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

[Lincoln Lavoie <lylavoie@iol.unh.edu>]

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Hi Mattia,

Yes, I think there is a plan to push the training (at least the
presentation parts) up to the site https://gitlab.eurecom.fr/oai/trainings
The Teams meeting was recorded, but there might be some post
processing required.  There is a lot of other good information in the other
sessions, but I think the one last week was the first focused on the O-RAN
7.2 fronthaul.

Cheers,
Lincoln

On Mon, Jun 3, 2024 at 2:36 AM Mattia Milani <mattia.milani@nokia.com>
wrote:

> 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@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
>> 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
>> 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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>>
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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@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@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@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@iol.unh.edu
https://www.iol.unh.edu
+1-603-674-2755 (m)
<https://www.iol.unh.edu>

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