Hi,

Continuing on Bridge-Domains on Mx, I came across using vlan-id “none” and initially was surprised by this knob, I mean we create bridge-domain based on a Vlan and associate / segregate traffic based on Vlan-id.

Lets explore a use case or a remote scenario where this might come in handy.

Let us say you have customers with different vlan’s and you are about to be in merger and provide a common Layer-3 IP. Obviously, if you are in a situation where you have them on your sub-interfaces, you cannot have same vlan-id for two Sub-interfaces.

Let see what Vlan-id None can do here

 

Topology

 

Looking closely at the configuration, we see that vlan-id none has been used instead of being specific, but as you see the interfaces, they are clearly in vlans 101 and 102. So, how does this  work ?

bridge_domain_config_2

There you go, there is a Pop in the inbound direction of the interface, a POP action popping out Vlan and the return traffic is now having PUSH action, hence traffic coming into bridge-domain will not care with what Dot1q tag the packet is coming-in.

interface_details_3

Lets initiate a Ping and see if this works from two customer ends who are in different Vlans.

final_results

There you Go

 

Regards

Rakesh M

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