Internet DRAFT - draft-li-spring-bw-guaranteed-sr

draft-li-spring-bw-guaranteed-sr







Network Working Group                                              Z. Li
Internet-Draft                                                     N. Wu
Intended status: Standards Track                     Huawei Technologies
Expires: September 10, 2015                                March 9, 2015


                  Bandwidth-Guaranteed Segment Routing
                  draft-li-spring-bw-guaranteed-sr-00

Abstract

   The document proposes the bandwidth-guaranteed segment for the
   segment routing which can be used to provide the bandwidth-guaranteed
   segment routing path to satisfy the QoS requirement of the service.
   Accordingly the forwarding mechanisms and the procedures of the
   control plane are explained for the bandwidth-guaranteed segment.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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
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   This Internet-Draft will expire on September 10, 2015.

Copyright Notice

   Copyright (c) 2015 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



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   publication of this document.  Please review these documents
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Bandwidth-Guaranteed Segment  . . . . . . . . . . . . . . . .   3
   4.  Use cases . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  End-to-End BW-Guaranteed SR-TE Path . . . . . . . . . . .   3
     4.2.  Bandwidth Guarantee at Network Boundary Node  . . . . . .   3
   5.  Forwarding Mechanisms . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Forwarding Mechanisms for BW-Guaranteed Adjacency Segment   4
     5.2.  Forwarding Mechanisms for BW-Guaranteed Node Segment  . .   4
   6.  Procedures of Control Plane . . . . . . . . . . . . . . . . .   5
     6.1.  Procedures of BW-Guaranteed Adjacency Segment . . . . . .   5
     6.2.  Procedures of BW-Guaranteed Node Segment  . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Segment Routing (SR), introduced by
   [I-D.ietf-spring-segment-routing], leverages the source routing
   paradigm.  A packet can be steered through an ordered list of
   instructions, which are also called segments . The node segment,
   adjacency segment, etc. have been proposed for different usecases.

   The document proposes the bandwidth-guaranteed segment for the
   segment routing which can be used to provide the bandwidth-guaranteed
   segment routing path to satisfy the QoS requirement of the service.
   Accordingly the forwarding mechanisms and the procedures of the
   control plane are explained for the bandwidth-guaranteed segment.

2.  Terminology

   SID: A Segment Identifier

   SR: Segment Routing




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   SR Path: Segment Routing Path

   SR-TE Path: Segment Routing Traffic Engineering Path

3.  Bandwidth-Guaranteed Segment

   In the Segment Routing, the bandwidth-guaranteed attributes can be
   applied for the node segment or the adjacency segment.  These
   segments can be called as bandwidth-guaranteed node segment and
   bandwidth-guaranteed adjacency segment.  When calculate the path to
   the specific destination with the bandwidth constraints, the BW-
   guaranteed node segment and the BW-guaranteed to compose the
   bandwidth-guaranteed segment routing path.

4.  Use cases

4.1.  End-to-End BW-Guaranteed SR-TE Path

   [RFC2702] defines the MPLS TE requirement to provide the end-to-end
   bandwidth-guaranteed service.  With the BW-guaranteed node segment
   and adjacency segment, the Segment Routing can also calculate the
   end-to-end BW-guaranteed SR-TE path.  Thus the bandwidth-guaranteed
   requirement could also be applied in the segment routing to satisfy
   the QoS requirement of different services.

4.2.  Bandwidth Guarantee at Network Boundary Node

   When the traffic leaves the network domain, the QoS process can be
   applied to guarantee the service traffic to the neighboring node in
   the other network domain.  The QoS process can be indicated by the
   bandwidth segment in the segment routing path.  For example, in the
   Figure 1, the bandwidth-guaranteed adjacency segment for the link
   between PE2 and CE2 or the bandwidth-guaranteed node segment for CE2
   is advertised into the network domain, it can be encapsulated to the
   packets at the PE1 as the SR path.  When the packet arrives at the
   PE2, the BW-guaranteed segment is popped to indicate the QoS process
   on the outgoing link to CE2.














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            +---------------------+
            |                     |
            |                     |
            |                     |
            |       Network       |
    CE1----PE1                   PE2----CE2
            |       Domain        |
            |                     |
            |                     |
            |                     |
            +---------------------+

           Figure 1 Network Domain

5.  Forwarding Mechanisms

5.1.  Forwarding Mechanisms for BW-Guaranteed Adjacency Segment

   For the BW-Guaranteed adjacency segment, since the SID only has the
   local semantics, it directly indicates the local outgoing interface
   and the corresponding BW-guaranteed process.

                                              +--------------+
     +--------+    +---------------------+    | QOS Process  |
     |   SID  |--->|      Link       |QID|--->|  based on    |
     +--------+    +---------------------+    |  Bandwidth   |
                                              +--------------+
     SID: Segment ID
     QID: QoS Queue ID

   Figure 2 Forwarding Mechanisms for BW-Guaranteed Link Segment

5.2.  Forwarding Mechanisms for BW-Guaranteed Node Segment

   For the BW-Guaranteed adjacency segment, since the SID only has the
   global semantics, it will indicate the outgoing interface to the
   specific node and the corresponding BW-guaranteed process on the
   outgoing interface.

                   +---------------------+    +--------------+
     +--------+    |  Outgoing Link  |   |    | QOS Process  |
     |   SID  |--->|        to       |QID|--->|  based on    |
     +--------+    |  Specified Node |   |    |  Bandwidth   |
                   +---------------------+    +--------------+
     SID: Segment ID
     QID: QoS Queue ID

   Figure 3 Forwarding Mechanisms for BW-Guaranteed Node Segment



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6.  Procedures of Control Plane

6.1.  Procedures of BW-Guaranteed Adjacency Segment

   IGP extensions or BGP-LS extensions can be introduced to advertised
   the BW-Guaranteed adjacency SID binding for the tuple { Adjacency
   Identification, Bandwidth Attribute }. For the initiation router
   which advertise the BW-Guaranteed SID binding for the adjacency, it
   will install the forwarding entry shown in the Figure 2.  The
   receiving router will keep the information and continue to flood the
   binding information.

6.2.  Procedures of BW-Guaranteed Node Segment

   IGP extensions or BGP-LS extensions can be introduced to advertised
   the BW-Guaranteed node SID binding for the tuple { Node
   Identification, Bandwidth Attribute }. For the router receives the
   BW-Guaranteed node SID binding, it will look up the FIB to get the
   outgoing interface to the node specified by the binding information
   and install the forwarding entry shown in the Figure 3.  Then it will
   continue to flood the binding information.

7.  IANA Considerations

   This document makes no request of IANA.

8.  Security Considerations

   TBD.

9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

9.2.  Informative References

   [I-D.ietf-spring-segment-routing]
              Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
              Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J.,
              and E. Crabbe, "Segment Routing Architecture", draft-ietf-
              spring-segment-routing-01 (work in progress), February
              2015.






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   [RFC2702]  Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
              McManus, "Requirements for Traffic Engineering Over MPLS",
              RFC 2702, September 1999.

Authors' Addresses

   Zhenbin Li
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: lizhenbin@huawei.com


   Nan Wu
   Huawei Technologies
   Huawei Bld., No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: eric.wu@huawei.com





























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