Product Note

Since mobile Internet data will continue to grow unabated in the foreseeable future, operators are aggressively deploying LTE networks to support these very high traffi c levels. However, prior to any deployment, networks and individual network elements must be tested in a lab environment to ensure that they deliver the quality of experience that subscribers expect. EXFO’s Wireless Core Testing application, designed for its QualityAssurer platform, is the industry’s leading performance validation tool for the wireless core network and its elements.

NEW CHALLENGESLong-term evolution (LTE), the next-generation mobile architecture, has been designated by 3GPP to effectively meet the growing mobile broadband demand triggered by the voracious consumption of data-hungry applications popular among consumers.

The fl attened, all-IP LTE architecture and the specifi c performance targets of LTE present new challenges for EPC network element testing. EPC elements must be able to handle increasing levels of signaling and user-plane loads under strict latency requirements. Network elements need to be tested and benchmarked under real-world load conditions before deployment. Moreover, LTE networks must interwork seamlessly with legacy 2G, 3G and CDMA networks, and these interRAT scenarios must be thoroughly tested. Combining LTE and 3G elements on the same platform is also becoming increasingly common and this presents its own unique set of testing challenges.

OVERCOMING THE CHALLENGESWhether a wireless core element is tested in isolation or in combination with other elements, the associated interfaces must be simulated to completely surround the system under test (SUT). The activity on one interface triggers activities on other interfaces and these interactions must be synchronized and cross-verifi ed. Millions of subscribers and bearers as well as thousands of network elements like eNodeBs must be simulated along with real-world traffi c patterns to effectively test the wireless core and its elements.

The Wireless Core Testing application allows users to:

› Test network element capacity and functionality both in isolation and in combination.

› Test wireless core capacity and functionality, including EPC and 2G/3G/CDMA.

› Test network element interoperability with third-party vendors.

› Test the control and user planes in a cohesive manner.

› Subject the SUT to traffi c patterns that mimic real-world conditions.

› Test proper quality of service (QoS) through gateways, especially under heavy load conditions.

› Test different types of mobility events, both for intra-LTE and iRAT mobility.

› Deploy networks with the right capacity, so as not to overspend on superfl uous capacity or fall short of required capacity.

Typical test scenarios are described below, but test confi gurations are not limited to these examples.

MME TestingTo test the MME in isolation, the Wireless Core Testing application can simulate as many of the following elements as needed: UE, eNodeB, SGW, HSS, MME, SGSN, MSC, EIR, HRPD, IWS, SMLC/GMLC, MBMS GW and CBC. The MME can therefore be completely surrounded by simulated elements, thus enabling the comprehensive load testing of basic functionalities as well as advanced features.

Each module in the platform can simulate up to one million subscribers. For HSS simulation, each module can simulate over two million subscribers. Up to 4000 eNBs can also be simulated from a single blade.

The Call Profi ling feature can be used to input BHCA (busy hour call attempts) data for different procedures, sending traffi c that refl ects patterns seen or anticipated in live networks toward the MME. Other traffi c patterns such as morning commute, lunch hour, evening rush hour as well as special events like concerts, games and emergencies, can also be simulated.

The MME can also be tested for:

› Ciphering and integrity protection

› Intra-LTE and iRAT mobility

› Location services

› Network-assisted cell change (NACC)

› Broadcast services

› MBMS

› Emergency calls

› Reliability

› Multihoming

Wireless Core Network TestingNisar Sanadi, Product Manager, and Saurav Jha, Product Specialist, Simulators Product Management

Figure 1. The complexity of MME testing

LTE-Uu

S1-MME

S10

S6aS13

SLs

SLg

SGs/Sv

S11S102

S101

SBcSm

S3/Gn4G MME

SGSN

E-SMLC

S101

Cdma2000 HRPD

S-GW

EIR

HSS

1xCS IWS

SGs/Sv 2G/3G MSC

CBCMBMS GW

MMEeNBGMLC

All elements aresimulated and controlledfrom a single system

© 2012 EXFO Inc. All rights reserved.

Product Note

SGW TestingTo test the SGW in isolation, the Wireless Core Testing application can simulate any of the following elements: UE, eNodeB, PDN-GW, MME, SGSN, PCRF, HSGW and RNC.

