PPP 介绍
PPP/MP/MC Frame Original PPP data frame Flag 0x7e 1 octet
Address 0xff 1 octet
Control 0x03 1 octet
Protocol (PID) 0x0021 2 octets
Payload M octets
FCS 2 or 4 octets
Flag 0x7e 1 octet
IPv4
1 octet
M octets
Data to be carried/ fragmented by ML PPP
PID 0x21
Payload
Fragmented data
Fragment data 1 N octets
Fragment data 2 N octets
....
Fragment data K N octets
ML PPP (MP) Header
ML PPP fragments (short format)
B =1
E =0
0
0
Sequence Number 12 bits
Fragment Data 1 N octets
.... Spare bits used by MC PPP as class number
B =0
E =1
0
0
Sequence Number 12 bits
Fragment Data K N octets
1 bit 1 bit 1 bit 1 bit
1 bit 1 bit 1 bit 1 bit
PPP Header
ML PPP in HDLC framing
Flag 0x7e 1 octet
Address 0xff 1 octet
Control 0x03 1 octet
Protocol (PID) 0x003d 2 octets
Information N+2 octets
FCS 2 or 4 octets
Flag 0x7e 1 octet
ML PPP
PPP
