rohc

three parameters

Asked by regulararmy on 2013-05-22

Good morning,Didier:
As for the rohc-1.5.1.tar.bz2,there is a struct rohc_comp with three parameters (size_t feedbacks_first; size_t feedbacks_first_unlocked;size_t feedbacks_next) in it,can you explain the meaning and fundamentals of them in detail, I can not understand them clearly.
In addtion, for the tunnel.c in the app/tunnel/ sub-directory of the library source code, at the end of the main(,,,), a function flush_feedback(comp,udp,raddr,port) is called,what is the meanings for this action? don't the feedback data be sent to the UDP socket together with the outgoing packets in the rohc_compress(...)? Thank you.

Regards
chenxisheng

Question information

Language:: English Edit question

Status:: Solved

For:: rohc Edit question

Assignee:: No assignee Edit question

Solved by:: Didier Barvaux

Solved:: 2013-05-24

Last query:: 2013-05-24

Last reply:: 2013-05-23

Link existing bug

This question was reopened

2013-05-23 by regulararmy

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Didier Barvaux (didier-barvaux) said on 2013-05-22:

Hello,

ROHC feebacks may be transmitted in 2 different ways: with a ROHC packet (piggybacking) or alone. The 1st way is preferred by the library (every ROHC packet generated will try to piggyback several feebacks), but it is not enough sometimes. If traffic is asymmetric, there are perhaps not enough reverse traffic to transmit all the ROHC feedbacks. In such a case, feedbacks are recorded in the compression context (feedbacks_first, feedbacks_first_unlocked and feedbacks_next are a ring of feedbacks) and must be flushed by the application manually. The flush_feedback() function does this.

Regards,
Didier

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regulararmy (regulararmy) said on 2013-05-22:

Thanks Didier Barvaux, that solved my question.

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regulararmy (regulararmy) said on 2013-05-23:

Good morning Didier,
As for the rohc-1.5.1.tar.bz2, the feedback mechanism or function in R_MODE has not been implemented yet, So, Is the library codes effective for a production application,especially when it is in the R_MODE?

Regards
chenxisheng

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Didier Barvaux (didier-barvaux) said on 2013-05-23:

Hello,

> feedback mechanism or function in R_MODE has not been implemented
> yet, So, Is the library codes effective for a production application,
> especially when it is in the R_MODE?

The ROHC library is ready for production in U- and O-mode. R-mode is not implemented at all. See the TODO list [1].

Regards,
Didier

[1] http://rohc-lib.org/wiki/doku.php?id=library-todo#rohc_features