Siemens GERAN Troubleshooting Using Signaling Analyzer

Application Note Siemens GERAN Troubleshooting Using Signaling Analyzer Introduction................................................................................ 2 Scope of this Document..................................................................... 2 Overview of GERAN Architecture............................................................ 2 Signaling Analyzer/Network Analyzer Solution.............................................. 5 Overview of the Testing Process.............................................................. 6 Connecting Cables.......................................................................... 7 Configuring DNAs and Verifying T1/E1 Connections......................................... 9 Configuring Timeslots..................................................................... 16 Grouping Logical BTS Ports................................................................ 25 Applying TRAU/PCU Hardware Capture and Software Options............................. 30 Running Signaling Analyzer Measurements............................................... 31 Conclusion................................................................................ 35 Appendix................................................................................. 36 WEBSITE: www.jdsu.com/test

2 Introduction Most of the world s digital mobile communications uses Global System for Mobile Communications (GSM). GSM is the world s leading standard in digital wireless communications. There has been an evolution from GSM to GPRS and EDGE, which provides packet-switched transmission services in addition to the already existing circuit-switched transmission services. The most recent advancement in GSM is the GERAN standardization, which is the term given to the 3GPP standard for GSM/EDGE Radio Access Networks. GERAN is now considered by the International Telecommunications Union as a 3G technology. In general, GERAN advancements have focused on improving throughput, flexibility, and spectral efficiency. High-performance testing and diagnostic tools are essential for monitoring, troubleshooting, and maintaining GERAN networks. Signaling Analyzer is a software-based diagnostic tool that provides real-time and offline analysis to troubleshoot problems associated with voice, data, and video traffic for the network under test. Signaling Analyzer provides GERAN decodes and analysis capabilities when monitoring the Abis and EDGE protocols over GERAN networks. Scope of this Document This application note provides a brief overview of the GERAN architecture, which is based on a GSM EDGE 200 khz radio access network. The application note tells you how to connect cables to Distributed Network Analyzers (DNAs) and the network under test, use the Signaling Analyzer and Network Analyzer to set and verify configurations, configure timeslots to set signaling links, group logical BTS ports, apply hardware and software filter options, and run call traces to perform GERAN network analysis. The information presented here should be used in conjunction with the online Network Analysis and Troubleshooting Solutions Setup Guide, which provides installation and setup instructions for the hardware and software. Also refer to the Signaling Analyzer and Network Analyzer online help systems for detailed procedures and reference information. Overview of GERAN Architecture GERAN is the term given to the 3GPP standard for GSM/EDGE Radio Access Networks. GSM is part of an evolution of wireless mobile telecommunication that includes General Packet Radio System (GPRS) and Enhanced Data rate for GSM Evolution (EDGE). A brief overview about these technologies is provided to explain how the GERAN standardization was adopted. GSM uses digital radio transmission to provide voice, data, and multimedia communication services. GSM has its own set of communication protocols, interfaces, and functional entities. A GSM system coordinates the communication between mobile stations, base stations, and mobile switching centers. Each radio channel in the GSM system has a frequency bandwidth of 200 khz. The GSM system uses Time Division Multiple Access (TDMA) to increase its ability to serve multiple users with a limited number of radio channels. GPRS networks enable the use of a packet-based air interface over the existing circuit-switched GSM network. This feature allows greater efficiency in the radio spectrum because the radio bandwidth is used only when packets are sent or received. The GPRS system provides access to standard data networks, such as TCP/IP and X.25. GPRS achieves data transmission speeds up to 160 kbps. A GPRS network has two major network elements: Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN). Since GPRS uses the GSM radio resources only when users are sending or receiving data, multiple GPRS users can share a single unused channel because each of them uses it only for occasional short bursts. GPRS improves the utilization of the radio resources, offers higher transfer rates, shorter access times, and simplifies the access to packet data networks.

