YANG Data Model for SR Service Programming

The Network Configuration Protocol (NETCONF) is one of the network management protocols that defines mechanisms to manage network devices. YANG is a modular language that represents data structures in an XML tree format, and is used as a data modeling language for the NETCONF. Segment Routing is an architecture based on the source routing paradigm that seeks the right balance between distributed intelligence and centralized programmability. SR can be used with an MPLS or an IPv6 data plane to steer packets through an ordered list of instructions, called segments. These segments may encode simple routing instructions for forwarding packets along a specific network path, but also steer them through Virtual Network Function (VNF) or physical service appliances available in the network. In an SR network, each of these services, running either on a physical appliance or in a virtual environment, are associated with a segment identifier (SID). These service SIDs are then leveraged as part of a SID-list to steer packets through the desired services in the service chain. Service SIDs may be combined together in a SID-list to achieve the service programming, but also with other types of segments as defined in . SR thus provides a fully integrated solution for overlay, underlay and service programming. Furthermore, the IPv6 instantiation of SR (SRv6) supports metadata transportation in the Segment Routing header , either natively in the tag field or with extensions such as TLVs. This document describes how a service can be associated with a SID, including legacy services with no SR capabilities, and how these service SIDs are integrated within an SR policy. The definition of an SR Policy and the traffic steering mechanisms are covered in and hence outside the scope of this document. This document introduces a YANG data model for the SR based service programming configuration and management. Furthermore, this document also covers the basic SR unaware behaviours as defined in . This document does not cover the following: SR-aware service specific management parameters The model currently defines the following constructs that are used for managing SR based service programming: Configuration Operational State Notifications

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 BCP 14 when, and only when, they appear in all capitals, as shown here.

This document defines the following four new YANG modules: ietf-service-function-types: Defines common service function types ietf-sr-service-programming-types: Defines common type definitions used for SR based service programming YANG model ietf-sr-service-programming: Defines management model for SR based service programming framework. This is a base and common framework for both SR-aware and SR-unaware services. ietf-sr-service-programming-proxy: Defines management model for SR service proxy for SR unaware services The modelling in this document complies with the Network Management Datastore Architecture (NMDA) defined in . The operational state data is combined with the associated configuration data in the same hierarchy . When protocol states are retrieved from the NMDA operational state datastore, the returned states cover all "config true" (rw) and "config false" (ro) nodes defined in the schema. In this document, when a simplified graphical representation of YANG model is presented in a tree diagram, the meaning of the symbols in these tree diagrams is defined in . In this document, the SR service programming YANG model is split based on dynamic SID allocation and static SID allocation. In the case of dynamic SID allocation, new SR service programming tree would be used. In the case of static MPLS SID allocation for the SR service programming, the existing SR MPLS YANG model would be augmented with the SR MPLS service programming specific parameters. Similarly the static SRv6 base YANG model (TBD) would be augmented with the SRv6 service programming specific parameters.

A service is identified by (type, variant, instance). The type represents the type of service functions (such as Firewall, DPI IPS etc.), The variant value is a unique identifier which could identify the vendor and its product informations, The instance is used to refer to a specific instance of the same (service, variant). We define a new YANG module ietf-service-function-types to specify common definitions and types for service and service function. The types and definitions are generic and hence can be used in any (SR based or non-SR) YANG models. The main definitions and types defined in ietf-service-function-types module include: service-function-type: A new identity type to specify service function types, such as firewall, dpi etc. Other identities can be define by other modules in future.

