I2RS S. Hares
Internet-Draft L. Dunbar
Intended status: Standards Track Huawei
Expires: August 13, 2016 February 10, 2016

A Yang model for I2RS service topology
draft-hares-i2rs-service-topo-dm-05.txt

Abstract

This document defines I2RS protocol-independent service layer virtual topology data model. This data model utilizes the concepts in the generic I2RS topology model of virtual networks (node, links, termination points) and cross-layer topologies. This virtual service topology may be a composite layer created from the combination of protocol-dependent service layers. Protocol-dependent services layers include: L3VPN, L2VPN, EVPN, E-Tree, and others.

Status of This Memo

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This Internet-Draft will expire on August 13, 2016.

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Table of Contents

1. Introduction

Service topology in [I-D.ietf-i2rs-yang-network-topo] includes the a virtual topology for a service layer above the L1, L2, and L3 layers. This virtual topology has the generic topology elements of node, link, and terminating point. The virtual service topology is a network-wide topology stored on one routing system which an I2RS agent is connected to.

The virtual service topology is a composite summary of the services available services gathered from the lower layer indications of L3VPN, L2VPN, and EVPN services, E-TREE services, Seamless MPLS topologies within an As and others. This is a "bottoms up" yang module providing composite protocol independent service topology based on these protocol services.

This "bottoms-up" yang model does provide a mechanism to link this bottoms up model to a top-down service model. One example of a top-down service model for L3 VPNs is the L3 Service yang data model [I-D.ietf-l3sm-l3vpn-service-model]. Although the two models are linked, the top-down service model cannot be derived from the lower layers.

1.1. 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 [RFC2119].

1.2. Base Model: the Service-Topology Component

            +----------------+
            |    network     | 
            |    topology    |<...
            +----------------+   :
              *           *  :   :
              |           |  :...:
              |           |
      +--------+        +--------+
  ...>|  node  |<.......|link    |<...
  :   +--------+<.......+--------+   :
  :    :   *             : :  *  :   :
  :.....   |             : :  |  :...:
           |             : :  |
.....>+--------+<........: :  |
:     |   TP   |<..........:  |
: ...>+--------+              |
: :                           |
: : .....................+---------+
.........................|Direction|
                         +---------+

The following diagram contains an informal graphical depiction of the main elements of the information model:

The link between the upper layer and the lower layer occurs by linking the bottoms up service network topologies to Top-down service topologies at certain service nodes to support transport of service across a virtual service link.

For example, the bottoms up topology could contain a composite of 3 L3VPN network topologies, 2 L2VPN network topologies, and 2 EVPN network topologies. Each of these physical networks can support virtual networks on top of the physical network. The service network base bottoms up is formed topology map with all of these topologies.

An L3SM might utilize have three VPN services topologies which support three services over 9 virtual topologies transiting the 2 of the L3VPN networks.

The nodes providing the L3VPN provider equipment (PE) overlap, but the customer equipment (CE) at all sites are unique.

  
  L3SM topologies 
            Service-topology [VPN-ID:1]
                /               \			
   cloud 1 topology 1         cloud 2 topology-1 
       /     |      \            /     |      \    
  Site-1A site-1B site1-C    site-1A Site-1B Site-1C 
    |          |       |       |         |     |
====|==========|=======|=======|=========|=====|====
    +-------+  |        \    /           /     |
 Bottoms-up |  |         \ /           /       | 
 service    |  |         /\           /        |
 topology   |  |       /    \        |         | 
 L3VPN-Service-topology 1  L3VPN-Service   Topology-2 
            |  |      |       |      |         |
        node1 node2 node3   node4   node5    node6 	
          PE   PE    PE       PE      PE       PE
          |     |     |        |       |        |
         CE    CE     CE      CE      CE       CE 		  

These two layers of service topologies are by two different composite models composite models and different supporiting models as follows:

The links between

2. High level Yang architecture

This section describes the Yang High level architecture.

