> It is probably the only reason at this time that makes Mobile IP still >necessary.
Not really. You will have the same issue with Mobile IP. Static allocation implies the UE’s session is anchored on a gateway node which is the topological anchor for that address block. Unless, the assigned prefixes are dynamically programmed (ignoring other issues), UE’s session always needs to anchored on the same node. Sri On 5/3/18, 12:06 AM, "Alexandre Petrescu" <[email protected]> wrote: > > >Le 02/05/2018 à 16:29, Sri Gundavelli (sgundave) a écrit : >>> I can agree that the possibility with RADIUS/DIAMETER permits to >>>alocate >> a stable prefix in RA to a UE. However, I have never seen it in practice >> in a cellular network. >> >> >> Enabling static IP allocation by default has a scaling issue. The IPv6 >> prefix that is allocated to the UE is part of an aggregate block >> configured on a given PGW node. Reserving IPv6 prefixes from that block >> makes that one PGW node as the anchor for that UE. Operators loose >> flexibility with respect to gateway assignments. > >Yes, I agree. > >> If you look at some of the work that went in 3GPP Rel 10 timeframe, it >>was >> about enhancements to gateway selection logic based on number of >> access-network parameters. It allowed operators to allow gateway >>selection >> based on proximity, policy and other parameters. Now, any time there is >>an >> IPv6 prefix reservation that flexibility is lost, as that creates a >> Gateway/Subscriber stickiness, and potentially resulting in uneven >> distribution of subscriber session across all the gateways. So, this is >>an >> operational problems and may be v6ops is the right group for such >> discussions. > >I can agree - it is an operational issue. > >It is probably the only reason at this time that makes Mobile IP still >necessary. > >Alex > >> >> >> Sri >> >> >> >> >> >> >> On 5/2/18, 12:28 AM, "Alexandre Petrescu" <[email protected]> >> wrote: >> >>> >>> >>> Le 25/04/2018 à 05:00, Sri Gundavelli (sgundave) a écrit : >>>> Hi Alex, >>>> >>>> I cannot comment on the supported network/service configuration in any >>>> operator's network. But, I’d think the allocation of stable /64’s is >>>> similar to static IPv4 (/32) address allocations that are supported in >>>> many operator networks today. There are also RADIUS / DIAMETER >>>> attributes >>>> such as Framed-IPv6-Prefix ..etc which can be used for obtaining >>>> statically configured values by PGW. So, IMO, its very much possible >>>>to >>>> allocate static IPv6 Per-UE prefixes for the UE. Its also possible to >>>> allocate static IPv6 prefixes for the networks behind UE. IMO, this is >>>> just a configuration and operators can surely do this today. >>>> >>>> But, I am not sure where we are going with this? >>> >>> I am asking because I would like it to happen as you describe as being >>> possible. >>> >>> I can agree that the possibility with RADIUS/DIAMETER permits to >>>alocate >>> a stable prefix in RA to a UE. >>> >>> However, I have never seen it in practice in a cellular network. >>> >>> When I connect I always get a different IPv6 prefix in RA. >>> >>> Where are we going with this? Let us go towards identifying first if >>> _anybody_ (any cellular network) allocates a stable IPv6 prefix in RA >>>to >>> UE. It may be someone does allocate such, as it may be nobody does. >>> >>> In the first case, then I will suggest my operator to do likewise. >>> >>> In the latter case, then let us go in a direction where we understand >>> _why_ operators dont implement stable IPv6 prefixes per UE. >>> >>> Alex >>> >>>> >>>> >>>> Sri >>>> >>>> >>>> >>>> >>>> On 4/24/18, 7:31 AM, "Alexandre Petrescu" >>>><[email protected]> >>>> wrote: >>>> >>>>> Hi Sri, >>>>> >>>>> Is there an operator today that allocates a stable /64 in RA to User >>>>> Equipment? (resists re-connection) >>>>> >>>>> Alex >>>>> >>>>> >>>>> Le 26/03/2018 à 07:14, Sri Gundavelli (sgundave) a écrit : >>>>>> Alex: >>>>>> >>>>>> This is a good point. Yes, there is DHCPv6 prefix delegation support >>>>>> in >>>>>> 3GPP architecture for supporting mobile router use-cases. This is >>>>>> essentially for delegating prefixes for the networks attached to the >>>>>> UE. >>>>>> This was introduced in Rel-10 by cisco. I have not followed the >>>>>>recent >>>>>> SA2 >>>>>> discussions and I do not know if MR support based on DHCPv6 will >>>>>> continue >>>>>> to be supported or not, and if they have considered the alternative >>>>>> options for supporting the same. I think we can certainly ask that >>>>>> question, but I also wonder if the coloring is specific to the PDU >>>>>> session, or if its broadly applicable for all UE address/prefix >>>>>> assignments. >>>>>> >>>>>> >>>>>> Sri >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On 