Spectra2 for EPC Testing

(1)

EPC OVERVIEW

As the demand for mobile experience increases, both in-terms of

bandwidth and applications, mobile network operators are turning to

4G LTE networks. Evolved packet core is the critical component of

the LTE deployment as it introduces new elements such as policy

servers, mobility servers, gateways, session controllers and

charging systems all interconnected. These elements interwork via

the Diameter protocol to exchange critical network, subscriber and

service information. The volume and complexity of Diameter traffic

places a very high demand on the EPC network elements raising

reliability concerns of the network. To alleviate this problem, DSC

and DRA elements are introduced, adding more complexity to the

Diameter network.

As you are getting ready to test your EPC, this specification helps

you understand the various EPC network nodes, typical

configuration challenges and Spectra2 features & capabilities to

address your test needs.

SUPPORTED TEST DOMAINS Spectra2 is powered by advanced signaling and media generation capabilities that enable high performance testing of protocols like SIP, Diameter, TCAP and RTP. This broad coverage of protocols helps you test and tune the following network nodes in Evolved Packet Core:

 Diameter Signaling Controller (DSC)

 Diameter Routing Agent (DRA)

 Mobility Management Entity (MME)

 Home Subscriber Server (HSS)

 Equipment Identify Register (EIR)

 Policy Charging Rules Function (PCRF)

 Policy Enforcement Function (PCEF)

 Online Charging Systems (OCS)

 Offline Charging Systems (OFCS)

 Authentication Authorization and Accounting (AAA)

Spectra2

for EPC Testing

Robust implementation of Evolved Packet Core is key to

a successful LTE deployment

(2)

EPC ARCHITECTURE

The EPC network architecture includes four main functional areas:

Diameter Routing, Policy Management, Mobility Management/

Roaming and WiFi-Offload. These functional areas span across

three possible locations of the network that a subscriber could

access their services

– HPMN (Home Public Mobile Network),

VPMN (Visited Public Mobile Network) and Non-3GPP (Wifi or

CDMA).

Diameter Routing

Nodes



DSC (Diameter Signaling Controller):

This element integrates all

Diameter-based control elements by relaying messages among them. It handles traffic management, routing and load balancing across the Diameter elements to ensure scalability and manage congestion.



DRA (Diameter Routing Agent)

: This element functionality is

embedded into the DSC and is primarily responsible for the Diameter proxy function among the nodes to address network scalability and PCRF static binding with dynamic load sharing.



DEA (Diameter Edge Agent)

: This element provides security and

interoperability support to hide the operator’s network architecture from the rest of the world. The DEA helps to gracefully control the flow of Diameter traffic by limiting the impact from internal signaling issues or malicious outside assaults.



IWF (Diameter Interworking Function)

: This element provides protocol

mediation and interworking functions that allow you to seamlessly manage 2G/3G-to-LTE and LTE-to-LTE roaming.

Test Challenges



Connectivity and Routing Testing

−Peer Connectivity −Topology Hiding −Admission Control −PCRF Binding −Route Management −Load-Balancing



Performance Attribute Testing

−Response Time Testing

−Open Transaction Testing

−Per port TPS Engineering



Message Manipulation Testing

−AVP Add/Modify/Delete

−Signaling Adaptions

Spectra2 Features



Functional Testing

−Diameter Functional Tester

−Diameter Conformance Suites

−Full state machine control

−SCTP Link Control

−AVP Customization

−Diameter Interworking

−IP address randomization

−Traffic correlation capabilities

−Multi-node simulation

−Mixed interface scenarios

−SLF Simulation

−Simulate IMS functions



Performance Testing

−Millions of Subscribers

−Million MPS traffic generation

−Less than 2ms loopback RTD

−Performance Cores

−Flexible Traffic Modelling

(3)

Policy Management

Nodes



PCRF (Policy Charging and Rules Function)

: This element receives

session and media-related information from the Application Function, such as the P-CSCF and controls policy decisions regarding the service data flow detection, gating, Quality of Service (QoS), and flow-based charging. This element is looked at as a bandwidth/resource

optimization function as well a key node for new revenue generation.



PCEF (Policy Charging and Enforcement Function)

: This element

enforces policy, handles flow-based charging, controls QoS and the handles user plane traffic. It provides service data flow detection and counting as well as online and offline charging interactions. This function can be embedded into the P-GW (Gx), the S-GW (Gxc) in VPMN or the HSGW (Gxa) in trusted a non-3GPP network or the ePDG

(Gxb) in a WiFi-Offload network.



P-CSCF (Proxy CSCF)

: This element is the first contact point for the users

of the IMS Core. It proxies UE SIP signalling traffic into the IMS network and is usually embedded in a Session Border Controller or IMS Call Server. It is also responsible for charging triggers into

charging/accounting systems based on the user’s activity.