3 EDGE is a digital mobile phone technology, which is an enhancement to 2G and 2.5G GPRS networks. Packetswitched EDGE - called enhanced GPRS (EGPRS) - is an evolutionary upgrade of existing GPRS networks. EGPRS provides three times the data capacity of GPRS, and provides high-speed data transmissions up to 384 kbps when all eight timeslots are used. EGPRS provides channel coding and modulation methods, which include a mixture of GMSK (Gaussian Minimum Shift Keying) and 8PSK (8 Phase Shift Keying). The following diagram illustrates the GMSK and 8PSK modulation coding schemes: Figure 1: GPRS GMSK and 8PSK Modulation For GPRS, four different coding schemes, designated CS1 through CS4, are defined. Each has different amounts of error-correcting coding that is optimized for different radio environments. For EGPRS, nine modulation coding schemes, designated MCS1 through MCS9, are introduced. These fulfill the same task as the GPRS coding schemes. The lower four EGPRS coding schemes (MSC1 to MSC4) use GMSK, whereas the upper five (MSC5 to MSC9) use 8PSK modulation. Additionally, EDGE ensures link quality control through the techniques of link adaptation and incremental redundancy. EDGE uses the same TDMA frame structure, logic channel, and 200 khz carrier bandwidth as GSM networks. GERAN incorporates GSM, GPRS, and EDGE technologies to provide higher bandwidth data services and better voice quality services. GERAN networks allow users to maintain a virtual connection to a wireless network for voice and data rates.

4 This simplified view illustrates the basic components of a GERAN network. Figure 2: GSM/GPRS/EDGE Network The MS (Mobile Station) is the term used in GSM to describe the mobile phone. It is comprised of two distinct elements, the Mobile Equipment and the Subscriber Identity Module. Um is the air interface between the MS and BSS (Base Station Subsystem), which provides circuit and packet data services over the radio interface to the MS. The BTS (Base Transceiver Station) comprises the radio transmission and reception devices, and also manages the signal processing related to the air interface. The BSC (Base Station Controller) manages the radio interface, mainly through the allocation, release, and handover of radio channels. The combined functions of the BTS and BSC are referred to as the BSS. The TRAU (Transcoder and Rate Adaptation Unit) performs a compression function for speech channels and data channels. The TRAU enables the use of lower rates (32, 16, or 8 Kbps) over the Abis interface instead of 64 Kbps. The physical location of the TRAU can be found at the BTS, the BSC, or in front of the MSC. TRAU voice channels can vary in bandwidth between 8 Kbps for half rate and 16 Kbps for full rate and enhanced full rate. PCU (Packet Control Unit) processes the packet service and manages the packet radio channel resources in the BSS. The PCU is logically associated with the BSC. PCU data channels can be concatenated, up to 5; PCU 16 Kbps makes one logical data channel. The allocation of channels between voice and data is controlled by the base station. However, once a channel is allocated to the PCU, the PCU takes full control over that channel. GSM/GPRS Interfaces The following GSM (Abis, Asub, A, and Lb) interfaces and GPRS (Gb, Gn, and Gr) interfaces show a particular pair of components in a GERAN network. These interfaces comprise hardware, software, protocols, and control mechanisms that are required to transport GERAN traffic from one point in the system to another point. The Abis interface provides the interconnection between the BTS and BSC. It allows control of the radio equipment and radio frequency allocation in the BTS, and transports signaling protocols and compressed voice data between the GERAN and core voice network. Typically, the Abis interface consists of T1 or E1 circuit lines. The primary protocol on the Abis interface is BTSM (Base Transceiver Station Management). The BTSM is responsible for transferring the RR (Radio Resource) information (not provided for in the BTS by the RR protocol) to the BSC.

