rohc

size smaller

Asked by regulararmy

Hello Didier,
       when doing "ping" business,I call the funciton rohc_decompress(...) to decompress the real IP data packets, I am surprised that the size of each rohc packet is samller than before,always two bytes samller,Although the sizes > 0. According to the common sense，after decompression,the size should be bigger than before. what kind of reason cause this result，do you know? Thanks.

Regards,
chenxisheng

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Didier Barvaux
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regulararmy (regulararmy) said : 		#1

         usually,the funciton rohc_decompress(...) return value > 0 if it succeed， the return value < 0 if it failed in the decompressing,however, the value > 0 but it has a smaller size than before ,is it right?

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Best Didier Barvaux (didier-barvaux) said : 		#2

When compressing, the first compressed ROHC packet of a stream may be larger than the uncompressed packets. As a consequence, when decompressing, the first decompressed IP packets may be smaller than the compressed ROHC packets. To be sure, look at the library traces.

Regards,
Didier

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regulararmy (regulararmy) said : 		#3

Thanks Didier Barvaux, that solved my question.