[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-long-ccamp-rsvp-te-bandwidth-availability) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16

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: August 2016                                  February 19, 2016

         Ethernet Traffic Parameters with Availability Information


   A Packet switching network 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 optional Availability TLV in 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.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time.  It is inappropriate to use Internet-Drafts as
   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at

   The list of Internet-Draft Shadow Directories can be accessed at

   This Internet-Draft will expire on August 19, 2016.

Long, et al.           Expires August 19, 2016                [Page 1]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with
   respect to this document. Code Components extracted from this
   document must include Simplified BSD License text as described in
   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.

Table of Contents

   1. Introduction ................................................ 3
   2. Overview .................................................... 4
   3. Extension to RSVP-TE Signaling............................... 4
      3.1. Availability TLV........................................ 4
      3.2. Signaling Process....................................... 5
   4. Security Considerations...................................... 6
   5. IANA Considerations ......................................... 6
      5.1  Ethernet Sender TSpec TLVs ............................. 6
   6. References .................................................. 7
      6.1. Normative References.................................... 7
      6.2. Informative References.................................. 7
   7. Appendix: Bandwidth Availability Example..................... 8
   8. Acknowledgments ............................................. 9

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

Long, et al.           Expires August 19, 2016                [Page 2]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

   TLV      Type Length Value

   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 be inherited from the availability
   requirements of the services expected to be carried on the LSP. For
   example, voice service usually needs ''five nines'' availability,
   while non-real time services may adequately perform at four or three
   nines availability. Since different service types 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 Availability TLV. The Availability TLV can be
   applicable to any kind of physical links with variable discrete
   bandwidth, such as microwave or DSL. Multiple Availability TLVs
   together with multiple Ethernet Bandwidth Profiles can be carried in
   the Ethernet SENDER_TSPEC object.

Long, et al.           Expires August 19, 2016                [Page 3]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

2. Overview

   A PSN tunnel may span one or more links in a network. To setup a
   label switching path (LSP), a node 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 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 node(s). The routing
   extension for availability can be found in [ARTE].

   When a node initiates a PATH/RESV signaling to set up an LSP, the
   PATH message 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 be returned if any <bandwidth, availability> request
   cannot be satisfied.

3. Extension to RSVP-TE Signaling

3.1. Availability TLV

   An Availability TLV is defined as a TLV of the Ethernet
   SENDEDR_TSPEC object [RFC6003] in this document. The Ethernet
   SENDER_TSPEC object MAY include more than one Availability TLV. The
   Availability TLV has the following format:

Long, et al.           Expires August 19, 2016                [Page 4]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

       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
      |    Index      |                 Reserved                      |
      |                          Availability                         |

                          Figure 1: Availability TLV

      Index (1 octet):

      The Availability TLV MUST come along with Ethernet Bandwidth
      Profile TLV. If the bandwidth requirements in the multiple
      Ethernet Bandwidth Profile TLVs have different Availability
      requirements, multiple Availability TLVs SHOULD be carried. In
      such a case, the Availability TLV has one to one correspondence
      with Ethernet Bandwidth Profile TLV by having the same value of
      Index field. If all the bandwidth requirements in the Ethernet
      Bandwidth Profile have the same Availability requirement, one
      Availability TLV SHOULD be carried. In this case, the Index field
      is set to 0.

      Reserved (3 octets): These bits SHOULD be set to zero when sent
      and MUST be ignored when received.

      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.

3.2. Signaling Process

   The source node initiates PATH messages which carry a number of
   bandwidth request information, including one or more Ethernet
   Bandwidth Profile TLVs and one or more Availability TLVs. Each
   Ethernet Bandwidth Profile TLV corresponds to an availability
   parameter in the Availability TLV.

   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 on the
   local link when received the PATH message.

Long, et al.           Expires August 19, 2016                [Page 5]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

     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 Availability 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
   Multi-Protocol Label Switching (GMPLS) Signaling Parameters''.

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

Long, et al.           Expires August 19, 2016                [Page 6]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

   Type       Description                            Reference

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

   TBD        Availability                           [This ID]

6. References

6.1. Normative References

   [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.

6.2. Informative References

   [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

Long, et al.           Expires August 19, 2016                [Page 7]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

   [EN 302 217] ETSI standard, ''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, 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.

Long, et al.           Expires August 19, 2016                [Page 8]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

   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

Long, et al.           Expires August 19, 2016                [Page 9]

Internet-Draft    RSVP-TE - Bandwidth Availability       February 2016

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

   Phone: +86-18615778750
   Email: longhao@huawei.com

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

   Email: amy.yemin@huawei.com

   Greg Mirsky (editor)

   Email: gregory.mirsky@ericsson.com

   Alessandro D'Alessandro
   Telecom Italia S.p.A

   Email: alessandro.dalessandro@telecomitalia.it

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

   Email: hshah@ciena.com

Long, et al.           Expires August 19, 2016               [Page 10]

Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/