The IMS Test Case

If your system is licensed with the VoLTE feature, you can use the IMS Node test case to emulate the IMS and provide a configuration in which an SIP/Proxy SIP Signalling, RTP Traffic, and session based MSRP (Message Session Relay Protocol) can be tested.

The IMS Node/Nodal supports the following functions:

SIP Proxy/Registrar and SIP Subscriber functions (also simultaneous role of the Registrar and SIP Subscribers when SIP Proxy is selected)
Terminates calls that was originated by UE
Originates calls toward UE
Routing calls back to the same UE population as SIP Proxy
Rx interface to PCRF that is used to set/get Control Triggers (Supports Rx Diameter interface to Real/emulated PCRF to trigger Dedicated Bearer creation or removal as required.)
I2 interface to/from MSC to IMS for SIP portion of VoLTE calls after SRVCC handover
Mw Interface to/from P-CSCF in IMS Node
Mx Interface (CSCF/BGCF and IBCF Testing) in IMS Nodal/Node.
Ml Interface (E-CSCF and GMLC Testing) in IMS Nodal/Node.
IMS Nodal Test Case to provide reference point for Mw Interface to/from P-CSCF.
ISC Interface - IMS Node/Nodal - Support for performance testing the TAS Portion of the IMS
SIP-T (RFC3372) / SIP-I (ISDN User Part) support. IMS Nodal
SMS-Over-IP (per 3GPP TS 24.241 and TS 24.011)
The Generic Interface on IMS Nodal can used to emulate Mg and Mj interfaces for X-CSCF testing.

IMS Node Emulates SIP Endpoints

IMS Node Emulates Proxy SIP

With this test case, you define:

Whether the P-CSCF (Proxy CSCF) that performs the gateway function for the IMS interface uses SIP or Proxy SIP signaling and enable register during SIP signaling or enable separate registrar during proxy SIP signaling
Whether enable authentication, Rx Interface and/or RTP Traffic
Parameters in Diameter messages (Rx interface), PCC, TCP settings
SIP subscribers and SIP Endpoint settings for the Phonebook
Gm interface settings to support SIP Protocol to define Control and RTP traffic parameters (Gm indicates the reference Point between a UE and a P-CSCF)
Gm interface settings to support MSRP

I2 Testing: IP Application Node and IMS Node

Case 1: I2 Testing without Mobility (Capacity Test)

Case 2: I2 Testing with Mobility (Inter Technology Mobility Test)

Option 1 - GM and I2 share the same IP Application Node

Case 3: I2 Testing with Mobility (Inter Technology Mobility Test)

Option 2 - GM and I2 are on separate IP Application Nodes

SIP-T (RFC3372) / SIP-I (ISDN User Part) IMS Nodal

Support to emulate PSTN subscribers or multiple trunk-groups of PSTN subscribers which are capable of making and terminating calls through a SIP transit network. Because SIP is chosen as a transit network, we will mainly focus on SIP-I/SIP-T protocols for transporting and translation throughout this project.

The following list and diagram provides a summary of main functions and how this formation will be layout in this document:

PSTN Subscribers Emulation – Provide configuration for subscriber identity information (i.e. telephone number), call patterns, possible call flows, test scenarios and edit able ISUP optional information elements parts.
Media Gateway Control Function (MGCF) Emulation – Provide configuration of emulated MGCF and its peers where all message translation and encapsulation take place and routing.

Supported Call Models

support the following 3 call models via static/manual peer setup. The call models are described in RFC 3372.

Landslide emulates “PSTN-Origination”

Landslide emulates “PSTN-Termination”

PSTN origination - PSTN termination: The originating gateway receives ISUP from the PSTN and it preserves this information (via encapsulation and translation) in the SIP messages that it transmits towards the terminating gateway. The terminator extracts the ISUP content from the SIP message that it receives and it reuses this information in signaling sent to the PSTN. Landslide new test case (IMS Nodal) can emulate either “PSTN origination” or “PSTN termination”.

PSTN origination - IP termination: The originating gateway receives ISUP from the PSTN and it preserves this ISUP information in the SIP messages (via encapsulation and translation) that it directs towards the terminating SIP user agent. The terminator has no use for the encapsulated ISUP and ignores it.

