Network Working Group                                    H. Long, M. Ye
Internet Draft                             Huawei Technologies Co., Ltd
Intended status: Standards Track                              G. Mirsky
                                                   Telecom Italia S.p.A
                                                                H. Shah
Expires: January April 13, 2016                                      July 2,                                October 16, 2015

        RSVP-TE Signaling Extension for Links

         Ethernet Traffic Parameters with Variable Discrete
           draft-ietf-ccamp-rsvp-te-bandwidth-availability-02.txt Availability Information


   A Packet switching network MAY may contain links with variable bandwidth,
   e.g., copper, radio, etc. The bandwidth of such links is sensitive
   to external environment. Availability is typically used for
   describing the link during network planning. This document
   introduces an Extended Ethernet Bandwidth Profile TLV and an
   optional Availability sub-TLV in RSVP-TE Resource ReSerVation Protocol -
   Traffic Engineer (RSVP-TE) signaling. This extension can be used to
   set up a label switching path (LSP) in a Packet Switched Network
   (PSN) that contains links with discretely variable bandwidth.

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Table of Contents

   1. Introduction ................................................ 3
   2. Overview .................................................... 4
   3. Extension to RSVP-TE Signaling............................... 4
         3.1.1. Extended Ethernet Bandwidth Profile TLV............ 5
         3.1.2. Availability sub-TLV............................... 6 5
      3.2. FLOWSPEC Object......................................... 6
      3.3. Signaling Process....................................... 6
   4. Security Considerations...................................... 7
   5. IANA Considerations ......................................... 7
      5.1  Ethernet Sender TSpec TLVs ............................. 7
      5.2  Extended Ethernet Bandwidth Profile TLV ................ 8
   6. References .................................................. 8
      6.1. Normative References.................................... 8
      6.2. Informative Reference .................................. References.................................. 9
   7. Appendix: Bandwidth Availability Example..................... 9
   8. Acknowledgments ............................................ 11

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

   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.

   Some data communication technologies allow seamless change of
   maximum physical bandwidth through a set of known discrete values.
   The parameter availability [G.827, F.1703, P.530] is often used to
   describe the link capacity during network planning. The availability
   is a time scale that the requested bandwidth is ensured. A more
   detailed example on the bandwidth availability can be found in
   Appendix A. Assigning different availability classes to different
   types of service over such kind of links provides more efficient
   planning of link capacity. To set up an LSP across these links,
   availability information is required for the nodes to verify
   bandwidth satisfaction and make bandwidth reservation. The
   availability information SHOULD should be inherited from the availability
   requirements of the services expected to be carried on the LSP. For
   example, voice service usually needs ''five nines'' "five nines" availability,
   while non-real time services MAY may adequately perform at four or three
   nines availability. Since different service types MAY may need different
   availabilities guarantees, multiple <availability, bandwidth> pairs
   may be required when signaling.

   If the availability requirement is not specified in the signaling
   message, the bandwidth will be reserved as the highest availability.
   For example, the bandwidth with 99.999% availability of a link is
   100 Mbps; the bandwidth with 99.99% availability is 200 Mbps. When a
   video application requests for 120 Mbps without availability
   requirement, the system will consider the request as 120 Mbps with
   99.999% availability, while the available bandwidth with 99.999%
   availability is only 100 Mbps, therefore the LSP path cannot be set
   up. But in fact, video application doesn't need 99.999% availability;
   99.99% availability is enough. In this case, the LSP could be set up
   if availability is specified in the signaling message.

   To fulfill LSP setup by signaling in these scenarios, this document
   specifies an Extended Ethernet Bandwidth Profile and an Availability
   sub-TLV. The Availability sub-TLV can be applicable to any kind of
   physical links with variable discrete bandwidth, such as microwave
   or DSL. Multiple Extended Ethernet Bandwidth Profiles with different
   availability can be carried in the Ethernet SENDER_TSPEC object.

2. Overview

   A PSN tunnel MAY may span one or more links in a network. To setup a
   label switching path (LSP), a PE node MAY may collect link information
   which is spread in routing message, e.g., OSPF TE LSA message, by
   network nodes to get to know about the network topology, and
   calculate out an 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 discrete bandwidth
   in a network, a <bandwidth, availability> requirement list SHOULD should be
   specified for an LSP. Each <bandwidth, availability> pair in the
   list means that listed bandwidth with specified availability is
   required. The list could be inherited from the results of service
   planning for the LSP.

