Network Working Group                                           H. Long
Internet Draft                                                     M.Ye
Intended status: Standards Track           Huawei Technologies Co., Ltd
                                                              G. Mirsky
                                                           A Alessandro
                                                   Telecom Italia S.p.A
Expires: January 2014                                      July 3, 2013

           RSVP-TE Signaling Extension for Bandwidth availability


   Packet switching network usually contains links with variable
   bandwidth, e.g., copper, radio, etc. The bandwidth of such link is
   sensitive to external environment. Availability is typically used
   for describing the link during network planning. This document
   describes an extension for RSVP-TE signaling for setting up a label
   switching path (LSP) in a Packet Switched Network (PSN) network
   which contains variable bandwidth link by introducing an optional
   availability field in RSVP-TE signaling.

Status of this Memo

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   This Internet-Draft will expire on January 7, 2009.

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Copyright Notice

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Table of Contents

   1. Introduction ................................................ 3
   2. Overview .................................................... 4
   3. Extension to RSVP-TE Signaling............................... 4
      3.1. SENDER_TSPEC Object..................................... 4
         3.1.1. Bandwidth Profile TLV.............................. 5
      3.2. FLOWSPEC Object......................................... 6
      3.3. Signaling Process....................................... 6
   4. Security Considerations...................................... 7
   5. IANA Considerations ......................................... 7
   6. References .................................................. 7
      6.1. Normative References.................................... 7
      6.2. Informative References.................................. 8
   7. Acknowledgments ............................................. 8

Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC-2119 [RFC2119].

   The following acronyms are used in this draft:

   RSVP-TE  Resource Reservation Protocol-Traffic Engineering

   LSP      Label Switched Path

   PSN      Packet Switched Network

   SNR      Signal-to-noise Ratio

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   TLV      Type Length Value

   PE       Provider Edge

   LSA      Link State Advertisement

1. Introduction

   The RSVP-TE specification [RFC3209] and GMPLS extensions [RFC3473]
   specify the signaling message including the bandwidth request for
   setting up a label switching path in a PSN network.

   There are some data communication technologies that allow seamless
   change of maximum physical bandwidth. For example, in mobile
   backhaul network, microwave links are very popular for providing
   connection of last hops. In case of heavy rain, to maintain the link
   connectivity, the microwave link will lower the modulation level
   since demodulating lower modulation level need lower signal-to-noise
   ratio (SNR). This is called adaptive modulation technology [EN 302
   217]. However, lower modulation level also means lower link
   bandwidth. When link bandwidth reduces by modulation down-shifting,
   high priority traffic can be maintained, while lower priority
   traffic is dropped. Similarly the cooper links may change their link
   bandwidth due to external interference.

   The parameter, availability [G.827, F.1703, P.530], is often used to
   describe the link capacity during network planning. Assigning
   different availability classes to different types of service over
   such kind of links provides more efficient planning of link capacity.
   To set up a LSP across these links, availability information is
   required for the nodes to verify bandwidth satisfaction and make
   bandwidth reservation. The availability information should be
   inherited from the availability requirements of the services
   expected to be carried on the LSP, voice service usually needs ''five
   nines'' availability, while non-real time data packets may needs four
   or three nines availability. Since different service types may need
   different availabilities guarantee, multiple <availability,
   bandwidth> pairs may be required when signaling.

   To fulfill LSP setup by signaling in these scenarios, this document
   specifies the following extension:

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     o A new SENDER_TSPEC object is defined which includes multiple
        bandwidth profiles with different availability. This object is
        an extension on the Ethernet SENDER_TSPEC defined by [RFC6003]
        which support multiple bandwidth profile TLVs, but limited in
        the scope of Ethernet. The extension uses the object
        generically, and amends availability information in the
        bandwidth profile TLV.

2. Overview

   A PSN tunnel may span one or more links in a network. To setup a
   label switching path (LSP), a PE node may collect link information
   which is spread in routing message, e.g., OSPF TE LSA message, by
   network nodes to get know about the network topology, and calculate
   out a LSP route based on the network topology, and send the
   calculated LSP route to signaling to initiate a PATH/RESV message
   for setting up the LSP.

   In case that there is(are) link(s) with variable bandwidth in a
   network, a <bandwidth, availability> requirement list should be
   specified for a LSP. Each <bandwidth, availability> pair in the list
   means a bandwidth with specified availability is required. The list
   could be inherited from the result of service planning for the LSP.

   When a PE node initiates a PATH/RESV signaling for setting up the
   LSP, the PATH message should carry the <bandwidth, availability>
   requirement list as bandwidth request, and the intermediate node(s)
   will allocate the bandwidth resource for each availability
   requirement from the remaining bandwidth with corresponding
   availability. An error message may be returned if any <bandwidth,
   availability> request cannot be satisfied.