Testing the SGW requires generating traffi c over both control and user planes. The control- and user-plane data need to be tightly coupled together to simulate realistic subscriber and network behaviour. Using the state-of-the-art W2CM user-plane module housed in the QualityAssurer platform, the Wireless Core Testing application can generate and analyze real-world, layer-7 application data in both 1 GbE and 10 GbE interfaces. A desired mix of user-plane data can also be generated according to data type (FTP, HTTP, video, etc.), types of bearers (default, dedicated, GBR, non-GBR, etc.) and other relevant parameters.

The SmartReplay feature on the W2CM module allows users to capture a single session of an application and have the system replicate it millions of times over, allowing the desired user-plane traffi c load to be generated toward the SGW.

The Call Profi ling feature can generate realistic traffi c patterns that not only cover LTE functionality, but also interactions between LTE and legacy networks.

PDN-GW TestingTo test the PDN-GW in isolation, the Wireless Core Testing application can simulate any of the following elements as needed: SGW, CGW, PCRF, OCS, HSGW and PDN.

One of the key features of a PDN-GW is deep packet inspection (DPI), which adds value to user data through preferential treatment depending on type, source, etc. This is done for security purposes (e.g., detecting DoS attacks) as well as to ensure the smooth operation of the network (e.g., throttling undesirable data like P2P).

The proper handling of data by the PDN-GW is also critical to delivering the highest QoS to operator services like VoLTE. Effectively testing these user-plane data-processing capabilities requires generating different types of pertinent data at high throughputs. The W2CM module is designed for this, specifi cally for wireless testing, and is the industry’s leading user-plane testing solution, both in terms of performance and functionality.

MME and SGSN Combo TestingTo test the MME and SGSN combo, the Wireless Core Testing application can simulate any of the following elements: UE, eNodeB, SGW, HSS, MME, SGSN, MSC, EIR, HRPD, IWS, SMLC/GMLC, MBMS GW, CBC, RNC, BSC, GGSN, HLR, SCF and SMS-GMSC.

It is becoming increasingly commonplace for NEMs to bundle LTE elements with 3G elements on the same platform. This provides several benefi ts to the operator including a cost-effective upgrade path from 3G to LTE and optimized interoperability between both domains. One of the most popular combinations is MME and SGSN. From the QualityAssurer platform, the Wireless Core Testing application can simulate 2G/3G as well as LTE elements to test this combination. The cutting-edge user-plane functionality of the W2CM module can also be used to test that aspect of the SGSN.

Real-world traffi c models can be simulated across both control and user planes, including mobility scenarios between 2G/3G and LTE.

Figure 2. SGW testing covering control and user planes

Figure 3. PDN-GW testing covering control and user planes

Figure 4. Combo-element testing covering 4G and 3G

S1-U

S11S4

S103

Gxc

S5/S8S12

MME

PDN-GW

HSGW

RNC

SGWeNB PCRF

SGSN

All elements aresimulated and controlledfrom a single system

S5/S8

S2a

Gy Gz

Gx

SGi

Ga

HSGW PCRF

CGW

PDN-GWSGW PDN/IMS

OFCSOCS

All elements aresimulated and controlledfrom a single system

LTE-Uu

Gb

luPS

Gr GeGd

S6a

S13

SLs

SGs/Sv

S11/S4S101

S102

4GBSC

GGSN

Gd

SMS-GMSC

Cdma2000 HRPD

SGs/Sv 2G/3G MSC

SMS-GMSCSCF

GGSNHLR

S-GW

MME

eNB

S6a

HSS

EIR

E-LSMC

RNC

MME/SGSN

1xCS IWS

S10

Gn/Gp

S1-MME

All elements aresimulated and controlledfrom a single system

© 2012 EXFO Inc. All rights reserved.

Product Note

End-to-End EPC TestingFor end-to-end testing of the EPC, the Wireless Core Testing application can simulate any of the following elements: UE, eNodeB, SGW, HSS, MME, SGSN, MSC, EIR, HRPD, IWS, SMLC/GMLC, MBMS GW, CBC, RNC, PCRF, OCS, CGW, HSGW and PDN.

This test confi guration will validate and qualify the capacity and service-delivery capabilities of the entire EPC across both the control and user planes. This planning test must be executed before deploying a live network. This test not only ensures the proper functioning of the system, it also ensures that the system is scaled correctly to meet the expected traffi c load.

