Proceedings of the 14th ACM SIGPLAN international conference on Functional programming - ICFP '09, 2009
We address the problem of testing and debugging concurrent, distributed Erlang applications. In c... more We address the problem of testing and debugging concurrent, distributed Erlang applications. In concurrent programs, race conditions are a common class of bugs and are very hard to find in practice. Traditional unit testing is normally unable to help finding all race conditions, because their occurrence depends so much on timing. Therefore, race conditions are often found during system testing, where due to the vast amount of code under test, it is often hard to diagnose the error resulting from race conditions. We present three tools (QuickCheck, PULSE, and a visualizer) that in combination can be used to test and debug concurrent programs in unit testing with a much better possibility of detecting race conditions. We evaluate our method on an industrial concurrent case study and illustrate how we find and analyze the race conditions.
Proceedings of the 2002 ACM SIGPLAN workshop on Erlang - ERLANG '02, 2002
It is now ten years ago since the decision was made to apply the functional programming language ... more It is now ten years ago since the decision was made to apply the functional programming language Erlang to real production projects at Ericsson. In late 1995, development on the Open Telecom Platform (OTP) started, and in mid 1996 the AXD 301 project became the first user of OTP. The AXD 301 Multi-service Switch was released in October 1998, and later became "the heart of ENGINE", Ericsson's leading Voice over Packet solution. This paper demonstrates how Erlang's declarative syntax and pattern matching provide an outstanding environment for test suite development.
The built-in process registry has proven to be an extremely useful feature of the Erlang language... more The built-in process registry has proven to be an extremely useful feature of the Erlang language. It makes it easy to provide named services, which can be reached without knowing the process iden-tifier of the serving process. However, the current registry also has limitations: names can only be atoms (unstructured), processes can register under at most one name, and it offers no means of efficient search and iteration. In Ericsson’s IMS Gateway products, a recurring task was to maintain mapping tables in order to locate call handling processes based on different properties. A common pattern, a form of index table, was identified, and resulted in the development of an ex-tended process registry. It was not immediately obvious that this would be worthwhile, or even efficient enough to be useful. But as implementation pro-gressed, designers found more and more uses for the extended process registry, which resulted in significant reduction of code volume and a more homogeneous impleme...
We present a case study in which a novel testing tool, Quviq QuickCheck, is used to test an indus... more We present a case study in which a novel testing tool, Quviq QuickCheck, is used to test an industrial implementation of the Megaco protocol. We considered positive and negative testing and we used our developed specification to test an old version in order to estimate how useful QuickCheck could potentially be when used early in development. The results of the case study indicate that, by using Quviq QuickCheck, we would have been able to detect faults early in the development. We detected faults that had not been detected by other testing techniques. We found unclarities in the specifications and potential faults when the software is used in a different setting. The results are considered promising enough to Ericsson that they are investing in an even larger case study, this time from the beginning of the development of a new product.
RELEASE: a high-level paradigm for reliable large-scale server software
Abstract. Erlang provides a fault-tolerant, reliable model for building concur-rent, distributed ... more Abstract. Erlang provides a fault-tolerant, reliable model for building concur-rent, distributed system based on functional programming. In the RELEASE pro-ject the Erlang model is extended to Scalable Distributed Erlang – SD Erlang – supporting general-purpose computation in massively multicore systems. This paper outlines the RELEASE proposal, and indicates the progress of the project in its first six months. 1
The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant a... more The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant and highly scalable backbone ATM switch, AXD 301 has enabled Ericsson to take the lead in the migration of public telephony networks to becoming true multiservice networks, offering both quality voice and broadband data services on the same backbone. Telecom-class products exhibit some very special characteristics, which are fast becoming essential even in other products, such as traditional datacom products, trading systems and application servers: iii (28) ETX/D/XPS-01:001 Uen Ulf Wiger, Ericsson Telecom AB 01-03-30 "Four-fold Increase in Productivity and Quality" Rev C 4 THE ERLANG PROGRAMMING LANGUAGE 4.1 BACKGROUND 4.2 SEQUENTIAL ERLANG 4.3 CONCURRENT ERLANG 4.3.1 CLIENT-SERVER EXAMPLE 4.3.2 FINITE STATE MACHINE 4.3.3 SUPERVISOR PROCESSES 4.4 BUILT-IN FUNCTIONS 4.5 EXTERNAL INTERFACES 4.6 DYNAMIC CODE LOADING 5 OPEN TELECOM PLATFORM 6 DEVELOPMENT OF AXD 301 6.1 BACKGROUND 6.2 ASSUMPTIONS 6.3 PROJECT 6.3.1 EARLY PHASES UNDER ONE ROOF 6.3.2 POWERFUL ARCHITECTURE TEAM 6.3.3 CLEAR CHAIN OF COMMAND 6.3.4 RAPID DECISIONS 6.3.