5 The Asub interface provides the interconnection between the BSC and TRAU. The Asub interface manages the voice signal coming from the BSC module to the TRAU module. The A interface provides the interconnection between the BSS and a MSC (Mobile Switching Center). The MSC controls calls to and from other networks. The A interface manages the allocation of suitable radio resources to the MSs and mobility management. The primary protocol on the A interface is BSSAP (BSS Application Part). BSSAP is further divided into DTAP (Direct Transfer Application Part) and BSSMAP (Base Station Subsystem Management Application Part) protocols. The Lb interface provides the interconnection between the BSS and the SMLC (Serving Mobile Location Center). The SMLC pulls the real-time NMR (Network Measurement Report) information from the BSC using an IP interface to the Abis probe units (APU) and the Abis control function (ACF). Messaging with the BSC to coordinate the location process is performed on the Lb interface over Signaling System 7 (SS7). Signaling on this Lb interface uses BSSAP-LE. The Gb interface provides the interconnection between the BSS and the SGSN. The SGSN keeps track of the location of an individual MS, and performs security functions and access control. When setting up virtual circuits between the BSS and SGSN, the Gb interface can use the connection-oriented Frame Relay protocol or Gb over IP Protocol Stack. The Gn interface provides the interconnection between the SGSN and the GGSN. GGSN is a wireless gateway that allows mobile cell phone users to access the public data network or private IP networks. The Gn interface is an IP-based interface, and most current implementations use Ethernet backbones at 100 base TX rates. The connection between the SGSN and the GGSN is enabled through a protocol called the GPRS Tunneling Protocol (GTP). This protocol encapsulates user data and carries GPRS signaling. The Gr interface provides the interconnection between the SGSN and the HLR (Home Location Register). The Gr interface is used to get the user profile, current SGSN address, and the PDP (Packet Data Protocol) address for each user in the PLMN (Public Land Mobile Network). The connection between the SGSN and HLR is enabled through the GSM MAP Protocol. The next section discusses the data acquisition systems used to capture GERAN data. Signaling Analyzer/Network Analyzer Solution When used for real-time analysis, the Signaling Analyzer relies on Network Analyzer hardware and software for its data acquisition system. This includes Distributed Network Analyzers (DNAs) used as network test hardware platforms. These hardware platforms use Line Interface Modules (LIMs) to provide the physical interface to the network under test. The Network Analyzer software controls the data acquisition hardware on the platforms on which it is installed, and is used to monitor network performance and gather statistical measurement data. For Signaling Analyzer Real-Time, the J6824A Eight-port T1/E1 LIMs and the Four-port STM-1/OC-3 LIM Multiplexers (when connected to J6810B LIMs) can be deployed to the GERAN network under test. When a J6824A LIM is installed in a DNA, data analysis for channelization with HDLC (SS7, Frame Relay, and ISDN) and TRAU/PCU 16K framing can be done. Any combination of Abis, Asub, A, Gb, or Gr interfaces can be connected to any of one of the eight ports. For example, there could be 4 Abis interfaces with 4 Gb interfaces, or just 8 Abis interfaces. When the Four-port STM-1/OC-3 LIM Multiplexer is connected to the J6810B STM-4/OC-12/STM-1/OC-3 LIM, and the J6810B LIM is installed in a DNA, data analysis for channelization can be done through the STM- 1/OC-3 fibre connection, which uses SONET/SDH services to de-multiplex the packets into T1/E1 frames. You must activate the Demux Channelization license in Signaling Analyzer before capturing data. Any combi-

6 nation of Abis, Asub, A, Gb, or Gr interfaces can be connected to any one of the four ports. For example, there could be 2 Abis interfaces and 2 Asub interfaces, or just 4 Abis interfaces. Refer to the Network Analysis and Troubleshooting Solutions Setup Guide for detailed information about these products and how they work together. Overview of the Testing Process This diagram shows the location of 1-8 E1/T1 lines and deployed DNAs in a GERAN environment. Figure 3: E1/T1 GERAN Environment This diagram shows DNAs deployed at the Abis and Asub interfaces over a STM-1/OC-3 fibre connection with SDH de-multiplexing into E1/T1 frames. Figure 4: STM-1/OC-3 (SONET/SDH) GERAN Environment Using the above diagrams, the discussion that follows focuses on DNAs deployed across the Abis and Asub interfaces. The Abis interface between the BTS and the BSC, and the Asub interface between the BSC and