3. Extension to RSVP-TE Signaling

3.1. SENDER_TSPEC Object

   The SENDER_TSPEC object (Class-Num = 12) has the following format:

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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      |            Length             | Class-Num (12)|     C-Type    |
      |             Class-Specific Information (Optional)             |
      |                                                               |
      ~                              TLVs                             ~
      |                                                               |

   Class-Specific Information: 32 bits

      This field indicates the specific information for each C-Type.

   TLV (Type-Length-Value):

      The SENDER_TSPEC object MUST include at least one TLV and MAY
       include more than one TLV.

3.1.1. Bandwidth Profile TLV

   The Bandwidth Profile TLV has the following format.

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      |              Type             |          Length               |
      |    Profile    |     Index     |          Reserved             |
      |                            ... ...                            |
      ~                      Traffic Parameters                       ~
      |                            ... ...                            |

      Type: TBD, 16 bits;

      Length: 16 bits;

      Profile: 8 bits

         This field is defined as a bit vector of binary flags.  The
         following flags are defined:

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            Flag 3 (bit 2): Availability Flag (AF)

         When The Flag 3 is set to value 1, there is an availability
         sub-TLV included in this Bandwidth Profile TLV. The
         availability sub-TLV has the following format:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      |               Type            |               Length          |
      |                          Availability                         |

           Type (2 octets): TBD
           Length (2 octets): 4
           Availability (4 octets): a 32-bit floating number describes
           availability requirement for this bandwidth request. The
           value must be less than 1.

     Index: 8 bits

       See [RFC6003] section 4.1.

     Traffic Parameters:

       This field includes the traffic parameters information. The
         format is different for different C-Type.

         C-Type = IntServ: See [RFC2210];
         C-Type = Ethernet: See [RFC6003];

3.2. FLOWSPEC Object

   The FLOWSPEC object (Class-Num = 9, Class-Type = TBD) has the same
   format as the Ethernet SENDER_TSPEC object.

3.3. Signaling Process

   The source node initiates PATH messages including one or more
   Bandwidth Profile TLVs with different availability value in the
   SENDER_TSPEC object. Each Bandwidth Profile TLV specifies the
   portion of bandwidth request with referred availability requirement.

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   The destination nodes check whether it can satisfy the bandwidth
   requirement by comparing each bandwidth requirement inside the
   SENDER_TSPEC objects with the remaining link sub-bandwidth resource
   with respective availability guarantee when received the PATH

     o   If all bandwidth requirements can be satisfied, it should
        reserve the bandwidth resource from each remaining sub-
        bandwidth portion to set up this LSP. Optionally, the higher
        availability bandwidth can be allocated to lower availability
        request when the lower availability bandwidth cannot satisfy
        the request.

     o   If at least one bandwidth requirement cannot be satisfied, it
        should generate PathErr message with the error code "Traffic
        Control Error" and the error value "Bad Tspec value" (see

4. Security Considerations

   This document does not introduce new security considerations to the
   existing RSVP-TE signaling protocol.

5. IANA Considerations


6. References

6.1. Normative References

   [RFC2210] Wroclawski, J., ''The Use of RSVP with IETF Integrated
             Services'', RFC 2210, September 1997.

   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
             V.,and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC 3209, December 2001.

   [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
             (GMPLS) Signaling Resource ReserVation Protocol-Traffic
             Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

    [RFC6003] Papadimitriou, D. ''Ethernet Traffic Parameters'', RFC
             6003, October 2010.

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   [G.827]  ITU-T Recommendation, ''Availability performance parameters
             and objectives for end-to-end international constant bit-
             rate digital paths'', September, 2003.

   [F.1703]  ITU-R Recommendation, ''Availability objectives for real
             digital fixed wireless links used in 27 500 km
             hypothetical reference paths and connections'', January,

   [P.530]   ITU-R Recommendation,'' Propagation data and prediction
             methods required for the design of terrestrial line-of-
             sight systems'', February, 2012

   [EN 302 217] ETSI standard, ''Fixed Radio Systems; Characteristics
             and requirements for point-to-point equipment and
             antennas'', April, 2009

6.2. Informative References

   [MCOS]    Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions
             for Differentiated Services-aware Traffic Engineered
             LSPs", Work in Progress, June 2006.

7. Acknowledgments

   Authors' Addresses

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   Hao Long
   Huawei Technologies Co., Ltd.
   No.1899, Xiyuan Avenue, Hi-tech Western District
   Chengdu 611731, P.R.China

   Phone: +86-18615778750

   Min Ye
   Huawei Technologies Co., Ltd.
   No.1899, Xiyuan Avenue, Hi-tech Western District
   Chengdu 611731, P.R.China


   Greg Mirsky


   Alessandro D'Alessandro
   Telecom Italia S.p.A


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