2.1. Network level

The service topology network level defines the following high-level yang architeture:

module: i2rs-service-topologies
   augment /nw:network/nw:network-types:
      +--rw service-topologies-types
   augment /nw:network:
     +--rw service-topology-attributes
         +--rw name?   string
		 +--rw flag	   flag_type;
 		 +--rw composite-flag identity-ref 
		 +--rw c-service-topo-id network-id
		 +--rw c-servic-id uint32 
		 +--rw c-node-cnt  uint32
		 +--rw composite-flag_status identity-ref 
         +--rw supports-td-attributes*
		 
Note: Composite flags are bottoms-up flags 

The service topology attributes for a network include the following

2.2. Node level

module: i2rs-service-topologies
.... 
   augment /nw:network/nw:node
      +--rw node-service-attributes
         +--rw c-svc-node-name?   inet:domain-name
         +--rw c-svc-flag*  identityref;
		 +--rw c-service-node-id  uint32
		 +--rw c-svc-node-type  identityref 
		 +--rw c-node-svc-status* identityref;
		 +--rw c-node-supports-td-attributes

The additional fields in the service attributes are the following:

2.3. Service Link and Termination point

   augment /nw:network/nt:link:
      +--rw service-link-attributes
         +--rw c-svc-link-name?     string
		 +--rw c-svc-link-id        uint32
         +--rw c-svc-link-type identityref 		 
         +--rw c-svc-link-metric?   uint32
		 +--rw c-svc-link-attributes* identityref
		 +--rw c-svc-link-td-supports-attr* identityref 
   augment /nw:network/nw:node/nt:termination-point:
      +--rw service-termination-point-attributes
	     +--rw tp-svc-id 	
         +--rw (supporting-termination-point) 
            +--:(service)
			|  +--rw service-network-id  leafref
            |  +--rw service-node-id     leafref
			|  +--rw service-tp-id       leafref
			+--:(ip)
			|  +--rw ip-address   inet:ip-address
            +--:(unnumbered)
               +--rw unnumbered-id?   uint32

The augmentation to the service topology is the service link attributes which include:

The augmentation to the termination point include the following

3. Yang Data Model

<CODE BEGINS> file "ietf-i2rs-service-topology@2016-02-09.yang"
module ietf-i2rs-service-topology{
  namespace "urn:ietf:params:xml:ns:yang:ietf-i2rs-service-topology";
  prefix i2rs-st;
  
    import ietf-inet-types {
    prefix inet;
  }
  
   import ietf-network {
     prefix nw;
   }
   import ietf-network-topology {
     prefix "nt";
   }  
   
    organization "IETF";
	  contact
     "email: shares@ndzh.com;	 
      email: linda.dunbar@huawei.com;	  
	 ";

   description
     "This module defines a model for the service topology.
	  This service model imports 
	  - ietf-network and ietf-network-topology from
	     draft-ietf-i2rs-yang-network-topo-02.txt,
	  - ietf-routing from draft-ietf-netmod-routing-cfg,
	  - ietf-l3vpn-svc from 
	      draft-ietf-l3sm-l3vpn-service-model.
		  (not defined yet )
	  ";
 
  revision 2016-02-09 {
    description
      "Version 1 - initial version;
	   Version 2 - yang format fixed
	   Version 3 - errro in xml file
	   version 4 - remove next-hops attribute.
	   version 5- links to top-level attributes.";
	   
     reference "draft-hares-i2rs-service-topo-dm-05.txt";
  }
  
      identity svc-topo-flag-identity {
        description "Base type for svc flags";
        }
      identity l3vpn-svc-topo {
        base svc-topo-flag-identity;
        description "L3VPN service type";
       }
      identity l2vpn-svc-topo {
        base svc-topo-flag-identity;
        description "L2VPN service type";
       }
       identity EVPN-svc-topo {
        base svc-topo-flag-identity;
        description "EVPN service type";
       }
        identity Seamless-MPLS-svc-topo {
        base svc-topo-flag-identity;
        description "Seamless MPLS service type";
       }
        identity Etree-svc-topo {
        base svc-topo-flag-identity;
        description "Seamless MPLS service type";
       }
        identity I2rs-svc-topo {
        base svc-topo-flag-identity;
        description "I2RS create service topo";
       }
	   
      identity svc-tp-type {
        description "Base type for service
          termination-point type flags";
        }
      identity svc-tp-type-service {
        base svc-tp-type;
        description "service type";
       }
      identity svc-tp-type-ip {
        base svc-tp-type;
        description "service IP";
       }
      identity svc-tp-type-unnum {
                base svc-tp-type;
        description "service unnumbered link";
       }
	   
	   identity service-topology-types{
	    description
		"service topology type";
	   }
	   
	   identity svc-link-identity {
	    description "Base type for composite
		  service link attribute flags";
	    }
		identity svc-link-ip-te {
		  base svc-tp-type; 
		  description "service link 
		  that support IP traffic engineering";
		}
		