7 TRAU must be monitored closely to ensure the appropriate Quality of Service. To achieve rapid fault detection and rectification, end-to-end monitoring must be used. Continuous monitoring allows network engineers to detect and preempt interference and noise in the wireless network, buffer management in the core network, defective equipment and cabling, handover performance, and traffic distribution. To test in a GERAN environment with the Signaling Analyzer, you typically perform the following tasks: Connecting cables from the DNA to the network under test Configuring DNAs and verifying connections Configuring Abis and PCU and TRAU timeslots Configuring Asub, Gb, A, Lb, and Gr timeslots Grouping logical BTS and physical ports Applying TRAU/PCU hardware and software capture options Running Signaling Analyzer measurements The following sections describe how to perform these tasks. Connecting Cables J6824A Eight-port T1/E1 LIM The Eight-port E1/T1 LIM has 8 ports, which are configurable for T1 or E1 framing. This LIM supports channelization with HDLC (SS7, Frame Relay and ISDN) or TRAU 16K framing for the Signaling Analyzer. When connecting cables from this LIM to the GERAN network, JDSU recommends using a balanced monitor tap connection. This diagram illustrates how to connect the LIM to the Balanced Monitor Tap using 3- foot Cat5 cables. It further shows how to connect the 7- foot Cat5 cables to the network under test. Figure 5: J6826A T1/E1 Balanced Monitor Tap Note: Refer to the online Network Analysis and Troubleshooting Solutions Setup Guide for detailed information about other connections using the J6824A Eightport T1/E1 LIM.

8 J6828A Four-port STM-1/OC-3 LIM Multiplexer The Four-port STM-1/OC-3 LIM Multiplexer is an external device used exclusively with the J6810B STM-4/ OC-12/STM-1/OC-3 LIM to multiplex four full-duplex STM-1/OC-3 data streams into the ports of the J6810B. The multiplexer comes with four pairs of STM-1/OC-3 full-duplex, receiver-only ports contained in a single enclosure. Optical Splitter When connecting cables from the J6828A Four-port STM-1/OC-3 LIM Multiplexer to the GERAN network under test, JDSU recommends using optical splitters for connection. Using optical splitters is the most convenient way to allow quick connections and testing without the risk of interrupting network service. Best results are obtained when you use full single-mode systems with power levels greater than -25 dbm. Note: Using multi-mode splitters are strongly discouraged and may lead to optical pulse shape distortion preventing accurate measurement by the J6828A. Figure 6: J6828A Four-port STM-1/OC-3 LIM Multiplexer

9 Configuring DNAs and Verifying T1/E1 Connections In this section, you will configure DNAs and verify that the physical connections to the Abis T1/E1 interfaces are correct. Each of the four steps describes how to perform these tasks with examples for the Eight- port T1/E1 LIM and the Four-port STM-1/OC-3 LIM Multiplexer. Note: Refer to the Signaling Analyzer and Network Analyzer online help for specific details concerning each view. Step 1: Launch the Signaling Analyzer Real-Time application. In the Bearer view of the Configuration window, you can view a list of DNAs on the network under test. Select an Eight-port T1/E1 LIM that is connected to the Abis or Asub interface, and assign a default configuration (Default Config) file to each DNA the first time. Set the Type to Eight-port E1 or Eight-port T1 and Mode to Channelized for the Eight-port T1/E1 LIM. Figure 7: Bearer View with the Select NA Configuration File dialog box opened (Eight-port T1/E1 LIM)

10 Select a Four-port STM-1/OC-3 LIM Multiplexer that is connected to the Abis or Asub interface, and assign a default configuration (Default Config) file to each DNA the first time. Set the Type to SDH (STM-1) or SONET (OC-3), Mode to Channelized, the Demux path to T1 (VC-11) or E1 (VC-12), and the AU Mode to AU3 or AU4. Figure 8: Bearer View after setting default configuration (Four-port STM- 1/OC3 LIM Multiplexer) Step 2: From the Signaling Analyzer Bearer View, launch the Network Analyzer application by clicking the Show Network Analyzer button. From the Interface/Protocols view, click to open the Eight-port T1 or E1 Configuration dialog box. The following parameters must be configured: Receiver mode - Monitor Jack -20dB Line code - HDB3 Framing - Multiframe w/crc4 Use Monitor Jack -20dB receiver mode for isolated T1/E1 test point signals along the EDGE Abis interface. Do not use Bridged Mode with the J6826A Monitor Tap or other monitor points. Use the Copy Configuration On This Tab To All Port Configuration Tabs button to copy this configuration across all eight ports of the T1/E1 LIM when all of the ports are electrically the same.

