1.
1
IxLoad
LTE
Components
1
IxLoad
LTE
Core
Access
Diameter
WiFi
Offload
Negative
Testing
VoLTE
and IMS
HetNets

2.
IxLoad Diameter Solution
2

3.
Diameter Testing Scenarios
•Diameter
•Server Test
•EPC Isolation
•DRA
3

4.
4
Policy Server (PCRF) Testing
• Emulation of the Policy Control Enforcement Function (PCEF) in the
PDN-GW to benchmark PCRF performance
– Measure transactions per second (TPS) with a minimum number of policy rules established
– Increase policy rules to understand the impact on TPS performance
– Measure the number of active subscriber sessions that can supported (capacity)
SGi
Rx
Sy
IMS
Network
PCEF/PDN-
GW/EPC
PCRF (DUT)
OCS
Sh HSS (AS)
Gx
Server
Test

5.
MME Isolation Testing
MME/SGSN (DUT)
S-GW
S1-MME
S6a
S6d
eNodeB
▪ Validate access control, security issues, and basic LTE mobility
▪ Simulate intra and inter eNodeB handovers, IRAT with RNC
▪ Test the scalability of next generation MME
HSS
S11
S4
RNC
IuPS EPC
Isolation

6.
Diameter Routing Agent (DRA)
PGW
DRA (DUT)
MME
OCS/OFCS
HSS
▪ Test the any-to-any Diameter node connectivity of the DRA
▪ Measure packet routing performance
▪ Measure load balancing, failover performance, and network congestion control
▪ Verify Diameter proxy/relay services (used in peering/roaming agreements)
S6a
Gz/Gy
S6a
Gz/Gy
DRA

7.
Interface Support
1. S6a - HSS and MME
2. S6d - HSS and SGSN
3. Gx - PCRF and PCEF
4. Ro/Gy - PCEF and OCS
5. S6b - AAA and PGW
6. Rx - CSCF and PCRF
7. STa - AAA and ANGW
8. Sh - HSS and AS
9. Cx - CSCF and HSS
10. Sy - OCS and PCRF
11. SWm – AAA and ePDG (Evolved Packet Data Gateway)
12. SWa - AAA and AN GW (Access Network GW for untrusted non-3GPP)
13. Rf/Gz - PGW and OFCS; OFCS and CSCF
14. Gr – SGSN and HLR
15. SGs – MME and VLR
16. S9 – V-PCRF and H-PCRF
17. SWx/Wx – AAA and HSS
18. S13/S13’ – MME and EIR; SGSN and EIR
19. Gxx (Gxc & Gxa) - SGW and PCRF; AN GW and PCRF
7

8.
Performance on Ixia HW
8
40 Million Subscribers
>400.000 Transactions per Second

9.
VM based solution (sw only)
9
• It runs as a VM but it is not the IxVM product (VMware format, can
be installed using VMware Player freeware); no Hypervisor
• Performance is not guaranteed
• Can run on the same machine as ixLoad Client or different one
• Still needs ixLoad CPD Base PartNumber (925-5001)

10.
Diameter Licensing
• 3 components:
– Interface (Client or Server): a-la-carte
– TPS level
– Total Number of Subscribers
TPS and Subscribers are total, no restriction per interface or nodes.
10

11.
Diameter Licensing – details
• TPS licenses are checked out in 1k batches, Subscribers in 10k
batches. Any number of users can run in parallel provided that
aggregated sum of checked out licenses doesn’t exceed the total
limit. E.g. for a 20k TPS: maximum 20 users can run in parallel tests
each of 1k TPS.
– Once TPS limit is reached, there’s a throttling mechanism in place;
warning is displayed at run time in ixLoad Log window.
– If Subscriber number is exceeded the user will not be able to run the
test (apply config error)
11

12.
What can be tested?
➢Functional testing:
➢Coordinated simulation across multiple interfaces or
nodes
➢Negative scenarios
➢Conformance testing
➢Performance
12

13.
Advanced Features - SmartEvents
13
❑ Define behavior across the Diameter network, nodes
and subscriber.
❖ Reacts to message content received
❖ Create dynamic subscriber behavior based on probabilities
or external stimuli
❖ Realistic response to network or protocol failure conditions
❖ Ability to dynamically change overall test behavior
❖ Coordinate events from multiple applications
❑ Each subscriber flows through its own state machine.
❖ Subscribers can be grouped to align with traffic model.

14.
SmartEventsTM: Volte call example
14
❑ Use SmartEvents to simulate real world traffic
profiles across multiple interfaces such as Gx & Rx
Coordinate Gx and Rx, here we
are able to verify CCA-I followed
by starting an AAR on Rx. The
Rx AAR will not be sent until the
CCA-I is received.
Verify the RAR is sent by the
PCRF for the appropriate
subscriber to insure the PCRF
has signaled to the PGW to
create a dedicated bearer
channel.
The order of the Rx AAA and Gx
RAR can vary based on network
conditions but can be handled
by the SmartEvent state
machine
❑ Coordinating multiple stateful interfaces such as Gx
and Rx allows the user to verify the PAS or PCRF are
properly handling and routing messages and
transactions to the appropriate subscribers.

