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The challenges of VoLTE Service Monitoring

LTE rollouts supported by TEMS around the world

Ensure QoE

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Currently no accepted standard for measurement, monitoring VoLTE Services

Ascom has defined a formal definition, implementation strategy to help Operations Covers issues related to EPC, IMS, Application Service

We will describe this solution in a number of short articles

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UnderstandTest Scenarios

RCS Service Monitoring Challenges

TEMS™ RCS Monitoring: 1-to-1 Chat Test Case

Contents

1. Title

2. Contents

3. Introduction

4. 24 x 7 Monitoring

5. The Agent

6. Multi-Layer Active Monitoring

7. The Overview dashboard

8. The Test Case dashboard

9. The Test Run dashboard

10. Service Steps

11. Quality Metrics

12. Signal Flow

13. Diagnostics

14. Related Posts

Copyright 2016, Ascom Network Testing Ltd 2

Introduction

#5 in a series of brief articles aboutthe challenges of RCS & VoLTE Service Monitoring.

There is currently no accepted standard for the measurement or monitoring of RCS Services, even though we believe that this is vital to assure the quality and reliability of such services - and to establish a framework for reliable comparison across implementations.

To this end Ascom has defined a formal definition and implementation strategy to help the Operations team solve a range of challenges, including issues related to EPC, IMS and the Application Server.

We will describe this solution in a number of short articles. This article describes the 1-to-1 Chat test case.

Copyright 2016, Ascom Network Testing Ltd 3

RCS Monitoring - 24 x 7

IMS Solution 2.7 for VoLTE, VoWiFi, RCS and VoB

Our RCS Monitoring Solution consists of a suite of test cases (described in a previous post), which is run to provide 24 x 7 monitoring of service availability and additional diagnostics to investigate outages or other issues.

Test cases are run on a high-availability, multiply-redundant Cloud-based system with a 99.95% uptime guarantee, to maintain 24 x 7 operation.

Results are published in near-real-time to dashboards on a web portal with the same uptime guarantee and can be accessed from any compatible web browser.

Confidentiality is protected by physical security for the servers and user authentication for remote access; encrypted protocols and client IP whitelisting are also available to further secure remote access.

The RCS Monitoring Solution monitors:

the entire set of RCS Services defined by the GSMA specs for RCS-e v1.2.2

the File Transfer over HTTP Service as defined in RCS release 5 onwards

the supporting procedures which these services require to run

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The Agent: Software and Hardware layers

Copyright 2016, Ascom Network Testing Ltd

TMM SWagent

TMM HWagent

Test Suites

IMDN

CPIM

SMSoIP

L3 Radio

USSDoIP

L3 Radio

FEMTOCELL

L3 Radio

SIP Procedures

SIP

OMA DM

provisionXCAP

HTTP

TLS

IMS Procedures

RTP

AMR H.264MSRP

MEDIA Procedures

GSMA IR.92

(VoLTE)

GSMA IR.94

(Video over LTE)OMA SIMPLE OMA CPM

VoWiFiGSMA RCS

FEMTOCELL

Procedures

COM SERVER

(TMM) TEMS Monitor Master LTE ProceduresSRVCC

LAN adapter 2G/3G Modem 4G Modem

Test Cases

API Layer

Service Layer

Network Layer

Protocol Layer

Access Layer

PCC

Procs.

Gx App

Diameter

Base

Device/Client

Simulation

IPSec

Our Agents implement all these SW layers on top of a HW interface layer. By using LTE, UMTS or GPRS modems to simulate a Smartphonewe get optimum control, flexibility & low level access – and a proven architecture refined by thousands of hours of testing.

MSRP / RTP

MSRP / RTPMME

6

S6a

SGi

S5/S8Uu S1-U

EnodeB

Rx ISC

LTE EPC IMS

HSS

SGW PGW

P-CSCF S-CSCFIM-AS

MRF

Mr’

SBCGm

TMMSW

Emulated InterfaceInternal InterfaceMedia Path

TOOL SUT

Multi-Layer Active Monitoring

Copyright 2016, Ascom Network Testing Ltd

The Solution runs on different Layers so it can test and monitor them all - to measure the reliability and performance of the many different Network Domains and Elements within the Network and help you identify any components that are failing in real time!