Proceedings of the 9th ACM SIGPLAN workshop on Erlang - Erlang '10, 2010
Although Telecoms, the domain for which Erlang was conceived, has strong and ubiquitous requireme... more Although Telecoms, the domain for which Erlang was conceived, has strong and ubiquitous requirements on overload protection, the Erlang/OTP platform offers no unified approach to addressing the problem. The Erlang community mailing list frequently sports discussions on how to avoid overload situations in individual components and processes, indicating that such an approach would be welcome. As Telecoms migrated from carefully regulated singleservice networks towards multimedia services on top of best-effort multi-service packet data backbones, much was learned about providing end-to-end quality of service with a network of loosely coupled components, with only basic means of prioritization and flow control. This paper explores the similarity of such networks with typical Erlang-based message-passing architectures, and argues that a robust way of managing high-load conditions is to regulate at the input edges of the system, and sampling known internal choke points in order to dynamically maintain optimum throughput. A selection of typical overload conditions are discussed, and a new load regulation framework-JOBS-is presented, together with examples of how such overload conditions can be mitigated.
Proceedings of the 2007 SIGPLAN workshop on Erlang Workshop - Erlang '07, 2007
The built-in process registry has proven to be an extremely useful feature of the Erlang language... more The built-in process registry has proven to be an extremely useful feature of the Erlang language. It makes it easy to provide named services, which can be reached without knowing the process identifier of the serving process. However, the current registry also has limitations: names can only be atoms (unstructured), processes can register under at most one name, and it offers no means of efficient search and iteration. In Ericsson's IMS Gateway products, a recurring task was to maintain mapping tables in order to locate call handling processes based on different properties. A common pattern, a form of index table, was identified, and resulted in the development of an extended process registry. It was not immediately obvious that this would be worthwhile, or even efficient enough to be useful. But as implementation progressed, designers found more and more uses for the extended process registry, which resulted in significant reduction of code volume and a more homogeneous implementation. It also provided a powerful means of debugging systems with many tens of thousand processes. This paper describes the extended process registry, critiques it, and proposes a new implementation that offers more symmetry, better performance and support for a global namespace.
ABSTRACT The telecommunications world is now moving rapidly towards SIP-based telephony and multi... more ABSTRACT The telecommunications world is now moving rapidly towards SIP-based telephony and multimedia. The vision is to merge mobile and fixed networks into one coherent multimedia network. Ericsson has been a pioneer in SIP technology, and the first Erlang-based SIP stack was presented in 1999. A fortunate turn of events allowed us to revive the early SIP experiments, rewrite the software and experiment to find an optimal architecture, and later verify our implementation with great success in international interop events. We believe this to be a superb example of how a small team of experts, armed with advanced programming tools, can see their ideas through, with prototypes, field trials, and later large-scale industrial development.
The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant a... more The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant and highly scalable backbone ATM switch, AXD 301 has enabled Ericsson to take the lead in the migration of public telephony networks to becoming true multiservice networks, offering both quality voice and broadband data services on the same backbone. Telecom-class products exhibit some very special characteristics, which are fast becoming essential even in other products, such as traditional datacom products, trading systems and application servers: iii (28) ETX/D/XPS-01:001 Uen Ulf Wiger, Ericsson Telecom AB 01-03-30 "Four-fold Increase in Productivity and Quality" Rev C 4 THE ERLANG PROGRAMMING LANGUAGE 4.1 BACKGROUND 4.2 SEQUENTIAL ERLANG 4.3 CONCURRENT ERLANG 4.3.1 CLIENT-SERVER EXAMPLE 4.3.2 FINITE STATE MACHINE 4.3.3 SUPERVISOR PROCESSES 4.4 BUILT-IN FUNCTIONS 4.5 EXTERNAL INTERFACES 4.6 DYNAMIC CODE LOADING 5 OPEN TELECOM PLATFORM 6 DEVELOPMENT OF AXD 301 6.1 BACKGROUND 6.2 ASSUMPTIONS 6.3 PROJECT 6.3.1 EARLY PHASES UNDER ONE ROOF 6.3.2 POWERFUL ARCHITECTURE TEAM 6.3.3 CLEAR CHAIN OF COMMAND 6.3.4 RAPID DECISIONS 6.3.