OCS (Online Charging System)

:

This element provides real-time

charging capability based on user initiated events and sessions. It controls user sessions and services based on the available credits. Some OCS implementations also work closely with the PCRF in the policy decision making process.



OFCS (Offline Charging System)

: This element collects charging

information for network resource usage which is then passed on to billing systems in the format of a CDR. This element does not control user service/session usage in real-time as they are rendered.

Test Challenges



Policy Rules Testing

−IPCAN Session Management

−Bill Shock Prevention

−Tiered Plans

−Fair Usage

−Smart Charging

−Boost Button

−Subscriber Policy



Charging Systems Testing

−Event Charging

−Session Charging

−Unit Reservation



Message Type Testing

−User Subscription Data

−User Behaviour Data

−User Status Data

−User Content

Spectra2 Features



Functional Testing

−PCRF Bracket Testing −CSCF Model for PCRF Testing

−PCRF Model for OCS Testing

−Rx Conformance Suite

−Rf/Ro Conformance Suite

−Flexible Nodes & Interfaces



Performance Testing

(4)

Mobility Management

Nodes



MME (Mobility Management Entity)

: This element is critical to the

network function of the EPC, managing session states, authentication, paging, mobility and other bearer management functions.



HSS (Home Subscriber Server)

:

This element manages user

subscription related information such as identity, security, access and service profiles in real time, for multi-access and multi-domain offerings.



SGSN (Serving GPRS Support Node)

: This element handles subscriber

mobility management, authentication and data network functions of 2G/3G networks.



V-PCRF (Visiting PCRF)

:

This element is responsible for policy

management in a visited network working with enforcement (S/P-GW) as well as application (CSCF) functions to support roaming with local breakout deployments.



DEA (Diameter Edge Agent)

: This element provides enables operators

to connect securely with third-party partners when needed and share resources, such as in roaming and billing use cases. Hiding home network configuration and protecting against DoS attacks are the primary functions of this node.



EIR (Equipment Identity Register)

: This element allows operators to

control access to mobile networks, protecting against device theft and fraud. The EIR enables provisioning of optimized services by device type.

Test Challenges



Session Management

−UE Attaches −User Activations −Hand-offs −Paging −Subscriber Authentication −MME Pooling −Fault Recovery −Notification



Mobility Testing

−Location Management

−Subscriber Data Handling

−Equipment Identity Checks



Performance Testing

−Congestion Management

−Load Sharing

−Authentication Rates

−Location Update Rates

−Traffic Overload Scenarios

Spectra2 Features



Functional Testing

−HSS bracket Testing

−IMS Core Modelling

−TCAP and Diameter

−UE Profiles

−Multi-VLAN Testing



Performance Testing

(5)

WiFi-Offload

Nodes



AAA (Authentication Authorization and Accounting)

: This element provides AAA services helping operators converge their subscriber data management across all network technologies supporting multiple protocols and access methods.



P-AAA (Proxy AAA Server)

: This element is responsible for AAA

functions in the visited network to support roaming architectures.



HSGW (HRPD Serving Gateway)

: This element is part of evolved HRPD

(eHRPD), an evolution option for CDMA operators that helps ensure converged mobility and management between HRPD and LTE networks.



ePDG (enhanced Packet Data Gateway)

: This is the primary element

responsible for interworking between the EPC and untrusted non-3GPP networks, such as a wireless LAN. It manages QoS, flow-based

charging data generation, gating, deep packet inspection, and other functions for UE data flows over WiFi.

Test Challenges



Functional Enablement

−Authentication Services

−Addressing and Bearers

−Inter/intra-AP Hand-offs −DoS attacks −Network Interoperability −Traffic Priorities −Quality of Service



Performance Testing

−APs and UEs

−Concurrent Sessions

Spectra2 Features



Functional Testing

−UE Profiles

−Voice/Video QoS



Performance Testing

−Numerous Nodes/APs

(6)

Spectra2 for EPC Testing

Spectra2’s support for Diameter network is

designed to address unique EPC test challenges in

each of the four domains addressed in this spec.

Diameter Functional Testing



Model Simulations:

Spectra2’s Advanced Signalling and Media Generator (ASMG) can support up to 10 inter-working call legs in a single test scenario. It can support up to 100 scenarios in a single test model empowering users to script complex diameter

signalling interactions that make up the

functionality of several nodes in the Diameter network.



Broad Protocol Coverage

: Spectra2 supports signalling and media protocols in EPC, IMS and PSTN domains making it ideal for testing multi-domain scenarios.



