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Versions: 00 01

Networking Working Group                                   Yongqing. Zhu
Internet-Draft                                             China Telecom
Intended status: Standards Track                               Ran. Chen
Expires: January 5, 2020                                    Shaofu. Peng
                                                         ZTE Corporation
                                                            July 4, 2019


IS-IS Extensions to Support Packet Network Slicing using Segment Routing
                 draft-zch-lsr-isis-network-slicing-00

Abstract

   [I-D.peng-lsr-network-slicing] defines a unified administrative
   instance identifier to distinguish different virtual network
   resources for both intra-domain and inter-domain network slicing
   scenarios.  This draft describes the IS-IS extensions required to
   support Packet Network Slicing using Segment Routing.

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 January 5, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
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   include Simplified BSD License text as described in Section 4.e of



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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   2
   3.  Advertising AII information as a new TE parameter of a link .   2
   4.  Advertising prefix-SID per AII information  . . . . . . . . .   4
   5.  Advertising Adjacency-SID per AII information . . . . . . . .   5
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  AII list sub-TLV  . . . . . . . . . . . . . . . . . . . .   6
     6.2.  Prefix-SID for AII sub-TLV  . . . . . . . . . . . . . . .   6
     6.3.  Adjacency -SID for AII sub-TLV  . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative references  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative references  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   For a packet network, network slicing requires the underlying network
   to support partitioning of the network resources to provide the
   client with dedicated (private) networking, computing, and storage
   resources drawn from a shared pool.  The slices may be seen as
   virtual networks.  [I-D.ietf-teas-enhanced-vpn] described a framework
   to create virtual networks in a packet network.
   [I-D.peng-lsr-network-slicing] specifies a detailed mechanism to
   signal association of shared resources required to create and manage
   an NSI called "Administrative Instance Identifier" (AII).

   This draft describes the IS-IS extensions required to distribute AII
   information in an AS.

2.  Conventions used in this document

   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 RFC2119.

3.  Advertising AII information as a new TE parameter of a link

   [RFC5305] describes extensions to the Intermediate System to
   Intermediate System (IS-IS) protocol to support Traffic Engineering
   (TE).




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   AII can be used to color links to partition underlay resource.  This
   document defines a new extension of the existing IGP-TE
   mechanisms[RFC5305] to distribute AII information in an AS as a new
   TE parameter of a link.

   The AII list 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=TBD1    |   Length      |    Reserved   |    Number     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                     AII for virtual networks 1                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |                       ......                                  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      AII for virtual networks N               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 1

   Type: 43 (Suggested value to be assigned by IANA)

   Length: variable.

   Number:Number of virtual networks.

   AII for VN: allocate different AII for different virtual networks.
   AII is used to distinguish different virtual network resources.

   This sub-TLV MAY be present in any of the following TLVs:

   TLV-22 (Extended IS reachability) [RFC5305].

   TLV-222 (Multitopology IS)[RFC5120].

   TLV-23 (IS Neighbor Attribute)[RFC5311].

   TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311].

   TLV-141 (inter-AS reachability information)[RFC5316].

   This sub-TLV SHOULD appear once at most in each TLV.  Indicates that
   a link can be belong to multiple virtual networks.

   Note that AII 0 does not require notification, and all links are
   always in AII 0 at the same time.



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4.  Advertising prefix-SID per AII information

   [I-D.ietf-isis-segment-routing-extensions] defines a new IS-IS sub-
   TLV: the Prefix Segment Identifier sub-TLV (Prefix-SID sub-TLV).  The
   Prefix-SID sub-TLV carries the Segment Routing IGP-Prefix-SID as
   defined in [RFC8402], and is associated to a prefix advertised by a
   node.

   To distinguish forwarding behavior of different virtual networks,
   Prefix-SID need to be allocated per AII and advertised in the IGP
   domain.  This document defines a new extension of the existing
   Prefix-SID sub-TLV.

   The Prefix-SID for AII 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=TBD2   |    Length     |     Flag      |   Algorithm   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                            AII                                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      SID/Index/Label(Variable)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 2

   where:

   Type:33 (Suggested value to be assigned by IANA)

   Length: Variable.  Depending on the size of the SID.

   The "Flags" and "SID/Index/Label" fields are the same as the Prefix-
   SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].

   AII: Identifies the AII information corresponding to the Prefix-SID.

   This sub-TLV MAY be present in any of the following TLVs:

   TLV-135 (Extended IPv4 reachability) defined in [RFC5305].

   TLV-235 (Multitopology IPv4 Reachability) defined in [RFC5120].

   TLV-236 (IPv6 IP Reachability) defined in [RFC5308].

