[Help] O-RAN Fronthaul CUS-U data structure implementation

[Mattia Milani]

Hi Lincoln,

Thank you very much for the feedback, I'll look into the documentation 
you provided.
In the meanwhile may I ask if there is a publicly available recording of 
the training session you mentioned? (or similar training sessions done 
in the past).

Thank you,
Mattia

On 31/05/2024 14:40, Lincoln Lavoie wrote:
>
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> Hi Mattia,
>
> The code is being used, and there are some patches in flight, but are 
> currently coming from Open Air Interface folks. There's a lot of 
> documentation here: 
> https://gitlab.eurecom.fr/oai/openairinterface5g/-/blob/develop/doc/ORAN_FHI7.2_Tutorial.md?ref_type=heads
>
> We are actually running this in the lab and even hosted a 
> training session on the O-RAN aspects of the setup yesterday with 
> Northeastern and the OAI / VIAVI teams. Point is, it's not really 
> completely dead, just not a lot of movement in that one repo.
>
> On the hardware, it has been run on both Nvidia and Intel NICs, but 
> there are some requirements on things like PTP time stamping, but that 
> comes with the O-RAN fronthaul requirements.
>
> For the VLAN header, that is handled with the VFs are creates and 
> "handed" to the xran processes that get embedded into the DU (at least 
> in the OAI implementation).
>
> Cheers,
> Lincoln
>
>
> On Wed, May 29, 2024 at 4:04 AM Mattia Milani 
> <mattia.milani at nokia.com> wrote:
>
>     Dear Lincoln,
>
>     Thank you very much for providing this reference.
>
>     I've to admit that I didn't know about this library but I'm
>     looking into it
>     but I have some questions/concerns.
>
>     This library seems to be abandoned since 2 years, at least this is
>     what I
>     see from both the documentation and also their version control system:
>     https://gerrit.o-ran-sc.org/r/gitweb?p=o-du%2Fphy.git;a=summary
>     <https://gerrit.o-ran-sc.org/r/gitweb?p=o-du%2Fphy.git;a=summary>Do
>     you think it's still reliable?
>
>     The assumptions seems to be quite restrictive on the HW
>     requirements of
>     this library listed here:
>     https://docs.o-ran-sc.org/projects/o-ran-sc-o-du-phy/en/latest/Assumptions_Dependencies.html#requirements
>     <https://docs.o-ran-sc.org/projects/o-ran-sc-o-du-phy/en/latest/Assumptions_Dependencies.html#requirements>With
>     my experiments I'm just exploring using virtual interfaces and my HW,
>     I would like to avoid those constraints.
>
>     From what I can see some of the data structures already provided
>     by DPDK
>     are re-defined by this library, like the eth header data structure
>     and the eCPRI header.
>     I don't know if this is due to implementation reasons or because
>     it has been
>     built with an old version of DPDK.
>     But without taking in consideration the endianess like rte_ecpri.h
>     already does in DPDK
>     and without supporting some msg types (line 94 file xran_pkt.h).
>
>     Digging into the source code a bit I found some of the data
>     structures I'm referring to
>     in my original message, i.e. the ecpri Seq. ID. The following code
>     puzzles me, source file at:
>     https://gerrit.o-ran-sc.org/r/gitweb?p=o-du/phy.git;a=blob;f=fhi_lib/lib/api/xran_pkt.h;h=314b8d6b7d08f153369de5ad535702f50a574a35;hb=HEAD
>     line 228:
>     struct xran_ecpri_hdr
>      {
>          union xran_ecpri_cmn_hdr cmnhdr;
>          rte_be16_t ecpri_xtc_id;            /**< 3.1.3.1.6 real time
>     control data / IQ data transfer message series identifier */
>          union ecpri_seq_id ecpri_seq_id;   /**< 3.1.3.1.7 message
>     identifier */
>      } __rte_packed;
>
>     Seems strange to me that ecpri_xtc_id is not a data structure on
>     it's own, providing access to DU port, Band Sector etc.
>     Also, the 'xran_pkt_comm_hdr' data structure at line 336 assumes
>     that the packet doesn't have a VLAN header, but,
>     I don't know if this is managed elsewhere.
>
>     Given all that, I'm still of the idea that could be useful to have
>     those kind of headers directly in DPDK
>     but I'm open to reconsider my statement, please let me know if you
>     have more information regarding
>     this library.
>
>     Best regards,
>     Mattia
>
>
>     On 28/05/2024 16:37, Lincoln Lavoie wrote:
>>
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>>
>>     Hi Mattia,
>>
>>     Have you looked into the O-RAN OSC open fronthaul phy
>>     implementation?
>>     https://docs.o-ran-sc.org/projects/o-ran-sc-o-du-phy/en/latest/Architecture-Overview_fh.html
>>
>>     Cheers,
>>     Lincoln
>>
>>     On Tue, May 28, 2024 at 10:31 AM Mattia Milani
>>     <mattia.milani at nokia.com> wrote:
>>
>>         Dear DPDK Dev community,
>>
>>         I hope this is the correct mailing list for my questions,
>>         otherwise
>>         please excuse me and let me know where my questions should be
>>         posted.
>>
>>         I was looking for a data structure capable to manage O-RAN
>>         Fronthaul
>>         CUS-U headers (attached a screenshot of the header structure
>>         form a
>>         packet analyzed with Wireshark)
>>         but I couldn't find one.
>>
>>         I would like to be capable to identify the different port ids
>>         but also
>>         the number of PRBs in the section part.
>>
>>         I wrote my own implementation for a simple use case (I don't
>>         take in
>>         consideration different versions and or data directions)
>>         but it's enough for me at the moment.
>>
>>         What I wanted to ask is the following:
>>         - Does a data structure for this kind of header already exists?
>>         - If it doesn't exists is it planned?
>>         - If it's not planned could it be of some interest?
>>
>>         If there is interest I would be happy to share what I
>>         developed up to
>>         now to receive comments and/or assistance on how to make it
>>         fully
>>         functioning.
>>
>>         Best regards,
>>         Mattia
>>
>>
>>
>>     -- 
>>     *Lincoln Lavoie*
>>     Principal Engineer, Broadband Technologies
>>     21 Madbury Rd., Ste. 100, Durham, NH 03824
>>     lylavoie at iol.unh.edu
>>     https://www.iol.unh.edu
>>     +1-603-674-2755 (m)
>>     <https://www.iol.unh.edu>
>
>
>
> -- 
> *Lincoln Lavoie*
> Principal Engineer, Broadband Technologies
> 21 Madbury Rd., Ste. 100, Durham, NH 03824
> lylavoie at iol.unh.edu
> https://www.iol.unh.edu
> +1-603-674-2755 (m)
> <https://www.iol.unh.edu>
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