IP origination - PSTN termination: A SIP phone originates a VoIP call that is routed by one or more proxy servers to the appropriate terminating gateway. The terminating gateway converts to ISUP signaling and directs the call to an appropriate PSTN interface, based on information that is present in the received SIP header.

Landslide will forward all messages to pre-configured peers MGC (DUT) with the assumption that peer MGC will perform necessary steps prior to forward messages to correct destinations.

For instances, to set up call model (PSTN origination - PSTN termination) and (IP origination - PSTN termination), Landslide can be configured with a peer SIP gateway which has direct interface with PSTN network; similarly, to set call model (PSTN origination - IP termination), Landslide can be configured with a peer gateway which has direct interface with IP network.

Mw Interface - IMS Node/Nodal

IMS Node emulates IMS Core nodes such as I-CSCF, M-CSCF and also SIP Endpoints “behind” these nodes for the purpose of:

- P-CSCF performance testing;

- P-CSCF functional testing in particular several scenarios defined in RFC 3665.

SUT: P-CSCF

IMS Node supports Mw; UE is emulated on Landslide’s VOLTE Nodal

IMS Node supports Mw

BTB: Landslide’s IMS Node supports Mw

IMS Node - Mw Interface

Landslide’s IMS Node emulates IMS Core plus SIP Endpoint. No forwarding functionality is provided.
Supporting Mw reference point IMS Node plays a combined role of I-CSCF and S-CSCF and a terminate/originate SIP Endpoint behind.
IMS Node provides multiple IP nodes (2 at least) to cover I-CSCF and S-CSCF nodes.
IMS Node may provide RTP traffic.
P-CSCF/ ATCF Testing - Mw Interface

IMS Nodal - Mw Interface

IMS Nodal provides Mw reference point only.
P-CSCF/ ATCF Testing - Mw Interface
Signaling for P-CSCF testing
IMS Nodal will be in use for back-to-back testing only.

Mx Interface - IMS Node/Nodal

Mx Reference Point between a CSCF/BGCF and IBCF. Per 3GPP TS 24.299 and TS 23.288 (IMS phase 2).

IMS Nodal provides Mx reference point.
IMS Nodal emulates both BGCF Node and MGW Node.
IMS Node plays a IBCF, supporting Mx reference point.
IMS Node provides IP node for IBCF Node
IMS Nodal/Node provide RTP traffic.

Ml Interface - IMS Node/Nodal

Ml Reference Point between a E-CSCF and GMLC. Per 3GPP TS 24.299 and TS 23.288 (IMS stage 2, version 13.4.0).

IMS Nodal provides Ml reference point.
IMS Nodal emulates E-CSCF.
IMS Node works as GMLC, supporting Ml reference point.
IMS Node provides IP node for GMLC Node
IMS Node works in SIP Endpoint mode. No forwarding functionality will be provided.

SUT: GMLC Landslide's IMS Node supports Ml Interface

ISC Interface - IMS Node/Nodal - Support for performance testing the TAS Portion of the IMS

ISC is the reference point to exchange messages between S-CSCF and AS (Application Server)
Per 3GPP TS 24.229 and 3GPP TS 23.228 and RFC 3455

SMS-over-IP

All the LS test cases that currently support VoLTE, to support SMS-over-IP as specified in the 3GPP TS 24.341 and 24.011 specifications. The following call flows will be supported at the mobile and IMS side (IMS side is for back-to-back testing only):

Mobile Oriented Submission Flows
Mobile Terminated Delivery Flows
Delivery Report Flows
Short Message Memory Available Flows (Phase II)
Registration Flows (no change needed)

The test cases to support this feature include MME nodal, SGW nodal, WiFi Offload nodal, IP Application node, IMS node and the new PGW nodal.

Overview

SMS-over-IP is one of the ways to support traditional short messages over the IMS network. Different from MSRP, SMS-over-IP does not establish and manage a separate session to send/receive short messages; instead, short messages are carried over SIP MESSAGE packets directly. The SMS messages in the format defined in 3GPP TS 24.011 are included in the payload of the SIP MESSAGE packets.
IP-Short-Message-Gateway (IP-SM-GW) is between the mobile subscribers and SMS Service Center (SC) to provide transport layer interworking for submission and delivery of short messages.
LS VoLTE nodal side will be able to emulate SM-over-IP sender and SM-over-IP receiver. The user will be able to customize the short message content via the SMS Tab. Emulated SM-over-IP sender will be able to send the SM periodically in a configured time interval. Emulated SM-over-IP receiver will be able to receive short messages and send delivery reports. Or it will respond with error if configured as not able to receive short messages. When it reports error because memory is exhausted, it will be able to send memory available notifications when the memory becomes available later as configured.
To facilitate back-to-back testing, minimum IP-SM-GW support will be added to IMS Node test case as well.

