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Tagged: reliable network disconnect
Lonny Knudson.
Ron LissackI have 20 or so unattended units. I use cross bridge AT&T . I have some locations where the network stays up and recovers from outages perfectly for weeks at a time. I have other locations/units that the ppp session is marked as up while I have no internet connectivity.
I have resorted to pinging my internet server periodically but even that is not reliable as the network stays up sometime for only a few minutes. Short of changing my application to an on demand solution. Are there any other options ? I would rather have the pppd manage itself.
# cat /etc/ppp/peers/cross-bridge
linkname ppp0
230400
defaultroute
replacedefaultroute
usepeerdns
ipcp-max-failure 4
ipcp-restart 10
lcp-echo-interval 30
lcp-echo-failure 8
lcp-max-terminate 10
noauth
novj
crtscts
persist
holdoff 10
maxfail 0
user cross-bridge
connect ‘/usr/sbin/chat -v -t 10 -f /etc/ppp/peers/cross-bridge_chat’
# cat /etc/ppp/peers/cross-bridge_chat
SAY “Cross Bridge chatn”
ECHO OFF
ABORT ‘NO DIAL TONE’
ABORT ‘NO DIALTONE’
ABORT ‘NO ANSWER’
ABORT ‘NO CARRIER’
ABORT ‘DELAYED’
ABORT ‘VOICE’
ABORT ‘BUSY’
” ‘AT’
OK ‘ATZ’
K ‘AT+CSQ’
OK ‘AT&D2*C1E-V1S0=0’
OK ‘AT&C1’
OK ‘AT+CGMI’
OK ‘AT+CGDCONT=1,”IP”,”a105.2way.net”‘
SAY “Dialing…n”
OK ‘ATD*99***1#’
SAY “Waiting for CONNECT…n”
TIMEOUT 60
CONNECT ”
SAY “Connectedn”
Lonny KnudsonHi Ron,
There’s not much you can do to make pppd manage itself, the persist option will make pppd automatically re-connect if the ppp layer goes down, and failed lcp-echo requests will tear down a presumably bad link. With cellular devices, lcp-echo requests are not likely to fail unless the cellular radio itself is in a bad state.
Your approach (having some process check the IP layer) is very common for cellular applications. It’s a good idea to keep in mind that the IP layer checks use metered data and could have a significant data usage impact on low bandwidth accounts. What action does your ping check take in the event that it doesn’t get a response from your server?