VLAN pool creation for L3 Out

[bineesh_philip]

Hi,

It looks like VLAN pool has to be created to configure L3 Out.

But if the border leaf is connected to an external router via 'physical port', why do we need VLAN( external port is routed port).

Regards,

Bineesh

[Imran.M]

L3Out configuration defines how the ACI fabric connects to external L3 networks using static routing or dynamic routing protocols.

VLAN pool is required to provide External encapsulation.

[Robert Burns]

This has more to do with the policy model than anything else.  When you configure any domain type (including L3), it requires the binding of a respective VLAN pool/range.   Domain + VLAN Pool + AEP > Interface Policy.

These access policies are independent/unaware of the how the tenant L3out will be configured.  The L3out config within the tenant can be Routed, Routed Sub, or SVI.  Only the routed option doesn't technically require a VLAN ID to function, but in ACI it is required to appease the policy model.  The VLAN Pool assigned can be a single VLAN ID, just ensure its unique (no overlap).  In the routed interface L3out, though the VLAN is assigned, it'll never be used on the wire.

Robert