Andrew Chisholm shows some real results where active tests are enriched with passive signalling data to more quickly and accurately provide root cause analysis of service outages. This thread is a great opportunity to give some details of a key capability we are very proud of. We enrich active results with relevant passive data. Our approach turns the big data problem around; as soon as we detect a network or service outage we pinpoint with root cause all the way to the core network element. We think this will be very interesting to help fix service and network problems much more quickly. Our approach is to use active testing as the true voice of the customer and to use these results as a key into the huge quantities of passive data waiting to be exploited. This gives us a very efficient way to include only relevant information and determine root causes. For example, during a VoLTE to VoLTE call, our active testing might determine there is an issue during audio exchange. With the addition of passive signalling data collected from the most relevant network interfaces, we might determine from the S11 interface that bearer update procedures have not been requested from the SGW to MME and from that, the root cause can be reported. In fact, you can see in this short 4 minute video an example of this working for real. We are rightly proud of this and we are looking forward to a busy time delivering.

1. 1
The challenges of VoLTE Service
Monitoring
LTE rollouts supported by TEMS around the world
Ensure
QoE
Understand
Scenarios
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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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Understand
Test Scenarios
VoLTE Service Monitoring
Challenges
TEMS™ VoLTE Service Monitoring: VoLTE Voice Call including passive signalling data analysis

2. The Agent: Software and Hardware layers
TMM SW
agent
TMM HW
agent
Test Suites
IMDN
CPIM
SMSoIP
L3 Radio
USSDoIP
L3 Radio
FEMTOCELL
L3 Radio
SIP Procedures
SIP
OMA DM
provision
XCAP
HTTP
TLS
IMS Procedures
RTP
AMR H.264
MSRP
MEDIA Procedures
GSMA IR.92
(VoLTE)
GSMA IR.94
(Video over LTE)
OMA SIMPLE OMA CPM
VoWiFi
GSMA 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 an LTE modem to simulate a Smartphone we
get optimum control, flexibility & low level access – and a
proven architecture refined by thousands of hours of testing.

3. Emulated Interface
Internal Interface
Media Path

4. TEMS Tracker: VoLTE to VoLTE calls
Element Service Metrics for MO and MT
Ascom TEMS Monitor Master
Active Agent
• Call setup preconditions
• Call setup resources confirmation
• Call setup alerting
• Call setup answer
• Audio exchange
• Call release
• Call setup time
• Audio POLQA score
• Audio average jitter
• Audio maximum jitter
• Audio minimum bit rate
• Audio average bit rate
• Audio maximum bit rate
• Audio packet loss rate
3rd Party
Passive Probe
• Collect signalling related S11, Gm, Gx and Rx network interfaces
• Call trace
TEMS Tracker
Analysis of signalling collected by Passive
Probing system
• Call Routing (User1, PCSCF1, PCRF1, PGW1, MME1)
• MO and MT S11 LTE Tunnel Info
• S11 GTP Failure Cause Code
• S11 GTPv2 Qos info
• Gx Auth Info
• Gx Diameter Failure Cause Code
• L1 and L2 audio SDP Info
• L1 and L2 SIP Failure Cause Code
• L1 and L2 SIP Reason Header
• src audio RTP Info
• dst audio RTP Info
• S11 GTPv2 Procedures
• Create Bearer
• Update Bearer
• Delete Bearer
• Gx Diameter Procedures
• Auth
• Re-Auth
• Credit Control
• L1 and L2 Call Start Time
• L1 and L2 Call Ringing/Progress Tim
• L1 and L2 Call Answer Time
• L1 and L2 Call Answer Confirm Time
• L1 and L2 Call End Tim
Ascom TEMS Monitor Master
IT Agent
• Subscriber profile within HSS database
• Subscriber profile within PCRF database
Analysis of Active Agent + Passive Signalling + Subscriber profile information
• Automated Root Cause of Failure Analysis
• Automated Service and Quality Degradation Analysis
Copyright 2016, Ascom Network Testing Ltd 8

5. The VoLTE Voice Call test case
The Test Case Dashboard
• Service availability over time
– when did the problem start?
• Service availability per step
– where did the problem start?
Copyright 2016, Ascom Network Testing Ltd
Displays recent results for the selected (VoLTE Voice Call) test case:
• Quality Metrics over time
– how well is the service operating?
• VoLTE to VoLTE service status by
region on a world map
10

6. The VoLTE Voice Call test case
The Test Run Details dashboard
The Test Run Details dashboard displays details of a single test, including:
Copyright 2016, Ascom Network Testing Ltd
• Subscriber details: network
operator, MSISDN, IMS and bearer
• Dependencies: the test cases
run to support this test run:
- LTE Attach,
- IMS Entry Point Discovery,
- IMS Registration and
- IMS Subscription to Events
• Links: to Radio Trace, IP Trace,
and Audio files to download
• Messages: information collected
during this test run from a Passive
Probe or CDR related to this scenario.
Such as Audio Information, Call
Routing, S11GTPv2 procedures,
S11GTPv2-Route, S11GTPv2-QoS,
S11GTPv2-Tunnel Info, …
• Root cause of failure: if there was an
issue, an analysis of all the collected
information designed to help identify
what caused it.
• Test Case Flow: a diagram of the test
case steps, showing the message flow
and status of each step.
See Signal Flow
11

7. 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 and services to
deliver the customer experience you really want?
• Day 7. VoLTE Customer Experience and Service Monitoring ... the perfect combination
for an Active Monitoring strategy
• Day 8. VoLTE Multi-layer monitoring
Check the VoLTE Service Monitoring posts for links to subsequent articles.
Copyright 2016, Ascom Network Testing Ltd 16

8. VoLTE Service Monitoring – Related documents
TEMS VoLTE Service Monitoring solution:
1. A New Standard & the Test Cases Overview
2. Solution architecture & the VoLTE Voice Call test case
3. VoLTE Voice Call including passive signalling data analysis
Copyright 2016, Ascom Network Testing Ltd 16