ENNI Ports

An ENNI port is also known as an “external network-to-network interface,” as defined in MEF 26.

ENNIs allows Q-in-Q tunneling, also known as IEEE 802.1ad or “stacked VLANs.” While carriers commonly use this to manage customer traffic, individuals might have various uses for Q-in-Q as well.

For more information on business use cases, see Announcing ENNI Support for Q-in-Q, Network Extension and Backbone Expansion.

Q-in-Q

With Q-in-Q tunneling, an Ethernet frame has two VLAN tags:

  • C-VLAN - Also known as the “Customer VLAN.” This is the inner tag.
  • S-VLAN - Also known as the “Service VLAN.” This is the outer tag.

You can use the S-VLAN to bundle and direct traffic, while still maintaining the C-VLAN identifier.

Technical notes

  • The default TPID value is 0x8100.
  • You cannot combine non-ENNI and ENNI ports together in a LAG.
  • You can have multiple EPL virtual circuits on an ENNI port.

Use case 1: ENNI to ENNI

This is essentially an EVPL connection.

Provider A has a customer who needs a virtual circuit between two locations on the provider’s network, and Provider A has NNIs with PacketFabric at those locations. Therefore, Provider A uses PacketFabric’s network to build the circuit.

Note the following:

  • The S-VLAN is unique to the NNI termination and does not need to match between NNIs.
  • If the customer wants different C-Tags to go on different EVCs then they must put the appropriate S-Tag on the frame. PacketFabric will not look at the C-Tag to steer traffic between two ENNI endpoints.

Click to expand:

ENNI use case 1

Use case 2: ENNI to access port

Provider A has a customer who needs a virtual circuit between one of the provider locations and a location on the PacketFabric network. Provider A orders an access port for the customer and the cross connect is arranged.

Provider A then builds a virtual between their NNI and the access port. There are 3 combinations of delivery, shown top to bottom:

  • EVC A - Untagged EPL access port to ENNI with an S-Tag and C-Tag, both of which must be removed at the ENNI.
  • EVC B - Untagged EPL access port to ENNI with an S-Tag, which must be removed at the ENNI.
  • EVC C - EVPL access port with C-Tag to ENNI with an S-Tag and a C-Tag. The S-Tag must be removed at the E-NNI. C-Tag COS must be maintained.

Click to expand:

ENNI use case 2

NOTE: If you are implementing the EPL scenarios, you need to ensure that your virtual circuit is an EPL. By default, virtual circuits are EVPL.

To make an EPL virtual circuit, expand the Advanced Configuration Options at the bottom of the virtual circuit order form and select EPL.

VC advanced options

Use case 3: ENNI to cloud on-ramp

Provider A has a customer who needs a virtual circuit from one of the provider’s locations to one of PacketFabric’s cloud On Ramps. Provider A orders the cloud on-ramp virtual circuit.

Click to expand:

ENNI use case 3