complex load testing of mobile ps and cs core · traffic generator key design concept design...

EuroNOG Conference Budapest 2012 September 10‒11. Péter Olaszi PhD, AITIA International, Inc.

Complex Load Testing of Mobile PS and CS Core

Péter Olaszi PhDAITIA International, Inc.

Hungary

EuroNOG Conference Budapest 2012 September 10‒11. Péter Olaszi PhD, AITIA International, Inc.2

Overview

● Why is there a constant demand for mobile network testing?

● Load testing of the packet switched and circuit switched core

● Design considerations for an automated traffic generator

● Implementation details: how to make it work● Future directions


Mobile core network

Source: http://www.tektronix.com/signaling


Mobile core network

Sources: http://wiki.wireshark.org/GsmProtocolFamily, http://www.tektronix.com/signaling

http://wiki.wireshark.org/GsmProtocolFamily


Changes are driven by various factors

● Mobile telephone core networks are evolving continuously:– Changes in the network transport layer

● Ethernet instead of PDH, SDH or ATM – Improvement in transmission speed

● From 155 Mbps SDH to 10 Gbps Ethernet– Introduction of SIGTRAN:

● Adopt the philosophies of TCP/IP to the telecom's well established SS7 world

– Standards are updated regularly– Broadening of the available services– And many other factors


New equipment in the core network

● New devices need to be tested before being deployed in the live network

● Testing is carried out in a pilot network● Complex testing requires automated generation

of control and user traffic● Existing traffic generators not always meet all

demands


Live vs pilot network

Live network● Subscriber traffic● Only tested devices

are allowed here

Pilot network● Same equipment as in the live network● No subscriber traffic● New devices, configurations and settings

are tried here first


Aspects of testing

● Functional testing● Compliance testing● Integration testing ● Load testing


Functional and compliance testing

● Functional testing– First thing off, does the device work at all?– Does it do what it needs to do?– Do all its required functions work?

● Compliance testing– Is the equipment compliant with the

telecommunication standards?– Does it talk the protocols it is supposed to

talk?


Integration and load testing

● Integration testing – Can the device be integrated into the

operator's network? – Can it work together with existing

devices in existing configurations?● Load testing

– Under full load does the device perform as expected?

– What are its limitations?– What is its peak performance? – What is the steady state performance?


Complex testing

● Complex testing involves all the above aspects in a combined form

● Traffic generators already exist for this purpose, often with limitations:– Protocol compliance testing works only for

one or a few subscribers– Load testing may be restricted to sending a

limited set of packet types– Packets do not necessarily follow actual

protocol message sequences


Traffic generator key design concept

● Design concepts for a versatile traffic generator:– Should produce large volume of traffic– Should be able to simulate a large number of

subscribers– Should handle a wide range of protocols– Message sequences should match protocol

standards– Should be customizable to support vendor

specific features– Need to be prepared for new generation of

mobile technology


Implementation requirements

● Mobile core testing should meet all the above requirements, and still remain ergonomic for human operators.

● Need to manage individual user behavior● Should support various quality of service (QoS)

demands● Should handle both control and user traffic at

high-speeds.


Implementation details

● AITIA's Signaling Generation and Analysis (SGA) Division implemented the SGA-TG traffic generator to meet the above requirements– The device is capable of simulating activities of hundreds

of thousands of users – User groups with specific activity profiles can be defined – Separate packet switched and circuit switched modules

are provided– Control and user data messages are handled on separate

interfaces– Over 700 Mbps traffic can be handled at the– network interfaces


Target audience and applications

● The primary target audience are mobile service providers and academic institutions

● The traffic generator can be used in the following fields:– Stress testing of networks or individual

equipment– Finding bottlenecks in core mobile

communication networks – Verifying the operation of network devices– Helping optimizing network topology


Handled components ‒ PS domain

RNC and BSC operations are

simulatedHLR, AuC and EIR operations are handled for the

simulated subscribers

RNC and BSC operations are

simulated

SGSN can be tested directly, GGSN indirectly

RNC communication

via SIGTRAN IuPS interface

BSC communication

via GboIP

Traffic Server module on the Gi interface


Handled components ‒ CS domain

RNC operations are simulated

HLR, VLR, AuC and EIR operations are

handled for the simulated subscribers

BSC simulation via AoIP interface may be

added on demand

RNC communication via SIGTRAN IuCS interface

MSC (MSS) under test


Simulated scenarios

● Session layer and mobility management● Subscriber mobility simulation:

– Handover among BSC's and RNC's:GPRS↔GPRS, GPRS↔UMTS, UMTS↔UMTS

● User profiles: uplink/downlink traffic volume and distribution among different traffic profiles

● User and traffic parameters are easy to specify– User data packet size– Uplink/downlink traffic volume ratio – QoS parameters

● Simulation of TCP and UDP traffic


Implementation details

● Assembled protocol data units are based on templates from real-life traffic

● Traffic patterns are based on actual captured scenarios

● Message sequences are implemented according to protocol standards

● Each subscriber is simulated separately– their activities are controlled through statistical

parameters


Hardware configuration

● Test equipment is an industrial PC with multiple network interfaces

● Separate interfaces for user data and control traffic● Commercial network interface cards can be replaced with

AITIA's special re-programmable cards:– SGA-GPLANAR: 2x1 Gbps, Virtex XCV5VLX50T FPGA– SGA-10GED: 2x10 Gbps, Virtex XCV5VLX110T FPGA

● Offload-engine implemented in FPGA firmware guarantees generation of precise, high speed traffic with lower CPU load.


Graphical user interfaceLog output in text box

as well as in file. Level of log detail can

be configured.

Link parameters can be set in the user interface and also from config file.

Statistics values are displayed in real time and also reported at the end of each test.

A sequence of tests can be specified with different

user activity profiles.Tests are fully automatic.


Example for subscriber traffic profilesSubscriber groups are

collections of user activity profiles

Subscriber activity parameters can be

set at detail

Test startup ramp, steady state

parameters and shutdown detach/deactivation rate can be specified


Reporting

● Reporting in HTML and CSV format● The report file contains the settings

for all tests● Statistics are reported for each test● Statistics values are updated and

logged with a one-second resolution


Conclusion

● Features of AITIA's SGA Traffic Generator:✔ Produces a large volume of traffic✔ Able to simulate a large number of subscribers✔ Handles a wide range of protocols✔ Message sequences match protocol standards✔ Customizable to support vendor specific features✔ Prepared for new generation of mobile technology


Thank you for your attention

Péter Olaszi [email protected]

AITIA International, Inc.http://sga.aitia.ai

mailto:[email protected]

http://sga.aitia.ai/

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