The document summarizes research comparing the programming languages C++ and Erlang for developing distributed telecom software. Two telecom components, a data mobility component and dispatch call controller, were reengineered in Erlang and C++. The Erlang implementations were found to be more robust and resilient to failures, have higher productivity through significantly less code, and could meet performance requirements while providing dynamic reconfiguration capabilities. Some performance penalties and higher memory usage were observed for the Erlang components that interfaced with C code and libraries. The research concluded Erlang is suitable for telecom software development by providing robustness, productivity and ability to specify required functionality.

1. Phil Trinder & Computer Science Department Heriot-Watt University, UK David King Software & Systems Engineering Research Motorola Labs, UK Comparing C++ and Erlang for Motorola Telecoms Software Henry Nyström Erlang Training & Consulting

13. Performance 2: Round Trip Times Pure Erlang is approximately 3 times faster Erlang/C is 26% - 50% slower ms

16. RQ1 Robustness 1: Resilience Load (queries/s) Throughput (queries/s)

18. DCC Resilience

23. Productivity: Source Code Sizes DM Implementations DCC Implementations Erlang DCC and DM are less than 1/3 rd of size of C++ impl. Consistent with Wiger & folklore 398 398 Erlang 863 616 247 Erl./C 3101 3101 C++ Total Erlang C/C++ Lang. 4882 4882 Erl. 14.9K 83 14.8K C++ Total Erl. IDL C++ Lang.

26. DM Code Breakdown

27. Code Difference Example void DataMobilityRxProcessor::processUnsupVer(void) { MSG_PTR msg_buf_ptr; MM_DEVICE_INFO_MSG *msg_ptr; RETURN_STATUS ret_status; UINT16 msg_size; // Determine size of ici message msg_size = sizeof( MM_DEVICE_INFO_MSG); // Create ICI message object to send to DMTX so it sends a Device Info // message to VLR and HLR clients IciMsg ici_msg_object( MM_DEVICE_INFO_OPC, ICI_DMTX_TASK_ID, msg_size); // Retrieve ICI message buffer pointer msg_buf_ptr = ici_msg_object.getIciMsgBufPtr(); // Typecast pointer from (void *) to (MM_DEVICE_INFO_MSG *) msg_ptr = (MM_DEVICE_INFO_MSG *)msg_buf_ptr; // Populate message buffer SET_MM_DEVICE_INFO_DEVICE_TYPE( msg_ptr, SERVER); SET_MM_DEVICE_INFO_NUM_VER_SUPPORTED( msg_ptr, NUM_VER_SUPPORTED); SET_MM_DEVICE_INFO_FIRST_SUP_PROTO_VERS( msg_ptr, PROTO_VERSION_ONE); // Send message to the DMTX task ret_status = m_ici_io_ptr->send(&ici_msg_object); // Check that message was sent successfully if (ret_status != SUCCESS) { // Report problem when sending ICI message sz_err_msg( MAJOR, SZ_ERR_MSG_ERR_OPCODE, __FILE__, __LINE__, "DataMobilityRxProcessor processUnsupVer: failure sending " " device info message to DMTX"); } } Erlang sz_dme_dmtx:cast(device_info) C++

28. Erlang DCC Reusability Considerable potential for reuse 36% 11 1741 Testing/Stat.s 3% 1 147 Specific Services 61% 26 2994 Reusable Platform Percentage No. Modules SLOC Part