus]

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bsimpliciano wrote: - Each switch A-D is connected through fiber, carrying specific VLANs - all trunked through Management Module A on each switch.

First error: uplinks (with permitted tagged VLANs) aren't trunked between MM but between backplanes that are controlled by MM (or MMs, if two MMs are installed).

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bsimpliciano wrote: We would like to use the B Management Modules of each switch, to connect the switches through the backplane, and allowing us to activate the radio link without creating a loop, and having a failover in case the radio link or fiber link goes down.

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Again: loop will always exist (and it will be managed by STP or RSTP if enabled) indipendently by the fact that each Aruba 5400R zl2 Switch is managed by one MM or by two MMs...simply because your idea of creatig a ring with uplinks (A-B-C-D-A) means really that your are interconnecting each backplane together forming the loop (which is bad).

I think the base issue is your faulty idea of how MMs (Management Modules) manage the chassis backplane: the Switch backplane is shared (or, better, it is unique to the considered Switch chassis) by installed MMs (at minimum you can have one MM, the Active one, at best you can have two MMs installed - Active and Standby - and where they are properly configured, those two MMs offer Nonstop switching and Hitless failover within that chassis - two redudancy modes are available when two MMs are installed: the "Nonstop Switching mode" and the "Warm Standby mode", the latter is the default redudancy mode when redudancy is enabled - that said is clearly valid only on the considered chassis not *between* chassis of different Switches): the idea that each MM is a separate "Switch" with control of a portion of the whole "backplane" within the same chassis is basically wrong because interconnections happen at backplane level (not at MMs level).

The baseline is to look at each Switch as a single backplane with one MM or two MMs: interconnecting two or more Aruba 5400R zl2 together means interconnecting two or more backplanes (via some ports on installed Modules on each chassis)...each backplane is controlled by one MM or, in case redudancy is enabled, by two MMs...nothing more, nothing less. You don't interact with MMs, you create interactions between backplanes via installed Modules' access ports.

What you're looking for is something like IRF (Ring Topology) - IRF is a feature provided by most of HPE Comware operating system based Switch Series - IRF isn't a feature of ArubaOS-Switch operating system based Aruba 5400R zl2: a (similar) idea could be to couple two couples of Aruba 5400R zl2 creating two distinct VSF fabrics and then interconnecting those two new fabrics via (multiple) fiber optic links aggregated together...but this means (a) disabling the second MM on each Aruba 5400R zl2 (so losing a total of 4 MMs) and (b) providing only a very partial solution to your initial idea (no ring - that will be a sort of bus topology between two VSF fabrics - and only two Aruba 5400R zl2 at time - exactly each VSF couple - are made redundant from the point of view of their switching and routing capabilities).

[bsimpliciano]

Hi @parnassus,

Thank you for your response. Since I don't think we would be able to implement the IRF Ring Topology due to the lack of hardware, as well as the VSF stacking, are there any other methods you have in mind? At the very best, we'd like to have both our fiber and radio links running without any failures.

Thank you,

Brandon

[parnassus]

The point is that what you want to achieve (correct me if I misunderstood your initial request) is to have a sort of data path redudancy between any involved and interconnected chassis: probably Switch Meshing, as you tried, is the way to go in your case (where any chassis should be connected to any other one for a fully interconnected mesh domain). Clearly loop(s) among Switches members of the Mesh Domain are not permitted (as you learned).

Have you followed the Chapter 10 "Switch meshing" of HPE ArubaOS-Switch Advanced Traffic Management Guide for KA/KB.16.03 manual? See mesh topology shown on figure at page 244...