Good PTP link conditions and packet loss
Posted: Fri Jan 23, 2015 9:49 pm
Hi there,
I'm having some problems with PTP link on SXT Lite5. Distance between devices is ~510m with clear line of sight.
This one is pretty damn hard to troubleshoot - mostly the link is pretty stable, wireless connection never drops, there's not much ping jitter. It worked this way for more than half a year, no problem.
However, lately I've noticed some problems. Most of the time 3 or 4 pings are lost every minute or so. It goes on for a while and stabilizes for a short while or it gets pretty bad. By bad, I mean there's more packets lost then transmitted - it can last for an hour or two.
I'm confident it's a problem with the wireless link; I have tested the connection with a laptop connected directly to SXT on both sides and packets are only lost between two SXT.
It's also not an issue of too much data going through - the link never almost never reaches even half of its throughput (~80Mbps).
I'm also pretty confident it's not a problem with the hardware - the link was rebuilt about half a year ago on new SXTs connected with F/UTP cables. On the off chance that it might be a hardware problem I've replaced both devices with brand new SXT and PoE injectors a week ago.
Here's what I've tried on the software side:
- Change frequency - works fine for a minute or two, then back to packet loss. Scans indicate most frequencies around are not busy, but for whatever reason there are problems on every one of them.
- Switch protocol from nv2 to nstreme - the overall ping latency is slightly improved over nv2, but when problems begin the link becomes basically unusable.
Here's how the link looks in Winbox: CCQ varies ~75% - ~95%.
Here's how the relevant configuration from /export looks:
So what I have here is a nice PTP link that's started to have packet loss problems with no obvious reason. Line of sight conditions and frequency usage is basically the same as half a year ago, but nothing works properly. What's really strange is that the actual wireless connection pretty much never disconnects. Any ideas?
I'm having some problems with PTP link on SXT Lite5. Distance between devices is ~510m with clear line of sight.
This one is pretty damn hard to troubleshoot - mostly the link is pretty stable, wireless connection never drops, there's not much ping jitter. It worked this way for more than half a year, no problem.
However, lately I've noticed some problems. Most of the time 3 or 4 pings are lost every minute or so. It goes on for a while and stabilizes for a short while or it gets pretty bad. By bad, I mean there's more packets lost then transmitted - it can last for an hour or two.
I'm confident it's a problem with the wireless link; I have tested the connection with a laptop connected directly to SXT on both sides and packets are only lost between two SXT.
It's also not an issue of too much data going through - the link never almost never reaches even half of its throughput (~80Mbps).
I'm also pretty confident it's not a problem with the hardware - the link was rebuilt about half a year ago on new SXTs connected with F/UTP cables. On the off chance that it might be a hardware problem I've replaced both devices with brand new SXT and PoE injectors a week ago.
Here's what I've tried on the software side:
- Change frequency - works fine for a minute or two, then back to packet loss. Scans indicate most frequencies around are not busy, but for whatever reason there are problems on every one of them.
- Switch protocol from nv2 to nstreme - the overall ping latency is slightly improved over nv2, but when problems begin the link becomes basically unusable.
Here's how the link looks in Winbox: CCQ varies ~75% - ~95%.
Here's how the relevant configuration from /export looks:
Code: Select all
/interface bridge
add mtu=1500 name=bridge1 protocol-mode=none
/interface wireless
set [ find default-name=wlan1 ] band=5ghz-onlyn country=poland \
default-authentication=no default-forwarding=no disabled=no frequency=\
5220 l2mtu=2290 mode=bridge name=pad-sp1 radio-name=pad-sp1 \
wireless-protocol=nv2
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=pad-sp1
Code: Select all
/interface bridge
add mtu=1500 name=bridge1
/interface wireless
set [ find default-name=wlan1 ] band=5ghz-onlyn country=poland \
default-authentication=no disabled=no frequency=5220 l2mtu=2290 mode=\
station-bridge name=SP1-Pad radio-name=SP1-Pad ssid=Pad-SP1
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=SP1-Pad