Some hardware platforms support Fabric Extend natively on any of its physical ports. However, the VSP 4450 Series requires an Open Networking Adapter (ONA) to enable this functionality. The ONA is the Fabric Extend packet encapsulation engine for the VSP 4450 Series. The ONA / VSP 4450 Series combination can also provide enhanced features such as IP fragmentation and reassembly on Fabric Extend tunnels.
Note
In a Layer 2 core Fabric Extend solution, the VSP 4450 Series does not require an ONA because the tunnels are point-to-point VLAN connections, not VXLAN. Therefore, there is no need for an ONA to encapsulate a VXLAN header to SPB packets.
The VSP 4450 Series manages the ONA in the following ways:
Controls and provisions the ONA.
If PoE capable, the VSP 4450 Series supplies power to the ONA. (The ONA also supports an optional wall unit power adapter.)
Transports traffic to and from the ONA over 1 GbE ports and sets QoS appropriately to the ONA‘s.
The ONA 1101GT can support basic Fabric Extend at line rate 1G traffic from the VSP 4450 Series at 1500 byte packet sizes.
Oversubscription of the ONA‘s packet engine may result if packets are smaller than 1500 bytes or if you enable enhanced features such as fragmentation and reassembly of packets. This results in packet drop starting with lower QoS queued packets consistent with PCP and DSCP markings on packets received from the VSP 4450 Series. For more details on the ONA 1101GT forwarding performance, see ONA Considerations.
The ONA can operate in different modes. Fabric Extend is Operational Mode 1. To enable Fabric Extend, use the ONA‘s Manual Configuration menu to change the Operational Mode parameter to 1. For more information, refer to the manual that ships with the ONA.
In the following figure, the VSP 8200 Series is in a Fabric Connect network and is configured with Fabric Extend (FE). The VSP 4450 Series is also in a Fabric Connect network and is configured with SPB. The VSP 8200 Series and the VSP 4450 Series use industry-standard VXLAN tunnels to create a flow for FE traffic between the VSP 8200 Series and the ONA attached to the VSP 4450 Series.
The following flow occurs when User A sends a packet to User B:
The VSP 8200 Series receives the packet and encapsulates it with a MAC-in-MAC header.
The VSP 8200 Series sends the MAC-in-MAC-encapsulated packet over the VXLAN tunnel to the VSP 4450 Series.
The VSP 4450 Series receives the packet and sends it to the ONA network port.
The ONA decapsulates the packet by removing the VXLAN header and sends the MAC-in-MAC packet header out the ONA device port back to the VSP 4450 Series.
The VSP 4450 Series decapsulates the MAC-in-MAC header and forwards the packet to User B.
The following flow occurs when User B sends a packet to User A:
The VSP 4450 Series receives the packet and sends it to the ONA over the ONA device port with MAC-in-MAC encapsulation.
The ONA encapsulates the packet with a VXLAN header.
The ONA then sends the packet out the ONA network port and back to the VSP 4450 Series.
The VSP 4450 Series sends the VXLAN-encapsulated packet over the Routed IP network to the VSP 8200 Series.
Note
To interoperate with the VSP 8200 Series, you must set the MTU on the VSP 4450 Series/ONA combination to 1950 bytes.
The VSP 8200 Series decapsulates the packet by removing the VXLAN header and the MAC-in-MAC header, and then forwards it to User A.
Note
Connect the ONA as shown with two ports to the VSP 4450 Series. You cannot connect the ONA directly to the IP core infrastructure.