The types required to model SR based service programming are defined in a new module ietf-sr-service-programming-types. The main types defined in this module includes: service-program-behaviour-type: Defines SR service program behaviours like sr-aware, static-proxy etc... service-program-oper-status-type: Defines SR service programming operational status. This includes the reason for down status as well service-proxy-inner-pkt-type: Defines SR service proxy inner packet types

The base model and framework for SR based service programming using dynamic SID allocation is defined in a new module ietf-sr-service-programming. In the case of static MPLS SID allocation for the SR service programming, the existing SR MPLS YANG model would be augmented with the SR MPLS service programming specific parameters. In the case of static SRv6 based YANG model (TBD) would be augmented with the SRv6 service programming specific parameters. This module provides a common base for both the SR-aware and SR-unaware service programming in terms of configuration, operation state and notifications. The ietf-sr-service-programming module hangs off main SR parent by augmenting "/rt:routing/sr:segment-routing".

This module defines some fundamental items required to configure SR based service programming. In particular, it defines service program provisioning as follows: service program behaviour: Defining a service program behaviour service offered: Defining a specific service (type, variant, instance) offered this service programming Assigning a SR service SID: Defining SID data plane, method to allocate the SID etc.. service program enablement: Administratively Enable/Disable a service program SR services: Defining a base container which could be augmented to define SR-aware or SR-unaware (via service-proxy) service specific parameters Following is a simplified graphical tree representation of the data model for SR service programming (Dynamic SID allocation) base configuration only

module: ietf-sr-service-programming augment /rt:routing/sr:segment-routing: +--rw service-programming +--rw service-program* [name] +--rw name -> /rt:routing/ sr:segment-routing/ sr-svc-pgm:service-programming/ service-program/ service-programming-info/ service-name +--rw sid-binding | +--ro alloc-mode? sr-svc-pgm-types:sid-alloc-mode-type | +--rw mpls | | +--ro sid? rt-types:mpls-label | +--rw srv6 | +--ro sid? srv6-types:srv6-sid | +--rw locator? -> /rt:routing/sr:segment-routing/ | srv6:srv6/locators/locator/name +--rw service-programming-info +--rw behaviour identityref +--rw dataplane sr-svc-pgm-types:dataplane-type +--rw service-name string +--rw service-type identityref +--rw service-variant string +--rw service-instance uint32 +--rw admin-status? sr-svc-pgm-types:admin-status-type +--rw sr-services Following is a simplified graphical tree representation of the data model for SR service programming (Static SR MPLS SID allocation) base configuration only. In this case SR MPLS base YANG model has been augmented to support SR service programming using static SR MPLS SID allocation. This has been done for the user convince to program all the SR service programming parameters from the based SR MPLS YANG itself

module: ietf-sr-service-programming augment /rt:routing/sr:segment-routing/sr-mpls:sr-mpls/sr-mpls:bindings: +--rw mpls-static-service-programming +--rw service-program* [name] +--rw name -> /rt:routing/ sr:segment-routing/ sr-svc-pgm:service-programming/ service-program/ service-programming-info/ service-name +--rw sid rt-types:mpls-label +--rw service-programming-info +--rw behaviour identityref +--ro dataplane? sr-svc-pgm-types:dataplane-type +--rw service-name string +--rw service-type identityref +--rw service-variant string +--rw service-instance uint32 +--rw admin-status? sr-svc-pgm-types:admin-status-type +--rw sr-services Following is a simplified graphical tree representation of the data model for SR service programming (Static SRv6 SID allocation) base configuration only. TBD (Once the based SRv6 static model is available, this section will be filled)

As per NMDA model, the state related to configuration items specified in above section can be retrieved from the same tree. This section defines other operational state items related to SR based service programming. The operational state corresponding to an SR based service program includes: Operational status: Provides detail information on the operational state of the SR service program. statistics: Provides the statistics details such as number of packets/bytes received, processed and dropped corresponding to a SR service program. Following is a simplified graphical tree representation of the data model for the SR service programming base operational state (for read-only items):