VoLTE is a key feature for operators and the end-to-end test confi guration is the perfect setup to properly validate it. All the elements within the EPC have to perform optimally for the end user to obtain the desired quality of experience.

Full Range of Testing PossibilitiesThe Wireless Core Testing application that runs on the QualityAssurer platform provides a full range of testing capabilities. Besides the most typical use cases described above, many other network elements in the wireless core (e.g., GGSN, HSS, PCRF, etc.) can be tested in isolation or in combination with other elements. Although the QualityAssurer platform is geared towards performance testing, the Wireless Core Testing application is capable of handling the full testing lifecycle: conformance, negative, functional, regression and performance testing. One of the key differentiators is the level of fl exibility provided by the Wireless Core Testing application. This enables practically any test scenario to be implemented, even by the end user. The ability to execute batch test cases, fi ltered according to the user’s selection criteria, enables effective conformance and functional testing. The following diagram illustrates one example of the type of complex test confi gurations that are possible with the Wireless Core Testing application.

KEY FEATURES› Scalable, multi-user system with a single control point ensures that

the system can grow along with the requirements

› The standard ATCA architecture leverages performance gains from Moore’s law in a timely manner

› One platform for different domains: 2G, 3G, CDMA, LTE and IMS

› End-to-end testing solution spanning multiple domains from a single high performance platform—this is especially critical for VoLTE testing

› Tightly integrated control- and user-plane functionality

› Highly fl exible solution that can be easily customized to each unique test environment

› One common platform for the full testing lifecycle: conformance, negative, functional, regression and performance testing

› Broad coverage of the many interfaces in the wireless core

› Extensive library of precanned test packages covering standard procedures defi ned in 3GPP specs

› Traffi c-profi ling capabilities that recreate real-world patterns in the lab

› Procedure Seqencing feature that allows users to precisely control the action sequence performed through groups of simulated UEs (e.g., a group of UEs travelling in a train doing HO at the same time)

› Support for advanced features like ciphering and integrity protection, piggybacking, CSFB, SRVCC, NACC, MBMS, location services, emergency calls and data continuity during mobility

› Support for mobility testing including all varieties of intra-LTE and iRAT handovers between LTE and 2G/3G/CDMA, as well as key data-continuity tests during mobility across multiple bearers and PDNs

LTE-Uu

S6a

SGi

S103

S2aS101

S102

S12

SUT

S4

S101

4G

SGSN

Cdma2000 HRPD

PDSN

MME

eNB

RNC

MME

S-GW

SGiPDN-GW

1xCS IWS

S10

S3/Gn

S1-MME

S1-U

HSS

SGiPDN/IMS

All elements aresimulated and controlledfrom a single system

confi guration is the perfect setup to properly validate it. All the elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user elements within the EPC have to perform optimally for the end user

RNC

RNC

eNBs

MSC

MSC

MSC

CS-IWS

PDN-GW

Server

SGW

MME

X-CSCF

SCC-AS

HSS

AAA

PCRF

SGSN

BSC

Server

GGSN

PDN

PDN

UMTS

IMS

EPC

GSM/GPRS

CDMA2000

System Under TestS1-MME

S1-U

S101

S103

S102

S2a

Gxa

STa

Gi

SGiS6a

S11 S5

S4

GnS3/Gn

Sy/SGs

Sy/SGs

I2I2

I2

Rx

Gb

GnluPS

luCS

S12

A

A1

HSGW

EUTRAN

Figure 5. EPC end-to-end testing

Figure 6. Multi-domain end-to-end testing across 4G/3G/2G/CDMA

© 2012 EXFO Inc. All rights reserved.