11 Figure 9: Eight-port E1 Configuration (or Eight-port T1 Configuration) dialog box You do not click to open the 4 port OC-3/STM-1 Configuration dialog box because the parameters are disabled when the Layer 2 Protocol is Channelized. For this LIM, the Type, Mode, Demux Path, and AU Mode are controlled directly from the Signaling Analyzer application as described in Step 1 above. Proceed to Step 3, Step 4, and Step 5, which are tasks done in the Network Analyzer application.

12 Step 3: Open the Line Status view, start the measurement, and verify the status of the signals. All green LEDs indicate the signals are in a Normal state. If any red LEDs are displayed for LOS, LOF, AIS, or RAI, check the network under test to ensure that the T1/E1 lines are connected properly and to verify that the network is up and running. Then, rerun this measurement. Figure 10: Network Analyzer Line Status Measurement for Eight-port T1/E1 LIM. The Line Status Measurement for the Four-port OC-3/STM-1 LIM Multiplexer is very similar.

13 Step 4: Open the Protocol Vitals view, start the measurement, and verify the power levels for the LN and EQ Signaling Amplitude for each port. The power levels should show between -1.2 dbdsx and -10.0 dbdsx. This range of levels indicates you are properly connected to the network under test. It is important to verify that the other statistics (Code Violations, LOF events, etc.) have counts of 0, or at most a few counts every 10 seconds or so. After verifying power levels and other statistics, save all the configurations from Step 2 through Step 4. Figure 11: Network Analyzer Protocol Vitals Measurement for Eight-port T1/E1LIM

14 Figure 12: Network Analyzer Protocol Vitals Measurement for Four-port OC-3/STM-1 LIM Multiplexer

15 Step 5: Select File Save (Data) to save the configurations you just made to a data file (*.dat) file. Browse to the directory where you want to save the data file. In the Save Options area, select only the Configuration option and deselect the other options, if enabled. Enter the file name of the data file and click Save. Figure 13: Save As Dialog Box in Network Analyzer After saving the data file, select File Exit to close the Network Analyzer application. You will return to the Bearer View in the Signaling Analyzer application.

16 Configuring Timeslots When configuring timeslots, you are setting channel rates for signaling links. The timeslot range is 1 through 31 for E1 interfaces, and 1 through 24 for T1 interfaces. Timeslot 0 is reserved for framing per G.703/704 ITU-T requirements. Each of the five steps describes how to configure timeslots with examples for the Eightport T1/E1 LIM and the Four-port STM-1/OC-3 LIM Multiplexer. Configuring Abis and TRAU/PCU Timeslots To configure proprietary Abis and PCU/TRAU 16K timeslots, follow these steps. Step 1: From the Bearer View in Signaling Analyzer, click to open the Timeslots Configuration dialog box. Select the first timeslot and add the signaling link. Click OK to open the Channel Properties dialog box. Figure 14: Timeslots Configuration Dialog Box (Eight-port T1/E1 LIM)

17 Figure 15: Timeslots Configuration Dialog Box for Four-port STM-1/OC-3 LIM Multiplexer Note: You will configure tributaries on all T1s and E1s that are present in the Four-port OC-3/STM-1 LIM Multiplexer in the Tributary Table, which is located above the timeslots. Select or deselect the tributary you want to activate in the table before configuring the timeslots. Refer to the Signaling Analyzer online help for more information.

