<div dir="auto">Yes, actually there is a difference between 5g and 4g infrastructure, that actually often involve different interfacing from IMS to it, particularly pcscf and icscf, eg: the way they interact with hss and pcf/pcrf.<div dir="auto">Problem is that 4g infrastructure is different from 5g. When they implement 4g+5g, they implement actually both (so, no problem)</div><div dir="auto"><br></div><div dir="auto">4g+5g is called NSA (not stand alone)</div><div dir="auto"><br></div><div dir="auto">A pure 5g is SA (stand alone) and offer different interfaces from the ones provided by 4g.</div><div dir="auto"><br></div><div dir="auto">In NSA you (IMS) can behave like it's pure 4g (you use 4g interfaces to do all things, even for the 5g part)</div><div dir="auto"><br></div><div dir="auto">In SA not at all, you must interface to 5g</div><div dir="auto"><br></div><div dir="auto">The main difference for what ims is concerned is pcf vs pcrf</div><div dir="auto"><br></div><div dir="auto">Let's note that most private networks (enterprise, etc) will be SA</div><div dir="auto"><br></div><div dir="auto">Most carriers will obviously be NSA</div><div dir="auto"><br></div><div dir="auto"><br><br><div data-smartmail="gmail_signature" dir="auto">answered from mobile, please pardon terseness and typos,<br>-giovanni</div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Nov 29, 2023, 18:25 Bogdan-Andrei Iancu <<a href="mailto:bogdan@opensips.org">bogdan@opensips.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>

  
    
  
  <div>
    <font face="monospace">Hi Johan,<br>
      <br>
      The lowest point we should address in the whole IMS arch is the
      P-CSCF, so we are agnostic to the actual transport layer below us
      (like the xG stuff). Or am I saying here something wrong and there
      are some implications to the upper layers ?<br>
      <br>
      Regards,<br>
    </font>
    <pre cols="72">Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
  <a href="https://www.opensips-solutions.com" target="_blank" rel="noreferrer">https://www.opensips-solutions.com</a>
  <a href="https://www.siphub.com" target="_blank" rel="noreferrer">https://www.siphub.com</a></pre>
    <div>On 29.11.2023 18:07, Johan De Clercq
      wrote:<br>
    </div>
    <blockquote type="cite">
      