   A node which has link(s) with variable discrete bandwidth attached
   should contain a <bandwidth, availability> information list in its
   OSPF TE LSA messages. The list provides the information that how
   much bandwidth a link can support for a specified availability. This
   information is used for path calculation by the PE node(s). The routing
   extension for availability can be found in [ARTE].

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

3. Extension to RSVP-TE Signaling

   The initial idea is to define an Availability sub-TLV under Ethernet
   Bandwidth Profile TLV [RFC6003]. However the Ethernet Bandwidth
   Profile TLV doesn't have the ability to carry a sub-TLV according to
   RFC6003. Therefore, an Extend Ethernet Bandwidth Profile TLV is
   defined in this document to avoid the backward compatibility issue.
   The Extended Ethernet Bandwidth Profile TLV includes Ethernet BW TLV
   and has variable length. It MAY include Availability sub-TLV which
   is also defined in this document.

3.1.1. Extended Ethernet Bandwidth Profile TLV

   The Extended Ethernet Bandwidth Profile TLV is included in the
   Ethernet SENDER_TSPEC, and MAY be included for more than one time.
   The Extended Ethernet 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               |
      |Pro|A|         |     Index     |          Reserved             |
      |                              CIR                              |
      |                              CBS                              |
      |                              EIR                              |
      |                              EBS                              |
      |                       sub-TLV(OPTIONAL)                       |

  Figure 1: A new ''AF'' "AF" filed in Extended Ethernet Bandwidth Profile TLV

   The difference between the Extended Ethernet Bandwidth Profile TLV
   and Ethernet Bandwidth Profile TLV is that a new AF field to
   indicate the sub-TLV is defined in the Extended Ethernet Bandwidth
   Profile TLV. The rest definitions are the same.

   A new filed is defined in this document:

     AF filed (bit 2): Availability Field (AF)

   If the AF filed is set to 1, Availability sub-TLV MUST be included
   in the Extended Ethernet Bandwidth Profile TLV. If the AF field is
   set to value 0, then an Availability sub-TLV SHOULD NOT be included.

3.1.2. Availability sub-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                         |

                        Figure 2: Availability sub-TLV

      Type (2 octets): TBD

      Length (2 octets): 4

      Availability (4 octets): a 32-bit floating number describes the
      decimal value of availability requirement for this bandwidth
      request. The value MUST be less than 1.

   As the Extended Ethernet Bandwidth Profile TLV can be carried for
   one or more times in the Ethernet SENDER_TSPEC object, the
   Availability sub-TLV can also be present for one or more times.

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
   Extended Bandwidth Profile TLVs with different availability values
   in the SENDER_TSPEC object. Each Extended Bandwidth Profile TLV
   specifies the portion of the bandwidth request with referred availability

   The intermediate and destination nodes check whether they can
   satisfy the bandwidth requirements 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 message.

     o   If all <bandwidth, availability> requirements can be
        satisfied (the requested bandwidth under each availability
        parameter is smaller than or equal to the remaining bandwidth
        under the corresponding availability parameter on its local
        link), it SHOULD reserve the bandwidth resource from each
        remaining sub-bandwidth portion on its local link 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, availability> requirement cannot
        be satisfied, it SHOULD generate PathErr message with the error
        code "Admission Control Error" and the error value "Requested
        Bandwidth Unavailable" (see [RFC2205]).

   If two LSPs request for the bandwidth with the same availability
   requirement, a way to resolve the contention is comparing the node
   ID, the node with the higher node ID will win the contention. More
   details can be found in [RFC3473].

   If a node does not support the Extended Bandwidth Profile TLV and
   Availability sub-TLV, it SHOULD generate PathErr message with the
   error code "Extended Class-Type Error" and the error value "Class-
   Type mismatch" (see [RFC2205]).

4. Security Considerations

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

5. IANA Considerations

   IANA maintains registries and sub-registries for RSVP-TE used by
   GMPLS. IANA is requested to make allocations from these registries
   as set out in the following sections.

5.1 Ethernet Sender TSpec TLVs

   IANA maintains a registry of GMPLS parameters called ''Generalized "Generalized
   Multi-Protocol Label Switching (GMPLS) Signaling Parameters''. Parameters".

