MPLS Pseudowire Status Signaling
 Feedback

Contents

MPLS Pseudowire Status Signaling

Last Updated: January 12, 2012

The MPLS Pseudowire Status Signaling feature enables you to configure the router so it can send pseudowire status to a peer router, even when the attachment circuit is down. In releases prior to Cisco IOS 12.2(33)SRC, if the attachment circuit was down, the pseudowire status messages were not sent to the peer.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for MPLS Pseudowire Status Signaling

  • Before configuring this feature, make sure that both peer routers are capable of sending and receiving pseudowire status messages. Specifically, both routers should be running Cisco IOS Release 12.2(33)SRC and have the supported hardware installed.

Restrictions for MPLS Pseudowire Status Signaling

  • Both peer routers must support the ability to send and receive pseudowire status messages in label advertisement and label notification messages. If both peer routers do not support pseudowire status messages, Cisco recommends that you disable the messages with the no status command.
  • This feature is not integrated with Any Transport over MPLS (AToM) Virtual Circuit Connection Verification (VCCV).
  • This feature is not integrated with Bidirectional Forwarding Detection (BFD).
  • The standby and required switchover values from IETF draft-muley-pwe3-redundancy-02.txt are not supported.
  • For a list of supported hardware for this feature, see the release notes for your platform.

Information About MPLS Pseudowire Status Signaling

How MPLS Pseudowire Status Signaling Works

In releases prior to Cisco IOS Release 12.2(33)SRC, the control plane for AToM does not have the ability to provide pseudowire status. Therefore, when an attachment circuit (AC) associated with a pseudowire is down (or is forced down as part of the Pseudowire Redundancy functionality), labels advertised to peers are withdrawn. In Cisco IOS Release 12.2(33)SRC, the MPLS Pseudowire Status Signaling feature enables the AC status to be sent to the peer through the Label Distribution Protocol.

The pseudowire status messages are sent in label advertisement and label notification messages if the peer also supports the MPLS Pseudowire Status Signaling feature. You can issue the show mpls l2transport vc detail command to show that both the local and remote routers support pseudowire status messages. The following example shows the line of output to look for: 

Router# show mpls l2transport vc detail 
.
.
.
status TLV support (local/remote): enabled/supported

When One Router Does Not Support MPLS Pseudowire Status Signaling

The peer routers must support the ability to send and receive pseudowire status messages in label advertisement and label notification messages. If one router does not support pseudowire status messages, Cisco recommends that you disable the messages with the no status command. This returns the router to label withdraw mode.

If the peer does not support the MPLS Pseudowire Status Signaling feature, the local router changes its mode of operation to label withdraw mode. You can issue the show mpls l2transport vc detail command to show that the remote router does not support pseudowire status messages. The following example shows the line of output to look for:

Router# show mpls l2transport vc detail 
.
.
.
status TLV support (local/remote): enabled/not supported


    

When you issue the following debug mpls l2transport vccommands, the messages show that the peer router does not supportthe MPLS Pseudowire Status Signaling feature and that the local router is changing to withdraw mode, as shown in bold in the following example: 


    

Router# debug mpls l2transport vc event
Router# debug mpls l2transport vc status event
Router# debug mpls l2transport vc status fsm
Router# debug mpls l2transport vc ldp


    


    

*Feb 26 13:41:40.707: AToM LDP [110.1.1.2]: Sending label withdraw msg
*Feb 26 13:41:40.707: AToM LDP [110.1.1.2]:   VC Type   5, mtu 1500
*Feb 26 13:41:40.707: AToM LDP [110.1.1.2]:   VC ID     100, label 18
*Feb 26 13:41:40.707: AToM LDP [110.1.1.2]:   Status 0x0000000A [PW Status NOT supported]



  










Status Messages Indicating That the Attachment Circuit Is Down



    

When the attachment circuit is down between the two routers, the output of the show mpls l2transport vc detail command shows the following status:


    
Router# show mpls l2transport vc detail 


    
.


    
.


    
.


    
Last remote LDP TLV    status rcvd: AC DOWN(rx,tx faults)


    


    

The debug messages also indicate that the attachment circuit is down, as shown in bold in the command output:


    

Router# debug mpls l2transport vc event
Router# debug mpls l2transport vc status event
Router# debug mpls l2transport vc status fsm
Router# debug mpls l2transport vc ldp


    
*Feb 26 11:51:42.427: AToM LDP [10.1.1.1]: Received notif msg, id 88
*Feb 26 11:51:42.427: AToM LDP [10.1.1.1]:   Status    0x00000007 [PW Status]
*Feb 26 11:51:42.427: AToM LDP [10.1.1.1]:   PW Status 0x00000006 [AC DOWN(rx,tx faults)]



    

Other pseudowire status messages include not-forwarding, pw-tx-fault, and pw-rx-fault. 


