Greetings to all,
I have a few queries about digest messages.
Can I capture a digest message with ie. Wireshark?
Can a digest messages be sent over to another node of the network, where the controller resides?
The digest extern seems to only send messages to a local controller.
If you use the P4Runtime API to configure a device, then Digest messages created by the data plane will typically first go to a local CPU running driver software, and then they will be sent over a TCP connection from the P4Runtime API server to the P4Runtime API client that should receive the Digest messages.
That TCP connection could be a local connection between a client and server running on the same host, or it could be between two different hosts.
If it is running on a different host, one could imagine using a packet capture program to see all of the packets in that TCP connection. However, since it is a TCP connection, the Digest messages might be split across 2 or more TCP packets due to TCP segmentation. Or there could be multiple Digest messages in a single packet, again due to TCP segmentation decisions made in the TCP implementation.
You could write a P4Runtime API client program that writes the Digest messages to a local file, or sends them in packets that it generates, or anything else you can imagine a program to do with the data in those messages.