S. Maffeis, "Adding Group Communication and FaultTolerance to CORBA", In Proceedings of the 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....the main technology for fault tolerance is very similar to that in process groups [13, 14] There are other fault tolerant middleware systems based on message logging [23] The discussion here only focuses on the object group approaches. Three main efforts in CORBA object groups are introduced [15 17]. We follow with a discussion of the Coign project, which is built on the COM middleware system [18, 19] An API instrumentation technique is used in the Coign project. We conclude with a discussion of a COM system on IP multicast transport built by P. Emerald Chung et al. in Bell Lab [20] 2.2.1 ....

....[14] To enable the ORB to communicate its messages over the underlying system, adapter objects are inter positioned between the reliable multicast system 18 and the ORB. The mechanisms for maintaining the object groups are embedded within the ORB, thus requiring internal modification of the ORB [17]. This approach can ensure transparency of the object groups to the application objects since all of the necessary mechanisms are incorporated into the ORB itself. The application objects simply use the ORB as a communication path for their requests and responses. There is some performance ....

Maffeis, S. Adding Group Communication and Fault-Tolerance to CORBA. in USENIX Conference on Object-Oriented Technologies. 1995. Monterey, CA.

....can be divided into the following three strategies [10] The integration strategy, where the ORB is modified to provide the necessary fault tolerance support and the extent of the modifications depends on the level of faulttolerance support that is being added. Orbix Isis [11] and Electra [12] are examples of the integration strategy. The interception strategy, where requests made by client objects are captured externally to the ORB via an OSlevel interceptor [13] which can enhance the application by providing support to tolerate faults. The Eternal system [14] and the AQuA ....

....SERVER OBJECT CORBA REQUEST RELIABLEMULTICAST TOOL KIT ADAPTEROBJECT GROUP MULTICAST MESSAGE Figure 13: Integration Fault Tolerance Strategy requests into multi cast messages of the underlying toolkit. Examples of the integration strategy include Orbix Isis [47, 11] and Electra [47, 12]. Orbix Isis was the first commercially available system that supported fault tolerant CORBAcompliant applications. The fault tolerance of server implementations is achieved using active (hot) replication, with reliable multicast support from low level group communication system [11] Electra was ....

Silvano Maffeis, "Adding Group Communication and Fault-Tolerance to CORBA," in Proceedings of the Conference on Object-Oriented Technologies, Monterey, CA, June 1995, USENIX.

.... Protocol, an ORB gateway, allowing the use of CORBA technology over large networks as the Internet; there is a proposed framework on object migration addressing availability of resources, fault tolerance or deploying autonomous agents paradigm; extensions in communication styles [Her 96 and Maf 95] accepting group communication and connection oriented streams are being studied. There is a RFP (Request for Proposal) opened by the OMG regarding this issue. With this extensions applications with video and audio media can be designed over CORBA and other QoS requirements can be addressed ....

Maffeis, S. "Adding group communication and fault-tolerance to CORBA", Proceedings of the 1995 USENIX Conference on Object Oriented Technologies, Monterey, CA, EUA, June, 1995.

....with other middleware platforms (DCOM, DCE) open specification; many existing products and solutions; WWW integration of Java applets with CORBA sup port. ihtt P: www infrmatik uni frankfurt .de mico cific QoS categories. TAO[12] provides real time support for CORBA. Elektra[7] enhces CORBA with group com munication for fault tolerce. Some commerci CORBA implementations provide security mechanisms and the OMG has released the specification for the Security Ser vice[8] However, we think that these efforts only allow distinct speciized parts of a distributed object ....

S. Maffeis. Adding Group Communication and Fault-Tolerance to CORBA. In Proceedings of the USENIX Conference on Object-Oriented Technologies, June 1995.

....provision for object oriented middleware is not only a topic within the AOP community. The need for QoS provision in middleware platforms has been targeted by several groups from research and industry. The Ace Orb (TAO) 18] is an extension of CORBA to provide hard real time guarantees. Electra [13] allows for the fault tolerant services via the integration of multicast protocols in CORBA. The Object Management Group has als recognized the need for distinct QoS categories and addresses them in actual specifications, like the CORBA messaging [15] or the CORBA Realtime [16] However, these ....

S. Maffeis. Adding Group Communication and Fault--Tolerance to CORBA. In Proceedings of the USENIX Conference on Object-- Oriented Technologies, June 1995.

....computing, such as messaging service, trading service, location management service, transaction service, security service, etc. These services are packaged as a set of interacting engineering objects in the platform. Some platforms, such as ISIS [1,2] Horus [3,4] Amoeba [5,6] Electra [7,8], Relacs [9] etc. provide group services, such as message multicasting protocols, membership management protocols, virtual synchrony, etc. to distributed applications. However in these platforms the applications are very closely tied to these low level group communication facilities, thereby ....

