[RE:] Re: [lwip-users] How to test IP over PPP ?

[Kishore]

Hi all



>         Packets are dropped because FCS (Frame Check Sequence) are bad. A FCS 
> is
>         a checksum used to ensure that sent and received data are identical.
>         Bad FCS can occur if your link is bad or not 8-bit clean (I had bad 
> FCS
>         when I set my serial port parameters using ISTRIP - Strip off eighth 
> bit
>         -).

Im using standard serial port setting,and i dont know why shd it happen only 
for IPCP and not LCP frames which are exchanged earlier.

 Do you use hardware or software flow control ? I read somewhere that
>         if you use software flow control you should use the following asyncmap
>         (0x000a0000) to escape control characters.
>         



I dont use  hardware and software flow control either.

What im sure is that as soon as link is established,  inAccm and outACCM values 
are reset to receive IPCP messages. I dont understand why this shd be 
reset,thus not escaping control chr anymore.

LCP: sensio_read:
  7e ff 7d 23 c0 21 7d 22 7d 21 7d 20 7d 34 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20
7d 25 7d 26 34 de 8c cf 7d 27 7d 22 7d 28 7d 22 bc e4 7e 7e 80 21  1  1 22  3  6
 c0 a8 fd 78 81  6 82  6 83  6 84  6 14 a0 7e
pppInProc[0]: got 68 bytes
pppInProc[0]: Dropping bad fcs 0x0A11 proto=0x8021
pppDrop: pbuf len=27
dpbuf len=27
pppInput[0]: LCP len=20
fsm_input(LCP):2,1,20
fsm_rconfack(LCP): Rcvd id 1 state=8
lcp_acki: Ack
ppp_send_config[0]: outACCM=0 0 0 0 <---------------
ppp_recv_config[0]: inACCM=0 0 0 0 <-----------------
link_established: 0
upap_lowerup: 0 s=0
IPCP: lowerup state 0 -> 2
pppWrite[0]: len=30
sio_write:
  7e ff  3 80 21  1  1  0 16  3  6  0  0  0  0 81  6  0  0  0  0 83  6  0  0  0
 0 6e db 7e.


and it is set again when link is needed termination.

IPCP: sending Configure-Request, id 1
IPCP: timeout sending Config-Requests state=6
np_finished: 0 proto=21
link_down: 0
upap_lowerdown: 0 s=1
IPCP: lowerdown state 3 -> 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 0 0 <-------------------------
pppWrite[0]: len=46
sio_write:
  7e ff 7d 23 c0 21 7d 25 7d 22 7d 20 20 4e 6f 20 6e 65 74 77 6f 72 6b 20 70 72
6f 74 6f 63 6f 6c 73 20 72 75 6e 6e 69 6e 67 7d 37 7d 38 7e
fsm_sdata(LCP): Sent code 5,2,32.
LCP: close reason=No network protocols running state 9 -> 4
LCP: timeout resending Terminate-Requests state=4

May be this is normal,but then i am not able to figure out the FCS error yet .
Anyone has such expierence,pls help

Thanks for your tips ,Serge!