	 	identity svc-link-ip-multicast {
		  base svc-tp-type; 
		  description "service link that 
		  supports IP multicast.";
		}
	 
	   identity td-svc-support-identity {
        description "Base type for svc flags";
        }
		
		identity td-L3sm-hub-spoke {
		    base td-svc-support-identity;
        description "Supports L3SM hub-spoke";
        }
	    identity td-L3sm-hub-spoke-disjoint {
		    base td-svc-support-identity;
        description "Supports L3SM hub-spoke disjoint";
        }
		
		identity td-L3sm-any-any {
		    base td-svc-support-identity;
        description "Supports L3SM any-any";
        }
		
      grouping service-topology-types {
       leaf service-type {
            type identityref {
            base svc-topo-flag-identity;
           }
           description "list of service
		     topology type supported";
         }
		 description
		 "service topology types";
      }

      grouping service-topology-attributes {
        leaf name {
		  type string;
          description "name of service
          topology";
		}
        
		leaf composite-flag {
           type identityref {
              base service-topology-types;
		   }
          description "other topologies
          this topology is configured to
           be a composite of
              (L3VPN, L2VPN, I2RS only)";
        }
        leaf c-service-topo-id {
            type nw:network-id;
             description  "service topology id 
	        	to a service topology instance.";
        }
        leaf c-service-id-number {
            type uint32;
            description "ID for topology";
        }
        leaf c-node-count {
            type uint32;
            description "count of service level nodes
            in the network.";
        }
        
		leaf composite-flag-status {
            type identityref {
            base svc-topo-flag-identity;}
            description "other topologies
            this topology is currently a
            composite of
            (L3VPN, L2VPN, I2RS only)";
        }
		list supports-td-attributes {
		   key c-svc-td-attribute-id;
		   leaf c-svc-td-attribute-id {
		    type uint8;
			description "top-down 
			service support attribute id number";
		   }
		  leaf td-supports-attribute {
             type identityref {
              base td-svc-support-identity;
		      }
		      description "top-down service
		     attribute this topology supports.";
			 
		   }
		   description "supporting top-down 
           service attributes. ";
		}
		description  "Group of attributes for
              service topology";  
			  	 
      }
	  
	  
      grouping node-svc-attribute {
        leaf c-svc-node-name{
           type inet:domain-name;
           description "Domain name for node";
        }
        leaf c-svc-flag {
          type identityref {
             base svc-topo-flag-identity;
		  }
          description "virtual network
           node can be composite of the
           topologies list
           (L3VPN, L2VPN, I2RS only)";
           }
        leaf c-svc-node-id {
           type uint32;
           description "ID for node at
             service level";
        }
        leaf node-svc-status {
           type identityref {
             base service-topology-types;
		   }
		   description "other topologies
             this topology is currewntly
             be composed of
			 (L3VPN, L2VPN, I2RS only)"; 
		 }
		 
		list c-node-supports-td-attributes {
		   key c-node-td-attribute-id;
		   leaf c-node-td-attribute-id {
		    type uint8;
			description "top-down 
			service support attribute id number";
		   }
		  leaf c-node-supports-attribute {
             type identityref {
              base td-svc-support-identity;
		      }
		      description "top-down service
		     attribute this topology supports.";
			 
		   }
		   description "list of top-down service
		   attributes this node supports";
		}       
  	
	   description
	   "grouping of composite flag";
      }
 
	grouping service-link-attributes {
        leaf c-svc-link-name {
		  type string;
          description "name of
            service link";
		}
        leaf c-svc-link-id {
		  type uint32;
		  description "link id";
		}
        leaf c-svc-link-type {
          type identityref {
             base service-topology-types;
		  }
          description "other topologies
            this link is current a 
			composite of
            (L3VPN, L2VPN, I2RS only)";
        }
        leaf c-svc-link-metric {
          type uint32;
          description "link metric
		    which may need to expand or
			 link to TE topologies.";
        }
		list c-svc-link-attributes {
		   key  c-svcl-attr-id;
		   leaf c-svcl-attr-id {
		    type uint8;
			description "composite
			service attribute id number";
		   }
		  leaf c-svc-link-attribute {
             type identityref {
              base svc-link-identity;
		      }
		      description "top-down service
		     attribute this link supports.";
		   }
		  description "list of service level 
		  link attributes";
		}
		list c-svc-link-td-supports-attributes {
		   key c-svcl-td-attr-id;
		   leaf c-svcl-td-attr-id {
		    type uint8;
			description "top-down 
			service support attribute id number";
		   }
		  leaf c-svc-link-td-support-attribute {
             type identityref {
              base td-svc-support-identity;
		      }
		      description "top-down service
		     attribute this link supports.";
		   }
		  description "list of service level
		   link attributes";
		}
	    description "grouping of 
		 service link attribute";
      }
	  