Dynamic SID allocation case: module: ietf-sr-service-programming augment /rt:routing/sr:segment-routing: +--rw service-programming +--rw service-program* [name] +--rw service-programming-info +--ro oper-status? identityref +--ro statistics +--ro in-packet-count? yang:counter64 +--ro in-bytes-count? yang:counter64 +--ro out-packet-count? yang:counter64 +--ro out-bytes-count? yang:counter64 +--ro in-drop-packet-count? yang:counter64 +--ro out-drop-packet-count? yang:counter64 Static SR MPLS SID allocation case: module: ietf-sr-service-programming augment /rt:routing/sr:segment-routing/sr-mpls:sr-mpls/sr-mpls:bindings: +--rw mpls-static-service-programming +--rw service-program* [name] +--rw service-programming-info +--ro oper-status? identityref +--ro statistics +--ro in-packet-count? yang:counter64 +--ro in-bytes-count? yang:counter64 +--ro out-packet-count? yang:counter64 +--ro out-bytes-count? yang:counter64 +--ro in-drop-packet-count? yang:counter64 +--ro out-drop-packet-count? yang:counter64 Static SRv6 SID allocation case: TBD

This model defines a list of notifications to inform an operator of important events detected during the SR service programming operation. These events are: SR service program operational state changes: This would also give the reason for the state change when it is down Following is a simplified graphical tree representation of the data model for the SR service programming notification:

module: ietf-sr-service-programming notifications: +---n service-program-oper-status +--ro name -> /rt:routing/sr:segment-routing/ sr-svc-pgm:service-programming/ service-program/name +--ro oper-status -> /rt:routing/sr:segment-routing/ sr-svc-pgm:service-programming/ service-program/oper-status

This document also defines a separate and new YANG data model for Service Proxy for SR unaware services. The model defines the configuration and operational state related to different proxy behaviours defined earlier in ietf-sr-service-programming-types. The model is defined in a new module ietf-sr-service-programming proxy. To support SR service programming proxy for dynamic SID allocation,this module augments the SR service program tree (/rt:routing/sr:segment-routing/sr-svc-pgm:service-programming/ sr-svc-pgm:service-program/sr-svc-pgm:sr-services) as defined earlier in ietf-sr-service-programming module. To support SR service programming proxy for static SR MPLS SID allocation, this module augments the base SR MPLS YANG mode defined in the RFC (/rt:routing/sr:segment-routing/sr-mpls:sr-mpls/sr-mpls:bindings/ sr-svc-pgm:mpls-static-service-programming/ sr-svc-pgm:service-program/sr-svc-pgm:service-programming-info/ sr-svc-pgm:sr-services:) To support SR service programming proxy for static SRv6 SID allocation, this module augments the base static SRv6 model - TBD The following sections describe different types of proxy behaviours and associated YANG modelling constructs.

The static proxy is an SR endpoint behaviour for processing SR-MPLS or SRv6 encapsulated traffic on behalf of an SR-unaware services. The following parameters are required to provision the SR static proxy: inner-packet-type: Inner packet type next-hop: Next hop Ethernet address (only for the inner type is IPv4 or IPv6) out-interface-name: Local interface for sending traffic towards the service Endpoint in-interface-name: Local interface receiving traffic coming back from the service Endpoint packet-cache-info: SR information to be attached on the traffic coming back from the service. This could be list of MPLS Label stack or SRv6 SIDs Following is a simplified graphical tree representation of the data model for the SR static proxy:

