Solved by adding ECHO parameters to ppp.conf: enable lqr set lqrperiod 5 + enable echo + set echoperiod 5
from man ppp: When this option is enabled, ppp will send LCP ECHO requests to the peer at the frequency defined by ``echoperiod''. Note: LQR requests will supersede LCP ECHO re- quests if enabled and negotiated. I think that lqr not supersede echo because it not negotiated win XP and Vista and dead link not eliminated by lqr timeout