TMM

SW

TMM

SW2. PGW

simulation

3. IMS

simulation

1. UE simulation

or real device

SGi ISC

The 1-to-1 Chat test caseThe Overview Dashboard

Copyright 2016, Ascom Network Testing Ltd

The Overview Dashboard summarises the status of RCS, using results from all the RCS test cases:

• Test executions per hour

• Status of each RCS Service

• Status of each RCS Supporting Procedure

• Status of each IMS Supporting Procedure

• A list of issues to investigate

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You can:

Drill down to details of any service, period, test case, test run, or issue.

The 1-to-1 Chat test caseThe Test Case Dashboard

Copyright 2016, Ascom Network Testing Ltd

The Test Case Dashboard displays recent results for the selected test case, 1-to-1 Chat:

• Service availability over time– when did the problem start?

• Service availability per step – where did the problem start?

• Quality Metrics over time – how well is the service operating?

• Failure Distribution– a list of any issues to investigate

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Drill down to details of any period, metric or issue by clicking it

The 1-to-1 Chat test caseThe Test Run Details dashboard

The Test Run Details Dashboard displays details of a single selected test, including:

Copyright 2016, Ascom Network Testing Ltd

• Operator name

• Probe location

• Start time and date

• User settings: bearer, IMS, MSISDN, DNS and other details

• Results: service availability and link to IP Trace (PCAP) file

• Test case flow: a diagram of the test case steps, showing the message flow and status of each step. See Signal Flow

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The 1-to-1 Chat test caseService Steps

The Solution monitors the key Service Steps for the Test Case to help identify what is failing and affecting the customer’s Quality of Service.

For each Service Step it:

• Plots the success:failure ratio for the period, in a pie chart

• Lists the diagnostics for any failures

• Plots successes and failures over time, in a bar chart

Copyright 2016, Ascom Network Testing Ltd

The Service Steps for 1-to-1 Chat are:

• Step 1: SIP dialogue setup

• Step 2: MSRP session setup

• Step 3: IM exchange via MRSP

Service Steps are monitored from end to end.

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The 1-to-1 Chat test caseQuality Metrics

With the Quality Pack option, the Solution measures a range of Quality Metrics for the test case to report the Quality of Service perceived by the customer.

It plots an average value for each timeslot; the maximum, minimum, average and standard deviation for the time period are also displayed.

The Quality Metrics for 1-to-1 Chat are:

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• INVITE propagation time (ms)

• 200 OK propagation time (ms)

• MESSAGE propagation time (ms)

• A-Party TCP setup time (ms)

• B-Party TCP setup time (ms)

• IM exchange time over MSRP (ms)

• IM delivery notification propagation time over MSRP (ms)

• IM display notification propagation time over MSRP (ms)

Metrics can be combined or reported separately for each party in the exchane

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The 1-to-1 Chat test caseSignal Flow

This test case consists of 3 steps which generate this exchange of messages:

Each step is monitored separately so that overall status and timings can be broken down into more meaningful elements.

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The 1-to-1 Chat test caseDiagnostics

This test case can detect a wide range of problems in each Service Step and report them as detailed Warning or Error Messages:

• A Warning Message describes a problem that may affect performance but may not be noticed by customers; it could indicate an opportunity for improving efficiency or the early stages of a more serious problem.

• An Error Message describes a failure, a serious problem that was detected and will be noticed by customers.

Alarms

• Configure the system to raise an Alarm for specific Warning or Error Messages.

• Configure the system to raise a Quality Alarm when a Quality Metric crosses a specific threshold.

Alarms can be reported via emails or SNMP traps.

Copyright 2016, Ascom Network Testing Ltd 13

RCS & VoLTE Service Monitoring – Related posts

Articles:

Day 1. VoLTE Service Monitoring

Day 2. How critical is the VoLTE Service for my company?

Day 3. New generation VoLTE Service Monitoring solution

Day 4. I already monitor LTE, so I must be good for VoLTE?

Day 5. Monitoring VoLTE Customer Experience

Day 6. How can you uncover hidden areas of your VoLTE network…?

Check the VoLTE Service Monitoring posts for links to subsequent articles.

TEMS Solutions:

1. A New Standard & VoLTE test cases overview

2. VoLTE Solution architecture & the VoLTE Voice Call test case

3. RCS test cases overview

4. The RCS 1-to-1 Chat test case

Additional details will be published every 1-2 weeks to describe this proposal, including test case flow, metrics, diagnostics and reporting.

Copyright 2016, Ascom Network Testing Ltd 14