Incompatible feedback format 'size' field in RFC 3095 and RFC 4995
Suneeta Rao <[email protected]>
| Newsgroups | gmane.ietf.rohc |
|---|---|
| Message-ID | <[email protected]> |
Dear ROHCers, I am implementing simulation for RFC 3095 and RFC 4995/5225. I was going through feedback formats of RFC 4995 when I realized the the interpretation of 'size' field is different for RFC 3095 / 4995.. This came as a suprise to me because RFC 4995 is not supposed to outdate RFC 3095. It was only supposed to extract the framework part out of RFC 3095. In RFC 4995 Section 5.2.4.1, the 'size' field covers the "Feedback data", i.e. it excludes the Add-CID / Large-CID Octets. In RFC 3095 Section 5.2.2, the 'size' field covers the "Feedback data", but the Feedback data includes the Add-CID / Large-CID Octets. I don't find any obvious reason for the above incompatibility. Can someone please comment on why the interpretation of 'size' field was changed? Doesn't RFC 4995 really update RFC 3095 atleast here? Best Regards, Suneeta Rao. Email: [email protected] Excerpts from RFC 3095 -------------------------- 5.2.2. ROHC feedback format 0 1 2 3 4 5 6 7 +---+---+---+---+---+---+---+---+ | 1 1 1 1 0 | Code | feedback type octet +---+---+---+---+---+---+---+---+ : Size : if Code = 0 +---+---+---+---+---+---+---+---+ / feedback data / variable length +---+---+---+---+---+---+---+---+ Size: Optional octet indicating the size of the feedback data field in octets. feedback data: Profile-specific feedback information. Includes CID information. Excerpt from RFC 4995 --------------------- 5.2.4..1. ROHC Feedback Format 0 1 2 3 4 5 6 7 +---+---+---+---+---+---+---+---+ | 1 1 1 1 0 | Code | feedback type +---+---+---+---+---+---+---+---+ : Size : if Code = 0 +---+---+---+---+---+---+---+---+ : Add-CID octet : if for small CIDs and (CID != 0) +---+---+---+---+---+---+---+---+ : : / large CID (5.3.2 encoding) / 1-2 octets if for large CIDs : : +---+---+---+---+---+---+---+---+ / FEEDBACK data / variable length +---+---+---+---+---+---+---+---+ Size: Indicates the size of the feedback data field, in octets. -------------------------------------------------------- [suneeta] As you can see above, RFC 4995 indicates that CID is not part of size field. _______________________________________________ Rohc mailing list [email protected] https://www.ietf.org/mailman/listinfo/rohc