  










Message Codes in the Pseudowire Status Messages



    

The debug mpls l2transport vcand the show mpls l2transport vc detail commands show output that contains message codes. For example: 


    
    Label/status state machine: established, LruRru


    


    
AToM MGR [10.9.9.9, 100]: S:Evt local up, LndRru->LnuRru


    


    

The message codes (LruRru, LndRru, and LnuRru) indicate the status of the local and remote routers. You can use the following key to interpret the message codes:


    

L--local router


    

R--remote router


    

r or n--ready (r) or not ready (n)


    

u or d--up (u) or down (d) status


    

The output also includes other values:


    

D--Dataplane 


    

S--Local shutdown


  














How to Configure MPLS Pseudowire Status Signaling


 
  


Enabling MPLS Pseudowire Status Signaling



      

Perform the following task to enable the router to send pseudowire status to a peer router even when the attachment circuit is down. If both routers do not support pseudowire status messages, then disable the messages with the no status command. 


    

SUMMARY STEPS
      
1.   
          
            enable
          
        


      
2.   
          
            configure
          
          
            terminal
          
        


      
3.   
          
            pseudowire-class
          
          
            name
          
        


      
4.   
          
            status
          
        


      
5.   
          
            encapsulation
            mpls
          
        


      
6.   
          
            exit
          
        


      
7.   
          
            exit
          
        


      
8.   
          
            show
            mpls
            l2transport
            vc
            detail
          
        


    
DETAILED STEPS
 Command or ActionPurpose

      
Step 1

          
            enable
          
        
 

Example:
          

Router> enable


         
 
          

Enables privileged EXEC mode. 


          
    
            
  • 
Enter your password if prompted.
    • 

          


         


      
Step 2

          
            configure
          
          
            terminal
          
        
 

Example:
          

Router# configure terminal


         
 
          

Enters global configuration mode.


         


      
Step 3

          
            pseudowire-class
          
          
            name
          
        
 

Example:
          

Router(config)# pseudowire-class atom 


         
 
          

Establishes a pseudowire class with a name that you specify and enters pseudowire class configuration mode. 


         


      
Step 4

          
            status
          
        
 

Example:
          

Router(config-pw)# status 


         
 
          

(Optional) Enables the router to send pseudowire status messages to the peer router through label advertisement and label notification messages.


          
Note   
By default, status messages are enabled. This step is included only in case status messages have been disabled. 


          

If you need to disable status messages because both peer routers do not support this functionality, enter the no statuscommand. 


         


      
Step 5

          
            encapsulation
            mpls
          
        
 

Example:
          

Router(config-pw)# encapsulation mpls


         
 
          

Specifies the tunneling encapsulation. 


         


      
Step 6

          
            exit
          
        
 

Example:
          

Router(config-pw)# exit


         
 
          

Exits pseudowire class configuration mode.


         


      
Step 7

          
            exit
          
        
 

Example:
          

Router(config)# exit


         
 
          

Exits global configuration mode.


         


      
Step 8

          
            show
            mpls
            l2transport
            vc
            detail
          
        
 

Example:
          

Router# show mpls l2transport vc detail 


         
 
          

Validates that pseudowire messages can be sent and received. 


         


    














Configuration Examples for MPLS Pseudowire Status Signaling


 
  


MPLS Pseudowire Status Signaling  Example



    

The following example configures the MPLS Pseudowire Status Signaling feature on two PE routers. By default, status messages are enabled. The status command is included in this example in case status messages have been disabled. 


    
PE1

      
      
interface Loopback0
 ip address 10.1.1.1 255.255.255.255
!
pseudowire-class atomstatus
 encapsulation mpls
 status
!
interface GigabitEthernet10/5
 xconnect 10.1.1.2 123 pw-class atomstatus


    


    
PE2

      
      
interface Loopback0
 ip address 10.1.1.2 255.255.255.255
!
pseudowire-class atomstatus
 encapsulation mpls
 status
!
interface GigabitEthernet3/3
 xconnect 10.1.1.1 123 pw-class atomstatus


    


  










Verifying That Both Routers Support Pseudowire Status Messages  Example



    

You can issue the show mpls l2transport vc detail command to show that both the local and remote routers support pseudowire status messages. The following example shows the line of output to look for: 


    
Router# show mpls l2transport vc detail 


    
.


