Difference Between BeforeClass & BeforeSuite TestNG Annotation

How BeforeClass & BeforeSuite TestNG Annotation Example In Selenium?

package com.selenium.TestNG;
import org.testng.annotations.AfterClass;
import org.testng.annotations.AfterSuite;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.BeforeSuite;
import org.testng.annotations.Test;
public class TestNG_BeforeClass 
{
   @BeforeSuite
   public void openBrowser()
   {
      System.out.println("Browser Opened");
   }
   @BeforeClass
   public void login()
   {
      System.out.println("Login Sucessfully");
   }
   @Test
   public void operation()
   {
      System.out.println("Openration Done");
   }
   @AfterClass
   public void logout()
   {
      System.out.println("Logout Sucessfully");
   }
   @AfterSuite
   public void closeBrowser()
   {
      System.out.println("Browser Closed");
   }
}