18 Step 2: In the Channel Properties dialog box, assign a name to each channel in the timeslots you want to monitor. Use a name that uniquely identifies the channel link. All channel link names must be in English or numeric format. For example, BTS 1:RSL 0. Set the Layer 2 Protocol to ISDN/Frame Relay/Abis and select Siemens Abis. Siemens Abis BR 8.0-9.0 represents the circuit-switched signaling channel. Use the Filtering Options area to enable or disable specific filters. Figure 16: Channel Properties Dialog Box (for Eight-port T1/E1 LIM and Four-port LIM Multiplexer) Note: You must license specific vendor proprietary decodes to use Siemens Abis and Siemens PCU and TRAU in Signaling Analyzer. Refer to the Signaling Analyzer online help for more information. Important: For different vendor proprietary decodes, configuration might be different.

19 Step 3: Return to the Timeslots Configuration dialog box to set the PCU and TRAU signaling channels. The TRAU unit codes the 64 Kbits/s signal originating from the PSTN network to a 16 Kbits/s signal, where user data rates are set at specific levels. Therefore, the timeslots format for PCU and TRAU signaling channels must be changed from 64 Kbits/s to 16 Kbits/s. Select the second timeslot, press the Shift key, and select the remaining timeslots. Right-click and select Add Multiple Links and apply 16 Kbits/s. This PCU and TRAU configuration auto detects 8 Kbits/s TRAU signaling as well. This selection will populate the PCU and TRAU signaling links across all highlighted timeslots. Click OK to open the Channel Properties dialog box. Figure 17: Timeslots Configuration Dialog Box for Eight-port T1/E1 LIM

20 Figure 18: Timeslots Configuration Dialog Box for Four-port STM-1/OC-3 LIM Multiplexer Note: Abis uplink/downlink must be connected in the correct direction, otherwise the PCU/TRAU auto detection will fail. For GERAN Abis, the messages coming from the phone must be on port x.1 direction (Uplink) and the messages coming from the BSC must be on port x.2 direction (Downlink). If the hardwired connectors are going in the opposite way, then the uplink messages and downlink messages are reversed. Rather than having connections rewired, use the Swap uplink and downlink for this port check box in the Timeslot Configuration dialog box to swap over data to correct this problem. Refer to the Signaling Analyzer online help for more information.

21 Step 4: In the Channel Properties dialog box, assign a name to each channel, set the Layer 2 Protocol to TRAU/PCU 16K, and select Siemens PCU and TRAU BR 8.0 or BR 9.0. Siemens PCU and TRAU represent the packetswitched signaling channel and traffic channel. Figure 19: Channel Properties Dialog Box (same for the Eight-port T1/E1 LIM and the Four-port STM-1/OC-3 LIM Multiplexer)

22 Return to the Timeslot Configuration dialog box where the actual configurations are displayed. Figure 20: Eight-port T1/E1 LIM Abis and PCU/TRAU Timeslots Figure 21: Four-port STM-1/OC-3 LIM Multiplexer Abis and PCU/TRAU Timeslots Step 5:

23 Step 5: Apply the previous four steps on other ports where the Gr, A, Asub, Lb, and Gb interfaces will be set. For the Gr, A, and Lb interfaces, the Layer 2 Protocol is SS7 MTP2. For the Asub interface, the Layer 2 Protocol is ISDN/ Frame Relay/Abis. Select one 64K timeslot for each of these interfaces. Figure 22: Channel Properties Dialog Box For the Gb interface, the Layer 2 Protocol is ISDN/Frame Relay/Abis. You may select all timeslots for the Gb interface, or only several depending on your setup. For Gb control, you can enable user filtering at a Multi-User Server, if connected to one, or locally through the Signaling Analyzer Real-Time application. Filtering is available only for Signaling Analyzer Real-Time or Multi-User Clients. Note: Refer to the Signaling Analyzer online help for more information about the Filters Disabled/Enabled dialog box where you enable filtering for Signaling Analyzer Real-Time or Multi-User Clients.

