In enterprise hub-and-spoke environments, the most scalable and efficient way to ensure the corporate Hub learns the internal networks of remote branches (such as 192.168.1.0/24) is through the use of dynamic routing protocols. Implementing OSPF over IPsec allows the Hub and Spoke units to exchange routing information automatically through the VPN tunnel. Once the OSPF adjacency is established over the IPsec interface, the spoke will advertise its local 192.168.1.0/24 network to the Hub, which then installs the route into its routing table. This avoids the administrative burden and potential errors associated with manually adding static routes for every remote site.

Comprehensive and Detailed Explanation From Exact Extract of Enterprise Firewall 7.6 Administrator documents:
Based on the FortiOS 7.6 Administration Guide and the HA Virtual Clustering documentation, the exhibit demonstrates a Virtual Clustering environment where multiple VDOMs are distributed across an HA cluster.
In a virtual cluster setup, VDOMs are assigned to either virtual cluster 1 (vcluster 1) or virtual cluster 2 (vcluster 2). Each virtual cluster has its own independent primary unit selection process. The primary unit for a virtual cluster is determined based on the standard HA selection criteria: Monitored Interfaces > HA Uptime > Priority > Serial Number.
According to the exhibit:
* Virtual Cluster 1 (edit 1) contains VDOMs "Core1" and "root".
* Virtual Cluster 2 (edit 2) contains VDOM "Core2".
* The HA uptime is stated to be the same for both devices.
* For edit 2 (Core2), HQ-NGFW-1 has a priority of 150, while HQ-NGFW-2 has a priority of 120.
* In both units, override is disabled (default).
Since the uptime is equal and no monitored interfaces are down, the cluster uses the Priority value to select the primary unit for each vcluster. Currently, HQ-NGFW-1 is the primary for Core2 because its priority (150) is higher than HQ-NGFW-2's (120). To ensure HQ-NGFW-2 handles the Core2 traffic, its priority for virtual cluster 2 must be increased to a value higher than 150. Option C (changing the priority from 120 to 200) achieves this.

When auto-asic-offload is enabled on a firewall policy, most traffic matching that policy is offloaded to the NP6 hardware processor. As a result, the CPU-based sniffer sees only the initial packets before the session is accelerated, which is why the sniffer output shows only a few packets.

Based on the FortiGate Infrastructure 7.6 study guide and the Hardware Acceleration technical documentation, the diagnose vpn tunnel list command provides the status of IPsec tunnel offloading to the Network Processor (NPU).
In the provided exhibit, the specific value npu_flag=20 (which corresponds to 0x20 in hexadecimal) indicates that the IPsec Security Association (SA) cannot be offloaded to the NPU. While the NPU may have visibility of the gateway IPs (npu_rgwy and npu_lgwy), the flag itself serves as a diagnostic indicator that the traffic must be processed by the system CPU rather than the hardware accelerator.
This lack of offloading typically occurs when the tunnel configuration uses a cipher (encryption algorithm) or an HMAC (authentication algorithm) that is not supported by the specific NPU model installed in the FortiGate. For example, if a tunnel is configured with a legacy or highly complex algorithm that the NP6 or NP7 chip is not designed to process in hardware, the FortiOS kernel handles the encryption and decryption, resulting in the npu_flag=20 status. Therefore, despite the presence of NPU-related fields, the specific flag value confirms that hardware acceleration is not active for these SAs.