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<rfc category="std" ipr="trust200902" docName="draft-liu-idr-bgp-network-slicing-01">

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<front>
	<title abbrev="BGP for NS in SR Policy">BGP Extensions to Support Packet Network Slicing in SR Policy</title>
 

	
 <author fullname="Liu Yao" initials="Yao" surname="Liu">
      <organization>ZTE Corporation</organization>  
      <address>
        <postal>
          <street>No. 50 Software Ave, Yuhuatai Distinct</street>
          
          <city>Nanjing</city>
          
          <region></region>
  
          <code></code>

          <country>China</country>
        </postal>

        <email>liu.yao71@zte.com.cn</email>
      </address>
    </author>

		<author fullname="Peng Shaofu" initials="Shaofu" surname="Peng">
      <organization>ZTE Corporation</organization>  
      <address>
        <postal>
          <street>No. 50 Software Ave, Yuhuatai Distinct</street>
          
          <city>Nanjing</city>
          
          <region></region>
  
          <code></code>

          <country>China</country>
        </postal>

        <email>peng.shaofu@zte.com.cn</email>
      </address>
    </author>
	
    <date year="2020"/>

    <area>Routing</area>

    <workgroup>IDR Group</workgroup>

   
   <keyword>NETWORK SLICING </keyword>
   <keyword>SR POLICY</keyword>
   <keyword>BGP Extensions</keyword>	
	<abstract>
	<t>
   <xref target="I-D.peng-teas-network-slicing"/> defines a unified TN-slice identifier, AII(administrative instance identifier), to indicate the topology, computing, storage resources of the dedicated virtual network for both intra-domain and inter-domain network slicing scenarios.
   This document defines extensions to BGP in order to advertise AII in SR policies. 
	 </t>
	</abstract>
</front>
 <!-- ***** MIDDLE MATTER ***** -->
<middle>
  <section anchor="intro" title="Introduction">
	<t>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. 
	</t>	
	<t><xref target="I-D.peng-teas-network-slicing"/> defines a unified TN-slice identifier, AII(administrative instance identifier), to indicate the topology, computing, storage resources of the dedicated virtual network for both intra-domain and inter-domain network slicing scenarios, and how to compute SR-BE or SR-TE path according to TN-slice Identifier combined with other creteria.
	</t>
	<t>
	<xref target="I-D.ietf-spring-segment-routing-policy"/> details the concepts of SR Policy and steering into an SR Policy.<xref target="I-D.ietf-idr-segment-routing-te-policy"/> specifies the way to use BGP to distribute one or more of the candidate paths of an SR Policy to the headend of that policy.
	</t>
	<t>
	This document defines extensions to BGP in order to advertise AII in SR-TE policies.	
	</t>


	</section>
	
<section title="SR policy with AII">
	<t>
To distinguish forwarding behavior of different virtual networks, each segment lists in SR policy need to be computed within the scope of TN-slice identified by AII. As AII has global significance, all segments of the same segment list can share a single AII.
This document defines a new AII sub-TLV in Segment List Sub-TLV to indicate which slice this segment list belongs to,
	</t>
	<t>
		<figure align="left" title="Figure 1: AII sub-TLV in Segment List Sub-TLV">
          <artwork><![CDATA[
    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      |     Flags     |   RESERVED    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              AII                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

			]]></artwork>
	        </figure> 
	</t>
	<t>
	where:
	</t>
	<t>
	o  Type: TBD1
	</t>
	<t>
	o  Length: 6
	</t>
	<t>
	o  Flags: 1 octet of flags.  None are defined at this stage.  Flags
      SHOULD be set to zero on transmission and MUST be ignored on
      receipt.
	</t>
	<t>
	o  RESERVED: 1 octet of reserved bits.  SHOULD be set to zero on
      transmission and MUST be ignored on receipt.
	</t>
	<t>
	o  AII: Identifies the TN-slice (AII) information corresponding to the segment list.
	</t>
 </section>		
 
 <section title="Operations">
 <t>The operations about advertisement and reception of SR policy can refer to <xref target="I-D.ietf-idr-segment-routing-te-policy"/>. Typically, a controller or a PCE can compute SR path taking acount of AII criteria, so that the SR path can be limited in the scope of TN-slice identified by AII. The AII information contained in Segment List Sub-TLV can help the headend to translate the segment to AII related SID, if the Segment Sub-TLV has not provided optional SID information. </t>
 <t>Even if Segment Sub-TLV has provided valid SID information, it is also beneficial for the headend to know which slice this path belongs to, according to the AII information contained in Segment List Sub-TLV.</t> 
 </section>
	
	   <section title="Security Considerations">
		<t>Procedures and protocol extensions defined in this document do not affect the security considerations discussed in <xref target="I-D.ietf-idr-segment-routing-te-policy"/>.</t>
	   </section>
		<section title="IANA Considerations">
		<t>TBD</t>
		</section>
  </middle>		
  <!--  *****BACK MATTER ***** -->
  <back>
    <references title='Normative References'>
	&I-D.peng-teas-network-slicing;
	&I-D.ietf-spring-segment-routing-policy;
	&I-D.ietf-idr-segment-routing-te-policy;
	</references>
   <references title="Informative References">
    &I-D.zch-lsr-isis-network-slicing;
   </references>
 </back>
 </rfc>