Dynamic SID allocation case: module: ietf-sr-service-programming-proxy augment /rt:routing/sr:segment-routing/ sr-svc-pgm:service-programming/ sr-svc-pgm:service-program/ sr-svc-pgm:service-programming-info/ sr-svc-pgm:sr-services: +--rw service-proxy +--rw (proxy-type) +--:(static) +--rw static-proxy +--rw inner-packet-type identityref +--rw next-hop? yang:mac-address +--rw out-interface-name string +--rw in-interface-name string +--rw packet-cache-info +--rw (cache-type) +--:(mpls) | +--rw mpls-sids* [index] | +--rw index uint8 | +--rw mpls-label rt-types:mpls-label +--:(srv6) +--rw ipv6-source-address? inet:ipv6-address +--rw srv6-sids* [index] +--rw index uint8 +--rw srv6-sid srv6-types:srv6-sid Static SR MPLS SID allocation case: module: ietf-sr-service-programming-proxy augment /rt:routing/sr:segment-routing/ sr-mpls:sr-mpls/sr-mpls:bindings/ sr-svc-pgm:mpls-static-service-programming/ sr-svc-pgm:service-program/ sr-svc-pgm:service-programming-info/ sr-svc-pgm:sr-services: +--rw static-mpls-service-proxy +--rw (proxy-type) +--:(static) +--rw static-proxy +--rw inner-packet-type identityref +--rw next-hop? yang:mac-address +--rw out-interface-name string +--rw in-interface-name string +--rw packet-cache-info +--rw (cache-type) +--:(mpls) | +--rw mpls-sids* [index] | +--rw index uint8 | +--rw mpls-label rt-types:mpls-label +--:(srv6) +--rw ipv6-source-address? inet:ipv6-address +--rw srv6-sids* [index] +--rw index uint8 +--rw srv6-sid srv6-types:srv6-sid Static SRv6 SID allocation case: TDB

The dynamic proxy is an improvement over the static proxy that dynamically learns the SR information before removing it from the incoming traffic. The same information can be re-attached to the traffic returning from the service Endpoints. The dynamic proxy relies on the local caching. The following parameters are required to provision the SR dynamic proxy: out-interface-name: Local interface for sending traffic towards the service Endpoint in-interface-name: Local interface receiving traffic coming back from the service Endpoint Following is a simplified graphical tree representation of the data model for the SR static proxy:

The masquerading proxy is an SR endpoint behaviour for processing SRv6 traffic on behalf of an SR-unaware service. This masquerading behaviour is independent from the inner payload type. The following parameters are required to provision the SR masquerading proxy next-hop: Next hop Ethernet address out-interface-name: Local interface for sending traffic towards the service Endpoint in-interface-name: Local interface receiving traffic coming back from the service Endpoint Following is a simplified graphical tree representation of the data model for the SR masquerading proxy:

Following are actual YANG definition for SR service programming modules defined earlier in the document.

Following are the Service Types definitions.

file "ietf-service-function-types.yang" --> module ietf-service-function-types { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-service-function-types"; prefix "service-types"; organization "IETF SPRING Working Group"; contact "WG Web: WG List: Editor: Jaganbabu Rajamanickam Editor: Kamran Raza Editor: Daniel Bernier Editor: Gaurav Dawra Editor: Cheng Li "; /* * Below are the definition for the service types * Any new service type could added by extending * this identity */ identity service-function-type { description "Base identity from which specific service function types are derived."; } identity firewall { base service-function-type; description "Firewall Service type"; } identity dpi { base service-function-type; description "Deep Packet Inspection Service type"; } identity napt44 { base service-function-type; description "Network Address and Port Translation 44 Service type"; } identity classifier { base service-function-type; description "classifier Service type"; } identity load-balancer { base service-function-type; description "load-balancer Service type"; } identity ips { base service-function-type; description "Intrusion Prevention System Service type (Ex: Snort)"; } }

]]>




      
        
          Following are the SR service programming specific types definitions.
        
        
          
             file "ietf-sr-service-programming-types.yang" -->

module ietf-sr-service-programming-types {
  yang-version 1.1;

  namespace "urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-types";
  prefix "sr-service-types";

  organization "IETF SPRING Working Group";

  contact
      "WG Web:   
       WG List:  

       Editor:   Jaganbabu Rajamanickam
                 

       Editor:   Kamran Raza
                 

       Editor:   Daniel Bernier
                 

       Editor:   Gaurav Dawra
                 

       Editor:   Cheng Li
                 ";

