Internet DRAFT - draft-chen-isis-source-identifier-distribution

draft-chen-isis-source-identifier-distribution







Network Working Group                                            M. Chen
Internet-Draft                                                    Huawei
Intended status: Standards Track                               G. Mirsky
Expires: April 16, 2015                                         Ericsson
                                                        October 13, 2014


         Extensions to ISIS for Source Identifier Distribution
           draft-chen-isis-source-identifier-distribution-00

Abstract

   A Source Identifier (SI) is carried in an MPLS Source Label and used
   to identify (one of) the ingress LSR(s) to a specific LSP.  This
   document defines extensions to ISIS protocol for distribution of the
   mapping of a Source Identifier to an specific LSR.  Therefore, the
   egress and intermediate LSRs can use the SI to determine from which
   LSR an MPLS packet is sent.

   This document also defines ISIS extensions to advertise the Source
   Label Capability (SLC) of each LSR that indicates whether an LSR can
   properly process the Source Label Indicator (SLI) special purpose
   label and Source Label (SL).  With the SLC, an ingress LSR can
   determine whether it is allowed to insert a SL into the label stack
   for a specific LSP.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on April 16, 2015.



Chen & Mirsky            Expires April 16, 2015                 [Page 1]

Internet-Draft     ISIS Source Identifier Distribution      October 2014


Copyright Notice

   Copyright (c) 2014 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Extensions to ISIS  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Elements of Procedure . . . . . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   As defined in [I-D.chen-mpls-source-label], a Source Identifier (SI)
   is a number in the range of [16, 65535].  Each node in a domain will
   be allocated one or more unique SIs.  A SI is carried in an
   MultiProtocol Label Switching (MPLS) Source Label (SL) and used to
   identify (one of) the ingress Label Switching Router (LSR) to a
   specific Label Switched Path (LSP).

   To identify from where an MPLS packet is sent, the egress/
   intermediate LSRs need to know to which ingress LSR a SI is
   correlated.  Therefore, a mechanism to distribute the correlation of
   a SI to its correlated LSR is required.

   In addition, for an ingress LSR, before inserting a SL in the label
   stack of an LSP, it needs to know whether the egress LSR has the
   capability to process the SLI and SL, otherwise the packet will be
   dropped at the egress LSR.  The capability is called Source Label
   Capability (SLC).




Chen & Mirsky            Expires April 16, 2015                 [Page 2]

Internet-Draft     ISIS Source Identifier Distribution      October 2014


   This document defines extensions to ISIS [RFC1195] protocol to
   distribute SI to LSR mapping and advertise the SLC of each LSR.

2.  Extensions to ISIS

   The Source Identifier sub-TLV is used to distribute the SI(s) to LSR
   mapping and the SLC.  The Source Identifier sub-TLV is advertised
   within an IS-IS CAPABILITY TLV that is defined in [RFC4971], it 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            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           System ID                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        System ID(cond.)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        Reserved       |          Source Identifier 1          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                             ...                               ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        Reserved       |          Source Identifier n          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    Figure 1 - ISIS Source Identifier sub-TLV format

   The value of "Type" field is TBD1.

   The "Length" field defines the length of the Reserved and Source
   Identifier fields in octets, which excludes the System ID field.

   Each "Source Identifier" field (20 bits) contains a SI that
   identifies the advertising LSR.

   The "Reserved" field MUST be set to zero when sending and MUST be
   ignored when received.

3.  Elements of Procedure

   The Source Identifier sub-TLV is carried within an IS-IS CAPABILITY
   TLV that is defined in [RFC4971].  All the procedures that defined in
   [RFC4971] are inherited here.

   The flooding scope of the Source Identifier sub-TLV can be either
   area local or entire IGP domain.  The flooding scope is controlled by
   the S flag in the IS-IS Router Capability TLV [RFC4971].  If the



Chen & Mirsky            Expires April 16, 2015                 [Page 3]

Internet-Draft     ISIS Source Identifier Distribution      October 2014


   flooding scope is area local, the Source Identifier sub-TLV MUST be
   carried within an IS-IS Router Capability TLV with the S flag clear.
   If the flooding scope is the entire IGP domain, the Source Identifier
   sub-TLV MUST be carried within an IS-IS Router Capability TLV with
   the S flag set.

   The Source Identifier sub-TLV is an optional sub-TLV.  Upon receipt
   the sub-TLV, a router will silently ignore the sub-TLV as defined in
   [RFC4971] if it does not support it.  If Source Identifier sub-TLV is
   not present that MUST be interpreted as signaling of non-support of
   SLC by the LSR.  Presence of a Source Identifier sub-TLV MUST be
   interpreted as support of SLC by the LSR.  A Source Identifier sub-
   TLV MUST appear only one time in an LSP.  When received, only first
   Source Identifier sub-TLV is valid, subsequent Source Identifier sub-
   TLVs MUST be ignored.

4.  IANA Considerations

   IANA is requested to assign a new sub-TLV code point for the Source
   Identifier sub-TLV carried within the IS-IS Router Capability TLV.

   Type Value  TLV Name            Reference
   ----------  ------------------  --------------
   TBD1        Source Identifier   (this document)

5.  Security Considerations

   TBD.

6.  Acknowledgements

7.  References

7.1.  Normative References

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

   [RFC4971]  Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
              System to Intermediate System (IS-IS) Extensions for
              Advertising Router Information", RFC 4971, July 2007.

7.2.  Informative References








Chen & Mirsky            Expires April 16, 2015                 [Page 4]

Internet-Draft     ISIS Source Identifier Distribution      October 2014


   [I-D.chen-mpls-source-label]
              Chen, M., Xu, X., Li, Z., Fang, L., and G. Mirsky,
              "MultiProtocol Label Switching (MPLS) Source Label",
              draft-chen-mpls-source-label-05 (work in progress), July
              2014.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, December 1990.

Authors' Addresses

   Mach(Guoyi) Chen
   Huawei

   Email: mach.chen@huawei.com


   Greg Mirsky
   Ericsson

   Email: Gregory.mirsky@ericsson.com






























Chen & Mirsky            Expires April 16, 2015                 [Page 5]