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Web Services Interview Questions
There are various features of XML-RPC that includes : 
* Platform independent 
* Allows diverse applications to communicate 
* Considered as the easiest and simplest way to get started with web services 
* Uses XML to encode its calls and HTTP as the transport protocol
A consumer of a web service is not tied to that web service directly. The web service interface can change over time without compromising the client's ability to interact with the service. A tightly coupled system implies that the client and server logic are closely tied to one another, implying that if one interface changes, the other must be updated. Adopting a loosely coupled architecture tends to make software systems more manageable and facilitates simpler integration between different systems.
Using XML eliminates any networking, operating system, or platform binding. So Web Services based applications are highly interoperable application at their core level.
Synchronicity is used to bind the client to the execution of the service. In synchronous invocations, the client blocks and waits for the service to complete its operation before continuing. On the other hand, synchronous operations facilitate a client to invoke a service and then execute different functions.
Every framework requires some type of architecture to ensure that the entire framework works perfectly as desired, the same goes for web services. Web service architecture is used to assist the developer with steps and procedures that are essential to complete the creation. Web service architecture includes three distinct roles i.e., service provider, service requester, and service registry. It also includes three different operations that include:  
Publish (Publication of Service Descriptions) : A service description needs to be published so that the service requestor can locate and have access to it. It can be published anywhere depending upon the requirements of the application. 
Find (Finding of Services Descriptions) : A service description is retrieved directly by a service requestor. The requestor consults the broker to locate a web service that is already published. 
Bind (Invoking of Service based on Service Description) : Every service needs to be invoked. To locate, contact, and invoke the service, the service requestor initiates the interaction with the service at runtime using details of binding in the service description.

Web Services Architecture
Web service requestor is the client application that requests for web service to use it. Its main purpose is to use an existing web service by opening a network connection and sending an XML request. In simple words, they are consumers of the web service. 
The web service registry is basically like a ‘phone book’ for web services. It allows client applications to be able to publish new services or can locate the already existing ones. Two widely-used registry standards are generally supported by application servers i.e., ebXML (Electronic Business using XML) and UDDI (Universal Description, Discovery, and Integration).
The Service Transport Layer is used to transport messages between applications.
This layer includes Hypertext Transport Protocol (HTTP), Simple Mail Transfer Protocol (SMTP), File Transfer Protocol (FTP), and newer protocols like Blocks Extensible Exchange Protocol (BEEP).
The Service Description layer is used to describe the public interface to a specific web service. Currently, service description is handled via the Web Service Description Language (WSDL).
The Service Discovery layer is used for centralizing services into a universal registry and providing easy publish/find functionality.
Currently, service discovery is handled via Universal Description, Discovery, and Integration (UDDI).