WCF Interview Questions and Answers Part 3

1.) What are the ways to host and activate services of WCF ?                                        
The Activation and hosting layer renders various options for the services in which they can be activate as well as hosted. Services can be hosted in two ways,

1. Self Hosted
2. Hosted on external agents

Such as IIS(Internet Information Services) or WAS (Windows Activation Services).
2.) What are the options provided by Activation and Hosting layer in WCF ?        
The Hosting and activation options provided by this layer as follows.

• Windows Activation Services(WAS):-It enables WCF application to automatically activate when deployed on a computer that is running WAS.
• Windows Services:- It enables you to run WCF services as windows services.
• .EXE :- It enables you to run WCF services as executable(.exe) files.
• COM+ :-It enables you to run WCF services as a com+ Application.

3.) What is end point support in WCF ?                                                                                 

An end point is a resource on a Network through which message can be sent.The end points of the services in WCF are responsible for enabling communication between client and server.
4.) What are the various elements in end point support in WCF ?                              
The end point include various elements which are as follows:-

• Address to locate the services where they are running.
• Bindings to communicate with services.
• Contracts to specify the tasks to be performed while communicating with services.
• A set of behaviours that specify local implementation of details of the end point.

5.) What is the ABCs of  WCF ?                                                                                                   
The Addresses ,Bindings and contracts elements of the end points are known as ABCs of WCF. 
6.) What is Address in  WCF ?                                                                                                    
Every end point is linked with address that are used to find and Identify services.Suppose you want to send message to a service,you need to have its address.An address in WCF consists of Uniform Resource Locator (URL) that determines the protocols used by service,the host on which it is running and the path of the service.
7.) What are the Specifications of an Address in WCF ?                                                 
The specifications of an address are as follows:

• Scheme:- It defines the transport layer protocol,such as HTTP and TCP of a service.
• Machine :- It defines the full domain name of the host machine. 
• Port :- It defines the port number where a WCF is running.It is a optional field in the address specification.The default port of the HTTP address is 8080.
• Path :- It defines the path of the services.The name of the directories and sub directories in the path can be separated by a forward slash.

8.) What are the formats of an Address of a service in WCF ?                                     
The format of the address of a service is as follows:-
scheme://domain_name:Port/Path1/Path2/Path3

• Scheme:-It refers to a protocol used to transfer services from servers to clients.
• Domain_name:-It refers to the name of the server where the service is running.
• Port:- It refers to the port number where the services is listening.
• Path:- It contains the name of the directories and their sub directories.

9.) What is the meaning of Address URL http://localhost:8080/dir/sub-dir ?      
In this URL,

• The http protocol is the scheme.
• localhost is the domain name (local host is the default name of the local machine.If the service is running on the remote server,then the name can be www.myfirstservice.com ) .
• 8080 is the port number where the services is listening.
• /dir/sub-dir is the path of the services.

10.) What are the different type of addressing formats in WCF ?                               
There are different type of addressing formats as follows:

• HTTP address
• TCP address
• MSMQ address
• IIS address
• Base address
• Named pipe address 

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