   TLV-237 (Multitopology IPv6 IP Reachability) defined in [RFC5120].



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   This sub-TLV MAY appear multiple times in each TLV.

5.  Advertising Adjacency-SID per AII information

   [I-D.ietf-isis-segment-routing-extensions]defines a new IS-IS sub-
   TLV: the Adjacency Segment Identifier sub-TLV (Adj-SID sub-TLV).The
   Adj-SID sub-TLV is an optional sub-TLV carrying the Segment Routing
   IGP-Adjacency-SID as defined in [RFC8402].

   To distinguish forwarding behavior of different virtual networks,
   Adjacency -SID need to be allocated per AII and advertised in the IGP
   domain.  This document defines a new extension of the existing
   Adjacency-SID sub-TLV.

   The Adjacency-SID for AII 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=TBD3   |    Length     |     Flag      |   Algorithm   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                            AII                                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      SID/Index/Label(Variable)                |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 3

   where:

   Type:44 (Suggested value to be assigned by IANA)

   Length: Variable.  Depending on the size of the SID.

   The "Flags" and "SID/Index/Label" fields are the same as the
   Adjacency-SID sub-TLV [I-D.ietf-isis-segment-routing-extensions].

   AII: Identifies the AII information corresponding to the Adjacency-
   SID.

   This sub-TLV MAY be present in any of the following TLVs:

   TLV-22 (Extended IS reachability) [RFC5305].

   TLV-222 (Multitopology IS)[RFC5120].

   TLV-23 (IS Neighbor Attribute)[RFC5311].



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   TLV-223 (Multitopology IS Neighbor Attribute)[RFC5311].

   TLV-141 (inter-AS reachability information)[RFC5316].

   Multiple Adj-SID sub-TLVs MAY be associated with a single IS-
   neighbor.  This sub-TLV MAY appear multiple times in each TLV.

6.  IANA Considerations

   This document requests allocation for the following Sub-TLVs.

6.1.  AII list sub-TLV

   This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22,
   222, 23,223 and 141 registry".

   Type:43(suggested - to be assigned by IANA).

6.2.  Prefix-SID for AII sub-TLV

   This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs
   135,235,226 and 237 registry".

   Type:33(suggested - to be assigned by IANA).

6.3.  Adjacency -SID for AII sub-TLV

   This TLV shares sub-TLV space with existing "Sub-TLVs for TLVs 22,
   222, 23,223 and 141 registry".

   Type:44(suggested - to be assigned by IANA).

7.  Security Considerations

   TBD.

8.  Acknowledgements

   TBD.

9.  References

9.1.  Normative references








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   [I-D.ietf-isis-segment-routing-extensions]
              Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
              Gredler, H., and B. Decraene, "IS-IS Extensions for
              Segment Routing", draft-ietf-isis-segment-routing-
              extensions-25 (work in progress), May 2019.

   [I-D.ietf-teas-enhanced-vpn]
              Dong, J., Bryant, S., Li, Z., Miyasaka, T., and Y. Lee, "A
              Framework for Enhanced Virtual Private Networks (VPN+)
              Service", draft-ietf-teas-enhanced-vpn-01 (work in
              progress), February 2019.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC5120]  Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
              Topology (MT) Routing in Intermediate System to
              Intermediate Systems (IS-ISs)", RFC 5120,
              DOI 10.17487/RFC5120, February 2008,
              <https://www.rfc-editor.org/info/rfc5120>.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.

   [RFC5308]  Hopps, C., "Routing IPv6 with IS-IS", RFC 5308,
              DOI 10.17487/RFC5308, October 2008,
              <https://www.rfc-editor.org/info/rfc5308>.

   [RFC5311]  McPherson, D., Ed., Ginsberg, L., Previdi, S., and M.
              Shand, "Simplified Extension of Link State PDU (LSP) Space
              for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009,
              <https://www.rfc-editor.org/info/rfc5311>.

   [RFC5316]  Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
              Support of Inter-Autonomous System (AS) MPLS and GMPLS
              Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316,
              December 2008, <https://www.rfc-editor.org/info/rfc5316>.

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.






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9.2.  Informative references

   [I-D.peng-lsr-network-slicing]
              Peng, S., Chen, R., and G. Mirsky, "Packet Network Slicing
              using Segment Routing", draft-peng-lsr-network-slicing-00
              (work in progress), February 2019.

Authors' Addresses

   Yongqing Zhu
   China Telecom

   Email: zhuyq@gsta.com


   Ran Chen
   ZTE Corporation

   Email: chen.ran@zte.com.cn


   Shaofu Peng
   ZTE Corporation

   Email: peng.shaofu@zte.com.cn


























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