...0xAA.
Actually, at present, we are free to use any byte with the control bit low except 0x00 ( DROP) and 0xFF ( TURN) -- however, in order for the data to look identical to all routers, it must be 2-bit rotationally invariant leaving us with 0xAA and 0x55 as the only two real possible encodings).

...components.
This is the same scheme described in Section . Faults are treated as permanently blocked paths.

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