24 The Protocol Stack Information area of the Bearer View in the Configuration window displays the newly configured channels to monitor for the Eight-port T1/E1 and Four-port STM-1/OC3. Figure 23. Bearer View in the Configuration window for Eight-port T1/E1 LIM Figure 24. Bearer View in the Configuration window for Four-port STM-1/OC-3 LIM Multiplexer

25 Grouping Logical BTS Ports After you configure your timeslots, you will configure your Port Mapping Table for Abis links only. By doing so, you can change the default values for the logical BTS number and BTS port number to reflect the actual network configuration to the BTS. The Port Mapping Table shows which Abis ports from a specific BTS are connected into the physical port on the LIM. To access the Port Mapping Table, click the GERAN Options button in the Timeslot Configuration dialog box. To enter values, click the Add Entry button to assign the appropriate BTS number that correctly matches the physical configuration for each LIM port. The following examples illustrate different scenarios to assist in making configuration changes to the BTS for the Eight-port T1/E1 LIM and Four-port STM-1/OC-3 LIM Multiplexer. Scenario 1 This figure shows a BTS that has 1 E1 (Logical Port ID = 0) and 1 RSL timeslot (BTS1/LIM Port 1) for the Eightport T1/E1 LIM. Figure 25: Port Mapping Table for the Eight-port T1/E1 LIM

26 Scenario 2 This figure shows a BTS that has multiple E1s (Logical Port IDs = 0, 2, 4, 6) and each E1 has its own load shared RSL (BTS1/LIM Ports 1, 2, 3, & 4) for the Eight-port T1/E1 LIM. Figure 26: Port Mapping Table for Eight-port T1/E1 LIM

27 Scenario 3 This figure shows two BTS that share an E1 (Logical Port ID = 0) and each has an RSL timeslot (BTS 1 & 2/LIM Port 1) for the Eight-port T1/E1 LIM. Figure 27: Port Mapping Table for Eight-port T1/E1 LIM

28 Scenario 4 This figure shows a BTS that has multiple E1s (Logical Port IDs = 0, 2, 4, 6) and only Port 1 has an RSL (BTS1/ LIM Port 1) for the Eight-port T1/E1 LIM. Figure 28: Port Mapping Table for Eight-port T1/E1 LIM

29 Scenario 5 This figure shows a BTS that has 1 E1 (Logical Port ID = 0), 1 RSL timeslot (BTS1/LIM Port 1) with a Tributary ID of 1.1.1 for the Four-port STM-1/OC-3 LIM Multiplexer. Figure 29: Port Mapping Table for Four-port STM-1/OC-3 LIM Multiplexer

30 Applying TRAU/PCU Hardware Capture and Software Options In the GERAN Options dialog box, you can apply TRAU/PCU hardware capture and software options to ensure that the data capture contains TRAU/PCU frames that are of particular interest. Additionally, network bandwidth is saved because the J6824A Eight-port T1/E1 LIM and Four- port STM-1/OC-3 LIM Multiplexer do not send the frames to Signaling Analyzer. To apply hardware and software options, follow these steps. Step 1: The Capture TRAU Frames and Capture PCU Frames check boxes are selected by default. Make selections in each category to suppress unwanted frames from the data capture. Figure 30: GERAN Options Dialog Box for TRAU/PCU Hardware Capture Options (same for Eight-port T1/E1 LIM and Four-Port STM-1/OC-3 LIM Multiplexer) Step 2: The TRAU/PCU software options are used to discard specific types of lower-layer frames or PDUs after reassembly occurs, to keep your data capture updated with the next higher-layer messages. Refer to the Signaling Analyzer online help for detailed information about each option.

31 Running Signaling Analyzer Measurements Before capturing data to perform analysis on a GERAN network, you may want to configure a Call Trace, Graphical Statistics, or Tabular Statistics view. For this test scenario, we will configure a call trace view that groups Abis Interface Signaling and RLC/MAC (Radio Link Control/Medium Access Control) PDUs, TRAU speech frames, and PCU packet data frames. To configure GERAN Call Traces, follow these steps. Step 1: Click the Call Trace toolbar in the Monitor window. The Call Trace Configuration dialog box appears. Use the list box to display the available A & Abis & Gb, Abis, and Abis & Gb profiles. Figure 31: Call Trace Configuration Dialog Box Step 2: Select the appropriate profile, and then return to the Call Trace Configuration dialog box. Then, select the required parameters in the Call Selection Tab, Call Warnings Tab, and Call Phase Tab to configure the appearance of the GERAN Call Trace view.

