So, I've a TD-W8970 v1 with LEDE (compiled from last commit available, 18.06.X is not enough stable on this device IMO). My connection works fine I've just to raise the maxfail parameter inside /etc/config/network (raised to 3 but even 2 would do the trick, or 0 since is equals to "unlimited"). This is needed on my because pppd will always fail the first attempt to connect, this is what I usually see (after enabling debug and logfile options inside /etc/ppp/options):
Plugin pppoatm.so loaded.
PPPoATM plugin_init
PPPoATM setdevname_pppoatm - SUCCESS:0.8.35
using channel 1
Using interface pppoa-wan
Connect: pppoa-wan <--> 0.8.35
sent [LCP ConfReq id=0x1 <mru 1478> <magic 0xc40af9fb>]
sent [LCP ConfReq id=0x1 <mru 1478> <magic 0xc40af9fb>]
Terminating on signal 15
sent [LCP TermReq id=0x2 "User request"]
sent [LCP TermReq id=0x3 "User request"]
Plugin pppoatm.so loaded.
PPPoATM plugin_init
PPPoATM setdevname_pppoatm - SUCCESS:0.8.35
using channel 2
Using interface pppoa-wan
Connect: pppoa-wan <--> 0.8.35
sent [LCP ConfReq id=0x1 <mru 1478> <magic 0xb5bea8d2>]
rcvd [LCP ConfReq id=0x22 <mru 1492> <auth chap MD5> <magic 0x53a7efed>] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ...
sent [LCP ConfAck id=0x22 <mru 1492> <auth chap MD5> <magic 0x53a7efed>]
rcvd [LCP ConfAck id=0x1 <mru 1478> <magic 0xb5bea8d2>]
sent [LCP EchoReq id=0x0 magic=0xb5bea8d2]
rcvd [CHAP Challenge id=0x1 <6da577c942db0b4f8108b1e9693f6d8b395e5c01b07b5ab3625b15b24e951c3bba1385fd6e104df0187eda01bdc78c76a5e97857e4d28a>, name = "VEMA-E35"]
sent [CHAP Response id=0x1 <6377a629cee61f81a32188650595674c>, name = "benvenuto"]
rcvd [LCP EchoRep id=0x0 magic=0x53a7efed]
rcvd [CHAP Success id=0x1 "CHAP authentication success"]
CHAP authentication succeeded: CHAP authentication success
CHAP authentication succeeded
sent [IPCP ConfReq id=0x1 <compress VJ 0f 01> <addr 0.0.0.0>]
rcvd [IPCP ConfReq id=0x2f <addr 151.6.141.16>]
sent [IPCP ConfAck id=0x2f <addr 151.6.141.16>]
rcvd [IPCP ConfRej id=0x1 <compress VJ 0f 01>]
sent [IPCP ConfReq id=0x2 <addr 0.0.0.0>]
rcvd [IPCP ConfNak id=0x2 <addr 151.49.120.113>]
sent [IPCP ConfReq id=0x3 <addr 151.49.120.113>]
rcvd [IPCP ConfAck id=0x3 <addr 151.49.120.113>]
local IP address 151.49.120.113
remote IP address 151.6.141.16
Script /lib/netifd/ppp-up started (pid 1288)
Script /lib/netifd/ppp-up finished (pid 1288), status = 0x1
System time change detected.
I do not know if the channel chosen by pppd is the problem, the first connection (using channel 1) fails always and the second one (using channel 2) always work (at least I've never observed a failure for now).
Is there a way to select which channel pppd start with? Or some onther trick thath allow me to skip channel 1? So I can find out if the first connection fail dependently or independently form the channel number.