Maffeis, S. Adding group communication and fault-tolerance to CORBA. In Proceedings of the

....replica is approximately 2 seconds, most of which stems from the view agreement protocol. 6 Related Work Many other projects have also addressed the problems related to making distributed applications fault tolerant, most of which are based on group communication [8] Primarily, research efforts [13, 19, 12, 7, 18, 6, 21] have focused on two slightly different distributed object technologies, namely CORBA [23] and Java RMI [26] Unfortunately, most efforts have been dedicated to CORBA and resulting object group systems may be classified into three categories [12] The integration approach involves modifying and ....

....The integration approach involves modifying and enhancing an object request broker (ORB) using an underlying group communication service. CORBA invocations are passed to the group communication service that multicasts them to replicated servers. This approach was pursued by the Electra system [13]. In the interception approach, low level messages containing CORBA invocations and responses are intercepted on client and server sides and mapped to a group communication service. This approach does not require any modification of the ORB, but relies on OS specific mechanisms for request ....

S. Maffeis. Adding Group Communication and Fault-Tolerance to CORBA. In Proc. of the 1st Conf. on Object-Oriented Technologies and Systems, Monterey, CA, June 1995.

....for different # values (b) Scale out for different ## values (c) Scale out for ## ###and different # Figure 1: Scale out for different values of # and ## 2.2 Related Work Previous work on reliable middleware has mainly concentrated on replicated ORBs. Examples of these approaches are [Maf95, MSEL99, NMMS99, FGS99] In contrast, this paper focuses on a novel middleware layer for database replication. The limitations of replication pointed out in the formal model of the previous section are well known 5 among database designers. Gray et al. GHOS96] provided an empirical evaluation ....

S. Maffeis. Adding Group Communication and Fault-Tolerance to CORBA. In Proc. of

....to put in their best performance optimization techniques. A disadvantage is that such architectures are usually not extensible. As a result, when low level system properties such as load balancing and fault tolerance are desirable, they need to be either tightly integrated with the infrastructure [Maffeis95] or provided through interception mechanisms outside the infrastructure [Narasimhan97] In this paper, we propose an extensible remoting architecture and demonstrate that it facilitates the incorporation of low level system properties into the infrastructure and allows them to be customized in a ....

....a standard remoting architecture. As a result, incorporating stronger system properties such as fault tolerance into CORBA based systems is usually not done by exploiting the extensibility in the remoting architecture. Instead, three other approaches have been taken [Narasimhan197] Electra [Maffeis95] and Orbix Isis [Landis97] build the mechanisms for object replication and consistency management into the ORB itself. The Eternal system [Narasimhan97] intercepts IIOP related system calls through the Unix proc interface, and maps them to routines supported by a reliable multicast group ....

S. Maffeis, "Adding group communication and fault-tolerance to CORBA," in Proc. Usenix Conf. on Object-Oriented Technologies, June 1995.

....this approach and the previous one are presented in [6] The service approach has been used for fault tolerance [5, 21] and the standard CORBA services, such as the security service, can be viewed as examples of this approach. The integration approach has been used to enhance fault tolerance [14, 16] and timeliness properties [26] and could naturally be used to enhance any other QoS attribute. The interception approach, as the name suggests, works by intercepting middleware messages or requests. These systems are classified based on whether the interception takes place above or below the ....

S. Maffeis. Adding group communication and fault tolerance to CORBA. In Proceedings of the

....Interface, Multicasting 1 Introduction Fault tolerance and high availability are supported in Common Object Request Broker Architecture (CORBA) 14] by means of object replication. Here a collection of object replicas cooperatively works for a common task, and they are called an object group [13]. The consistent state of an object group needs to be maintained for constructing reliable, fault tolerant distributed applications [10] Group communication service(GCS) is a useful mechanism guaranteeing the consistency of the state of all the member objects. It maintains a view, a list of the ....

....messages to the members in the current view. There have been several approaches for supporting group communication service in CORBA. In general, they are categorized into three approaches integration, service, and interception approach. An example of each of 2 the three approaches is Electra [13], Object Group Service (OGS) 7] and Eternal [9] respectively. The approaches do not support transparent plug in of group communication protocols into CORBA, and thus CORBA application programmers cannot directly exploit the protocols. With the integration approach, the GCS module is an integral ....

[Article contains additional citation context not shown here]

S. Maffeis, "Adding Group Communication and Fault-Tolerance to CORBA", Proceedings of the

....objects to transparently interact with each other in heterogeneous and distributed environment. As such, a single group communication protocol would not satisfy all the needs of CORBA group applications. There have been several approaches for supporting group communication service in CORBA [2, 8, 10, 12, 13]. However, the approaches do not support transparent plug in of group communication protocols into CORBA, and thus CORBA application programmers cannot directly exploit the protocols. Therefore, there must be a generic group communication framework that allows transparent plug in of various group ....

....And Section 4 analyses the performance of the extended OCI. Conclusion follows in Section 5. 2. Related Work Group communication services for CORBA can be categorized into three approaches such as integration approach, service approach, and interception approach [3, 13] Examples are Electra [8], Object Group Service [2, 3] Eternal [10] and respectively. Electra integrates group communication service with CORBA by extending Basic Object Adapter (BOA) The implementation and performance of the system are efficient since there is no intermediate object between ORB and group communication ....

