Биллинговая система Nodeny

Добрый день всем.
Столкнулись с проблемой, у половины клиентов отваливается в хаотичном порядке PPPoE сессии, у некоторых коннект есть но нет интернета.
Куда копать, кто подскажет?

Apr 27 07:23:13 cityline-ksm mpd: [ix1-832] PPPoE connection timeout after 9 seconds
Apr 27 07:23:13 cityline-ksm mpd: [ix1-834] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-835] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-836] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-837] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-838] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-839] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-840] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-841] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-842] PPPoE connection timeout after 9 seconds
Apr 27 07:23:14 cityline-ksm mpd: [ix1-843] PPPoE connection timeout after 9 seconds
Apr 27 07:23:34 cityline-ksm mpd: [ix1-834] PPPoE connection timeout after 9 seconds
Apr 27 07:23:49 cityline-ksm mpd: [ix1-835] PPPoE connection timeout after 9 seconds
Apr 27 07:23:49 cityline-ksm mpd: [ix1-836] PPPoE connection timeout after 9 seconds
Apr 27 07:23:56 cityline-ksm mpd: [ix1-837] PPPoE connection timeout after 9 seconds

А причем тут биллинг вообще? Копайте в сторону физики/логики сети.