CHAPTER 15 Modifying

The last step in packet processing, as well as of our description of EZchip processing, is modifying: the phase in which actual modifications are made to the packets, determining the forwarding, queueing, and routing parameters, and releasing the processed packets to their destinations.

TOPmodify decodes modify instructions, as well as messages from previous stages and TOPsearch II results, and modifies the frame contents accordingly. An unlimited number of bytes anywhere in the frame and in any order can be overwritten or modified. Modified frames and added headers are written to the frame memory (if required; e.g., for backplane switching).

Three possible modification types are available according to TOPmodify microcode ...

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