Conditional Branching

: This Spectra2 feature enables users to handle conditional scripting options such as If/Then/Else to simulate complex transaction flows. These constructs use regular expression capabilities to extract the portion of an AVP as required.



Message Libraries

: Spectra2 contains message PDU libraries of all supported Diameter interface requests and responses. Customers can also import PDUs from the production Wireshark capture files.



Interface Correlation

: Spectra2’s capture analyzer application can apply pre-defined protocol

correlation rules to produce ladder diagrams for call flows from captured traffic.



Transport Protocols

: Spectra2 supports both TCP and SCTP transports for Diameter transactions. These per call-leg configurable options enable creating a multi-vendor, multi-transport environment.



Scheduler

: Spectra2’s Scheduler allows users to launch tests from folders on a specific date and time or designated hourly interval. Scheduler folders contain test suites that include traffic models and scripts.

Conformance Testing



Diameter Tester

: Spectra2 includes a Diameter Test environment that gives state machine control to the user. This enables testing of custom state models and negative test scenarios.



Conformance Test Suites

: Spectra2 Diameter interfaces are equipped with Conformance test suites defined by IETF and IMS Forum. Diameter

base conformance suite covers all basic Diameter agent configuration scenarios as per RFC3588.

Diameter Performance Testing



Subscriber Profiles

: Spectra2 allows grouping of subscribers in several ValueSets to simulate regions and customer value for testing policy and mobility scenarios.



Performance Cores

: Spectra2’s Performance Cores increase the TPS/MPS capacities of the Spectra2 application by leveraging the HW processor architecture. These Performance cores are available on Spectra2 Hardware options as well as Software Edition.

Interoperability Testing



Base Protocol Profiles

: Spectra2 allows Diameter base protocol message contents and message sequence to be configured on a per call-leg basis enabling multi-vendor interoperability testing.



AVP Customization

: Spectra2 provides bit (micro) level access to 100% of the Diameter message content for testing negative scenarios. It also provides the ability to add/remove AVPs as well as change the characteristics of standard AVPs for testing custom Diameter implementations.

Test Harness Integration



API Support

: Spectra2 API gives run-time control of the test workspace over network socket with the ability to get event log messages and return codes for response analysis.



Export Statistics

: Spectra2 collects Diameter interface level statistics by command code and response code. It also collects TPS and open transaction counts on active tests by network interface. These statistics can be exported

periodically into external database environment for test harness integration.

(7)

Spectra2 Standard Compliance

Diameter – Interface Compliance

Diameter Base Protocol IETF RFC 3588

Diameter Cx/Dx Interface ETSI TS 129.228/3GPP TS 29.228 v.10.3.0 Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS);

IP Multimedia (IM) Subsystem Cx and Dx Interfaces; Signaling flows and message contents

ETSI TS 129.229/3GPP TS 29.229 v.10.3.0 Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System

(UMTS);Cx and Dx interfaces based on the Diameter protocol; Protocol details

Diameter Sh/Dh Interface ETSI TS 129.328/3GPP TS 29.328 v.10.3.0 Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System

(UMTS);IP Multimedia Subsystem (IMS) Sh interface; Signaling flows and message contents

ETSI TS 129.329/3GPP TS 29.329 v.10.3.0 Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System

(UMTS);Sh interface based on the Diameter protocol; Protocol details

Diameter Rx Interface ETSI TS 129.214/3GPP TS 29.214 v10.3.0 Policy and charging control over Rx interface

Diameter Gx Interface ETSI TS 129.212/3GPP TS 29.212 v10.3.0 Charging rule provisioning over Gx interface

Diameter S9 Interface ETSI TS 123.203, 129.215/3GPP TS 23.203,29.215 10.3.0 Policy and Charging Control interface between home and visited network.

Diameter Gxx Interface 3GPP TS 29.212 v10.3.0, 3GPP TS 29.213 v10.3.0

Diameter S6a/S6d Interface ETSI TS 129.272/3GPP TS 29.272 v10.3.0 Communication interface between MME in Evolved Packet Core and HSS in IMS

Diameter S13/S13’ Interface ETSI TS 129.272/3GPP TS 29.272 v10.3.0 Communication interface between MME in Evolved Packet Core and HSS in IMS

Diameter Rf/Gz Interface ETSI TS 132.299/3GPP TS 32.299 v 10.3.0 Telecommunication management; Charging management; Diameter charging applications

ETSI TS 132.240/3GPP TS 32.240 v 10.1.0 Telecommunication management; Charging management; Charging architecture and Principles

Diameter Ro/Gy Interface 3GPP TS 32.299 v.10.3.0 0 Telecommunication management; Charging management; Diameter charging applications

