Sending basic PDU in Packet Tracer continues indefinitely?

[Student68000]

Hi, sending a basic PDU in Packet Tracer just continues indefinitely - why is this? I've created a video.

https://m.youtube.com/watch?v=7rH6x_Z6E4I&feature=emb_logo

If I just leave it it will continue forever.
As you can tell i'm just a beginner student but I'd like to know why? My rather useless teacher can't advice me.

[Student68000]

I'm going to bump this and if it's a stupid question maybe someone could tell me why?

Thanks

[Tony Deng · Accepted solution]

The pink and red envelopes are Spanning Tree and DTP packets that originate from the switch. The switch runs these protocols and will periodically send such packets out and thats what you are seeing. The brown packet is the original basic PDU you created and it went from one end to the other end, and a response was made and that was the end of it.

[Student68000]

You Sir deserve a medal. Such a simple question yet so hard to get an answer. Thank you so much. Have a great day.