15.
SmartEvents: Example 2
15
❑ Conditional event handlers allow users to create real
world traffic profiles
Conditional event handler can
use probability assignments that
cause users to take action
based on probabilities of
occurrence assigned
Subscribers will take a different
path each time through the
SmartEvents state machine
based on the probability
assignments, in this case 40%
of subscribers will place a
VoLTE call
❑ Conditional event handlers can be used many
different ways including creating loops until a
condition such as credit pool balance are met.

16.
SmartAVPsTM
16
❑ AVP customization and substitution
❑ Create/modify/remove any AVP in any Diameter Application Message
❑ Configure an AVP from scratch
❑ Include vendor-specific or other optional AVPs in Diameter messages
❑ Insert multiple AVPs inside an AVP (nested AVPs)
❑ Define proprietary signaling or corrupt AVPs for negative testing
❑ Possibility of being compatible with any 3GPP spec version
❑ Simulate scenarios that are not as per specification in order to
address some custom/specific scenarios (eq EUTRAN simulation with
UTRAN parameters)
❑ Support for subscriber specific-data as AVPs data through the use of
„transparent-data” option e.g. IMSI, IMEI, MSISDN, public/private
identity, IP address of the subscriber (IPv4 or IPv6).
❑ Inter-operability with any customer equipment

17.
17
Smart AVPs: Example 1

18.
18
Smart AVPs – Example 2 (Nested AVPs)

19.
SmartAVPs: Example 3
19
❑ Once the SmartAVP is defined users insert one or many
into the SmartEvent state machine
SmartAVPs are added
into the state where
users want them to
occur

20.
Diameter Protocol
20
❖ Defined by RFC6733
❖ All data delivered by the protocol is in the form of AVPs.
❖ Runs over TCP or SCTP
The Diameter protocol provides the following facilities:
❖ Ability to exchange messages and deliver AVPs
❖ Capabilities negotiation
❖ Error notification
❖ Extensibility, required in [RFC2989], through addition of new
applications, commands, and AVPs
❖ Basic services necessary for applications, such as the handling of
user sessions or accounting

21.
Diameter Protocol
21
Diameter is a client – server protocol BUT:
• A Diameter node may act as an agent for certain requests while
acting as a server for others.
• Any node can initiate a request. In that sense, Diameter is a peer-
to-peer protocol.
• The Diameter protocol also supports server-initiated messages,
such as a request to abort service to a particular user.
• A Diameter client generates Diameter messages to request
authentication, authorization, and accounting services for the user
• A Diameter server performs authentication and/or authorization of
the user and/or and accounting requests.

22.
Why IxLoad Diameter?
1 Reason: Performance
22
Metric 1 Appliance
Max Subscribers 16M
Max Rate 400.000
Are you sure your DRA is strong enough?
How do you really measure MME/PGW
performance if the HSS/PCRF is slow?
VoLTE makes it much worse!

23.
VoLTE and Diameter
• One single VoLTE call involves:
– 5 Diameter nodes (DRA, HSS, OFCS, OCS, PCRF)
– 3 EPC nodes (MME, PGW, CSCF)
– 6 Diameter interfaces (S6a, Gx, Rx, Sh, Sy, Cx)
• IxLoad is the only test tool that can run all the above in one single
test, with coordinated simulation between multiple interfaces.
23

24.
VoLTE and Diameter
• VoLTE impact in Diameter signaling:
– 1 VoLTE call triggers 13 Diameter messages (!!!)
– Note: Attach/VoLTE call/Detach sequence triggers 30 Diameter
messages
24
3 Million UEs BHCA Diameter Transactions per
Second
Nominal test 2.4M 20.000
Earthquake scenario (20x
overload)
48M 410.000
Your VoLTE and Diameter test tools must scale appropriately!

25.
Diameter - IxLoad vs Competition
Area Performance IxLoad XT80v2 Competition
Performance
Max Subscribers 16M <5M
Max Transactions 400K 400K
Flexibility
Can edit state machine YES YES
Can create events for
synchronization across
interfaces
YES NO
Can add/remove/modify
AVPs, including for specific
message and/or state
YES Partially
25

26.
Diameter Roadmap
26
Date Feature set
4/15 Add support for Sd interface
6/30 EventViewer support for error reporting
6/30 Support for PerfectStorm HW
7/30 (in planning) Add support for AAA and 3GPP AAA Radius
9/30 (in planning) Add support for SLh, SLs, SLg interfaces