[lwip-users] ppp and gprs problem?

[xcb]

lwip-users:     
        I use lwip and ppp(newest version) to connect gprs,first my link is 
up,show down:
"pppLinkStatusCB  PPPERR_NONE 
local  IP address 10.95.25.125
remote IP address 192.168.254.254
primary   DNS address 211.138.151.161
secondary DNS address 211.136.18.171"

i do nothing about 10 secs,the link is auto down ,see down debug info.

my ppp debug info :

lcp_init: xmit_accm=0 0 0 0

pppOpen Ok
pppMain: unit 0: Connecting
pppStartCB: unit 0
ppp_set_xaccm[0]: outACCM=0 0 0 0
ppp_send_config[0]: outACCM=FF FF FF FF
ppp_recv_config[0]: inACCM=0 0 0 0
lcp_lowerup: asyncmap=0 0 0 0
LCP: lowerup state 0 -> 2
auth_reset: 0
lcp_addci: L opt=2 0
lcp_addci: L opt=5 7812A0B0
lcp_addci: opt=7
lcp_addci: opt=8
pppWrite[0]: len=46
fsm_sdata(LCP): Sent code 1,1,20.
LCP: sending Configure-Request, id 1
LCP: open state 2 -> 6
pppInProc[0]: got 84 bytes
pppInput[0]: LCP len=25
fsm_input(LCP):1,3,25
fsm_rconfreq(LCP): Rcvd id 3 state=6
lcp_reqci: rcvd ASYNCMAP=A0000 PCOMPRESSION ACCOMPRESSION MAGICNUMBER (92A7D62E)
lcp_reqci: Nak AUTHTYPE CHAP not allowed
lcp_reqci: returning CONFNAK.
pppWrite[0]: len=22
fsm_sdata(LCP): Sent code 3,3,8.
pppInput[0]: LCP len=10
fsm_input(LCP):3,1,10
fsm_rconfnakrej(LCP): Rcvd id 1 state=6
lcp_addci: L opt=2 A0000
lcp_addci: L opt=5 7812A0B0
lcp_addci: opt=7
lcp_addci: opt=8
pppWrite[0]: len=45
fsm_sdata(LCP): Sent code 1,2,20.
LCP: sending Configure-Request, id 2
pppInProc[0]: got 99 bytes
pppInput[0]: LCP len=24
fsm_input(LCP):1,5,24
fsm_rconfreq(LCP): Rcvd id 5 state=6
lcp_reqci: rcvd ASYNCMAP=A0000 PCOMPRESSION ACCOMPRESSION MAGICNUMBER (92A7D62E)
lcp_reqci:  PAP (C023)
lcp_reqci: returning CONFACK.
pppWrite[0]: len=50
fsm_sdata(LCP): Sent code 2,5,24.
pppInput[0]: LCP len=20
fsm_input(LCP):2,2,20
fsm_rconfack(LCP): Rcvd id 2 state=8
lcp_acki: Ack
ppp_send_config[0]: outACCM=0 0 A 0
ppp_recv_config[0]: inACCM=0 0 A 0
link_established: 0
upap_lowerup: 0 s=0
IPCP: lowerup state 0 -> 2
upap_authwithpeer: 0 user=none password=none s=1
pppWrite[0]: len=21
pap_sauth: Sent id 1
pppInProc[0]: got 8 bytes
pppInProc[0]: got 3 bytes
pppInput[0]: PAP len=5
pap_rauthack: Rcvd id 1 s=3
Remote message: 
auth_withpeer_success: 0 proto=C023
pppWrite[0]: len=36
fsm_sdata(IPCP): Sent code 1,1,28.
IPCP: sending Configure-Request, id 1
IPCP: open state 2 -> 6
pppInProc[0]: got 16 bytes
pppInput[0]: IPCP len=10
fsm_input(IPCP):1,1,10
fsm_rconfreq(IPCP): Rcvd id 1 state=6
ipcp_reqci: ADDR 192.168.254.254
ipcp_reqci: returning Configure-ACK
pppWrite[0]: len=18
fsm_sdata(IPCP): Sent code 2,1,10.
upap_timeout: 0 timeout 6 expired s=4
IPCP: timeout resending Config-Request state=8
pppWrite[0]: len=37
fsm_sdata(IPCP): Sent code 1,1,28.
IPCP: sending Configure-Request, id 1
pppInProc[0]: got 16 bytes
pppInput[0]: IPCP len=10
fsm_input(IPCP):4,1,10
fsm_rconfnakrej(IPCP): Rcvd id 1 state=8
pppWrite[0]: len=29
fsm_sdata(IPCP): Sent code 1,2,22.
IPCP: sending Configure-Request, id 2
pppInProc[0]: got 29 bytes
pppInput[0]: IPCP len=22
fsm_input(IPCP):3,2,22
fsm_rconfnakrej(IPCP): Rcvd id 2 state=8
local IP address 10.95.25.125
primary DNS address 211.138.151.161
secondary DNS address 211.136.18.171
pppWrite[0]: len=30
fsm_sdata(IPCP): Sent code 1,3,22.
IPCP: sending Configure-Request, id 3
pppInProc[0]: got 29 bytes
pppInput[0]: IPCP len=22
fsm_input(IPCP):2,3,22
fsm_rconfack(IPCP): Rcvd id 3 state=8
np_up: 0 proto=21
np_up: maxconnect=0 idle_time_limit=0
ipcp: up
sifvjcomp: VJ compress enable=0 slot=0 max slot=0
sifup: unit 0: linkStatusCB=c0004a8 errCode=0