Product Note

› Time measurement stats that allow users to monitor the responsiveness of the system being tested—system responsiveness is directly correlated to customer experience and satisfaction

› Customizable statistics that allow users to set the counters and time-measurent stats to their specifi c needs

› Industry-leading, highest performance user-plane blade that is custom built for wireless testing applications

› SmartReplay feature that allows users to generate realistic loads based on the capture of a single data session and quickly test new and unique application data types that may be seen in the network

› An intuitive, graphical test creation environment that allows users to quickly and easily create their own test scenarions, including negative test cases

TECHNICAL SPECIFICATIONS QualityAssurer› ATCA-based chassis

› System controller, shelf manager and 500GB HDD included

› Can be daisy chained to scale as needed

› Two options:

QA-805 › 6-slot chassis that holds

up to fi ve processor blades

› 19” rackmount 7U system

› Weight: 25.50 kg

› AC power: 90-250V

QA-813 › 14-slot chassis that holds

up to 13 processor blades

› 9” rackmount 13U system

› Weight: 29 kg

› DC power: 48V

Processor blade› Single-slot ATCA blade

› Intel Xeon-based quadcore processor

› 12GB RAM

› One AMC slot

W2CM user-plane blade› Two 10 GbE ports and eight 1 GbE ports

› Up to 2 FPGA modules

› Line rate, layer-7 application data generation and analysis on 1 GbE and 10 GbE ports

› 2M total bearers per 10 GbE port; 1M active bearers

Performance› Up to 1M simulated UEs per blade

› 4K simulated eNBs per blade

› 40K msgs/s on S1-MME

› 32K msgs/s on GTP-C-based interfaces like S10, S11, S3, etc.

› 15K msgs/s on S6a

Interfaces and standards› S1: 3GPP TS 24.301 v8.2.0 (R8-Jun08), v8.3.0 (R8-Sept08),

v8.4.1 (R8-Dec08), v8.5.0 (R8-Mar09), v8.6.0(R8-Jun09), v8.8.0 (R8-Dec09), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9-Dec10), v9.6.0 (R9-Mar11), v10.6.0 (R10-Dec11)

› S1-U: 3GPP TS 36.414 v8.1.0 (R8-Mar08), v8.2.0 (R8-Jun08), v8.3.0 (R8-Dec08), v8.4.0 (R8-Mar09)

› S1-AP: 3GPP TS 36.413 v8.2.0 (R8-Jun08), v8.3.0 (R8-Sept08), v8.4.0 (R8-Dec08), v8.5.1 (R8-Mar09), v8.6.0 (R8-Jun09), v8.8.0 (R8-Dec09), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9-Dec10), v9.6.0 (R9-Apr11), v10.4.0 (R10-Dec11)

› NAS: 3GPP TS 24.301 v0.3.0 (June 08), v1.1.1 (Oct 08), v8.0.0 (R8-Dec08), v8.1.0 (R8-Mar09), v8.2.1 (R8-Jun09), v8.4.0 (R8-Dec09), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9-Dec10), v9.6.0 (R9-Mar11), v10.6.0 (R10-Dec11)

› S6a: 3GPP TS 29.272 v1.0.0 (June 08), v.8.0.0 (R8-Sept08), v8.1.1 (R8-Jan09), v8.2.0 (R8-Mar09), v8.3.0 (R8-Jun09), v8.5.0 (R8-Dec09) and RFC 3588 Diameter, v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9-Dec10), v9.6.0 (R9-Apr11), v10.5.0 (R10-Dec11)

› S10/S11/S5: GTP TS 29.803 v0.6.2 (Mar 08), v0.9.0 (Jul08)

› GTP-C: 3GPP TS 29.274 v1.3.0 (Oct 08), v8.0.0 (R8-Dec08), v8.1.0 (R8-Mar09), v8.2.0 (R8-Jun09), v8.4.0 (R8-Dec09), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9-Dec10), v9.6.0 (R9-Apr11), v10.5.0 (R10-Dec11)

› PMIPv6: 3GPP TS 29.275 v8.1.0 (R8-Dec08), v8.2.0 (R8-Mar09), v8.3.0 (R8-Jun09), v8.5.0 (R8-Dec09), v9.2.0 (R9-Jun10)

› SGs: 3GPP TS 29.118 v8.4.0 (R8-Dec09), v9.1.0 (R9-Mar10), v9.3.0 (R9-Sept10), v10.6.0 (R10-Dec11)

› SMS: 3GPP TS 24.011 v9.0.1 (R9-Mar10), v10.0.0 (R10-Dec11)

› SMS GSM: 3GPP TS 23.040 v8.6.0 (R8-Mar09), v9.2.0 (R9-Mar10), v9.3.0 (R9-Sept10)

› S3: 3GPP TS 23.401 v8.8.0 (R8-Dec09), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.5.0 (R9- Dec10), v9.6.0 (R9-Mar11), v10.6.0 (R10-Dec11)

