Only three packets were needed to complete the TFTP download.
The first packet was the read request, which uses an opcode of 1.
The filename being downloaded is R1.cfg,
and because TFTP is so lightweight,
all of the details fit into the Wireshark Info column.
The packet has a UDP destination port of 69 in a random source port.
TFTP is commonly misunderstood as using UDP port 69 exclusively,
but like FTP, it uses dynamically allocated ports also.
I'm highlighting the second packet because I want to show its contents.
The server has chosen UDP port 40081 for the data channel,
and any upstream traffic related to this flow from the client must
use destination port 40081 from this point forward.
Also notice the ASCII text in the payload of the message.
This is the file being downloaded and Wireshark
attempts to print the text for us.
The client replies with an acknowledgement of the data block by reversing the UDP port numbers used for the data channel.