pppLinkStatusCB  PPPERR_NONE 
local  IP address 10.95.25.125
remote IP address 192.168.254.254
primary   DNS address 211.138.151.161
secondary DNS address 211.136.18.171

//*********why this happen**********//
pppInProc[0]: got 17 bytes
pppInput[0]: LCP len=4
fsm_input(LCP):5,5,4
fsm_rtermreq(LCP): Rcvd id 5 state=9
LCP terminated by peer
link_down: 0
upap_lowerdown: 0 s=4
ipcp: down
np_down: 0 proto=21
sifvjcomp: VJ compress enable=0 slot=0 max slot=0
sifdown: unit 0: linkStatusCB=c0004a8 errCode=0

pppLinkStatusCB  PPPERR_CONNECT 
IPCP: lowerdown state 9 -> 1
IPCP: close reason=LCP down state 1 -> 0
pppMainWakeup: unit 0
ppp_send_config[0]: outACCM=FF FF FF FF
ppp_recv_config[0]: inACCM=0 0 A 0
pppWrite[0]: len=17
fsm_sdata(LCP): Sent code 6,5,4.
pppInProc[0]: got 17 bytes
pppInput[0]: LCP len=4
fsm_input(LCP):5,5,4
fsm_rtermreq(LCP): Rcvd id 5 state=5
pppWrite[0]: len=17
fsm_sdata(LCP): Sent code 6,5,4.
LCP: timeout sending Terminate-Request state=5
link_terminated: 0
Connection terminated.
pppMainWakeup: unit 0
pppMain: unit 0: PHASE_DEAD
pppMain: unit 0: linkStatusCB=c0004a8 errCode=0

pppLinkStatusCB  PPPERR_PROTOCOL 
pppMain: unit 0: Connecting
pppStartCB: unit 0
ppp_set_xaccm[0]: outACCM=0 0 0 0
ppp_send_config[0]: outACCM=FF FF FF FF
ppp_recv_config[0]: inACCM=0 0 0 0
lcp_lowerup: asyncmap=0 0 0 0
LCP: Up event in state 3!
LCP: lowerup state 3 -> 3
LCP: open state 3 -> 3
pppInProc[0]: got 14 bytes