  /*
   * SR Service programming behaviour
   */
  identity service-program-behaviour-type {
      description
        "Base identity for SR service programming behaviour";
  }

  identity sr-aware {
      base service-program-behaviour-type;
      description
        "SR aware native applications.";
  }

  identity static-proxy {
      base service-program-behaviour-type;
      description
        "Static Proxy";
  }

  identity dynamic-proxy {
      base service-program-behaviour-type;
      description
        "Dynamic Proxy";
  }

  identity Masquerading-proxy {
      base service-program-behaviour-type;
      description
        "Masquerading Proxy";
  }

  identity Masquerading-NAT-proxy {
      base service-program-behaviour-type;
      description
        "Masquerading Proxy with NAT flavor";
  }

  identity Masquerading-caching-proxy {
      base service-program-behaviour-type;
      description
        "Masquerading Proxy with caching flavor";
  }

  identity Masquerading-NAT-caching-proxy {
      base service-program-behaviour-type;
      description
        "Masquerading Proxy with caching flavor";
  }


  /*
   * Below are the definition for the service proxy inner packet types
   * Any new service proxy inner packet type could added by extending
   * this identity
   */
  identity service-proxy-inner-pkt-type {
      description
        "Base identity from which SR service proxy types are derived.";
  }

  identity Ethernet {
      base service-proxy-inner-pkt-type;
      description
        "Expected inner packet type as Ethernet - derived from
         service-proxy-inner-pkt-type";
  }

  identity IPv4 {
      base service-proxy-inner-pkt-type;
      description
        "Expected inner packet type as IPv4 - derived from
         service-proxy-inner-pkt-type";
  }

  identity IPv6 {
      base service-proxy-inner-pkt-type;
      description
        "Expected inner packet type as IPv6 - derived from
         service-proxy-inner-pkt-type";
  }


  /*
   * SR Service SID operational status
   */
  identity service-program-oper-status-type {
      description
        "Base identity from which SR service program operational
         status types are derived.";
  }

  identity up {
      base service-program-oper-status-type;
      description
        "Service program status is operational";
  }

  identity down-unknown {
      base service-program-oper-status-type;
      description
        "Service program status is down because of unknown reason";
  }

  identity sid-allocation-pending {
      base service-program-oper-status-type;
      description
        "Service program status is down because of SID allocation is pending";
  }

  identity sid-allocation-conflict {
      base service-program-oper-status-type;
      description
        "Service program status is down because of SID conflict";
  }

  identity sid-out-of-bound {
      base service-program-oper-status-type;
      description
        "Service program status is down because of SID is out of bound";
  }

  identity interface-down {
      base service-program-oper-status-type;
      description
        "Service program status is down because of out/in interface is down";
  }

  identity admin-forced-down {
      base service-program-oper-status-type;
      description
        "Service program status is administratively forced down";
  }

  /*
   * Typedefs
   */
  typedef admin-status-type {
    type enumeration {
      enum up {
        description "Admin Up";
      }
      enum down {
        description "Admin Down";
      }
    }
  }

  typedef dataplane-type {
    type enumeration {
      enum mpls {
        description "MPLS dataplane";
      }
      enum srv6 {
        description "SRv6 dataplane";
      }
    }
  }

  typedef sid-alloc-mode-type {
    type enumeration {
      enum static {
        description "Static SID allocation";
      }
      enum dynamic {
        description "Dynamic SID allocation";
      }
    }
  }
}

            
             ]]>
          
        

      



      
        
          Following are the SR service programming base model definition.
        
        
          
             file "ietf-sr-service-programming.yang" -->

module ietf-sr-service-programming {
  yang-version 1.1;

  namespace "urn:ietf:params:xml:ns:yang:ietf-sr-service-programming";
  prefix "sr-svc-pgm";

  import ietf-yang-types {
    prefix "yang";
  }

  import ietf-srv6-base {
    prefix "srv6";
  }

  import ietf-routing {
    prefix rt;
    reference "RFC 8349: A YANG Data Model for Routing
               Management (NMDA Version)";
  }

  import ietf-service-function-types {
    prefix "service-types";
  }

  import ietf-segment-routing {
    prefix sr;
  }

  import ietf-segment-routing-mpls {
    prefix srmpls;
  }

  import ietf-sr-service-programming-types {
    prefix "sr-svc-pgm-types";
  }

  import ietf-routing-types {
    prefix "rt-types";
  }

  import ietf-srv6-types {
    prefix "srv6-types";
  }

  organization "IETF SPRING Working Group";

  contact
      "WG Web:   
       WG List:  

