1. MCC TF160 / SS Vendors Sidebar
Tuesday 20th August 2017

2. Agenda TTCN-2 UTRA AccessStratumReleaseIndicator upgrade
Encoding rules for RRC ASN.1:
UTRA, E-UTRA, 5G NR
IMSoWLAN: XCAP signalling
Supporting DS2 in WLAN Test Model.

3. TTCN-2 UTRA AccessStratumReleaseIndicator upgrade
In order to ensure the IE AccessStratrumReleaseIndicator is logged correctly for Rel-14 UE’s it is proposed to upgrade the type AccessStratumReleaseIndicator.
AccessStratumReleaseIndicator ::= ENUMERATED { rel-4, rel-5, rel-6, rel-7, rel-8, rel-9, rel-10, rel-11, rel-12, rel-13, rel-14, spare5, spare4, spare3, spare2, spare1 }
This change will be implemented in TTCN-2 delivery iWD17wk35.

4. Encoding rules for RRC ASN.1
3GPP requirements regarding RRC ASN.1 encoding:
TS cl. 12.1: basic production = unaligned PER encoding according to X.691(07/2002) except for the 0 to 7 bits added at the end to produce a multiple of 8 bits.
TS (and TS ) cl. 8.3: basic production = unaligned PER encoding according to X.691(07/2002) (i.e. octet aligned).
 Different encoding rules for UTRA ASN.1 & LTE(incl. NB-IoT) ASN.1.
Problem statement:
No provision of encoding rules in TTCN to distinguish the 2 slightly separate encoding rules.
import from UTRAN_RRC_ASN1_Definitions language "ASN.1:2002“ all;
import from EUTRA_RRC_ASN1_Definitions language "ASN.1:2002" all;
import from NBIOT_RRC_ASN1_Definitions language "ASN.1:2002" all;

5. Encoding rules for RRC ASN.1
Solution:
Prose:
Add a new normative clause in to specify encoding rules for RRC ASN.1.
TTCN:
Update TTCN import statements as follows:
import from UTRAN_RRC_ASN1_Definitions language "ASN.1:2002“ all with {encode "UNALIGNED_PER_25331_EncRule"};
import from EUTRA_RRC_ASN1_Definitions language "ASN.1:2002" all with {encode "UNALIGNED_PER_EncRule"};
import from NBIOT_RRC_ASN1_Definitions language "ASN.1:2002" all with {encode "UNALIGNED_PER_EncRule"};
f_OctetAlignedBitString():
Perform a clean-up of TTCN where f_OctetAlignedBitString() is used.
TF160 to raise a TTCN CR.

6. XCAP in IMSoWLAN after R5-172937 RAN 5 agreement
IR. 51 provides two main deployment scenarios (DSs)
(DS1) Wi-Fi access without PDN connection
Current TTCN approach
(DS2) with the APN to be used for XCAP requests in Wi-Fi access.
RAN5 decided after R agreement that test procedure in IMSoWLAN Supplementary Services TC with XCAP signaling shall be testable with either DS1 or DS2.
RAN5 CRs being presented at RAN5#76 to address the new requirement on XCAP test cases.

7. DS2 Scenario Overview According to IR.51 section 4.7.3
„The UE must establish a separate Swu instance (i.e a separte Ipsec Tunnel) for the PDN connection to the IMS well-known APN and to the APN to be used for XCAP request.“
Swu1: IMS PDN Connection
Swu2 : XCAP PDN Connection
TS Figure : Non-Roaming Architecture within EPS using S5, S2a, S2b

8. TTCN-3 Test model: DS1 vs DS2
DS1 : Wi-Fi access without PDN connection
DS2: EPC-integrated WLAN
TTCN -3
EPDG Tunnel –> Normal IMS
P-CSCF Server
HTTP/XCAP Server
Without PDN - XCAP UE
TTCN -3
EPDG Tunnel –> Normal IMS
P-CSCF Server
HTTP/XCAP Server UE
EPDG Tunnel -> XCAP
IP PTC

9. DS2: XCAP/HTTP server inside of the 3GPP networkUE
non-3GPP network: WLAN
ePDG
IPsec tunnel
non-3GPP IP-Address
3GPP IP-Address
3GPP network
3GPP IP-Address
non-3GPP IP-Address
ICMPv6-Server
DHCP-Server
DNS-Server
remote UE
AAA-Server
NOTE: in general non-3GPP and 3GPP addresses are different (different networks; un-trusted network)
non-3GPP IP-Address
HTTP-Server
3GPP IP-Address

10. DS2: IP Address Overview
px_WLAN_UE_AddrIPvx
px_WLAN_UE_AddrIPvx
px_IPvx_Address1_UE
px_IPvx_Address1_NW
IMS IpSec Tunnel
px_IPvx_Address2_UE
XCAP IpSec Tunnel
px_IPvx_Address2_NW
P-CSCF NW
EPDG UE
IMS NW
WLAN UE
WLAN
XCAP/
HTTP
Server

11. DS2: APN Handling IMS IPSec Tunnel Establishment
XCAP IPSec Tunnel Establishment
UE/SS
TTCN
UE/SS
TTCN
IKE_SA_INIT_Ind
IKE_SA_INIT_Ind
IKE_AUTH_Req without AccessPointName
IKE_AUTH_Req with AccessPointName
EAP_AKA_Cmpl
EAP_AKA_Cmpl
IPSecTunnelEstabCmpl
IPSecTunnelEstabCmpl
According to : “ The UE indicates a request for the default APN by omitting the "IDr" payload“. Therefore, AccessPointName included in IKE_AUTH_REQ might be omitted when IMS is the Default APN (pc_IMS_APN_default set to true) during the IMS IPSec Tunnel Establishment.

12. DS2: Test Model Open Issues
Test Model updates
XCAP/HTTP server is inside of the 3GPP Network
ASP extensions
Handling multiple IPSec tunnels is not supported by current ePDG ASP Definition. Non-backwards compatible changes likely to be required.
APN name might be needed in order to identify the PDN type.
IP_DrbInfo_Type only considers one IPsecTunnel to be routed. IPSecTunnel union field to be extended to support multiple IPsec Tunnels.
Test procedure to cover multiple PDN Connections
New generic procedure for XCAP establishment to be added (R , R )