IMS Nodal can used to emulate Mg and Mj interfaces for X-CSCF testing

Use the Generic Interface on IMS Nodal Test case to emulate Mg and Mj interfaces for X-CSCF testing. IMS Nodal Test Cnfg, IMS Nodal Parameters, Test Activity, GEN Node, GEN RTP Traffic Node, SIP VoIP Tab (with limited input fields) become available for input. Enable Supplementary and Enable Call setup are auto enabled and cannot be disabled.

Standard

Protocol

Description

SIP over UDP or TCP

3GPP 23.002

3GPP 23.228

3GPP 24.229

3GPP 29.163

BGCF to MGCF, MGCF to BGCF

SIP over UDP

3GPP 23.002

3GPP 23.228

3GPP 24.229

MGCF to I-CSCF

Message Session Relay Protocol (MSRP)

IMS supports two modes of messaging, Immediate Messaging and Session-Based Messaging. Session-based messaging, also called Message Session Relay Protocol (MSRP), supports message exchange between users within a session (similar to instant messengers).

Landslide emulates a MSRP session between users, as an additional media in VoLTE, to test MSRP initiation, dedicated bearer setup/teardown, and basic MSRP data exchange. This feature supports MSRP with SIP signaling to setup MSRP session and P-CSCF control messages to PCRF to provide service information for dedicated bearer setup.

The Message Session Relay Protocol (MSRP) supports SMS-over-IMS in MME, SGW Nodal, and IMS Node test cases.

Immediate Messaging/Page Mode	Immediate messaging uses SIP MESSAGE without the concept of sessions. Each message is an immediate message and is independent of other messages.
Session-Based Messaging (MSRP)/Session Mode	In session-based messaging (MSRP), a session is established for the UE, which uses MSRP established via SIP/SDP messaging. A session-based messaging requires a dedicated bearer to be setup, where MSRP traffic may be exchanged. Setup of MSRP session is similar to setting up audio/video media, as defined in [RFC 4975].

Session Initiation

To initiate an MSRP session, an INVITE is sent from user 1 to user 2, with information about the media used and the path to the user accepting MSRP requests, within SDP. Since MSRP session establishment is performed over SIP/SDP, it uses default bearer towards IMS APN.

MSRP Session Initiation and Dedicated Bearer Setup

Dedicated Bearer Setup

MSRP session is established via the default bearer. However, a dedicated bearer is required for MSRP data traffic, setup triggered by SDP Offer/Answer towards the P-CSCF, which causes the P-CSCF to originate an AAR towards the PCRF including the derived/configured MCD AVPs within the message.

Session Termination

During MSRP session termination, the P-CSCF sends SIP BYE towards the UE, followed by a Session Termination Request (STR) towards the PCRF over Rx. After successful session termination via Rx, PCRF sends an RAR to remove charging rules, then proceeds to delete bearer.

Connection Establishment for Media Anchoring (CEMA)

In order for MSRP endpoints to communicate, the CEMA extension (RFC 6714), allows endpoints to use the c and m-lines to establish transport connection for MSRP messaging. For CEMA back-to-back testing, the Landslide IMS Node P-CSCF provides an option to enable CEMA to perform modification of c and m-lines.

The CEMA supports modification of c and m-lines (from IMS Node), and use of the address information from the c and m-lines from UE to establish transport connection for MSRP messages (UE include msrp-cema attribute within the media-level when CEMA option is enabled).

DiffServ Code Point (DSCP)

Each bearer includes a DSCP value mapped to its QCI for purposes of QoS. The DSCP provided in the IP header allows classification of network traffic for QoS.

Learn more about:

Learn how to:

Configure a test session

Measurements

Measurements collected for the basic PCRF Node test case (Diameter Base, RADIUS, TCP, and IP Instance processing measurements) are reported on the following tabs. Additional measurements may be available depending on the test activity and options executed with the test case.