       Editor:   Jaganbabu Rajamanickam
                 

       Editor:   Kamran Raza
                 

       Editor:   Daniel Bernier
                 

       Editor:   Gaurav Dawra
                 

       Editor:   Cheng Li
                 ";

  grouping service-statistics {

    container statistics {

      config false;
      description "Service statistics";

      leaf in-packet-count {
        type yang:counter64;
        description
          "Total number of packets processed by this service";
      }

      leaf in-bytes-count {
        type yang:counter64;
        description
          "Total number of bytes processed by this service";
      }

      leaf out-packet-count {
        type yang:counter64;
        description
          "Total number of packets end out after processing by this service";
      }

      leaf out-bytes-count {
        type yang:counter64;
        description
          "Total number of bytes end out after processing by this service";
      }

      leaf in-drop-packet-count {
        type yang:counter64;
        description
          "Total number of packets dropped while processing by this service";
      }

      leaf out-drop-packet-count {
        type yang:counter64;
        description
          "Total number of packets dropped while this service try to
           forward to its destination";
      }
    }
  }

  grouping service-mpls-sid-binding {
    container mpls {
      description
        "MPLS Service SID binding Container";

      when "../../service-programming-info/dataplane = 'mpls'";

      leaf sid {
        config false;
        type rt-types:mpls-label;
        description
          "MPLS SID value.";
      }
    }
  }

  grouping service-srv6-sid-binding {
    container srv6 {
      description
        "SRv6 Service SID binding Container";

      when "../../service-programming-info/dataplane = 'srv6'";

      leaf sid {
        config false;
        type srv6-types:srv6-sid;
        description
          "SRv6 SID value.";
      }

      leaf locator {
        type leafref {
          path "/rt:routing/sr:segment-routing"
              + "/srv6:srv6/srv6:locators/srv6:locator/srv6:name";
        }
        description
          "Reference to a SRv6 locator. This is valid only when
           the SID allocation mode is dynamic";
      }
    }
  }

  grouping service-sid-binding {
    container sid-binding {
      description
        "Service SID binding Container";

      leaf alloc-mode {
        config false;
        default dynamic;
        type sr-svc-pgm-types:sid-alloc-mode-type;
        description
          "Service SID allocation mode";
      }

      uses service-mpls-sid-binding;
      uses service-srv6-sid-binding;
    }
  }

  grouping service-programming-infos {
    container service-programming-info {

        leaf behaviour {
          mandatory true;
          type identityref {
            base sr-svc-pgm-types:service-program-behaviour-type;
          }
          description
            "SR program behaviour";
        }

        leaf dataplane {
          mandatory true;
          type sr-svc-pgm-types:dataplane-type;
          description
            "Service SID dataplane.";
        }

        leaf service-name {
          mandatory true;
          type string;
          description
            "Service program name to identify a specific program.";
        }

        leaf service-type {
          mandatory true;
          type identityref {
            base service-types:service-function-type;
          }
          description
            "Service-Type defined by IANA Service Type Table (STT). Like
             Firewall, DPI etc..."; 
        }

        leaf service-variant {
          mandatory true;
          type string;
          description
            "This identifies the variant of the service. This value should 
             be unique in the given network. Example Format: 
             --.";
        }

        leaf service-instance {
          mandatory true;
          type uint32;
          description
            "Service instance which differentiates the same service -- e.g.
             same vendors Firewall service could have several instances 
             available. This could be used to differentiate the VPN
             customers or for load sharing purposes.";
        }