32 Step 3: For real-time analysis, click the REC button in the Monitor window to begin data capture. Click Stop to stop the data capture. Signaling Analyzer displays the Traffic Overview and the Call Trace view. Figure 32: Traffic Overview and Call Trace View with Abis CS Speech Calls (using the Eight- port T1/E1 LIM)

33 Figure 33: Traffic Overview and Call Trace View with Abis CS Speech Calls (using the Four- port OC-3/STM-1 LIM Multiplexer)

34 Step 4: For offline analysis, you can import a data file of GERAN network traffic. This first figure illustrates the Abis Signaling and RLC/MAC PDUs Call Trace with RLC/MAC Statistics. In the Traffic Overview, the circled item indicates the retransmit labeling of RLC/MAC blocks. In the Call Trace view, the circled item indicates the RLC/MAC Statistics where you can see the Bad FQI Ratio and %, the RLC Uplink Retransmits, and the RLC Downlink Retransmits. Figure 34: Abis Signaling and RLC/MAC PDUs Call Trace with RLC/MAC Statistics

35 This next figure illustrates an Abis and Gb Call Trace. Figure 35: Traffic Overview and Abis and Gb Call Trace Conclusion To monitor and troubleshoot GERAN network infrastructures, Signaling Analyzer relies on Distributed Network Analyzers (DNAs) as its data acquisition system. After configuring DNAs and verifying configurations, several basic tasks are performed using Signaling Analyzer to set and configure parameters associated with timeslots, port mapping, and filters. Before running Signaling Analyzer measurements, configure your GERAN call trace information as directed in this application note. You may also configure your graphical and tabular statistics to provide specific count/ ratio information. You can analyze traffic as it is captured in real-time or you can import a previously captured data file.

36 Appendix Converting the J6810B LIM to a single-port J6828A STM-1/OC-3 LIM Multiplexer for VC11/VC12 de-multiplexing capability allows you to run as a single-port LIM in channelized mode. When the J6810B is not connected to the J6828A Four-port STM-1/OC-3 LIM Multiplexer, follow the procedure below to convert the J6810B to a single-port J6828A STM-1/OC-3 LIM: 1. Launch the Network Analyzer software. 2. Open the Select Network Analyzer LIM dialog box. 3. Right-click the J6810B LIM, and select LIM Properties. 4. Choose STM-1/OC3 Demux. When this change occurs, the LIM reboots automatically and becomes a J6828A LIM Multiplexer with only one port. Although the Network Analyzer software recognizes this J6828A LIM Multiplexer as having four ports, only Port 1 is actually configured in this mode and available for monitoring. After converting the J6810B to a single-port J6828A STM-1/OC-3 LIM, use the Signaling Analyzer and Network Analyzer to set and verify configurations, configure timeslots to set signaling links, group logical BTS ports, apply hardware and software filter options, and run call traces to perform GERAN network analysis. Simply follow the steps in this document for the Four-Port OC-3/STM-1 LIM Multiplexer and apply to the single-port J6828A STM-1/OC-3 LIM. To return the J6810B to its normal mode, follow these steps: 1. Right-click the J6810B LIM, and select LIM Properties. 2. Choose STM-4/OC12. When this change occurs, the LIM reboots automatically and becomes a single-port OC-3/OC-12 LIM. Test & Measurement Regional Sales NORTH AMERICA TEL: 1 866 228 3762 FAX: +1 301 353 9216 LATIN AMERICA TEL: +1 954 688 5660 FAX: +1 954 345 4668 ASIA PACIFIC TEL: +852 2892 0990 FAX: +852 2892 0770 EMEA TEL: +49 7121 86 2222 FAX: +49 7121 86 1222 WEBSITE: www.jdsu.com/test Product specifications and descriptions in this document subject to change without notice. 2010 JDS Uniphase Corporation 30168078 500 0610 GERAN.AN.NSD.TM.AE June 2010