   IANA has created a new sub-registry called ''Ethernet "Ethernet Sender TSpec
   TLVs / Ethernet Flowspec TLVs'' TLVs" to contain the TLV type values for
   TLVs carried in the Ethernet SENDER_TSPEC object. A new value is as

   Type       Description                            Reference

   -----      -----------------------------------    ---------

   TBD        Extended Ethernet Bandwidth Profile    [This ID]

5.2 Extended Ethernet Bandwidth Profile TLV

   IANA has created a new sub-registry called ''Extended "Extended Ethernet
   Bandwidth Profiles'' Profiles" to contain bit flags carried in the Extended
   Ethernet Bandwidth Profile TLV of the Ethernet SENDER_TSPEC object.

   Bits are to be allocated by Standards Action. Bits are numbered from
   bit 0 as the low order bit. A new bit field is as follow:

   Bit     Hex               Description              Reference

   ---     ----              ------------------       -----------

   0       0x01              Coupling Flag (CF)        [RFC6003]

   1       0x02              Color Mode (CM)           [RFC6003]

   2       0x04              Availability Field (AF)   [This ID]

   Sub-TLV types for Extended Ethernet Bandwidth Profiles are to be
   allocated by Standards Action. Initial values are as follows:

   Type    Length          Format                        Description

   ---     ----            ------------------            -----------

   0        -              Reserved                      Reserved value

   0x01     4              see Section 3.1.2 of this ID  Availability

6. References

6.1. Normative References

   [RFC2210] Wroclawski, J., ''The "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 "Ethernet Traffic Parameters'', Parameters", RFC 6003,
             October 2010.

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.

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

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

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

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

   [ARTE]    H., Long, M., Ye, Mirsky, G., Alessandro, A., Shah, H.,
             "OSPF Routing Extension for Links with Variable Discrete
             Bandwidth'', Work in Progress, February, 2014

6.2. Informative References

   [MCOS]    Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions
             for Differentiated Services-aware Traffic Engineered
             Bandwidth", Work in Progress, June 2006. June, 2015

7. Appendix: Bandwidth Availability 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 MAY lower the
   modulation level since demodulating the lower modulation level needs
   a lower Signal-to-Noise Ratio (SNR). This is called adaptive
   modulation technology [EN 302 217]. However, a lower modulation
   level also means lower link bandwidth. When link bandwidth is
   reduced because of modulation down-shifting, high-priority traffic
   can be maintained, while lower-priority traffic is dropped.
   Similarly, the copper links MAY change their link bandwidth due to
   external interference.

   Presuming that a link has three discrete bandwidth levels:

   The link bandwidth under modulation level 1, e.g., QPSK, is 100 Mbps;

   The link bandwidth under modulation level 2, e.g., 16QAM, is 200

   The link bandwidth under modulation level 3, e.g., 256QAM, is 400

   In sunny day, the modulation level 3 can be used to achieve 400 Mbps
   link bandwidth.

   A light rain with X mm/h rate triggers the system to change the
   modulation level from level 3 to level 2, with bandwidth changing
   from 400 Mbps to 200 Mbps. The probability of X mm/h rain in the
   local area is 52 minutes in a year. Then the dropped 200 Mbps
   bandwidth has 99.99% availability.

   A heavy rain with Y(Y>X) mm/h rate triggers the system to change the
   modulation level from level 2 to level 1, with bandwidth changing
   from 200 Mbps to 100 Mbps. The probability of Y mm/h rain in the
   local area is 26 minutes in a year. Then the dropped 100 Mbps
   bandwidth has 99.995% availability.

   For the 100M bandwidth of the modulation level 1, only the extreme
   weather condition can cause the whole system unavailable, which only
   happens for 5 minutes in a year. So the 100 Mbps bandwidth of the
   modulation level 1 owns the availability of 99.999%.

   In a word, the maximum bandwidth is 400 Mbps. According to the
   weather condition, the sub-bandwidth and its availability are shown
   as follows:

   Sub-bandwidth(Mbps)    Availability

   ------------------     ------------

   200                    99.99%

   100                    99.995%

   100                    99.999%

8. Acknowledgments

   The authors would like to thank Khuzema Pithewan, Lou Berger, Yuji
   Tochio, Dieter Beller, and Autumn Liu for their comments on the

   Authors' Addresses

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

   Phone: +86-18615778750

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


   Greg Mirsky (editor)


   Alessandro D'Alessandro
   Telecom Italia S.p.A


   Himanshu Shah
   Ciena Corp.
   3939 North First Street
   San Jose, CA 95134