نوشته اصلی توسط shabake_karan
البته سوئیچ ها (3750 و 3550) با GRE هم مشکل دارند.
High CPU Utilization After Enabling GRE Tunnels
Generic Routing Encapsulation (GRE) tunnels are not supported on the Cisco Catalyst 3550 Switch. Even though the CLI commands are there to configure the GRE, it is not officially supported. Refer to the Unsupported VPN Configuration Commands
section of Unsupported CLI Commands for Catalyst 3550
for this information. The reason for this is that the Cisco Catalyst 3550 Switch uses hardware-based Cisco Express Forwarding (CEF) switching. There is no method to CEF-switch GRE packets. GRE packets must be encapsulated by the software. The hardware does not have the capability to encapsulate the packets. Consequently, this traffic is processed or software switched. The process or software switched traffic can quickly cause the CPU to spike
شاید مشکل دوستمون با IPIP هم به همین دلیل باشه.