Re: [Idr] 3GPP SSC Mode 3 in draft-dunbar-idr-5g-edge-compute-app-meta-data-03

[Gyan Mishra <[e-mail]>]

Great!

Thanks Linda

Gyan

On Fri, Nov 19, 2021 at 12:33 PM Linda Dunbar <[e-mail]>
wrote:

> Gyan and Jeffrey,
>
>
>
> For 5G Edge Computing (and mission critical new features), please use
> TR23.501 versions for Release 17:
> https://itectec.com/archive/3gpp-specification-ts-23-501/#google_vignette
>
>
>
> Section 5.8.2.2 of TR23.501-h20, released Sept 2021, has the detailed
> description of UE IP address management. There are many options, UE can
> choose its own static IP address, use DHCP, or get assigned by SMF based on
> a pool of UPFs. For 4G, the P-GW is centralized, UE most likely to change
> IP addresses when anchored to a different P-GW. For 5G, there are many
> UPFs, SMF might assign one IP address for  a pool of UPFs to an UE (if UE
> opts for getting IP address assignment from SMF).
>
>
>
> I will update the document with the detailed description.
>
>
>
> Thanks, Linda
>
>
>
> *From:* Gyan Mishra <[e-mail]>
> *Sent:* Friday, November 12, 2021 10:14 PM
> *To:* Jeffrey (Zhaohui) Zhang <zzhang=[e-mail]>
> *Cc:* Linda Dunbar <[e-mail]>; idr@ietf. org <
> [e-mail]>
> *Subject:* Re: [Idr] 3GPP SSC Mode 3 in
> draft-dunbar-idr-5g-edge-compute-app-meta-data-03
>
>
>
>
>
> Hi Jeffrey
>
>
>
> I read the text as well and as long mode 1 the address does not change and
> mode 2 it does change and mode 3 is dual homed is like a MOB (make before
> break) where it disconnects the old IP once the new is established.
>
>
>
> So mode 2 is the where the session will reset
>
>
>
>
> https://www.etsi.org/deliver/etsi_ts/123500_123599/123501/15.02.00_60/ts_123501v150200p.pdf
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.etsi.org%2Fdeliver%2Fetsi_ts%2F123500_123599%2F123501%2F15.02.00_60%2Fts_123501v150200p.pdf&data=04%7C01%7Clinda.dunbar%40futurewei.com%7C120e5d94fd244c0b3ddb08d9a65c13ed%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637723736671027898%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ai3aaBPA9JxEMDHb7aELj2BRXu7FfTi1Mb9GsjL0kY4%3D&reserved=0>
>
>
>
> Mode 3
>
>
>
> After the new IP address/prefix has been allocated, the old IP
> address/prefix is maintained during some time indicated to the UE via NAS
> signalling (as described in TS 23.502 [3] clause 4.3.5.2) or via Router
> Advertisement (as described in TS 23.502 [3] clause 4.3.5.3) and then
> released.
>
>
>
>
>
> If a PDU Session of SSC mode 3 has multiple PDU Session Anchors (i.e., in
> the case of multi-homed PDU Sessions or in the case that UL CL applies to a
> PDU Session of SSC mode 3), the additional PDU Session Anchors may be
> released or allocated.
>
>
>
> 5.6.9.3 SSC mode selection
>
> The SSC mode selection policy shall be used to determine the type of
> session and service continuity mode associated with an application or group
> of applications for the UE.
>
>
>
> I wonder what determines what mode is used by the N6 interface.
>
>
>
> Thanks
>
>
>
> Gyan
>
>
>
> On Thu, Nov 11, 2021 at 3:27 PM Jeffrey (Zhaohui) Zhang <zzhang=
> [e-mail]> wrote:
>
> Hi Linda,
>
>
>
> In draft-dunbar-idr-5g-edge-compute-app-meta-data-03 there is the
> following updated text:
>
>
>
>    When the UE moves out of coverage of its current gNB (next-
>
>    generation Node B) (gNB1), handover procedures are initiated,
>
>    and the 5G SMF (Session Management Function) selects a new
>
>    UPF-PSA. The standard handover procedures described in 3GPP TS
>
>    23.501 and TS 23.502 are followed. When the handover process
>
>    is complete, the UE is anchored to the new UPF-PSA, meaning
>
>    the packets to/from the UE is carried by the GTP tunnel to the
>
>    new UPF-PSA. The UE usually maintains its IP address when
>
>    anchored to the new UPF-PSA unless the new UFP-PSA belongs to
>
>    different mobile operators. 5GC may maintain a path from the
>
>    old UPF to new the UPF for a short time for the SSC [Session
>
