You didn't specify the release.  Assuming pre-NetBackup 6.0 cold catalog
backups here.

> 1. Is All catalog information which I need to restore/backup
> contained in the master server.

Restore, yes.  

> I mean if one media server has gone, does the
> information in master server contains the information which
> belong to the media server which has gone? 

> 2. When I configure the catalog backup, Do I need to 
> configure "catalog
> backup" to backup  the catalog for all other media server catalog? 

System Administrator's Guide Volume I | Managing Catalogs and Images |
   Catalog Backups | Configuring Catalog Backups | Catalog Files Tab

> 3. Is the catalog information in master server enough to do 
> everything?
> Or if the media server has gone, Do I need to restore that 
> media server
> catalog to anywhere to use that information? 

It's enough to do restores.  When you replace the media server, you
bprecover its database from the catalog backup.  The media server will
then know all about its own media; backups and restores are then back to
normal.