Re: [Rohc] Rohctunnel with rohc 2.1.0 library

[Didier Barvaux]

Hello,


>Is it any possibility to use the rohctunnel app with the 2.1.0 library?
>The rohctunnel source has compiled using the 2.1.0 library and it
>creates
>the tunnel when running both sides, but it's failed when decompressing.

What do you call rohctunnel? Is it the application that was once located in the 
app/tunnel/ subdir of the librohc sources? Or the IP/ROHC application available 
on github https://github.com/didier-barvaux/iprohc ?

Regards,
Didier

___
Mailing list: https://launchpad.net/~rohc
Post to : rohc@lists.launchpad.net
Unsubscribe : https://launchpad.net/~rohc
More help   : https://help.launchpad.net/ListHelp

Re: [Rohc] rohc performance on lossy media

[mehmet sulak]

Thanks for your detailed response first;

First I tried method  rohc_comp_set_wlsb_window_width(comp,8) by giving
8bits window width but I still observe the following in the log files;

rohc_decomp_rfc3095.c:1463 parse_uo0() 4 SN bits = 0xe

So I think it still uses 4 bit window length? If yes did I do something
wrong?

Secondly I think for UDP packets ROHC_LSB_SHIFT_SN(-1) is used for
compressor and decompressor which makes parsing delayed packets impossible.

So I need to use something half of (2 ^ lsb_width)  instead of -1 by adding
a new enumeration value.

Do have any idea about this parameter?

Best Regards..

2018-01-29 22:11 GMT+03:00 Didier Barvaux :

> Hello,
>
> > I am using Rohc comressor/decomressor pair on a lossy media(sometimes
> > at receiver side some packets are lost) and the orderings of the  UDP
> > packets are not guaranteed.(packets are not coming in right order all
> > the time).
> >
> > I am using Unidirectional mode and observe some decomression failures
> > about CRC check, malformed packets...
> >
> > Any recommendation to overcome these issues?
>
> The ROHC protocol provides several ways to handle packet loss or
> reordering:
>
> a/ Increasing the width of the window used by the W-LSB algorithm
>improves the robustness of the ROHC protocol by sending more bits for
>changing fields. Given a W-LSB width , up to
>( - 1) packets may be lost without causing additional
>loss.
>The default width is set to 4 by the ROHC library ; please use the
>rohc_comp_set_wlsb_window_width() function to change the value ; see
>[1] for more details.
>
> b/ Increasing the number of transmissions N required for a changing
>static fields or a changing pattern for a dynamic field ensures that
>the loss of N-1 packets during such a change will cause no
>additional loss.
>The default number of transmissions is set to 3 by the ROHC
>library ; there is no API to change the value at that time, but you
>may change the value of the constant MAX_IR_COUNT in the source file
>src/comp/rohc_comp_internals.h and re-build/re-install the library.
>
> c/ Same as b/ but for lists of extensions headers (such as IPv6
>extension headers, GRE, AH...). Use the function
>rohc_comp_set_list_trans_nr() to change the value ; the default
>value is set to 5 ; see [2] for more details.
>
> d/ You may enable packet/context repair upon CRC failures, so that the
>decompressor tries to fix the context or packet if it detects a
>decompression problem (due to packet loss/reordering for example).
>The feature is disabled by default. Enable it with the function
>rohc_decomp_set_features() and the feature
>ROHC_DECOMP_FEATURE_CRC_REPAIR ; see [3] for more details.
>
> Configuring options a-c is easier if you know the largest number of
> consecutive losses that you may expect and/or you want to be protected
> against.
>
> Let me know if my explanations are clear enough or if you need more
> details. And, of course, let me know if one of the options solves your
> problem.
>
> Regards,
> Didier
>
>
> [1] documentation of rohc_comp_set_wlsb_window_width():
> https://rohc-lib.org/support/documentation/API/rohc-doc-2.
> 1.0/group__rohc__comp.html#ga2b68070dddbc038cd55490952a7b3fa4
>
> [2] documentation of rohc_comp_set_list_trans_nr():
> https://rohc-lib.org/support/documentation/API/rohc-doc-2.
> 1.0/group__rohc__comp.html#ga32608bc06e1b0d1656e463eeb1ccbd7f
>
> [3] documentation of rohc_decomp_set_features():
> https://rohc-lib.org/support/documentation/API/rohc-doc-2.
> 1.0/group__rohc__decomp.html#ga2298148ca8dc277a1c1905f550f21f7b
>
>
> ___
> Mailing list: https://launchpad.net/~rohc
> Post to : rohc@lists.launchpad.net
> Unsubscribe : https://launchpad.net/~rohc
> More help   : https://help.launchpad.net/ListHelp
>
___
Mailing list: https://launchpad.net/~rohc
Post to : rohc@lists.launchpad.net
Unsubscribe : https://launchpad.net/~rohc
More help   : https://help.launchpad.net/ListHelp

[Rohc] Rohctunnel with rohc 2.1.0 library

[Csaba Horváth]

Hello!

Is it any possibility to use the rohctunnel app with the 2.1.0 library?
The rohctunnel source has compiled using the 2.1.0 library and it creates
the tunnel when running both sides, but it's failed when decompressing.

[rohc_decomp.c:763 rohc_decompress3()] decompress the 68-byte packet #9
[rohc_decomp.c:3785 rohc_decomp_parse_padding()] skip 0 byte(s) of padding
[rohc_decomp.c:1010 d_decode_header()] decompressor received 0 bytes of
feedback for the same-side associated compressor
[rohc_decomp.c:3721 rohc_decomp_decode_cid()] add-CID present (0xe1)
contains CID = 1
[rohc_decomp.c:3894 rohc_decomp_find_context()] context with CID 1 not found
[rohc_decomp.c:3900 rohc_decomp_find_context()] only IR or IR-CR packets
can create a new context with CID 1
[rohc_decomp.c:875 rohc_decompress3()] packet decompression failed: no
matching context and creation was impossible or failed (3)

Do I have to use the older version of rohc library if I want to use tunnel
interface, or I am on a totally wrong way?

Thanks for the answer!

Csabi
___
Mailing list: https://launchpad.net/~rohc
Post to : rohc@lists.launchpad.net
Unsubscribe : https://launchpad.net/~rohc
More help   : https://help.launchpad.net/ListHelp