Multihomed Device with MC-LAG on the PBB-EVPN Edge (AApF-LB)

[j.hoffmann]

Hi colleagues,

I have some strange problems to configure a multihome topology on the edge of a PBB-EVPN infrastructure.

PBB-EVPN allows in contrast to VPLS and PW an all-active topology, which means all memberlinks of the MC-LAG distributed over multiple devices are usable for traffic flows, with an elective configuration of a per-flow or a per service loadbalancing.

The following picture shows my current configuration:

This is the general recommended configuration to achieve the desired behaviour as described above.

The only difference is that normally it should be possible to configure the "mode singleton" instead of explicit ICCP neighbour addresses. In singleton mode an ICCP node finds its ICCP peers using the locally learned LACP credentials of the multihomed device and match these with the learned Ethernet Segment Identifiers. But in my case (and this is the first problem) the ICCP nodes don't find each other. How ever, explicit ICCP neighbour configuration solves this problem.

The much bigger problem for me: One of the both memberlinks stays in hot standby instead to be active and usable.

On side of the DHD R5 the hot-standby link is stated as "suspended".

The "sh bundle" output of R1 and R4 is as follows:

The following screenshot shows that All-Active and per flow LB should be active.

But how, if one of the both links is only in standby-mode?

The diagnostic error in one of the sh-bundle-outputs above is also conspicuous. 

The switchover between active and standby link performs in a proper way so far. But its not the desired design.

It would be great, if somebody in the community can give me any helpful hint to solve my problem or my misunderstanding.

Regards,

Jens

[pigallo]

Hello,
the real problem is why your PEs do not see each other ?
mode singleton and iccp neighborship cannot be used together. They are mutually exclusive.
Within EVPN you have type4 ES route which allows ES and redundancy-group discovery so you do not need anymore iccp protocol to do this task.
The reason why you see suspended on bundle link is because you're running classic MCLAG configuration with ICCP negotiating with peer.
So, i believe you should first verify that your multihomed PEs can see each other via BGP evpn address families to exchange such NLRIs. Then, try again to activate mode singleton and to remove iccp neighbor configuration as it's not needed.

Regards

[j.hoffmann]

Hi pigallo,

you wrote "mode singleton and iccp neighborship cannot be used together".

But how about this config example from a Cisco config guide?

[pigallo]

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@j.hoffmann wrote:

Hi pigallo,

you wrote "mode singleton and iccp neighborship cannot be used together".

But how about this config example from a Cisco config guide?

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The config example is indeed correct and confirms what i exactly stated in my previous post.
The ICCP member neighborship is not needed in your case, as you want to achieve active/active load balancing flavor in dual homed topology. So, mode singleton is the right option you need to enable for such goal.
Hope i clarified your concerns.



Regards