basic web service questions include:
1)what do you mean by a Web service? what is the advantage 
of using a Web service?
2)what is an WSDL?Specifications ?How are they generated? 
How do you generate proxies from a WSDL?
3)what is an UDDI? Who takes care of registering 
services ,modifying and deleting them?

the term Web Services refers to the technologies that allow
for making connections. Services are what you connect
together using Web Services. A service is the endpoint of a
connection. Also, a service has some type of underlying
computer system that supports the connection offered. The
combination of services - internal and external to an
organization - make up a service-oriented architecture

Basic question related to webservices 
SOA
SOAP
WSDL
Service Provider
Service Consumer
XML
UDDI
CORBA/RMI

These are basic step for web services

SOAP stands for simple object Access protocol .
 
 SOAP structures a message into two main parts: the headers
and the body. 
SOAP is more than just a sender-receiver protocol, although
that, too, is certainly the dominant use today. SOAP
supports the concept of a message passing from a recipient,
possibly through one or more intermediaries, and ending up
at its destination, more precisely known as the ultimate
receiver.

SOAP is core part of WEB-SERVICE. Mainly SOAP is an XML
syntax for exchanging message because of XML is language and
platform
indepent.SOAP is use when we are creating web services
because  Web services means publish a method(method resolve
business logic) globally.

Simple object access protocal

we can sent and receive soap msg with the help of HTTP, FTP 
or SMTP protocols. we need to bind the soap envelope in 
protocol and then we can send and receive our msg over the 
netwok.

SOAP-DSIG is used to satisfy the message authentication 
requirement. It is important to note that you can use SOAP-
DSIG and SSL simultaneously by exchanging 


    the above HTTP messages over SSL.     





Technology Satisfied security requirements 
SSL Confidentiality, sender/recipient authentication, and 
message authentication by MAC 
SOAP-DSIG Message authentication by digital signature and 
MAC 


        SSL provides confidentiality and sender/recipient 
authentication. SSL also has functionality for adding MACs 
to transmitted messages. On the other hand, 


SOAP-DSIG can be used to add not only MACs but also digital 
signatures to transmitted messages, but it is not 
sufficient for sender/recipient authentication 


because it is vulnerable to attacks such as replay attacks. 
Therefore, SOAP-DSIG and SSL complement the functionalities 
that the other system lacks. 

         

         Remember that in order to satisfy the requirement 
of non-repudiation, at a minimum you need to simultaneously 
guarantee both message authentication by using a 

        digital signature and sender authentication. 
Therefore, using SOAP-DSIG and SSL (with client 
authentication) simultaneously is the first step towards 
realizing non-        repudiation. Specifically, you use 
SOAP-DSIG for message authentication by using a digital 
signature and SSL client/server authentication for 
sender/recipient authentication.

At a minimum, all you really need is an XML processor and 
an HTTP server.If you're using Visual Basic 6.0 or VBA, 
then you probably want to use either Microsoft SOAP Toolkit 
or PocketSOAP. If you're using VB.NET or C#, then you       
probably want to use Visual Studio.NET or the .NET 
Framework. If you're using Delphi, then you want to use 
Borland's Web services support in Delphi. If you're       
using C++, then you probably want to use Systinet WASP 
Server for C++ or gSOAP. If you're using Java, then you 
have a choice of about a dozen     implementations (Apache 
Axis, Systinet WASP Server for Java, The Mind Electric 
GLUE, Cape Clear Cape Connect, IONA XMLBus, BEA Workshop, 
etc.)

 

            Favorite Java environments are WASP, GLUE, and 
Axis. All offer excellent tools, they're portable across a 
wide range of servlet engines, and they work!WASP and GLUE 
can run standalone.

The difference lies in where the error occurs - on the 
client side (during the generation of the soap request or 
the unmarshalling the response) - or on the server side 
(when unmarshalling the request, processing the message or 
marshalling the response). The client side raises an 
exception  whereas the server side sends a SOAP response to 
the client indicating an error occured on the server side 
(ie. you get a SOAP fault). 

        For example, sending a SOAP encoded request for a 
method that does not exist results in a SOAP fault whereas 
if the server sends a response with a field that does not 
exist in a client side class a SOAP exception will be 
raised.

In SOAP, procedures take named parameters and order is 
irrelevant. In XML-RPC order is relevant and parameters do 
not have names.

SOAP version 1.2 is a lightweight protocol for exchange of 
information in a decentralized, distributed environment. It 
is an XML based protocol that consists of four parts: an 
envelope that defines a framework for describing what is in 
a message and how to process it, a set of encoding rules 
for expressing instances of application-defined data types, 
a convention for representing remote procedure calls and 
responses and a binding convention for exchanging messages 
using an underlying protocol. SOAP can potentially be used 
in combination with a variety of other protocols; however, 
the only bindings defined in this document describe how to 
use SOAP in combination with HTTP and the experimental HTTP 
Extension Framework.

An Enterprise Service Bus (ESB) is a standards-based, 
Service Oriented Architecture (SOA) backbone, capable of 
connecting applications through service interfaces. By 
combining Messaging, Web Services, XML, Data Transformation 
and Management, an ESB can reliably connect, mediate and 
control all communications and interactions between 
services.

An esb is a very important component of SOA. Imagine all 
your web services built on different technologies 
(java,.net,mainframe)..interacting with each other using 
xml for data transmission..One doesn't have to worry about 
the schema transformation,protocol switching or message 
enrichment..the esb does it all for you ..

it basically means that the services that you use are 
reusable.One service does not depend upon the other.A 
change in a .net service shall not affect another service 
developed in java.All the components that is needed for an 
application must not be tightly coupled so that a single 
change in some class changes all other parts of the 
application.Instead break the whole application into small 
components ,expose them as web services and orchestrate .

A.SOAP uses an XML format to encode data. There are two ways
in which it maps high level datatypes like integers, arrays
to a serialized XML format- Section 5 encoding and Literal
encoding. Section 5 encoding, also called SOAP encoding, is
named after the section in the SOAP 1.1 specification that
defines it. Literal encoding on the other hand uses a XML
Schema to validate...