6 IP roles and IP based procedures

24.3223GPPRelease 17Stage 3TSTunnelling of IP Multimedia Subsystem (IMS) services over restrictive access networks

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

6.1 General

This subclause describes IP roles and IP based procedures.

6.2 IP roles

6.2.1 UE procedures

If IPv4 is supported, the UE shall support acting as host according to IETF RFC 791 [5].

If IPv6 is supported, the UE shall support acting as host according to IETF RFC 2460 [7].

6.2.2 EFTF procedures

If IPv4 is supported, the EFTF shall support acting as gateway according to IETF RFC 791 [5].

If IPv6 is supported, the EFTF shall support acting as router according to IETF RFC 2460 [7].

6.3 Inner IP address assignment procedure

6.3.1 UE procedures

If the UE has a network interface with a universally administered MAC address, the UE shall use a universally administered MAC address of a network interface of the UE as the UE FTT-IMS MAC address. If the UE does not have a network interface with a universally administered MAC address, the UE shall use a locally administered MAC address where the least significant bit of the last octet is set to zero as the UE FTT-IMS MAC address.

If IPv4 is supported, the UE shall support acting as DHCPv4 client according to IETF RFC 2131 [6].

If IPv6 is supported, the UE shall support acting as host supporting the IPv6 stateless address autoconfiguration according to IETF RFC 4862 [11].

Once the FTT-IMS is established, the UE shall:

1) if the UE needs IPv4 connectivity, request IPv4 address using DHCPv4 according to IETF RFC 2131 [6]. The UE shall use the htype, hlen, chaddr according to the UE FTT-IMS MAC address; and

2) if the UE needs IPv6 connectivity, generate IPv6 address using IPv6 stateless address autoconfiguration according to IETF RFC 4862 [11]. The UE shall create a link-local address according to IETF RFC 4291 [10] using the UE FTT-IMS MAC address.

NOTE 1: Further IPv6 configuration can be done using stateless DHCPv6 according to IETF RFC 3736 [9].

NOTE 2: DHCPv4 uses IPv4 as transport; IPv6 stateless address autoconfiguration uses IPv6 as transport and DHCPv6 uses IPv6 as transport. Thus, the DHCPv4 messages, IPv6 stateless address autoconfiguration messages and DHCPv6 messages are transported via the FTT-IMS using the IP packet transport FTT-IMS procedure according to subclause 5.3.

6.3.2 EFTF procedures

If IPv4 is supported, the EFTF shall support acting as DHCPv4 server according to IETF RFC 2131 [6]. When acting as DHCPv4 server, the EFTF shall handle each existing FTT-IMS as a different subnet.

If the EFTF has a network interface with a universally administered MAC address, the EFTF shall use a universally administered MAC address of a network interface of the EFTF as the EFTF FTT-IMS MAC address. If the EFTF does not have a network interface with a universally administered MAC address, the EFTF shall use a locally administered MAC address where the least significant bit of the last octet is set to one as the EFTF FTT-IMS MAC address.

If IPv6 is supported, the EFTF shall support acting as router supporting the IPv6 stateless address autoconfiguration according to IETF RFC 4862 [11]. The EFTF shall create a link-local address according to IETF RFC 4291 [10] using the EFTF FTT-IMS MAC address.