    
.


    
.


    
status TLV support (local/remote): enabled/supported


    


  












Additional References


 
	 
 
		
 The following sections provide references related to the MPLS Pseudowire Status Signaling feature.
		

 
	 

 
	 
Related Documents
 
		 
		

 
			  
			  
			  
				
 
				   
					 
 Related Topic
					 

 
				  		
 
				   
					 
 Document Title
					 

 
				  		
 
				

 
			 
 
			  
				
 
				   
					 
 Any Transport over MPLS 
					 

 
				  		
 
				   
					 
 Any Transport over MPLS 
					 

 
				  		
 
				

 
				
 
				   
					 
 Virtual Private LAN Services
					 

 
				  		
 
				   
					 
 
						Virtual Private LAN Services on the Optical Services Modules 
						 
					 

 
				  		
 
				

 
			 
 
		  



 
	 

 
	 
Standards
 
		 
		

 
			  
			  
			  
				
 
				   
					 
 Standard
					 

 
				  		
 
				   
					 
 Title
					 

 
				  		
 
				

 
			 
 
			  
				
 
				   
					 
 draft-ietf-pwe3-control-protocol-15.txt
					 

 
				  		
 
				   
					 
 Pseudowire Setup and Maintenance Using LDP
					 

 
				  		
 
				

 
				
 
				   
					 
 draft-ietf-pwe3-iana-allocation-08.txt
					 

 
				  		
 
				   
					 
 IANA Allocations for Pseudo Wire Edge to Edge Emulation (PWE3)
					 

 
				  		
 
				

 
				
 
				   
					 
 draft-martini-pwe3-pw-switching-03.txt
					 

 
				  		
 
				   
					 
 Pseudo Wire Switching
					 

 
				  		
 
				

 
			 
 
		  



 
	 

 
	 
MIBs
 
		 
		

 
			  
			  
			  
				
 
				   
					 
 MIB
					 

 
				  		
 
				   
					 
 MIBs Link
					 

 
				  		
 
				

 
			 
 
			  
				
 
				   
					 
 Pseudowire Emulation Edge-to-Edge MIBs for Ethernet, Frame Relay, and ATM Services
					 

 
				  		
 
				   
					 
 To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
					 

 
					 
 
						http://www.cisco.com/go/mibs 
					 

 
				  		
 
				

 
			 
 
		  



 
	 

 
	 
RFCs
 
		 
		

 
			  
			  
			  
				
 
				   
					 
 RFC
					 

 
				  		
 
				   
					 
 Title
					 

 
				  		
 
				

 
			 
 
			  
				
 
				   
					 
 None
					 

 
				  		
 
				   
					 
 --
					 

 
				  		
 
				

 
			 
 
		  



 
	 

 
	 
Technical Assistance
 
		 
		

 
			  
			  
			  
				
 
				   
					 
 Description
					 

 
				  		
 
				   
					 
 Link
					 

 
				  		
 
				

 
			 
 
			  
				
 
				   
					 
 The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.
					 

 
					 
 To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.
					 

 
					 
 Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.
					 

 
				  		
 
				   
					 
 
						http://www.cisco.com/techsupport 
						 
					 

 
				  		
 
				

 
			 
 
		  



 
	 

 
  










Feature Information for MPLS Pseudowire Status Signaling


 
	 
 
		
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature. 
		

 
		
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to 
		  www.cisco.com/go/cfn. An account on Cisco.com is not required. 
		

 
	 


	 

		

Table 1Feature Information for MPLS Pseudowire Status Signaling

			 

				
				  
Feature Name
				  


						

				
				  
Releases
				  


						

				
				  
Feature Information
				  


						

			 



		  
			 

				
				  
MPLS Pseudowire Status Signaling 
				  


						

				
				  
12.2(33)SRC
				  


				  
12.2(50)SY
				  


						

				
				  
 The MPLS Pseudowire Status Signaling feature enables you to configure the router so that it can send the pseudowire status to a peer router, even when the attachment circuit is down. 
				  

 
				  
 The following commands were introduced or modified: 
					 debug 
						mpls 
						l2transport 
						vc, 
					 show 
						mpls 
						l2transport 
						vc, 
					 status (pseudowire class). 
				  


						

			 


		  

		



 
	 

 
  










 


 
	 
 
		
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: 
		  www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R) 
		

 
		
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental. 
		

 
	 

 
  





































© 2012 Cisco Systems, Inc. All rights reserved.