Proceedings of the 14th ACM SIGPLAN international conference on Functional programming - ICFP '09, 2009
We address the problem of testing and debugging concurrent, distributed Erlang applications. In c... more We address the problem of testing and debugging concurrent, distributed Erlang applications. In concurrent programs, race conditions are a common class of bugs and are very hard to find in practice. Traditional unit testing is normally unable to help finding all race conditions, because their occurrence depends so much on timing. Therefore, race conditions are often found during system testing, where due to the vast amount of code under test, it is often hard to diagnose the error resulting from race conditions. We present three tools (QuickCheck, PULSE, and a visualizer) that in combination can be used to test and debug concurrent programs in unit testing with a much better possibility of detecting race conditions. We evaluate our method on an industrial concurrent case study and illustrate how we find and analyze the race conditions.
Proceedings of the 2002 ACM SIGPLAN workshop on Erlang - ERLANG '02, 2002
It is now ten years ago since the decision was made to apply the functional programming language ... more It is now ten years ago since the decision was made to apply the functional programming language Erlang to real production projects at Ericsson. In late 1995, development on the Open Telecom Platform (OTP) started, and in mid 1996 the AXD 301 project became the first user of OTP. The AXD 301 Multi-service Switch was released in October 1998, and later became "the heart of ENGINE", Ericsson's leading Voice over Packet solution. This paper demonstrates how Erlang's declarative syntax and pattern matching provide an outstanding environment for test suite development.
The built-in process registry has proven to be an extremely useful feature of the Erlang language... more The built-in process registry has proven to be an extremely useful feature of the Erlang language. It makes it easy to provide named services, which can be reached without knowing the process iden-tifier of the serving process. However, the current registry also has limitations: names can only be atoms (unstructured), processes can register under at most one name, and it offers no means of efficient search and iteration. In Ericsson’s IMS Gateway products, a recurring task was to maintain mapping tables in order to locate call handling processes based on different properties. A common pattern, a form of index table, was identified, and resulted in the development of an ex-tended process registry. It was not immediately obvious that this would be worthwhile, or even efficient enough to be useful. But as implementation pro-gressed, designers found more and more uses for the extended process registry, which resulted in significant reduction of code volume and a more homogeneous impleme...
We present a case study in which a novel testing tool, Quviq QuickCheck, is used to test an indus... more We present a case study in which a novel testing tool, Quviq QuickCheck, is used to test an industrial implementation of the Megaco protocol. We considered positive and negative testing and we used our developed specification to test an old version in order to estimate how useful QuickCheck could potentially be when used early in development. The results of the case study indicate that, by using Quviq QuickCheck, we would have been able to detect faults early in the development. We detected faults that had not been detected by other testing techniques. We found unclarities in the specifications and potential faults when the software is used in a different setting. The results are considered promising enough to Ericsson that they are investing in an even larger case study, this time from the beginning of the development of a new product.
RELEASE: a high-level paradigm for reliable large-scale server software
Abstract. Erlang provides a fault-tolerant, reliable model for building concur-rent, distributed ... more Abstract. Erlang provides a fault-tolerant, reliable model for building concur-rent, distributed system based on functional programming. In the RELEASE pro-ject the Erlang model is extended to Scalable Distributed Erlang – SD Erlang – supporting general-purpose computation in massively multicore systems. This paper outlines the RELEASE proposal, and indicates the progress of the project in its first six months. 1
The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant a... more The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant and highly scalable backbone ATM switch, AXD 301 has enabled Ericsson to take the lead in the migration of public telephony networks to becoming true multiservice networks, offering both quality voice and broadband data services on the same backbone. Telecom-class products exhibit some very special characteristics, which are fast becoming essential even in other products, such as traditional datacom products, trading systems and application servers: iii (28) ETX/D/XPS-01:001 Uen Ulf Wiger, Ericsson Telecom AB 01-03-30 "Four-fold Increase in Productivity and Quality" Rev C 4 THE ERLANG PROGRAMMING LANGUAGE 4.1 BACKGROUND 4.2 SEQUENTIAL ERLANG 4.3 CONCURRENT ERLANG 4.3.1 CLIENT-SERVER EXAMPLE 4.3.2 FINITE STATE MACHINE 4.3.3 SUPERVISOR PROCESSES 4.4 BUILT-IN FUNCTIONS 4.5 EXTERNAL INTERFACES 4.6 DYNAMIC CODE LOADING 5 OPEN TELECOM PLATFORM 6 DEVELOPMENT OF AXD 301 6.1 BACKGROUND 6.2 ASSUMPTIONS 6.3 PROJECT 6.3.1 EARLY PHASES UNDER ONE ROOF 6.3.2 POWERFUL ARCHITECTURE TEAM 6.3.3 CLEAR CHAIN OF COMMAND 6.3.4 RAPID DECISIONS 6.3.