Diameter S6b/H2 Interface 3GPP TS 29.273 v10.3.0

Diameter STa/SWa Interface 3GPP TS 29.273 v10.3.0

Diameter Gq/Gq’ Interface ETSI 129.209/3GPP TS 29.209 v6.5.0 Policy control over Gq interface

TISPAN ETSI TS 183 017 v 1.4.0 Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Resource and Admission Control: DIAMETER protocol for session based policy set-up information exchange between the Application Function (AF) and the Service Policy Decision Function (SPDF);Protocol specification

Diameter Rq Interface TISPAN ETSI ES 283 026 v 1.4.0 Diameter Rq Interface Protocol Details and Signaling Flows

Diameter – Conformance Test Suites

Diameter Base IMS Forum Diameter Base Protocol Test Suite v1.0

Diameter Cx Interface IMS Forum Protocol Compliance Test Specification Cx interface v1.0

Diameter Sh Interface IMS Forum Protocol Compliance Test Specification Sh interface v1.0

Diameter Rx Interface ETSI TS 101 580-1 v1.1.1 ETSI TS 101 580-2 v1.1.1 ETSI TS 101 580-3 v1.1.1

Diameter Rf/Ro Interface IMS Forum Protocol Compliance Test Specification Rf/Ro interface v1.0

TCAP

M2PA IETF RFC 4165 (Sept 2005, PS)

M3UA IETF RFC 3332 (MTP3-User Adaptation Layer)

CAMEL 3GPP TS 29.078 version 10.1.0 (2012-01) – Phase4 3GPP TS 29.078 version 5.9.0 (2004-09) – Phase3

(8)

Spectra2 Solution Specification

Solution Highlights

Test Domains LTE EPC Testing, Core Network Testing, Policy Testing, IMS/VoIP Testing, TDM Testing Form Factors Chassis (3U and PCIe-1), Software-Only (SE2)

Line Speeds 1G and 10G Ethernet

User Interface Intuitive Point and Click GUI to simplify the scripting of complex scenarios Traffic Generation Traffic Mix/Shaping w/ Multiple Protocols, Call-legs, Scripts and Scenarios

Built-In Features Subscriber Profiles and Protocol Message Libraries w/ options to edit, save and reuse Troubleshooting SIP Auto scripting, SIP InjectRAW

Test Automation API for Test Harness, Batch Execution, Scheduler

Programmability Procedures, If/Then/Else Programming, Run-time Parameter Get/Put Management Protocol Interworking Diameter Interfaces, SIP, TCAP

Conformance Test Suites Diameter, SIP, H.323, MGCP, Megaco

Diameter Network

Policy Interfaces Rx, Gx, S9, Gxa/Gxb/Gxc

Charging Interfaces Ro/Gy, Rf/Gz

HSS Interfaces Cx/Dx, Sh/Dh, S6a/S6d

EIR Interfaces S13/S13’

AAA Interfaces S6b, STa

NGN Interfaces Rq, Gq/Gq’, E2/E4

Model Simulations PCRF, HSS/HLR, AAA, CSCF, IMS-AS, MSS, OCS, PCEF, SLF, CTF, CGF, UE

Core Network

VoIP Signaling Protocols SIP, SIP-I/T, SIP TLS, H.323, HTTP, RTSP, XCAP

Media Control Protocols Megaco Text, Megaco Binary, MGCP

CODECs Voice: G.711, G.723, G.726, G.729, AMR WB/NB, EVRC

Tones: RFC 2833, DTMF, SF Video: H.263, H.263+, H.264, MPEG4 Fax : T.38

Media RTP, RTCP and SRTP

QoS Testing Audio/Video, Active/Passive, PESQ, MOS, R-Factor

PSTN Protocols ISUP, TCAP, BICC

TCAP AIN, MAP, CAMEL, GSM, INAP, IS-41, IS-634A, IS-826, INCS2

Node Simulations CSCF, SBC, MGC, SGW, MGW, IMS-AS, MSS, SSP, STP

IP Versions IPv4, IPv6

IP Transports TCP, UDP, SCTP and SIGTRAN (M2PA, M3UA)

PSTN Transports TDM (T1/E1, OC3)

About Tektronix Communications:

Tektronix Communications provides service providers and equipment manufacturers around the world an unparalleled suite of network diagnostics and service assurance solutions for fixed, mobile, IP and converged multi-service networks. This comprehensive set of solutions support a range of architectures and applications such as LTE, fixed mobile convergence, IMS,broadband wireless access, WiMAX, VoIP and triple play.

Tektronix Communications is headquartered in Plano, Texas.

Learn more about the company’s test, measurement and service assurance solutions by visiting www.tekcomms.com

Contact Tektronix Communications:

Please visit www.tekcomms.com/spectra2

Phone: 1-800-833-9200 option 1 +1-469-330-4000

(9)