WSDL: Files with the WSDL extension contain web service 
interfaces expressed in the Web Service Description 
Language (WSDL). WSDL is a standard XML document type 
specified by the World Wide Web Consortium.

WSDL files are used to communicate interface information 
between web service producers and consumers. A WSDL 
description allows a client to utilize a web service’s 
capabilities without knowledge of the implementation 
details of the web service.

Disco: It is a Microsoft technology for publishing and 
discovering Web Services. DISCO can define a document 
format along with an interrogation algorithm, making it 
possible to discover the Web Services exposed on a given 
server. DISCO makes it possible to discover the 
capabilities of each Web Service (via documentation) and 
how to interact with it. To publish a deployed Web Service 
using DISCO, you simply need to create a .disco file and 
place it in the vroot along with the other service-related 
configuration.

WSDL-Web Service Description Language-

- WSDL is an XML format for describing network services as 
a set of endpoints operating on 

messages containing either document-oriented or procedure-
oriented information. 

-The operations and messages are described abstractly, and 
then bound to a concrete network 

protocol and message format to define an endpoint.

- Related concrete endpoints are combined into abstract 
endpoints (services).

- WSDL is extensible to allow description of endpoints and 
their messages regardless of what 

message formats or network protocols are used to 
communicate, however, the only bindings 

described in this document describe how to use WSDL in 
conjunction with SOAP 1.1, HTTP 

GET/POST, and MIME.

-The WSDL defines services as collections of network 
endpoints, or ports. WSDL specification 

provides an XML format for documents for this purpose. 

-The abstract definition of ports and messages is separated 
from their concrete use or 

instance, allowing the reuse of these definitions.

- A port is defined by associating a network address with a 
reusable binding, and a 

collection of ports define a service. 

-Messages are abstract descriptions of the data being 
exchanged, and port types are abstract 

collections of supported operations. 

-The concrete protocol and data format specifications for a 
particular port type constitutes 

a reusable binding, where the messages and operations are 
then bound to a concrete network 

protocol and message format. In this way, WSDL describes 
the public interface to the web 

service.



-Web Services Description Language Version 2.0 (WSDL 2.0) 
provides a model and an XML format 

for describing Web services. 

-WSDL 2.0 enables one to separate the description of the 
abstract functionality offered by a 

service from concrete details of a service description such 
as “how” and “where” that 

functionality is offered.

DISCO (Discovery OF File)


DISCO is the discovery file which gives path to the 
Webservices
It contains WSDL(Web Service Description Language)
When one searches for the Web Services, it will go to the 
DISCO whcih gives actual info. about the particular 
Webservices.

Discovery with DISCO

In the past, most consumers found out about new Web 
Services (and their endpoint addresses) 

by browsing the Web, receiving an e-mail, or by word-of-
mouth. Now, DISCO can define a 

document format along with an interrogation algorithm, 
making it possible to discover the 

Web Services exposed on a given server. DISCO also makes it 
possible to discover the 

capabilities of each Web Service (via documentation) and 
how to interact with it (via WSDL). 

To publish a deployed Web Service using DISCO, you simply 
need to create a .disco file and 

place it in the vroot along with the other service-related 
configuration files, like so:


\inetpub
  \wwwroot
    \math  (vroot)
       math.asmx
       web.config
       math.disco
      \bin
         simpleMath.dll
         complexMath.dll

The .disco document is an XML document that simply contains 
links to other resources that 

describe the Web Service, much like an HTML file that 
contains human-readable documentation 

or a WSDL file containing the interface contract. The 
following is a DISCO document skeleton 

that will serve as a starting point.

<disco:discovery 
  xmlns:disco="http://schemas.xmlsoap.org/disco/">
  <!-- references go here -->
</disco:discovery>

Notice that the root element has the name discovery from 
the 

http://schemas.xmlsoap.org/disco/ namespace. The references 
to other resources are placed 

within the discovery element:


<disco:discovery 
  xmlns:disco="http://schemas.xmlsoap.org/disco/"
  xmlns:scl="http://schemas.xmlsoap.org/disco/scl/">
  <!-- reference to other DISCO document -->
  <disco:discoveryRef 
    ref="related-services/default.disco"/>
  <!-- reference to WSDL and documentation -->
  <scl:contractRef ref="math.asmx?wsdl" 
    docRef="math.asmx"/> 
</disco:discovery>


The main element is contractRef, which belongs to a 
different namespace than the rest of the 

DISCO-related elements. contractRef has two attributes, ref 
and docRef, which point to the 

WSDL and documentation files for a given Web Service.
The discoveryRef element lets you link the given DISCO 
document to other DISCO documents. 

This linking allows you to create a Web of related DISCO 
documents spanning multiple 

machines and even multiple organizations. This is 
especially useful if the DISCO client 

utility provides a mechanism to traverse the links. These 
are the only elements that you 

have to be concerned about in the DISCO namespace.

DISCO Client Utilities

There are currently two tools available for discovering the 
DISCO document once it's in 

place. One is a command-line client called disco.exe; the 
other is the Add Web Reference 

feature in Visual Studio® .NET.