I'm having a strange problem using Zoom video conferencing (yeah, I know) inside my network. My girlfriend uses it for university.
We have an RB4011 with up-to-date RouterOS and a pretty tame config -- just a NAT hairpin and some simple port forwarding rules, IP reso's and local DNS entries. Attached to the POE port on the RB4011 is a cAP, which is configured to "WISP AP" in bridge mode using the "Quick Set" menu.
The reason I'm posting here is that it seems as if there is something particular to our network that is causing Zoom is perform poorly. Downloading of other participants' video is fine, and the local video "mirror" rending is smooth (so it's not an encoding issue) [this is also on a brand new Dell laptop]. The issue is that other users see very, very poor video from her that constantly freezes for long periods of time, and Zoom complains about poor/inconsistent connection quality. We have symmetric gigbit that tests at ~200/200 on her Wifi. The interesting thing is: If the laptop is connected to the internet via a (very slow) LTE hotspot, not the local MiktoTik router, the outbound video is fine for the other participants. We also tried using WebRTC (via Google Meet or whatever it's called now) on the local MiktoTik router and that worked just fine.
If there some sort of IP configuration that may be interfering with Zoom's outbound video?
Appreciate the thoughts...
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goosesensor
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Re: Video conferencing poor upstream video
That's hard to say without knowing what the "Zoom's outbound video" actually means in terms of network traffic.If there some sort of IP configuration that may be interfering with Zoom's outbound video?
Zoom's security-related documentation features a section "Firewall Compatibility", which states that the network environment is analysed and UDP and TCP connections are set up to "appropriate multimedia router".
Hence, before diving into traffic sniffing, you may want to connect the 4011 to the internet via the "very slow LTE hotspot" (exclude one wireless interface from the CAPsMAN management, make it a STAtion client of the hotspot, and make it a WAN in the 4011's configuration, then disconnect the "real" WAN). If the issue doesn't exist with this setup, it is likely not caused by the 4011 configuration but rather something is wrong on the path between the 4011's WAN and the Zoom's servers elected, so it might be helpful to disable access to those servers, thus forcing the client to use other ones. It is also possible that the video quality (and thus bandwidth) is adjusted to the detected uplink bandwidth, and the adjustment is inappropriate.
If the above doesn't help, you have to sniff the traffic and analyse it - determine what UDP and TCP connections the Zoom session establishes, and how they look like. A lot of TCP retransmissions clearly indicates a network issue; if UDP is used, much less information can be found from the sniff, but also in this case you can at least check whether all packets which came in from the laptop have been forwarded out via WAN, i.e. you can find out whether the issue is inside the 4011 or outside it.
If you find the issue outside the 4011, the next logical step is to talk to your ISP and to Zoom; if doing so doesn't lead to a solution, blocking access to the automatically chosen "multimedia router" (Zoom server) may resolve the situation; if that breaks the functionality completely, a public VPN may be a solution (the one used to let someone else than your ISP to spy on you, and to bypass geographical lock of some services).
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neutronlaser
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Re: Video conferencing poor upstream video
What do you mean, 'yeah, I know'?I'm having a strange problem using Zoom video conferencing (yeah, I know) inside my network. My girlfriend uses it for university.
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goosesensor
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Re: Video conferencing poor upstream video
Thanks for the info.That's hard to say without knowing what the "Zoom's outbound video" actually means in terms of network traffic.If there some sort of IP configuration that may be interfering with Zoom's outbound video?
Zoom's security-related documentation features a section "Firewall Compatibility", which states that the network environment is analysed and UDP and TCP connections are set up to "appropriate multimedia router".
Hence, before diving into traffic sniffing, you may want to connect the 4011 to the internet via the "very slow LTE hotspot" (exclude one wireless interface from the CAPsMAN management, make it a STAtion client of the hotspot, and make it a WAN in the 4011's configuration, then disconnect the "real" WAN). If the issue doesn't exist with this setup, it is likely not caused by the 4011 configuration but rather something is wrong on the path between the 4011's WAN and the Zoom's servers elected, so it might be helpful to disable access to those servers, thus forcing the client to use other ones. It is also possible that the video quality (and thus bandwidth) is adjusted to the detected uplink bandwidth, and the adjustment is inappropriate.
If the above doesn't help, you have to sniff the traffic and analyse it - determine what UDP and TCP connections the Zoom session establishes, and how they look like. A lot of TCP retransmissions clearly indicates a network issue; if UDP is used, much less information can be found from the sniff, but also in this case you can at least check whether all packets which came in from the laptop have been forwarded out via WAN, i.e. you can find out whether the issue is inside the 4011 or outside it.
If you find the issue outside the 4011, the next logical step is to talk to your ISP and to Zoom; if doing so doesn't lead to a solution, blocking access to the automatically chosen "multimedia router" (Zoom server) may resolve the situation; if that breaks the functionality completely, a public VPN may be a solution (the one used to let someone else than your ISP to spy on you, and to bypass geographical lock of some services).
While I would have liked to have gotten to the bottom of this, we just enabled the Wifi on the ATT Fiber box that is the RB's WAN, and after connecting directly to that Zoom worked as expected. She doesn't use any network services within the house anyway so doesn't matter. Sometimes the simplest solution is the best. :)
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