Question #219566 on rohc changed: https://answers.launchpad.net/rohc/+question/219566
Didier Barvaux proposed the following answer: > 1. The offset IP-ID encoding in RFC 3095 section 4.5.5 > "When receiving a compressed packet m, the decompressor calculates > Offset_ref = ID_ref - SN_ref, where ID_ref and SN_ref are the > values of IP-ID and RTP SN in the reference header, respectively." > > so here ID_ref is nothing but the IP ID that decompresser decoded > successfully in the previous packet? but then it conflicts with the > statement "The Offset IP-ID decoded at step a/ is not used." This one is not correct. > 2. [d_generic.c:7193 parse_extension3()] 16 bits of outer IP-ID in > EXT3 = 0x136f > Does this mean, the IP ID has to be sent in the EXT 3 FIELDs when > RND changed to 0 so that we donot need to look at the ip id > decompressor decoded in prev packet? The trace is not fully accurate. One should read: "16 bits of W-LSB-encoded IP-ID Offset for outer IP header in EXT3 = 0x136f". So, a/ the library W-LSB-decodes the 0x136f value to retrieve the Offset IP-ID, then b/ the library adds the Offset IP-ID to the current SN to retrieve the decoded IP-ID value. Regards, Didier -- You received this question notification because you are a member of ROHC Team, which is an answer contact for rohc. _______________________________________________ Mailing list: https://launchpad.net/~rohc Post to : [email protected] Unsubscribe : https://launchpad.net/~rohc More help : https://help.launchpad.net/ListHelp
