The most sophisicated and versatile VoIP test solution on the market Nexus8610 Traffic Simulation System Nexus8610 VoIP
The telecommunications industry is undergoing a fundamental shift in technology as service providers continue to build global networks based on IP. Driven by lower capital expenditures, reduced operational costs, and opportunities to generate new revenues, carriers are upgrading their voice circuit networks to open, distributed, and highly scalable packet telephony networks. The development of new types of network elements and deploying them in real networks demands intensive testing to avoid any disruption and malfunction. Tests are usually classified into three groups: Functional tests verify whether a network element can perform such basic functions as message forwarding and error detection correctly. Functional tests also examine interworking issues, such as appropriate responses to a network problem or the proper implementation of a new service. Load tests investigate the behavior of the network element under different traffic load conditions. Acceptance and regression tests verify that the original functionality continues to be maintained when new functionality or patches have been implemented. These tests can be executed more efficiently using test automation that can be utilized 24 x 7 to produce dramatic cost savings and accelerate time-to-market. The Nexus8610 Traffic Simulation System is especially designed to test core network elements and offers the features needed to support all three types of tests. Highlights Nexus8610VoIP performs functional, load, acceptance and regression tests. Measures QoS parameters and Speech Quality with PAMS, PSQM / PSQM+ and PESQ algorithm. Fully OPTEC compatible with other Nexus8610 applications. Test Automation application optional for fully automated for 24 x7 testing. Supports 3G/2G Mobile, SIP / SDP, / RTCP, H.248 / MEGACO, PSTN, ISDN Tests control and user plane interworking for 3G/2GMobile VoIP PSTN Features highest load generation and most versatile call simulator. Nexus8610VoIP Page 2
The Nexus8610VoIP executes the principal testing methods needed to verify that features and functionalities in any system under test (SUT) are implemented correctly. The behavior of the SUT can be tested with only a few subscribers, or under real traffic conditions by simulating thousands of subscribers in parallel. Nexus8610VoIP offers multi-user capability in a networked system. Different users can test multiple interfaces and protocols simultaneously, to optimize the use of the Nexus8610, produce dramatic cost savings and accelerate time-to-market. Unique load generation and load handling capabilities Fully scalable platform with multi-interface and multiprotocol testing capability. Independent processing resources in each hardware test module for scalability. Flexibility of the OPTEC method for writing test cases Full compliance with other OPTEC applications makes Nexus8610VoIP the most versatile test solution on the market. The versatility of the Nexus8610VoIP allows testing of the signaling plane and user plane of media gateways and media gateways controllers, as well as the testing of any combination including network elements of other technologies such as UMTS, GPRS, GSM, SS7, and ISDN. On the user plane the speech quality of individual connections can be analyzed using standardized algorithm such as PAMS, PSQM (ITU-T P.861) or PESQ (ITU-T P.862). -MOS rate - SQA val ASTS MOS ASTS reference file is sent as payload Nexus8610TU3 ASTS Degraded file is decoded and compared with Reference file Payload TC Signaling TC Payload TC Signaling TC RTCP SIP SDP RTCP SIP SDP UDP TCP IPv4 / IPv6 Ethernet UDP TCP IPv4 / IPv6 Ethernet SUT Figure 1: Nexus8610VoIP - Speech Quality Analysis Nexus8610VoIP Page 3
For the Nexus8610VoIP, ASTS (Artificial Speech Test Samples) are available for British and American English. The ASTS is built-up by a mixture of male, female and infantile utterances simulating real voice calls. The ASTS are stored in the Nexus8610 and become part of the appropriate OPTEC test case when the speech quality shall be analyzed. The reference ASTS file is encoded according to the chosen codec and then sent through the SUT (System Under Test). At the receiving side, the degraded ASTS is decoded according the chosen codec into the same format as the reference ASTS file. Both files are compared than using one of the algorithm Either PAMS, PSQM or PESQ. Depending on the chosen algorithm the following parameters are calculated as results PAMS Average Utterance Time Offset [msec] PAMS Time Offset Confidence [%] PAMS Maximum Utterance Time Offset [msec] PAMS Longest Muted section [msec] PSQM score [5..0] PSQM+ score [5..0] PESQ Score [5..0] PESQ Average Utterance Time Offset [msec] PESQ Time Offset Confidence [%] and many more Figure 2 shows the Nexus8610VoIP used as Media Gateway Controller (MGC) simulator for Media Gateway (MG) testing. The Nexus8610 VoIP simulates the behavior of the MGC on the H.248 / MEGACO interface towards the Media Gateway. The Media Gateway controls the payload flow, for example, the E1 bearer channel or port allocation, according to the information from the H.248 / MEGACO protocol. Additionally to the control plane simulation Nexus8610VoIP also simulates different user plane interfaces and protocols. The user plane tests include bearer verification with tones and bit patterns. Nexus8610VoIP provides different codecs such as G.711 (A/u law), G.723, G.726, G.729, GSM-EFR, GSM-FR, AMR, WB-AMR. Nexus8610VoIP not only tests the features and functionality of the system under test, but also verifies the protection mechanism in Nexus8610VoIP Page 4
