Liaison statement
LS on indicating service continuity usage of the additional IPv6 prefix in Router Advertisement

State Posted
Posted Date 2018-03-22
From Group 3GPP-TSGSA-SA2
From Contact Suresh Krishnan
To Groups 6man, dmm, INT
To Contacts Sri Gundavelli
Dapeng Liu
Terry Manderson
Suresh Krishnan
Robert Hinden
Ole Troan
CcDapeng Liu
Terry Manderson
IPv6 Maintenance Discussion List
Ole Troan
Sri Gundavelli
The IETF Chair
Robert Hinden
Distributed Mobility Management Discussion List
Suresh Krishnan
Response Contact georg.mayer.huawei@gmx.com
Purpose For information
Attachments S2-182967_was2844_LS_IETF_SSC3
Body
1       Overall description

SA2 would like to thank the IETF DMM working group chairs for their LS reply on indicating the mobility property of the additional IPv6 prefix in Router Advertisement in S2-181481.

Regarding the following components in the IETF’s reply LS:
     1.) The approach of coloring IPv4 and IPv6 addresses/prefixes with mobility properties.
     3.) The approach of indicating the coloring meta-data to the applications on the mobile node (UE in 3GPP terminology).

SA2 has noted that both aspects are covered in the IETF DMM draft draft-ietf-dmm-ondemand-mobility-13 and has also noted that it will be released soon as informational standard.

Regarding the following component in the IETF’s reply LS:
    2.) The approach of network including property meta-data in address assignment procedures

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.

With respect to the following question in the IETF’s 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