S. Maffeis, Adding Group Communication and Fault-Tolerance to CORBA," The

....support level, what would be hard if we consider heterogeneous distributed systems. The ORBs, with specific facilities for group communication, support the implementation of the replication techniques according to the proposed integration model. The integration model was used with the Electra [11] and Orbix Isis [8] systems. This paper concentrates on those implementation experiences, describing aspects related with the means offered by those CORBA platforms to facilitate the implementation of the replication techniques. The potentialities of those ORBs and the proposed model are ....

....a set of object services that simplify the application designer s task. In this way, the COSS (Common Object Services Specifications) was introduced describing a set of services (interfaces) that provide basic functions for using and implementing application objects. 2.2. ELECTRA Electra [11] is an ORB compatible with the CORBA specifications, presenting support for objects group. For the development of distributed applications, this model combines the benefits of the CORBA standard with the power of lower level tools, such as: Isis [2] Horus [17] Transis [1] Consul [12] Chorus ....

S. Maffeis, "Adding Group Communication and FaultTolerance to CORBA", In Proceedings of the 1995 USENIX Conference on Object-Oriented Technologies, Monterey - CA, June 1995.

....In any case the above algorithm can be safely applied independently of the state of the agent. 8 COMPARISONS TOMAS has strong similarities to concurrent languages and environments supporting fault tolerant computation and the mobility of objects (for instance, Arjuna [9] DOME [3] Electra [8]) An interesting, very recent stream of research about multi agent systems, inspired by advanced transaction concepts, is Interaction Oriented Programming (IOP) 15, 16] IOP is essentially concerned with the coordination of agents which cooperate to achieve a common task, possibly over a long ....

S. Maffeis. Adding Group Communication and Fault-Tolerance to CORBA. In Proceedings of the 1995 USENIX Conference on Object-Oriented Technologies, Monterey, CA, 1995.

....Communication Interface. 1 INTRODUCTION Fault tolerance and high availability are supported in Common Object Request Broker Architecture (CORBA) 15] by means of object replication. Here a collection of object replicas cooperatively work for a common task, and they are called an object group [14]. Here consistent state of an object group needs to be maintained for constructing reliable, fault tolerant distributed applications [11] Group communication service (GCS) is a useful mechanism guaranteeing the consistency of the states of all the member objects. It maintains a view, a list of ....

....of messages to the members in the current view. There have been several approaches for supporting group communication service in CORBA. In general, they are categorized into three approaches integration, service, and interception approach. An example of each of the three approaches is Electra [14], Object Group Service (OGS) 8] and Eternal [10] respectively. The approaches do not support transparent plug in of group communication protocols into CORBA, and thus CORBA application programmers cannot directly exploit the protocols. In the integration approach, the GCS module is an integral ....

[Article contains additional citation context not shown here]

S. Maffeis, Adding Group Communication and FaultTolerance to CORBA, Proceedings of the 1995 USENIX Conference on Object-Oriented Technologies, Monterey, CA, June 1995.

No context found.

S. Maffeis, "Adding Group Communication and FaultTolerance to CORBA", In Proceedings of the 1995.

No context found.

S. Maffeis, "Adding group communication and fault-tolerance to CORBA," in Proceedings of the Conference on Object-Oriented Technologies, pp. 135--146, 1995.

No context found.

S. Maffeis. Adding group communication and fault tolerance to CORBA. In Proceedings of the 1995.

No context found.

S. Maffeis, "Adding group communication and faulttolerance to CORBA," in Proceedings of the Conference on Object-Oriented Technologies, pp. 135--146, 1995.

No context found.

S. Maffeis, "Adding group communication and fault-tolerance to CORBA," in Proceedings of the Conference on Object-Oriented Technologies, pp. 135--146, 1995.

No context found.

S. Maffeis, "Adding group communication and fault-tolerance to corba," in USENIX Conference on Object-Oriented Technologies, 1995.

No context found.

Silvano Maffeis, Adding Group Communication and Fault-Tolerance to CORBA, Proceedings of the USENIX Conference on Object-Oriented Technologies, Monterey, CA, June 1995.

No context found.

Maffeis, S. "Adding group communication and fault-tolerance to CORBA", Proceedings of the 1995 USENIX Conference on Object Oriented Technologies, Monterey, CA, EUA, junho de 1995.

No context found.

S. Maffeis, "Adding Group Communication and Fault-Tolerance to CORBA," Proc. USENIX Conf. Object-Oriented Technologies, Monterey, Calif., 1995, pp. 135-146.

No context found.

MAFF95 Maffeis, S., Adding Group Communication and Fault Tolerance to CORBA, Proceedings of the 1995 USENIX Conference on Object-Oriented Technologies, Monterey, CA, June 1995.

First 50 documents  Next 50

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC