Hi All,
I have a doubt on PPP over serial. Can you please help me out...
My doubt goes like this;
Test Set-Up:
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System Details: All the three machines are standard Pentium PCs with
Linux-2.4.2 loaded. The PPP has been enabled in machine-1 and machine-3.
Requirement: Is to establish a PPP session between machine-1 and machine-3.
Machine-2 should do nothing with the PPP frame. It should receive the PPP
frame on the serial and maybe send it to machine-3 on the Ethernet.
Approach: Have written a small module in machine-2, that should receive the
PPP frame from the serial interface and send it on the Ethernet interface.
Also tested the module on machine-2 with a simulator working from machine-1
(instead of the actual PPP). The simulator would send packets of varied
sizes, from 3 bytes upto 1500 bytes, with the header and trailer as the
same no. like 7E as in ppp. For the simulator the character 7E wasn't
repeated anywhere inside the data.
Tests and Findings: With the simulator, the module seems to work fine, if
anything less than 8 bytes is sent, the module in machine-2 receives it in
one go. If anything above 8-bytes, the machine-2 module receives it
multiple times, but the logic in the module converts it into a single
message and sends it on the ethernet using UDP to machine-3. when running
the actual PPP module from machine-1, the module behaves erroneously. PPP
has header and trailer as 7E but the module is printing characters like 4f.
If anyone has done similar testings, can u please point out what the
problem could be with respect to PPP. Or is there any better way of doing
whatever I am trying to do. The requirement section would help u people in
knowing what is required.
pic00041.pcx
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