GRE-In-UDP Tunnel Decapsulation

The GRE-In-UDP tunnel is a new tunnel type that supports decapsulating the GRE-in-UDP headers in the vTAP captured data packets. The decapsulation of the tunnel headers is common for both control and data packets. However, the control packets (with JSON metadata format) are dropped based on the GRE Key value '0'. The data packets (either fragmented or unfragmented) are handled as follows:

S. No Process Description

Reassembly of fragmented data packets (if fragmented packets are received)

The fragmented packets are reassembled based on standard IP header-based reassembly using the following fields:

More Fragments (MF) field in IPv4 packets
Identification field in IPv6 packets

Decap tunnel lookup

The ingress packet fields are parsed to find a matching Tunnel End Point (TEP) based on the following header fields:

Destination IP
Source IP
UDP port numbers
GRE key

Decapsulation of headers

If a matching TEP is found, the encapsulation headers in the packet are removed and the packet is forwarded to the PCAPng application. Refer to the PCAPng Application section for more details.

Note:  Refer to the "Add Applications to Monitoring Session" topic in the respective Cloud (GigaVUE V Series 2 Solution) Guides for detailed information.