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is down (or is forced down as part of the Pseudowire Redundancy functionality), labels advertised to peers are withdrawn.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 Action 
         Purpose 
        
 
        
 
          
          
 
           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 1 
          Feature 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). 
 		 
         
 
         
       
 
      
 
     
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
 
 
    
 
     
 
       
        
      
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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. 
 
     
 
    
 
    
 
     
 
     
 
     
 
     
 
     
 
     
 
     
 
     
 
     
 
     
 
    
 
   
 
   
  

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