Re: How to compute the checksum and crc-32 for MPE and ULE

[Moritz Vieth <moritz.vieth@fokus.fraunhofer.de>]

Hi simon,

Simon Teh wrote:
> Dear all experts,
>
>  
>
>         Currently I’m studying the encapsulation method on MPE and ULE. 
> But I’m confusing on how the crc32 and the checksum been calculate. Are 
> they compute from the datagram section or the hold packet? I hope 
> somebody can help me or send me some paper or website related with these 
> topics.. Thanks in advance!!
>
>  

The current ULE draft (draft-fair-ipdvb-ule-02) says on page 14 (4.6): 
"It then accumulates a transmit value for the CRC32 that includes all 
bytes from the start of the SNDU header to the end of the SNDU 
(excluding the 32-bit trailer),...".
This means the CRC32 vlaues are computed from the whole packet 
(including the header) exept the CRC itself.

Hope this helps.

Regards,
Moritz Vieth

FhG FOKUS