        leaf admin-status {
          type sr-svc-pgm-types:admin-status-type;
          default down;
          description
            "Admin Status";
        }

        leaf oper-status {
          config false;
          type identityref {
            base sr-svc-pgm-types:service-program-oper-status-type;
          }
          description
            "Service SID operational mode.";
        }

        uses service-statistics;


        container sr-services {

          description
              "Any SR-aware or AR-unaware services could augment this container";
          reference "Segment Routing Service Programming Architecture.";
        }
    }
  }

  grouping service-programmings {
    container service-programming {
      description
        "service programming container.
         Any new services programming added could augment
         this container to support that specific services.
         Currently in this model, only service proxy
         is defined. (i.e) For example if
         a Firewall services needs to be added then
         they could augment this container and
         extend this model";

      list service-program {
        key "name";
        description
          "Service program is keyed by the service program name";

        leaf name {
          mandatory true;
          type leafref {
            path "/rt:routing/sr:segment-routing/"
                + "sr-svc-pgm:service-programming/"
                + "sr-svc-pgm:service-program/"
                + "sr-svc-pgm:service-programming-info/"
                + "sr-svc-pgm:service-name";
          }
        }

        uses service-sid-binding;
        uses service-programming-infos;
      }
    }
  }

  /*
   * MPLS/SRv6 SR service programming using dynamic SID allocation
   */
  augment "/rt:routing/sr:segment-routing" {
    description
      "Augmenting the segment-routing to add SR service programming";

    uses service-programmings;
  }

  /*
   * MPLS SR service programming using static MPLS binding SID
   */
  augment "/rt:routing/sr:segment-routing/srmpls:sr-mpls/srmpls:bindings" {
    description
      "Augmenting the segment-routing MPLS static binding to add static 
       MPLS SR service programming";

    container mpls-static-service-programming {
      description
        "Augmenting the MPLS segment-routing bindings with the SR service 
         programming";
      list service-program {
        key "name";
        description
          "Service program is keyed by the service program name";

        leaf name {
          mandatory true;
          type leafref {
            path "/rt:routing/sr:segment-routing/"
                + "sr-svc-pgm:service-programming/"
                + "sr-svc-pgm:service-program/"
                + "sr-svc-pgm:service-programming-info/"
                + "sr-svc-pgm:service-name";
          }
        }

        leaf sid {
          mandatory true;
          type rt-types:mpls-label;
          description
            "MPLS SID value.";
        }

        uses service-programming-infos {
          /*
           * In the case of MPLs static binding configuration
           * the dataplane is set to mpls and not allowed to
           * configure
           */
          refine service-programming-info/dataplane {
            mandatory false;
            default mpls;
            config false;
          }
        }
      }
    }

  }

  /*
   * SRv6 SR service programming using static SRv6 binding SID
   */
  augment "/rt:routing/sr:segment-routing/srv6:srv6/srv6:locators/srv6:locator" {
    description
      "Augmenting the segment-routing SRv6 static to add static binding to
       SRv6 SR service programming";
       
    container end-AS {
      description
        "End.AS - Static Proxy SID behaviour";
      list service-program {
        key "name";
        description
          "Service program is keyed by the service program name";

        leaf name {
          mandatory true;
          type leafref {
            path "/rt:routing/sr:segment-routing/"
                + "sr-svc-pgm:service-programming/"
                + "sr-svc-pgm:service-program/"
                + "sr-svc-pgm:service-programming-info/"
                + "sr-svc-pgm:service-name";
          }
        }

        uses service-programming-infos {
          /*
           * In the case of SRv6 static binding configuration
           * the dataplane is set to mpls and not allowed to
           * configure
           */
          refine service-programming-info/dataplane {
            config false;
            mandatory false;
            default srv6;
          }
          refine service-programming-info/behaviour {
            config false;
            //when "service-programming-info/dataplane = 'srv6'";
            mandatory false;
            default sr-svc-pgm-types:static-proxy;
          }

