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FabricPath and LID/LTL index

Dear,

i understand that in a fabricpath network any classical ethernet frame received by edge switch is tagged with vlan id before it's encapsulated in a fabricpath frame. I think that is necessary to segregates broadcast/multicast/unknown unicast in respective vlans....

But this "automatic tagging" seems not necessary in a "known unicast delivery" because after the initial packet flow (arp request and arp reply) the edge switchs mac table containg the respective remote mac mapped to vlan/sid/lid. And in this case the vlan id seems not necessary to the receiving edge switch to lookup destination MAC because it's contains the LID ( in a Nexus7K). Is this correct ?

In a immaginary situation - without tagging - the only problem could be if the receiving edge is learning the same MAC address (for ex vmac hsrp) from the same trunk port but in different vlans. In this case if the LID/LTL index is the same for both MAC  then the edge switch could'not to discriminate to what vlan this frame is directed ...

My question is :

- The Local ID (LTL)  of the trunk port , from this command:

show system internal pixm info interface ex/y

 

is the same for both frame originated from different vlans or the LID is different ?

 

- Another doubt.. can a mac table of an edge switch to contains two remote mac entry with the same mac/same sid.lid / different vlan ?

 

thanks so much

giuseppe

 

 

 

 

 

 

 

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