MPLS Working Group                                        Zafar Ali 
   Internet Draft                                   Cisco Systems, Inc. 
   Intended status: Informational                          July 07 2008 
   Expires: January 06 2009 
                                       
    
                                        
     Signaled PID When Multiplexing Multiple Payloads over RSVP-TE LSPs 
                draft-ali-mpls-sig-pid-multiplexing-case-00.txt 


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   Copyright Notice 

      Copyright (C) The IETF Trust (2008). 

   Abstract 

      There are many deployment scenarios where an RSVP-TE LSP carries 
      multiple payloads. In these cases, it gets ambiguous on what 
      should value should be carried as L3PID in the Label Request 
      Object [RFC3209] or G-PID in the Generalized Label Request Object 
    
    
    
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      [RFC3471], [RFC3473]. The document propose use of some dedicated 
      PID values to cover some typical cases of multiple payload 
      carried by the LSP, including that indicates to the egress node 
      to ignore signaling to learn payload carried by the LSP.  

   Table of Contents 

       
      1. Introduction...............................................2 
      2. Some use cases.............................................3 
         2.1. PID = 0x0800 (IPv4 Payload)...........................3 
         2.2. PID = 0x86DD (IPv6 Payload)...........................3 
         2.3. IPv4+IPv6 PID.........................................3 
         2.4. Unknown PID...........................................3 
      3. Security Considerations....................................4 
      4. IANA Considerations........................................4 
      5. References.................................................4 
         5.1. Normative References..................................4 
         5.2. Informative References................................4 
      Author's Addresses............................................4 
      Intellectual Property Statement...............................4 
      Disclaimer of Validity........................................5 
       
   1. Introduction 

      When an RSVP-TE LSP is used to carry multiple payload type (e.g., 
      IPv6 and IPv4 payloads on the same LSP), it gets ambiguous on 
      what value should be carried as L3PID in the Label Request Object 
      [RFC3209] or G-PID in the Generalized Label Request Object 
      [RFC3471], [RFC3473]. It also gets unclear at the receiver that 
      source may be multiplexing multiple payloads on the same RSVP-TE 
      LSP. The document clarifies some of the use cases where RSVP-TE 
      LSP is used to carry multiple payloads and what PID should be 
      used during signaling. It also suggests use of an "unknown" PID 
      in signaling when PID is completely determined by scope outside 
      of signaling.  



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      At this stage document is written without use of formal language, 
      but the idea is to first see if the WG feedback on the need for 
      this work.    

   2. Some use cases 

      This section outlines some used cases.   

   2.1. PID = 0x0800 (IPv4 Payload) 

      This case is optimized for carrying IPv4 payload such that IPv4 
      packets travel without need for any additional information 
      (label) to identify the payload, i.e., IPv4 payload is identified 
      by the signaling. If multiplexing of additional payloads is 
      desired, some in-band data plane mechanisms are needed to 
      identify the payload. E.g., if IPv4 and IPv6 payloads are 
      multiplexed on the same tunnel, an IPv6 Explicit Null Label or 
      some other application label is used to identify IPv6 payload.  

   2.2. PID = 0x86DD (IPv6 Payload) 

      This case is optimized for carrying IPv6 payload such that IPv6 
      packets travel without need for any additional information 
      (label) to identify the payload, i.e., IPv6 payload is identified 
      by the signaling. If multiplexing of additional payloads is 
      desired, some in-band data plane mechanisms are needed to 
      identify the payload. E.g., if IPv4 and IPv6 payloads are 
      multiplexed on the same tunnel, an IPv4 Explicit Null Label or 
      some other application label is used to identify IPv4 payload.  

   2.3. IPv4+IPv6 PID 

      This case is optimized for multiplexing IPv4 and IPv6 payloads 
      such that both IPv6 and IPv6 packets travel without need for any 
      additional information (label) to identify the payload. In this 
      case the Egress node looks at the IP version field to identify 
      the payload type (while demultiplexing the traffic). If 
      multiplexing of additional payloads or application is desired, 
      some in-band data plane mechanisms are needed to identify the 
      payload.  

      L3PID and G-PID code point for this are TBA.  

   2.4. Unknown PID 

      This case is the case where payload to be carried by the LSP is 
      not known to the Ingress node. Payload identification is obtained 
      via some means other than signaling and egress node ignores the 
      signaled PID.  
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      Unknown PID with code point of 0x00 is already defined for G-PID 
      in the Generalized Label Request Object [RFC3471], [RFC3473]. 
      L3PID code point for this is TBA.  

   3. Security Considerations 

      TBA 

   4. IANA Considerations 

      TBA 

    
   5. References 

   5.1. Normative References 

      [RFC3209] Awduche D., Berger, L., Gan, D., Li T., Srinivasan, V., 
      Swallow, G., "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 
      3209, December 2001. 
       
      [RFC3471]  Berger, L., "Generalized Multi-Protocol Label 
      Switching (GMPLS) Signaling Functional Description", RFC 3471, 
      January 2003. 
       
      [RFC3473]  Berger, L., "Generalized Multi-Protocol Label 
      Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic 
      Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. 
    
   5.2. Informative References 

    
   Author's Addresses 

      Zafar Ali 
      Cisco Systems, Inc. 
      Email: zali@cisco.com 
       
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