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Re: VXLAN/EVPN multihoming question:

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Hi !

You do not need to open a TAC case, as they will tell you that you have an unsupported design.

as stated in my first reply, EVPN is a kind of MC-LAG and at least in active/active the otherside must be either a singel device or a LAG or MC-LAG or a VC or VCF

 

The reason for that is the following:

assume a BUM-packet comes from another PE via MPLS core to the PEs for the ESI ( PE1 or PE2)

assume PE1 is the DF ( designated forwarder) for that ESI

-> PE1 will forward the packet to switch 1, whereas PE2 will drop the packet

switch 1 forwards the BUM packet to switch 2, switch to forwards the BUM packet to PE2

 

Now PE2 gets a BUM packet from an ESI and will forward this packet to all other PEs but as it is the non-DF with a split-horizon-label,

therefore PE 1 will not forward the packet out to the ESI BUT

all other PEs will forward the BUM packet, and thus creating loops, especially if you have this L2-open loop via 2 switches more than once in your network.

 

So I hope you now understand why my first answer was mentioning MC-LAG or VC.... which is the only recommended design.

 

Eventually your design will work with actrive/passive ES9 ( single-active) as the nonDF will not accept any packets over the ESI from the CE-switch ( not tested personally)

 

regards

 

alexander marhold

senior consultant and trainer

fastlane germany

JNCIP*4,JNCISP*3,JNCDS*3

 

PS I designed and I am teaching very detail level EVPN courses ( 3-5 days) on EVPN/MPLS and EVPN/VXLAN  ( see the fastlane website if you are interested)


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