› S4: 3GPP TS 23.401 v8.8.0 (R8-Dec09), v9.7.0 (R9-Dec10)

› SLs: 3GPP TS 29.171 v9.2.0 (R9-Sept10), v10.3.0 (R10-Dec11)

› SLg: 3GPP TS 29.172 v9.2.0 (R9-Sept10), v10.1.0 (R10-Dec11)

› S101: 3GPP TS 29.276 v9.2.0 (R9-Apr10), v10.3.0 (R10-Dec11)

› S102: 3GPP TS 29.277 v9.2.0 (R9-Jun10), v10.0.0 (R10-Dec11)

Two 10 GbE ports and eight 1 GbE ports

Line rate, layer-7 application data generation and analysis on 1 GbE and 10 GbE ports

 

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Product Note

PNOTE041.1AN © 2012 EXFO Inc. All rights reserved. 2008

Printed in Canada 13/01

› SBc: 3GPP TS 29.168 v9.2.0 (R9-Sept10)

› Sv: 3GPP TS 29.280 v9.6.0 (R9-Apr11), v10.3.0 (R10-Dec11)

› S13: 3GPP TS 29.272 v8.8.0 (R8-Sept10), v9.2.0 (R9-Mar10), v9.4.0 (R9-Sept10), v9.6.0 (R9-Apr11), v10.5.0 (R10-Dec11)

› Sm: 3GPP TS 23.246 v9.5.0 (R9-Jun10)

› Gx/Gxc: 3GPP TS 29.212 v8.3.0 (R8-Mar09), v8.4.0 (R8-Jun09), v8.6.0 (R8-Dec09), v9.3.0 (R9-Jun10)

› 3GPP TS 29.213 v9.3.0 (R9-Jun10)

› Ga/Gz: 3GPP TS 32.295 v8.1.0 (R8-Sept09), v9.0.0 (R9-Jun10)

› Gy: 3GPP TS 32.299 v8.11.0 (R8-Jun10)

› Ge: 3GPP TS 29.078 v9.2.0 (R9-Dec10)

› Gd: 3GPP TS 29.002 v9.4.0 (R9-Dec10)

› IuPS: 3GPP TS 24.008 v3.14.0, v4.12.0, v5.11.0, v6.7.0, v7.13.0, v8.8.0, v9.5.0

› 3GPP TS 25.413 v3.12.0,v4.1.0, v6.4.0, v7.9.0, v8.4.0

› 3GPP TS 24.040 v4.11.0

› 3GPP TS 29.060 v3.7.0, v5.7.0

› GB: 3GPP TS 24.008 v3.14.0, v4.12.0, v5.11.0, v6.7.0, v8.8.0, v9.5.0

› 3GPP TS 24.040 v4.11.0

› 3GPP TS 44.065 v5.0.0, v6.3.0

› 3GPP TS 44.064 v5.1.0

› 3GPP TS 48.018 v5.5.0, v5.8.0, v6.5.0

› 3GPP TS 48.016 v5.1.0, v6.4.0

› Gn/Gi: 3GPP TS 29.060 v3.9.0, v5.9.0, v6.7.0, v7.9.0, v8.10.0, v9.5.0

› Gr: 3GPP TS 29.002 v3.9.0, v4.9.0, v5.11.0, v6.8.0, v7.9.0, v8.12.0, v9.4.0

› 3GPP TS 23.078 v3.11.0, v6.5.0

› IuCS: 3GPP TS 23.040 v4.11.0, v5.1.0, v9.3.0

› 3GPP TS 24.008 v4.15.0, v4.3.0, v4.12.0,v5.16.0,v6.7.0, v7.13.0, v9.5.0

› 3GPP TS 24.080 v4.4.0, v 5.5.0

› 3GPP TS 25.413 v4.1.0, v4.11.0, v5.12.0, v6.4.0, v7.9.0

› A: 3GPP TS 23.040 v4.11.0, v5.1.0

› 3GPP TS 24.008 v4.15.0, v4.3.0, v4.12.0, v5.16.0

› 3GPP TS 24.080 v4.4.0, v5.5.0

› 3GPP TS 48.008 v4.10.0, v5.6.3, v5.12.0

› 3GPP TS 48.006 v4.10.0, v5.6.3, v5.16.0