3/23/18, 2:48 AM, "dmm on behalf of Alexandre Petrescu" >>>>>> <[email protected] on behalf of [email protected]> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> >>>>>>> Le 22/03/2018 à 18:49, Liaison Statement Management Tool a écrit : >>>>>>> [...] >>>>>>> >>>>>>>> SA2 would like to point out that among the four mechanisms for >>>>>>>> address configuration delivery mentioned in your LS reply (i.e. >>>>>>>> DHCPv4, DHCPv6, IPv6 ND and IKEv2) only the IPv6 ND mechanisms, >>>>>>>>and >>>>>>>> in particular the Router Advertisement message, seem to be >>>>>>>> applicable >>>>>>>> in the 5G System architecture in the specific context of >>>>>>>>Multi-homed >>>>>>>> IPv6 PDU Sessions. >>>>>>> Please tell SA2 that current 4G cellular networks are specified to, >>>>>>> and >>>>>>> do use to some extent, DHCPv6 Prefix Delegation to assign a prefix >>>>>>>to >>>>>>> an >>>>>>> end node like an IoT Router. >>>>>>> >>>>>>> A /56 prefix delivered to the end node should have the same >>>>>>> capabilities >>>>>>> as an address. We also want that /56 prefix to be more stable, or >>>>>>> less >>>>>>> stable, etc. >>>>>>> >>>>>>> I dont understand why 5G System architecture excludes DHCPv6 from >>>>>>>the >>>>>>> list of applicable address configuration delivery. >>>>>>> >>>>>>> I understand why 5G System architectures prefers ND - it is for >>>>>>> addresses. >>>>>>> >>>>>>> Alex >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> With respect to the following question in the IETF¹s reply LS: >>>>>>>> We also like to point out that, all though >>>>>>>>the LS >>>>>>>> statement explicitly refers to both IPv4 and IPv6 address types, >>>>>>>> however >>>>>>>> it only mentions about (RA) (IPv6 >>>>>>>> ND implied) as the mechanism for address >>>>>>>>property >>>>>>>> delivery. It is to be noted that the approach of delivering >>>>>>>>coloring >>>>>>>> meta-data in RA messages will most >>>>>>>> likely be to limited to IPv6 address/prefix >>>>>>>>types >>>>>>>> and >>>>>>>> will not be extended to IPv4 addresses. If this capability is >>>>>>>> required >>>>>>>> for IPv4, we may have to possibly >>>>>>>> extend DHCP protocol(s). >>>>>>>> >>>>>>>> We request 3GPP to clarify if the Ask is >>>>>>>> explicitly >>>>>>>> for IPv6, or if its for both IPv4 and IPv6 address/prefix types. >>>>>>>> >>>>>>>> >>>>>>>> SA2 would like to clarify that the request is explicitly for IPv6. >>>>>>>> SA2 >>>>>>>> discussed the example documents that were referenced in your LS >>>>>>>> reply >>>>>>>> and concluded that the following draft seems to be the most >>>>>>>> promising >>>>>>>> candidate for the problem under discussion in this correspondence: >>>>>>>> https://www.ietf.org/id/draft-feng-dmm-ra-prefixtype-01.txt. >>>>>>>> SA2 would like to kindly ask IETF DMM working group to keep SA2 >>>>>>>> updated >>>>>>>> of the work on the subject of including property meta-data in IPv6 >>>>>>>> ND >>>>>>>> address assignment procedures for potential use in the 5G System >>>>>>>>to >>>>>>>> indicate the mobility property of additional IPv6 prefixes >>>>>>>>assigned >>>>>>>> as >>>>>>>> part of the Multi-homed IPv6 PDU Session functionality. >>>>>>>> >>>>>>>> >>>>>>>> 2 Actions >>>>>>>> To IETF DMM working group: >>>>>>>> ACTION: SA2 would like to kindly ask IETF DMM working >>>>>>>>group >>>>>>>> to >>>>>>>> keep SA2 updated of the work on the subject of including property >>>>>>>> meta-data in IPv6 ND address assignment procedures for potential >>>>>>>>use >>>>>>>> in >>>>>>>> the 5G System to indicate the mobility property of additional IPv6 >>>>>>>> prefixes assigned as part of the Multi-homed IPv6 PDU Session >>>>>>>> functionality. >>>>>>>> >>>>>>>> >>>>>>>> 3 Dates of next TSG SA WG2 meetings >>>>>>>> TSG SA WG2 Meeting 127 16 - 20 Apr 2018 Sanya, CN >>>>>>>> TSG SA WG2 Meeting 127-Bis 28 May 1 Jun 2018 Newport Beach, >>>>>>>> US >>>>>>>> Attachments: >>>>>>>> >>>>>>>> S2-182967_was2844_LS_IETF_SSC3 >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>https://www.ietf.org/lib/dt/documents/LIAISON/liaison-2018-03-22-3g >>>>>>>>pp >>>>>>>> -t >>>>>>>> sg >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>sa-sa2-int-6man-dmm-ls-on-indicating-service-continuity-usage-of-th >>>>>>>>e- >>>>>>>> ad >>>>>>>> di >>>>>>>> tional-ipv6-prefix-in-router-advertisement-attachment-1.docx >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> dmm mailing list >>>>>>>> [email protected] >>>>>>>> https://www.ietf.org/mailman/listinfo/dmm >>>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> dmm mailing list >>>>>>> [email protected] >>>>>>> https://www.ietf.org/mailman/listinfo/dmm >>>>>> >>>>>> >>>> >>>> >> >> _______________________________________________ dmm mailing list [email protected] https://www.ietf.org/mailman/listinfo/dmm
