Siglent WiFi totally flakey with DHCP on (but rock solid with DHCP off) - Page 1
Forum section: electronics / testgear

author: puterboy
author_rank: Regular Contributor
timestamp: September 03, 2020, 05:36:15 am
content: I am using the TL-WN725N WiFi dongle on my 1104X-E scope.When I use:WLAN TL-WN725N + DHCP on + Netgear R6700v3 router,I get very flakey performance with the link constantly connecting and disconnecting. Actually, it connects for a couple of seconds and then disconnects for multiple seconds.However, the following combinations all work:WLAN TL-WIN725N + DHCP off + Netgear router = rock solid connection with fast pings (even if I set it to the same IP address as used under dhcp)LAN + DHCP on (or off) + Netgear router = rock solid connection with fast pingsWLAN TL-WIN725N + DHCP on (or off) + SMC Barricade N router = reasonably solid connection (though still have occasional disconnects and slow pings) Windows PC + TL-WIN725N + DHCP on (or off) + Netgear router = rock solid connectionSo as you see it's only the combination of Siglent scope + WLAN TL-WIN725N + Netgear router (and to a lesser extent my other router) that gives terribly flakey (and thus unusable) performance.Specifically,Pings are unreliable. A couple of pings go through (typically 1-4) with relative long delays and then I get multiple request timeouts or even destination host unreachable.For example:Pinging 192.168.1.103 with 32 bytes of data:Reply from 192.168.1.103: bytes=32 time=376ms TTL=64Reply from 192.168.1.103: bytes=32 time=12ms TTL=64Reply from 192.168.1.103: bytes=32 time=115ms TTL=64Request timed out.Request timed out.Request timed out.Reply from 192.168.1.103: bytes=32 time=81ms TTL=64Reply from 192.168.1.103: bytes=32 time=100ms TTL=64Reply from 192.168.1.103: bytes=32 time=118ms TTL=64Request timed out.My router syslog shows that the Siglent WLAN is constantly asking for a new DHCP connectionSep 2 14:48:41 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:41 myrouter daemon.info dnsmasq-dhcp: DHCPREQUEST(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:41 myrouter daemon.info dnsmasq-dhcp: DHCPACK(br0) 192.168.1.103 7f:a3:91:6f:6c:b6 siglent-1104X-ESep 2 14:48:42 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:42 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:43 myrouter daemon.info dnsmasq-dhcp: DHCPREQUEST(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:43 myrouter daemon.info dnsmasq-dhcp: DHCPACK(br0) 192.168.1.103 7f:a3:91:6f:6c:b6 siglent-1104X-ESep 2 14:48:44 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:44 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:44 myrouter daemon.info dnsmasq-dhcp: DHCPREQUEST(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:44 myrouter daemon.info dnsmasq-dhcp: DHCPACK(br0) 192.168.1.103 7f:a3:91:6f:6c:b6 siglent-1104X-ESep 2 14:48:45 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:45 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:48 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:48 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:51 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:51 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:48:56 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:48:56 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:49:02 myrouter daemon.info dnsmasq-dhcp: DHCPDISCOVER(br0) 7f:a3:91:6f:6c:b6Sep 2 14:49:02 myrouter daemon.info dnsmasq-dhcp: DHCPOFFER(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:49:02 myrouter daemon.info dnsmasq-dhcp: DHCPREQUEST(br0) 192.168.1.103 7f:a3:91:6f:6c:b6Sep 2 14:49:02 myrouter daemon.info dnsmasq-dhcp: DHCPACK(br0) 192.168.1.103 7f:a3:91:6f:6c:b6 siglent-1104X-ETelneting into the scope, killing the existing wpa_supplicant and launching a new process with -d (for verbose debugging) and saving to a file, shows that the WLAN is indeed repeatedly renegotiating connections every few seconds (though seemingly less frequently than the DHCP requests above)The scope itself even less frequently (perhaps every ~10 minutes) flashes a WLAN connected/disconnected notification on the screen along with an audible beepBottom line is that I am perplexed about why DHCP fails for WLAN but not for LAN on the Siglent scope.And it doesn't seem to be a problem with the TL-WN725N WiFi dongle or with the Netgear router since they work fine with dhcp with multiple other devices on my network.Also, there are no IP address conflicts or anything basic like that to explain it.Finally, the problem persist whether the WiFi signal is strong (scope right next to the router), weak (scope two floors away from the router) or anywhere in between.Any ideas?

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2020, 08:41:14 am
content: Quote from: puterboy on September 03, 2020, 05:36:15 amYes, see here:https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg3127054/#msg3127054It seems some access points disable inactive connections and as all use different management consoles terminology used for settings to change this behavior are different so a universal recommendation of what settings to change is not possible.All I can suggest is study of the router/AP manual for clues as to what to try to maintain rock solid connections.My suspicions are Lease or Handshake issues and also need to further investigate my own WiFi reliability issues.

author: puterboy
author_rank: Regular Contributor
timestamp: September 03, 2020, 01:44:55 pm
content: Quote from: tautech on September 03, 2020, 08:41:14 amYes - I saw that post but my wpa_supplicant log doesn't show the DISASSOC event that patman27 found nor do I have "advanced" router bandwidth features turned on -- in particular, nothing like:QuoteI am using dd-wrt with just the default settings for such things.While our problems may be related, I don't see anything "advanced" in my settings to turn off to make it work -- though I guess I could try a game of trial-and-error...Any thoughts on how to troubleshoot further?

author: puterboy
author_rank: Regular Contributor
timestamp: September 03, 2020, 01:59:18 pm
content: And none of this explains why WiFi is rock solid without dhcp -- i.e. if it were a bandwidth management issue, then this should be occurring at a level below dhcp I would think...