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The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Network Interface Layer (OSI Data Link Layer) Protocols            9  TCP/IP Serial Line Internet Protocol (SLIP) and Point-to-Point Protocol (PPP)                 9  Point-to-Point Protocol (PPP)                      9  PPP Protocol Frame Formats

PPP Authentication Protocol (PAP, CHAP) Frame Formats 1 2 3 4 TCP/IP Network Interface / Internet "Layer Connection" Protocols

PPP Multilink Protocol Fragmentation Demonstration

A demonstration of fragmenting a PPP data frame can be seen in Figure 43. At top is the same PPP data frame shown in Figure 33. The eight bytes grayed out are the ones not used when a frame is to be fragmented. Thus, the PPP frame used for MP is 24 bytes long, as seen in the smaller table at left (note that the eight bytes are not created and removed, I just showed them in the upper table for illustration). This frame is split into 8-byte chunks, each carried in the Fragment Data fields of an MP fragment. Note the consecutive Sequence Number (“Seq”) values in the fragment frames. Also, note that the Beginning Fragment field is set only for the first fragment, and the Ending Fragment only for the last one.

PPP Authentication Protocol (PAP, CHAP) Frame Formats 1 2 3 4 TCP/IP Network Interface / Internet "Layer Connection" Protocols