Wifi issues with mvebu Linksys WRT1200AC

Installing and Using OpenWrt
1

Hi!
I've seen latency fluctuations in my Linksys WRT1200AC with clients connecting with Wi-Fi.

I've seen the same issue using three different compilations of lede

You can reproduce the problem using this steps:

  • Download image from https://downloads.lede-project.org/snapshots/targets/mvebu/generic/
    Start router with default config (eth1.2 with dhcp client, br-lan (eth0.1) with 192.168.1.1/24 and dhcp server active)

  • Enable wireless

     uci delete wireless.@wifi-device[0].disabled
 uci set wireless.@wifi-iface[0].ssid=LEDE_5
 uci delete wireless.@wifi-device[1].disabled
 uci set wireless.@wifi-iface[1].ssid=LEDE_2
 uci commit wireless
 wifi up

  • Install FPing

      opkg update
  opkg install fping

  • Connect device using wireless LEDE_2

  • Get device ip from /tmp/dhcp.leases

  • FPing it (also happens using ping)

     root@LEDE:/# fping -p25 -b1472 -c100 -q 192.168.1.123
 192.168.1.123 : xmt/rcv/%loss = 100/100/0%, min/avg/max = 6.55/62.3/512

  • Connect device using wireless LEDE_5

  • Get device ip from /tmp/dhcp.leases

  • FPing it (also happens using ping)

      root@LEDE:/# fping -p25 -b1472 -c100 -q 192.168.1.123
  192.168.1.123 : xmt/rcv/%loss = 100/100/0%, min/avg/max = 2.64/39.5/157

As you can see ping fluctuation happens either using 2.4Ghz and 5Ghz and goes from 2ms to 512ms

It only happens when pinging client from inside LEDE, forwarded packets don't fluctuate! and wireless bandwidth is as good as my Internet connection (200Mbps/200Mbps).

It is not a big problem, as clients works fine, but I there is something that bugs me.

Thanks!
Xavier.

P.S: I've opened a ticket here (don't know how to edit to fix formatting)