Each time I use Zwift I get the same behavior. First the rider list keeps disappearing and any avatars disappear with it. Then after around 5-10s it all comes back again only to repeat again 10-15s later. This goes on for a while over and over until eventually the rider list never populates again. I can complete my ride with no other riders showing but when i save it at the end the app exits and it hasn’t saved.
I noticed after I packed up each time that my router had stopped working - it’s PPP light was off but DSL was on. Tonight I though I would try this again connecting my computer directly to the ADSL router and just putting it into “Watching” mode. The same thing happened. After about 5 minutes of the 15s on, 10s off routine the router lost PPP and stopped routing traffic. It had to be rebooted.
I’m not saying that Zwift is at issue as it seems like no traffic should kill the router but I have used the same router for 4 years and never had a problem with it (maybe restarted it 5 times before) so something about the Zwift traffic is making my router very unhappy. It is a Dynalink of some kind (I can get more details but it probably doesn’t matter).
I’ll try another router tomorrow but was just putting this out there in case anyone else has seen the same problem.
For more a more detailed look at the up-and-down nature of the rider list I took a tcpdump while the app was running. While the rider list is up I see a traffic pattern like
00:15:39.906258 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
00:15:40.079233 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1456
00:15:40.080530 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1461
00:15:40.081845 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1442
00:15:40.082126 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1467
00:15:40.083178 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 313
00:15:40.106858 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
00:15:40.277597 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1456
00:15:40.278543 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1461
00:15:40.279948 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1442
00:15:40.281256 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 1467
00:15:40.281616 IP us-relay-28-64.zwift.com.csregagent > 192.168.10.111.55340: UDP, length 313
00:15:40.308349 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
but when the rider list disappears I see
00:15:38.916545 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
00:15:39.104211 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
00:15:39.305791 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
00:15:39.505755 IP 192.168.10.111.55340 > us-relay-28-64.zwift.com.csregagent: UDP, length 122
so no response coming back. Of course because this is UDP seeing the outgoing packet from my laptop does not mean it made it through my router so the first port of call is to try a different router.
I’ll update if the problem can be repeated on another router.