order to provide information on the behavior of the SUT in the event of overload conditions or wrong subscriber behavior. Nexus8610TU3 H.248 Nexus8610TU AAL2 TDM AAL2 TDM MGW Figure 2: Nexus8610VoIP - MGW test setup This test setup enables the following to be tested: The correctness of the H.248 / MEGACO implementation in the media gateway under any load conditions. The circuit switched (CS) and packet switched (PS) interworking of the user plane on various interfaces such as AAL2 channels (e.g. IuCS), sessions and TDM (64kbps bearer channels). Conversion of encoded payload Any functionality implemented in the media gateway Speech Quality Analysis QoS Parameter verification The Nexus8610VoIP supports verification of QoS parameters. The verification procedure for each of the QoS parameters checks for each frame whether a userdefined threshold (e.g. 500ms for Jitter) has been exceeded and accumulates the number of violations. The following QoS parameters are verified: SIP Call setup delay Speech Latency Packet Loss Jitter Round Trip Delay Nexus8610VoIP Page 5
Technical Specifications Protocols Nexus8610VoIP supports the following protocols: SIP / SDP / RTCP H.248 / Megaco SS7 ISUP ISDN PRA / BRI POTS IuCS GSM-A Please request for the latest Protocol List of the Nexus8610 Traffic Simulation System. Codecs Nexus8610VoIP supports the following codecs on the related interfaces G.711 G.723 G.726. G.729.A GSM-EFR GSM-FR AMR WB-AMR Speech Quality Analysis PAMS PSQM / PSQM+ acc ITU-T P.861 PESQ acc ITU-T P.862 HW test modules STM-1OC3 Ethernet E1 T1 1 or 2 optical STM-1 port(s), single mode multi mode, G.957, G.707 10/100BT/ Gigabit Ethernet 2.048 kbps 1 signaling channel for 48/56/64 kbps, termination 75/120, G.711 A- /u law codec for bearer channels, line code AMI/HDB3 1544 kbps 1 signaling channel for 48/56/64 kbps, termination 75/100, A-/u law Nexus8610VoIP Page 6
ISDN BA POTS codec for bearer channels, line code AMI/B8ZS So/To 8 or 16 subscriber lines, A-/u law codec for bearer channels 16 subscriber lines, A-/u law codec for bearer channels, line termination 600 or 900, Signaling DTMF - Decadic, Metering 50/60 Hz 12/16 khz, Loop - Ground start, Flashing, a-b wire polarity detection. Optional HW modules SLE Signaling Link Extension, extends the number of HDLC links of an E1 or T1 HW test module in steps of 8 links. DFB Performance Digital Filter Board, performs accurate measurements of levels and frequencies of tones received in bearer channels or used for MFC signaling. DFB can be put to all Nexus8610VoIP HW test modules, except Ethernet (10/100BT) and STM-1. Per DFB up to 30 bearer channels (Analog or 64kbps) can simultaneously be measured All figures are as per HW test module AAL2 up to 2000 concurrent voice channels SIP / SDP up to 250 simultaneous SIP sessions up to 400 00 BHCA (signaling only) / RTCP up to 90 simultaneous sessions one Speech Quality Analysis of a connection at the time H.248 up to 700 000 message transactions / hour SS7 ISUP up to 380,000 BHCA (8 HDLC links) without speech path verification up to 20,000 BHCA with speech path verification (call duration 1 sec) ISDN PRA ISDN BA POTS Up to 160,000 BHCA without speech path verification up to 13,000 BHCA with speech path verification (call duration 1 sec) up to 135,000 BHCA without speech path verification up to 11,500 BHCA with speech path verification (call duration 1 sec) up to 8,000 BHCA with speech path verification (call duration 1 sec) Nexus8610VoIP Page 7
Notice Every effort was made to ensure that the information in this document was accurate at the time of printing. However, information is subject to change without notice, and Nexus Telecom reserves the right to provide an addendum to this document with information not available at the time that this document was created. Copyright Copyright 2005 Nexus Telecom. All rights reserved. No part of this guide may be reproduced or transmitted electronically or otherwise without written permission of the publisher. Trademarks Nexus Telecom and its logo are trademarks of Nexus Telecom AG. All other trademarks and registered trademarks are the property of their respective owners. Revision History Version Date Author 2.0 May 20 th 2005 Franz Neeser All General Inquiries: info@nexus-ag.com Nexus Telecom AG System Solutions Feldbachstrasse 80 P.O. Box 215 CH-8634 Hombrechtikon Switzerland Tel. +41 55 254 5111 Fax +41 55 254 5112 sales@nexus-ag.com support@nexus-ag.com Nexus Telecom AG Wireless Network Systems Muertschenstrasse 27 P.O. Box 1413 CH-8048 Zürich Switzerland Tel. +41 44 355 6611 Fax +41 44 355 6612 sales@nexus-ag.com help@nexus-ag.com Nexus Telecom (Americas) Inc. (NA and CALA) Suite 100 1101 Prince of Wales Drive Ottawa, Ontario Canada K2C 3W7 Tel. +1 613 224 2637 Fax +1 613 224 2761 sales@nxssolutions.com support@nexus-ag.com Nexus8610VoIP Page 8