Comprehensive and Detailed Explanation From Exact Extract documents and Knowledge:
VXLAN (Virtual Extensible LAN) is a Layer 2 overlay scheme on a Layer 3 network. It uses MAC-in-UDP encapsulation, which adds 50 bytes of overhead to each packet. Processing this encapsulation and decapsulation in software (CPU) is resource-intensive and can lead to performance bottlenecks.
The NPU7 (Network Processor 7) is specifically designed to provide hardware acceleration for various tunnel protocols, including VXLAN. It allows the FortiGate to offload the encapsulation/decapsulation process to the hardware, enabling wire-speed performance and reducing the load on the main CPU. While older NPUs had limited support, the NPU7 architecture includes dedicated engines for VXLAN offloading, making it the required hardware for high-performance VXLAN environments.

The TCP Maximum Segment Size (MSS) defines the largest payload (the data part of a TCP segment) that a device can receive in a single segment. Configuring tcp-mss-sender and tcp-mss-receiver on a FortiGate interface or within an IPsec tunnel configuration allows the firewall to intercept and modify the MSS value in the TCP SYN and SYN-ACK packets. This is primarily used to prevent packet fragmentation over links with lower MTUs (like IPsec or VXLAN) by ensuring the sender produces segments that fit within the tunnel ' s available payload space once encapsulation headers are added.
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In an FGSP (FortiGate Session Life Support Protocol) cluster, sessions are synchronized between members to provide seamless failover or handle asymmetric traffic. By default, FortiGate only synchronizes connection- oriented sessions (TCP). For connectionless sessions such as ICMP or UDP , synchronization must be explicitly enabled using the session-pickup-connectionless setting under the HA configuration. Without this setting, connectionless traffic remains local to the device that processed it and is not reflected in the session table of peer members.

VXLAN (Virtual Extensible LAN) is an overlay network technology that extends Layer 2 networks over Layer 3 infrastructure. When VXLAN is used extensively on FortiGate, hardware acceleration is crucial for maintaining performance.
* NP7 (Network Processor 7) is Fortinet's latest network processor designed to accelerate high-performance networking features, including:
* VXLAN encapsulation/decapsulation
* IPsec VPN offloading
* Firewall policy enforcement
* Advanced threat protection at wire speed
NP7 significantly reduces latency and improves throughput when handling VXLAN traffic, making it the best choice for large-scale VXLAN deployments.