TFS 2012 RC - Test Controller is shown as offline

If you go to Microsoft Test Manager->Lab Center->Controllers and see the Test Controller as offline, check the event logs on the same machine.
If you see the below error:
The description for Event ID 0 from source VSTTExecution cannot be found. Either the component that raises this event is not installed on your local computer
or the installation is corrupted. You can install or repair the component on the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:
(mtm.exe, PID 2968, Thread 13) ControllerConnectionManager : InternalConnect : System.Net.Sockets.SocketException (0x80004005): The requested name is valid,
but no data of the requested type was found
Server stack trace:
   at System.Net.Dns.GetAddrInfo(String name)
   at System.Net.Dns.InternalGetHostByName(String hostName, Boolean includeIPv6)
   at System.Net.Dns.GetHostAddresses(String hostNameOrAddress)
   at System.Runtime.Remoting.Channels.RemoteConnection.CreateNewSocket()
   at System.Runtime.Remoting.Channels.RemoteConnection.GetSocket()
   at System.Runtime.Remoting.Channels.SocketCache.GetSocket(String machinePortAndSid, Boolean openNew)
   at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.SendRequestWithRetry(IMessage msg, ITransportHeaders requestHeaders, Stream requestStream)
   at System.Runtime.Remoting.Channels.Tcp.TcpClientTransportSink.ProcessMessage(IMessage msg, ITransportHeaders requestHeaders, Stream requestStream,
ITransportHeaders& responseHeaders, Stream& responseStream)
   at System.Runtime.Remoting.Channels.BinaryClientFormatterSink.SyncProcessMessage(IMessage msg)
Exception rethrown at [0]:
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at Microsoft.VisualStudio.TestTools.Execution.IControllerAccessManager.get_ControllerVersion()
   at Microsoft.VisualStudio.TestTools.Execution.ExecutionUtilities.GetControllerVersion(IControllerAccessManager accessManager, Boolean
tolerateOldControllers)
   at Microsoft.VisualStudio.TestTools.Controller.ControllerConnectionManager.InternalConnect(ControllerConnectionInfo controllerConnectionInfo)
the message resource is present but the message is not found in the string/message table

Find out the exact machine name for the test controller by running the following query:
USE [Tfs_DefaultCollection]
GO
SELECT [PartitionId]
      ,[InternalId]
      ,[Name]
      ,[Description]
      ,[GroupId]
      ,[LastHeartbeat]
  FROM [dbo].[tbl_TestController]
GO

Then make sure that you are able to ping the full computer name which is present in the [Name] column (exclude the port number) .
The issue I was facing was that I was able to ping the computer name but not the full computer name. Once you are able to ping the full computer name, reconfiguring the test controller should fix the issue.