      <div dir="ltr">In addition, the IMS should be able to handle 4G
        and 5G calls.   
        <div>In my opinion, we should no longer about 2 and 3 G as they
          are being phased out everywhere. </div>
        <div><br>
        </div>
        <div>wkr, </div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">Op wo 29 nov 2023 om 16:39
          schreef Bogdan-Andrei Iancu <<a href="mailto:bogdan@opensips.org" target="_blank" rel="noreferrer">bogdan@opensips.org</a>>:<br>
        </div>
        <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
          <div> <font face="monospace">Hi Giovanni,<br>
              <br>
              Thanks for the feedback here, a valuable one as usual :).<br>
              <br>
              On the HSS, what you are saying aligns with the my own
              thoughts - that its functioning logic is somehow outside
              the our scope here, but we need to pay attention to the
              interfacing (DIAMETER or HTTP2.0).<br>
              <br>
              Now, on the AS side - as I understand, it holds whatever
              custom logic the operator may have in routing and proving
              services (included VAS's). So to say, I see it as a highly
              programmable component. And if so, what we need to provide
              here is probably a very high level interface / API to
              allow call manipulation in a very abstract way... :-/ ??<br>
              <br>
              Best Regards, <br>
            </font>
            <pre cols="72">Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
  <a href="https://www.opensips-solutions.com" target="_blank" rel="noreferrer">https://www.opensips-solutions.com</a>
  <a href="https://www.siphub.com" target="_blank" rel="noreferrer">https://www.siphub.com</a></pre>
            <div>On 29.11.2023 11:11, Giovanni Maruzzelli wrote:<br>
            </div>
            <blockquote type="cite">
              <div dir="ltr">First of all:<br>
                CONGRATULATIONS to the OpenSIPS community !!!<br>
                (I believe this is the first step of a long and
                satisfying journey)<br>
                <br>
                On the topic:<br>
                in addition to the CSCF component, I would like to see
                efforts on the AS (Application Server) component of the
                IMS infrastructure.
                <div><br>
                </div>
                <div>The AS is probably way the simplest of it all, it
                  will probably require the least
                  modifications/additions to OpenSIPS.</div>
                <div><br>
                </div>
                <div>But I would say AS will be crucial to a lot of
                  people/use cases.</div>
                <div><br>
                </div>
                <div>While for sure there will be a lot of cases for our
                  community to build the voice/video complete IMS
                  infrastructure on top of private 5G networks in
                  enterprises and public administrations, I see as very
                  much relevant also the use case of building
                  infrastructure to provide additional third party
                  services to big carriers, and to big carriers
                  partners.</div>
                <div><br>
                </div>
                <div>Also, AS is the correct and manageable way to
                  provide additional services even if you build the core
                  IMS infrastructure.</div>
                <div><br>
                </div>
                <div>About HSS: this is the sancta sanctorum of a
                  carrier/provider<br>
                  Apart from the venerable fraunhofer java
                  implementation, now we can count on the flexible java
                  implementation in <a href="https://github.com/nickvsnetworking/pyhss" target="_blank" rel="noreferrer">https://github.com/nickvsnetworking/pyhss</a>
                  with a lot of features, good performances, and
                  actually built for production.</div>
                <div><br>
                </div>
                <div>I would say better we concentrate on accessing the
                  various different protocols of HSS (diameter/http2)
                  from the various components (each component in IMS
                  access HSS with a different interface with
                  different vocabularies and actions.<br>
                  <br>
                  MGCF/MGW, if needed, will be a natural extension of
                  our CSCF/AS architecture.</div>
                <div><br>
                </div>
                <div>Just my two cents, to keep the ball rolling,</div>
                <div><br>
                  Congratulation again,<br>
                  <br>
                </div>
                <div>-giovanni<br>
                  <br>
                </div>
              </div>
              <br>
              <div class="gmail_quote">
                <div dir="ltr" class="gmail_attr">On Tue, Nov 28, 2023
                  at 2:02 PM Bogdan-Andrei Iancu <<a href="mailto:bogdan@opensips.org" target="_blank" rel="noreferrer">bogdan@opensips.org</a>>
                  wrote:<br>
                </div>
                <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
                  <div> <font face="monospace">Hi all,<br>
                      <br>
                      (disclaimer : cross lists posting is not a good
                      practice - we will do this only to catch the
                      attention and get momentum with this initial
                      topic)<br>
                      <br>
                      As a first step here, is to work out the scope of
                      the IMS implementation in OpenSIPS. IMS is a vast
                      concept, with SIP and non-SIP components, and we
                      want to understand and agree on which components
                      of IMS may be subject of work from the OpenSIPS
                      perspective. For example, we do consider the CSCF
                      as a must here, but we may explore the HSS, AS,
                      MGW or other components.<br>
                      <br>
                      From the OpenSIPS perspective, we look for IMS
                      components which are SIP related. At least as a
                      starting point. So, the first obvious candidate is
                      the <b>Call Session Control Function (CSCF)</b>.
                      And here we need to look into and address the
                      specific functionalities of each sub-component: <br>
                          * P-CSCF<br>
                          * I-CSCF<br>
                          * S-CSCF<br>
                      <br>
                      Again, these are the pretty obvious components,
                      still may look into and evaluate (if of an
                      interest of the OpenSIPS IMS implementation) areas
                      as:<br>
                          * HSS </font><font face="monospace"> (from
                      interconnection perspective)<br>
                    </font><font face="monospace">    * MGCF / MGW 
                      (from interconnection perspective)<br>
                          * SIP AS<br>
                          * others ?<br>
                      <br>
                      Any feedback (with explanations and arguments)
                      about what we should consider for our IMS
                      implementation is more the welcome. I set here
                      just a simple starting point, with no limitations
                      or so. Feel free to contribute to the topic<br>
                      <br>
                      <br>
                      Best regards,<br>
                    </font>
                    <pre cols="72">-- 
Bogdan-Andrei Iancu

OpenSIPS Founder and Developer
  <a href="https://www.opensips-solutions.com" target="_blank" rel="noreferrer">https://www.opensips-solutions.com</a>
  <a href="https://www.siphub.com" target="_blank" rel="noreferrer">https://www.siphub.com</a></pre>
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                </blockquote>
              </div>
              <br clear="all">
              <div><br>
              </div>
              <span class="gmail_signature_prefix">-- </span><br>
              <div dir="ltr" class="gmail_signature">Sincerely,<br>
                <br>
                Giovanni Maruzzelli<br>
                OpenTelecom.IT<br>
                cell: +39 347 266 56 18<br>
                <br>
              </div>
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      </div>
    </blockquote>
    <br>
  </div>

</blockquote></div>