>    and Service Continuity] mode 3 to make the handover process
>
>    more seamless.
>
>
>
> It's different from -02 which says that a new address would be assigned. I
> am curious which is correct -
> http://4g5gworld.com/blog/session-and-service-continuity-evolution-5g-networks
> <https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2F4g5gworld.com%2Fblog%2Fsession-and-service-continuity-evolution-5g-networks&data=04%7C01%7Clinda.dunbar%40futurewei.com%7C120e5d94fd244c0b3ddb08d9a65c13ed%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637723736671037847%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=2K5lY2rG4F6G5GfnOxaj4mF%2FjXSeKWuy9XFSGJdSeAg%3D&reserved=0>
> says that only mode 1 (where the anchoring UPF does not change) maintains
> persistent address. That seems to be consistent with 23.501:
>
>
>
> ---------------------23.501------
>
> 5.6.9.2.3       SSC Mode 3
>
> For PDU Session of SSC mode 3, the network allows the establishment of UE
> connectivity via a new PDU Session Anchor to the same data network before
> connectivity between the UE and the previous PDU Session Anchor is
> released. When trigger conditions apply, the network decides whether to
> select a PDU Session Anchor UPF suitable for the UE's new conditions (e.g.
> point of attachment to the network).
>
> In this Release of specification, SSC mode 3 only applies to IP PDU
> Session type and to any access type.
>
> In the case of a PDU Session of IPv4 or IPv6 or IPv4v6 type, during the
> procedure of change of PDU Session Anchor, the following applies:
>
> a.      For a PDU Session of IPv6 type, the new IP prefix anchored on the
> new PDU Session Anchor may be allocated within the same PDU Session
> (relying on IPv6 multi-homing specified in clause 5.6.4.3), or
>
> b.      The new IP address and/or IP prefix may be allocated within a new
> PDU Session that the UE is triggered to establish.
>
> After the new IP address/prefix has been allocated, the old IP
> address/prefix is maintained during some time indicated to the UE via NAS
> signalling (as described in TS 23.502 [3] clause 4.3.5.2) or via Router
> Advertisement (as described in TS 23.502 [3] clause 4.3.5.3) and then
> released.
>
> If a PDU Session of SSC mode 3 has multiple PDU Session Anchors (i.e., in
> the case of multi-homed PDU Sessions or in the case that UL CL applies to a
> PDU Session of SSC mode 3), the additional PDU Session Anchors may be
> released or allocated.
>
> ------------------------
>
>
>
> In fact, I introduced a proposal in 3GPP to assign persistent addresses in
> Release 17 EC Enhancement SID. It was accepted in the early stage but I was
> not available to defend the proposal when it came to the final conclusion
> stage so it was not eventually taken to WID. It would be nice if we could
> push that through in Release 18.
>
>
>
> Thanks.
>
> Jeffrey
>
>
>
>
>
> Juniper Business Use Only
>
> _______________________________________________
> Idr mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/idr
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Fmailman%2Flistinfo%2Fidr&data=04%7C01%7Clinda.dunbar%40futurewei.com%7C120e5d94fd244c0b3ddb08d9a65c13ed%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637723736671037847%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ROP6y2VuQJd%2B0Nu6uB0XYSn0jWqQ%2FYDJ89Rg63A09iI%3D&reserved=0>
>
> --
>
>
> <https://nam11.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.verizon.com%2F&data=04%7C01%7Clinda.dunbar%40futurewei.com%7C120e5d94fd244c0b3ddb08d9a65c13ed%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C1%7C637723736671047804%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=AxP4YGAlapWdkSG5NKZ5Si1hi5Tvr3QsyUIbEpHxdsA%3D&reserved=0>
>
> *Gyan Mishra*
>
> *Network Solutions Architect *
>
> *Email [e-mail] <[e-mail]>*
>
> *M 301 502-1347*
>
>
>
-- 

<http://www.verizon.com/>

*Gyan Mishra*

*Network Solutions A**rchitect *

*Email [e-mail] <[e-mail]>*



*M 301 502-1347*