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Re: How to configure and do cabling for BFD MAD on 4 IRF switches

 
Stefano Colombo
Regular Advisor

Re: How to configure and do cabling for BFD MAD on 4 IRF switches

Hello @parnassus
How or where can we check whether the 4500 supports the “extended” LACP required?
What extension are they referring to ?

The peer system, at the moment, are not thought to be multihomed but it might be a future option
I understand your point, however, and it’s being evaluated to fail back to a two IRF design
Thanks
parnassus
Honored Contributor

Re: How to configure and do cabling for BFD MAD on 4 IRF switches


@Stefano Colombo wrote: How or where can we check whether the 4500 supports the “extended” LACP required?
What extension are they referring to ?

I stole the word from the LACP-MAD Overview: "LACP-MAD is implemented by sending extended LACP Data Units (LACPDUs) with a type length value (TLV) that conveys the Active ID of an IRF virtual device. The Active ID is identical to the IRF Member ID of the Master and is thus unique to the IRF virtual device. When LACP MAD detection is enabled, the IRF Members exchange their Active IDs by sending extended LACPDUs." (taken from an HP ProVision OS based web page about LACP-MAD! that's because some HP ProVision/ArubaOS-Switch switch series can be used as MAD assist devices...but those exact same words came from this H3C Guide...so perfectly Comware OS based switch series related).

The point is, if I understood you correctly, that you are dealing with a Stack (VSS) of Cisco 4500...and so....I believe you are forced to activate (Cisco 4500 stack side) a MEC (Multi-Chassis EtherChannel) against the IRF (stretched or not the IRF is, stretched or not the Cisco 4500 VSS is)...so the question is not only if a Cisco 4500 VSS supports to act as a MAD assist device from the IRF Stack standpoint but also if the MEC (LACP) you're going to use to interconnect the VSS Stack with the IRF Stack supports extended LACPDUs (and, if so, it would ALSO let the IRF to act as an IRF MAD for the VSS...not that will be necessary but just to prove that a LACP could transport required extented LACPDUs either way we "source" them)...and I fear that - from what I've understood (I'm not a Cisco expert) - this is probably not supported (see here)...I mean - have a look at pages 15 - 20 - it seems to me that "standard" MEC LACP - also referenced as "cross-stack EtherChannel" - can't be used for MAD in the "Cisco way" and for a "pure Cisco scenario" standpoints...so, based to requirements/restrictions noted, exploring how Cisco solves the MAD deployment methods from the Cisco standoint (to infere if methods are reversible and so applicable to IRF as "orginator"), it seems to me you need to use Cisco ePAgP (which requires Cisco PAgP) on the VSS which is an alternative way to deploy MEC to upstream/downstream devices with respect to MEC LACP (keep in mind that HPE IRF doesn't support Cisco PAgP) and it also suggest me that the usage of ePAgP to deploy the MAD mechanism is the only way when upstream/downstream devices are connected with a MEC (as per our case)...if Cisco doesn't rely on MEC LACP to deploty its MAD mechanism (indeed preferring the ePAgP on supported involved devices) but forces you to fail back to the alternative Dual Active IP BFD mechanism it means that "standard" MEC LACP are not so developed in terms of extended LACPDUs (otherwise a MEC LACP would be enough)...that's the reason I believe could be an hard way relying on a VSS of two Cisco 4500 for MAD...much better a basic Aruba switch a that point.


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Stefano Colombo
Regular Advisor

Re: How to configure and do cabling for BFD MAD on 4 IRF switches

Hello @parnassus

could you advise for an Aruba switch we could use as supporting device for MAD , in order to solve the issue ?

We could install it on one side and connect all the IRF nodes and use BFD MAD 

thanks

SC

parnassus
Honored Contributor

Re: How to configure and do cabling for BFD MAD on 4 IRF switches

Hi Stefano, as far as I know below is a (partial?) list of ArubaOS-Switch operating system based Switch Series currently supporting LACP MAD Passthrough:

  1. Aruba 2530 (also known as HP 2530)
  2. Aruba 2540
  3. Aruba 2920 (also knonw as HP 2920, discontinued in favor of Aruba 2930F/2930M Switch series)
  4. Aruba 2930F / Aruba 2930M
  5. Aruba 3810M
  6. Aruba 5400R zl2

On their latest Management and Configuration Guides you should be able to find a small dedicated LACP-MAD chapter (OTOH also this document could be useful in case of troubleshooting).

All the above Switch sereis, excluding the Aruba 2920, supports ArubaOS-Switch up to latest 16.10.0013 (ArubaOS-Switch for Aruba 2920 seems to have stopped at 16.10.0012), I suggest you to work with latest version whenever possible.

Giving the above list a small 8 ports HP/Aruba 2530 Switch should suffice.

 

 


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Stefano Colombo
Regular Advisor

Re: How to configure and do cabling for BFD MAD on 4 IRF switches

Hello @parnassus 

Thanks a lot for your help