Method and apparatus for implementing alterations on multiple concurrent frames

A method and apparatus are provided for implementing frame header alterations on multiple concurrent frames. Each of a plurality of frame data alteration engines includes a pair of a command decoder and an associated data aligner. A command buffer arbiter sequentially receives frame alteration commands and sequentially selects one of the frame data alteration engines for the sequentially received frame alteration commands. Each command decoder receives and decodes frame alteration commands and provides frame alignment commands and alteration instructions and each associated data aligner receives frame data and selectively latches data bytes of the received frame data responsive to the frame alignment commands and sequentially provides an aligned frame data output of a predefined number of bytes. An alteration engine receives sequentially provided aligned frame data output and alteration instructions from a selected one the plurality of frame data alteration engines and provides sequential altered frame data responsive to the received alteration instructions.