Transport tunnel termination applies to packets with destination MAC address within the chassis MAC address and considered “destined to us”.
The chassis MAC address is a non-configurable parameter and is configured in data path at boot-up time.
Transport tunnel termination supports decapsulation of GRE or ERSPAN headers. To terminate destination MAC in the packet, the packet is checked for IPv4 address and type of encapsulation. If source IPv4 address and configured encapsulation type match, an intermediate SAP is assigned to the packet and the packet is marked for dropping. The intermediate SAP is matched along with tunnel or encapsulation type and tunnel ID. If all the parameters match, it is considered a successful termination and a network SAP is derived from it. The packet is marked for decapsulation of transport header, and as the transport header is removed, the scope is automatically shifted to the next header in the packet.
The transport tunnel terminated packets are classified according to non-transport tunnel parameters configured as part of the ingress group. Based on ingress group configurations, the inner header is terminated, scope is shifted to the next header, or packets are classified and SAP is updated in the packet metadata to inner SAP (tunnel SAP). For transport packets, both transport (transport header termination) and non-transport configuration (decapsulate outer header and/or scope-shift operations and/or non-transport tunnel classification) are applied and packet classification is done based on both configurations.
