Re: [Discuss-gnuradio] Problem in framer_sink

[Dan Halperin]

Johnathan Corgan wrote:
> The CRC check on the payload is of course dependent on the correct
> length.  If the length value gets corrupted but both copies are
> identical, the packet will still get rejected at the CRC check stage.
>
> Except in your case, where the state machine hangs up with a payload
> length of zero.  Good catch. The length field in the received packet
> should always be at least four bytes, as that is the length of the CRC
> field in use, so the check will get added to the code for payload_len < 4.
Is the CRC actually required? In the version of the code I'm using on
the lab machines (which is from early January), the framer_sink only
uses the length field to form the packet and the CRC is checked later.
We actually do the CRC after doing some ECC on the bits themselves.

-Dan