  grouping service-termination-point-attributes {
        leaf svc-tp-id {
            type uint32;
            description "termination point id";
         }
        container supporting-termination-point {
          leaf svc-tp-type {
            type identityref {
              base svc-tp-type;
			}
          description "other topologies
            this link termination point is
            part of (L3VPN, L2VPN, 
		    or I2RS only)";
		  }
          choice svc-tp-support-type{
            case svc-tp-type-service {

              leaf service-network-id {
                type uint32;
                description "service network id";
		       }
              leaf service-node-id {
                type uint32;
				description "service node id";
			  }
              leaf service-link-id {
                type uint32;
				description "service link id";
			  }
			  description "network, node,
                 tp that supports this
                 termination point";
			}
            case svc-tp-type-inet {
              leaf ip-address{
			    type inet:ip-address;
			    description "ip address";
			  }
			  description "inet svc tp";
            }
            
			case svc-tp-type-unnum {
              leaf unnumbered-id {
                type uint32;
			    description "unnumbered id";
			  }
			 description "unnumber svc tp";
			}
		   description "service termination
		       point type cases";
          }
        description "container of 
	       supporting termination point";
        }
		description
		"grouping of service-termination-point-attributes";
      }
	  
		   
      /*
       * Data nodes
       */
	    augment "/nw:networks/nw:network/nw:network-types"{
        uses service-topology-types;
		description
		"augment the network-tpyes with
		the service-topology-types grouping";
		}
      augment "/nw:networks/nw:network/nw:node" {
	   leaf name {
	   type inet:domain-name;
	    description "service name.";
	   }
	   list composite_flag {
	     key "service-node-id";
	     leaf service-node-id{
	       type uint32;
	       description "service node id.";
	     }
	     leaf node-svc-type{
	       type string;
	       description "node service type.";
	      }
	   description
	     "the list of composite flag.";
	  }
	  
	 description "augments node list";
	 }
	
			   

  augment "/nw:networks/nw:network"{
       uses service-topology-attributes;
	   description
	   "augment the network with 
	   the servcie-topolgoy-attributes";
	   }
  augment "/nw:networks/nw:network/nw:node"{
      uses node-svc-attribute;
	  description
	  "augment the node with the node-svc-attribute";
	  }
  augment "/nw:networks/nw:network/nt:link" {
    uses service-link-attributes;
	description
	"augment the link with 
	service-link-attributes";
	}
 augment "/nw:networks/nw:network/nw:node/nt:termination-point"{
    uses service-termination-point-attributes;
	description
	"augment the termination-point with
	service-termination-point-attributes";
	}
} // module i2rs-service-topology  

<CODE ENDS>

4. IANA Considerations

TBD

5. Security Considerations

TBD

6. References

6.1. Normative References

[I-D.ietf-i2rs-yang-network-topo] Clemm, A., Medved, J., Varga, R., Tkacik, T., Bahadur, N. and H. Ananthakrishnan, "A Data Model for Network Topologies", Internet-Draft draft-ietf-i2rs-yang-network-topo-02, December 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.

6.2. Informative References

[I-D.ietf-i2rs-yang-l3-topology] Clemm, A., Medved, J., Varga, R., Tkacik, T., Liu, X., Bryskin, I., Guo, A., Ananthakrishnan, H., Bahadur, N. and V. Beeram, "A YANG Data Model for Layer 3 Topologies", Internet-Draft draft-ietf-i2rs-yang-l3-topology-01, December 2015.
[I-D.ietf-l3sm-l3vpn-service-model] Litkowski, S., Shakir, R., Tomotaki, L. and K. D'Souza, "YANG Data Model for L3VPN service delivery", Internet-Draft draft-ietf-l3sm-l3vpn-service-model-02, December 2015.

Authors' Addresses

Susan Hares Huawei 7453 Hickory Hill Saline, MI 48176 USA EMail: shares@ndzh.com
Linda Dunbar Huawei USA EMail: linda.dunbar@huawei.com