Proceedings of the 9th ACM SIGPLAN workshop on Erlang - Erlang '10, 2010
Although Telecoms, the domain for which Erlang was conceived, has strong and ubiquitous requireme... more Although Telecoms, the domain for which Erlang was conceived, has strong and ubiquitous requirements on overload protection, the Erlang/OTP platform offers no unified approach to addressing the problem. The Erlang community mailing list frequently sports discussions on how to avoid overload situations in individual components and processes, indicating that such an approach would be welcome. As Telecoms migrated from carefully regulated singleservice networks towards multimedia services on top of best-effort multi-service packet data backbones, much was learned about providing end-to-end quality of service with a network of loosely coupled components, with only basic means of prioritization and flow control. This paper explores the similarity of such networks with typical Erlang-based message-passing architectures, and argues that a robust way of managing high-load conditions is to regulate at the input edges of the system, and sampling known internal choke points in order to dynamically maintain optimum throughput. A selection of typical overload conditions are discussed, and a new load regulation framework-JOBS-is presented, together with examples of how such overload conditions can be mitigated.
Proceedings of the 2007 SIGPLAN workshop on Erlang Workshop - Erlang '07, 2007
The built-in process registry has proven to be an extremely useful feature of the Erlang language... more The built-in process registry has proven to be an extremely useful feature of the Erlang language. It makes it easy to provide named services, which can be reached without knowing the process identifier of the serving process. However, the current registry also has limitations: names can only be atoms (unstructured), processes can register under at most one name, and it offers no means of efficient search and iteration. In Ericsson's IMS Gateway products, a recurring task was to maintain mapping tables in order to locate call handling processes based on different properties. A common pattern, a form of index table, was identified, and resulted in the development of an extended process registry. It was not immediately obvious that this would be worthwhile, or even efficient enough to be useful. But as implementation progressed, designers found more and more uses for the extended process registry, which resulted in significant reduction of code volume and a more homogeneous implementation. It also provided a powerful means of debugging systems with many tens of thousand processes. This paper describes the extended process registry, critiques it, and proposes a new implementation that offers more symmetry, better performance and support for a global namespace.
ABSTRACT The telecommunications world is now moving rapidly towards SIP-based telephony and multi... more ABSTRACT The telecommunications world is now moving rapidly towards SIP-based telephony and multimedia. The vision is to merge mobile and fixed networks into one coherent multimedia network. Ericsson has been a pioneer in SIP technology, and the first Erlang-based SIP stack was presented in 1999. A fortunate turn of events allowed us to revive the early SIP experiments, rewrite the software and experiment to find an optimal architecture, and later verify our implementation with great success in international interop events. We believe this to be a superb example of how a small team of experts, armed with advanced programming tools, can see their ideas through, with prototypes, field trials, and later large-scale industrial development.
The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant a... more The AXD 301 ATM Switch is the flagship in Ericsson's line of Datacom products. A fault tolerant and highly scalable backbone ATM switch, AXD 301 has enabled Ericsson to take the lead in the migration of public telephony networks to becoming true multiservice networks, offering both quality voice and broadband data services on the same backbone. Telecom-class products exhibit some very special characteristics, which are fast becoming essential even in other products, such as traditional datacom products, trading systems and application servers: iii (28) ETX/D/XPS-01:001 Uen Ulf Wiger, Ericsson Telecom AB 01-03-30 "Four-fold Increase in Productivity and Quality" Rev C 4 THE ERLANG PROGRAMMING LANGUAGE 4.1 BACKGROUND 4.2 SEQUENTIAL ERLANG 4.3 CONCURRENT ERLANG 4.3.1 CLIENT-SERVER EXAMPLE 4.3.2 FINITE STATE MACHINE 4.3.3 SUPERVISOR PROCESSES 4.4 BUILT-IN FUNCTIONS 4.5 EXTERNAL INTERFACES 4.6 DYNAMIC CODE LOADING 5 OPEN TELECOM PLATFORM 6 DEVELOPMENT OF AXD 301 6.1 BACKGROUND 6.2 ASSUMPTIONS 6.3 PROJECT 6.3.1 EARLY PHASES UNDER ONE ROOF 6.3.2 POWERFUL ARCHITECTURE TEAM 6.3.3 CLEAR CHAIN OF COMMAND 6.3.4 RAPID DECISIONS 6.3.
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