Paper12

Paper Title:

Three Critical Questions

Group 1:

Member Name:Bokka Satya Saradhi

1)How can it is possible to build loosely coupled orchestration technologies to make
it an platform independent technology?

2)Does web service mechanism involving orchestration satisfies the requirements of
workflows that indulges real time or day to day communication?

3) What are the requirements to built a working environment in that involves
orchestration of fine grained low latency system ?

Member Name:Vallurupalli Anusha

1)How SCXML serves as a control language for domain independent applications?
2)Doesn't BPEL processes require a run time environment for execution?
3) How fault handling is implemented in BPEL?
4)How BPEL process will execute any of its functionality in the same way as any other web service ?

Group 2:

Member Name:Chiranjeevi Ashok Puvvula

Critical Questions:

1.How can we achieve reliability and fault tolerance in complex work flows using these languages? There will many faults like , failure of already orchestrated services , failure in communication between these orchestrated services and hardware failures .
2.Can these languages be expressive enough in dealing with more complex workflows?
3. IS BPEL or CCXML or SCXML based service orchestration is applicable to all kinds of services or not? Are there any constraints to do the service orchestration?
4.Why can’t call control be developed in VOICE XML?

Group 3:

Member Name: Sharat Chandra Dammadapu

1) In case of communication between BPEL and CCXML/SCXML if any error occurred how can it be handled and how the root cause can be known like the error is from BPEL or it’s from CCXML/SCXML?
2) Will there be any performance degradation if Web Services of BPEL interacts with telecom domain such as CCXML and SCXML? Or is it the same as of data environment?
3) How SCXML will get interacted by external objects such as VoiceXML sessions which are explained in presentation tier?

Group 4:

Member Name:B.K Prashant Pelluri

The main aim of orchestration is to provide coordination among communication services but BPEL just provides an interface between web services, it just helps in calling other web service to do actual work. Consider a situation where a web service has to interact with a real time application which can not be accessed via SOAP. How BPEL deals with such a situation?

When we consider SCXML, when different states use same anchor tag it always holds the information of the last one that was visited. But the information of the other states cannot be accessed, they might be over written. This may create problem if some service is in need of the lost information (ie; information of the state other than the last visited one). What mechanism will be implemented in gaining this lost information?

What type of mechanism is involved in message passing of BPEL. Is it synchronous or asynchronous? If it is asynchronous lets consider a situation where a <invoke>command is executed and waiting for a response. If it is asynchronous communication if a partner does nt respond then it may have to wait for a long time in waiting. What type of mechanism is implemented to deal with such type of situation to exclude such unnecessary waiting?

Group 5:

Member Name: Sunil Kakaraparthi

1. The author states that it is not practical to assure ACID behavior for long running transactions. Why this scenario does happen?
2. CCXML script is read and structured to handle the events in a process. Does the script handles the exceptions occurred during the process?
3. BPEL process is a language that models long running transactions which are stateful. How does the BPEL language hold the faults and ensure security constraints during the transaction?

Group 6:

Member Name: Bhargav Sandeep Ramayanam

1. In the paper mentioned that BPEL does not guarantee ACID behavior. ACID properties are very important for the transactions. Does the BPEL provide necessary security without following ACID properties? Even though it may have the <scope> activity through which only the Atomicity property can be achieved. But the remaining properties are not followed.

2. The author does not mention clearly about the correlation mechanism. What does correlation mechanism actually do? Is there any advantage by using that mechanism in the BPEL?

3. The SCXML code is compatible with CCXML and has more advanced features than the CCXML. SCXML notations will replace the state machines in CCXML which simplifies its behavior. Then, why does the author use CCXML for marshaling telephony servers? He can use SCXML which is more convenient and also it has more advanced features.

Member Name: Debargh Acharya

1. During web service composition using BPEL a fault handler is generally connected to the process. The user gets disconnected from the working server if at all the connection between two server fails then how the system is rolled backed or stable state is achieved is not discussed by the author.

2. One of the limitation of BPEL is some kind of over-head compensation is incurred with functionalities associated with scopes are concerned. But how it is going to be resolved is not explained.

3. It is stated by the author that the state machines are high level of abstractions for communicating protocols and are better supported in SCXML than in BPEL. But how and what are the reasons behind it are not been explained.

Group 7:

Member Name:

Group 8:

Member Name:Ramya Devabhakthuni

Critical Questions:
1. The paper stated that the SCXML can run parallel states and provide transition between them. What happens when a parent state is terminated while the child state is running?
2.The author concluded that it is best to use a partition of BPEL, CCXML and SCXML for an application. Each of these has different set of variables and syntax. How can the matching of these variables be done when each of these has different variables?
3. In the BPEL, the Fault Handler is used to undo the transaction when an error occurs. This Fault Handler code is implemented compulsorily even when there is no error. What is necessity to implement this functionality when there is no error also?
Member name : Nikhilesh Katakam
1) The paper claims that using theses 3 orchestration languages , i.e. SCXML, BPEL and CCXML would yield more efficient results , but did not provide sufficient information to say , how it will improve the efficiency?

2) BEPL provides fault handling , by simply undoing the completed work in a scope , but it is not correct method as , the entire work in a particular scope might not be faulty. So how far is it correct to handle errors this way? As even correctly done work also needs to be redone.

3) On arrival of a new process BPEL creates a new instance every time, how far is it correct , as for a similar process two or more identical instances might be created?

Group 9:

Member Name:Muppalla Durga Maheswari

1.How the manipulations of objects in BPEL can be done in multi caller applications like conferencing.

2. How BPEL, CCXML and SCXML can invoke one another when they are used in the applications.

3. As web service invocations tend to have more overhead during encoding and decoding and during the monitoring the errors how can it handle when an error occurs.

Group 10:

Member Name:Jonnalagadda, Harideep Reddy

1) In ccxml, when an event arrives, it's executed only if its guard condition is matched. What happens if it fails???? Will it not execute????

2) What is the advantage of using parent state machines when already some state machines are present???? Will its presence decrease any complexity or will there be any increase in efficiency????

3) How can communications takes place when parts of incoming message are copied in output message??? What exactly happens there???

Member Name: Gayathri Devi Bojja

1. BPEL provides various activities to interact with partners. But there is no acknowledgement provided when an activity takes place. So how will a partner know that an activity has failed?
2. When user uses a call connection for logging there is a chance of disconnection due to some signal problems or so. What would be the other way for the user to reconnect and login?
3. SCXML is provided with a special feature to mark a point in the executable and use it later called anchor. The state which is recently visited is used when many states are named similarly. But what should a user do when he requires a previous anchor?

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