Multicast over wireless ceases to work properly after a while on ath9k with many clients connected
Username: Michael Marley
Origin: https://bugs.openwrt.org/index.php?do=details&task_id=253
I am having a problem on a UBNT UAP-LR where, if many clients stay connected the router for a long time, multicast packets will stop being reliably sent to the wireless clients. I can reproduce this with LEDE r1953, but it goes back at least as far as OpenWRT 15.05.1 with kernel 3.18. I can not, however, reproduce it on another network with the same
WAP
but with only one or two wireless clients.
This originally manifested as IPv6 ceasing to work since the (multicasted) RA packets were not reaching the wireless clients. I used tcpdump on the
WAP
and determined that the RAs were arriving through the wired interface and leaving through the wireless interface as they should, but tcpdump on the client indicates that a vast majority of the RAs are never received. (Please note that the IPv6 issue is not reproducible with the router running OpenWRT/LEDE and odhcpd, since odhcpd unicasts RAs sent as a response to an RS instead of multicasting them, while it is reproducible when the router is running radvd, for example as pfSense does.)