        }
      }
    }

    container end-AD {
      description
        "End.AD - Dynamic Proxy SID behaviour";
      list service-program {
        key "name";
        description
          "Service program is keyed by the service program name";

        leaf name {
          mandatory true;
          type leafref {
            path "/rt:routing/sr:segment-routing/"
                + "sr-svc-pgm:service-programming/"
                + "sr-svc-pgm:service-program/"
                + "sr-svc-pgm:service-programming-info/"
                + "sr-svc-pgm:service-name";
          }
        }

        uses service-programming-infos {

          refine service-programming-info/dataplane {
            config false;
            mandatory false;
            default srv6;
          }
          refine service-programming-info/behaviour {
            //when "service-programming-info/dataplane = 'srv6'";
            config false;
            mandatory false;
            default sr-svc-pgm-types:dynamic-proxy;
          }

        }
      }
    }

    container end-AM {
      description
        "End.AD - Masquerading Proxy SID behaviour";
      list service-program {
        key "name";
        description
          "Service program is keyed by the service program name";

        leaf name {
          mandatory true;
          type leafref {
            path "/rt:routing/sr:segment-routing/"
                + "sr-svc-pgm:service-programming/"
                + "sr-svc-pgm:service-program/"
                + "sr-svc-pgm:service-programming-info/"
                + "sr-svc-pgm:service-name";
          }
        }

        uses service-programming-infos {

          refine service-programming-info/dataplane {
            config false;
            mandatory false;
            default srv6;
          }
          refine service-programming-info/behaviour {
            //when "service-programming-info/dataplane = 'srv6'";
            mandatory false;
            default sr-svc-pgm-types:Masquerading-proxy;
          }

        }
      }
    }

  }

  notification service-program-oper-status {
    description
      "This notification is sent when there is a change in the service
       program oper status.";
    leaf name {
      mandatory true;
      type leafref {
        path "/rt:routing/sr:segment-routing/"
            + "sr-svc-pgm:service-programming/"
            + "sr-svc-pgm:service-program/"
            + "sr-svc-pgm:name";
      }
      description
        "Service program name to identify a specific programming.";
    }

    leaf oper-status {
      mandatory true;
      type leafref {
        path "/rt:routing/sr:segment-routing/"
            + "sr-svc-pgm:service-programming/"
            + "sr-svc-pgm:service-program/"
            + "sr-svc-pgm:service-programming-info/"
            + "sr-svc-pgm:oper-status";
      }
      description
        "Service program operational status.";
    }

  }
}

            
             ]]>
          
        

      



      
        
          Following are the SR service programming service proxy model definition.
        
        
          
             file "ietf-sr-service-programming-proxy.yang" -->
module ietf-sr-service-programming-proxy {
  yang-version 1.1;

  namespace "urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-proxy";
  prefix "sr-svc-proxy";

  import ietf-yang-types {
    prefix yang;
  }

  import ietf-routing {
    prefix rt;
    reference "RFC 8349: A YANG Data Model for Routing
               Management (NMDA Version)";
  }

  import ietf-inet-types {
    prefix "inet";
  }

  import ietf-segment-routing {
    prefix sr;
  }

  import ietf-sr-service-programming {
    prefix "sr-svc-pgm";
  }

  import ietf-sr-service-programming-types {
    prefix "sr-svc-pgm-types";
  }

  import ietf-routing-types {
    prefix "rt-types";
  }

  import ietf-srv6-types {
    prefix "srv6-types";
  }

  import ietf-segment-routing-mpls {
    prefix sr-mpls;
  }

  organization "IETF SPRING Working Group";

  contact
      "WG Web:   
       WG List:  

       Editor:   Jaganbabu Rajamanickam
                 

       Editor:   Kamran Raza
                 

       Editor:   Daniel Bernier
                 

       Editor:   Gaurav Dawra
                 

       Editor:   Cheng Li
                 ";

  grouping service-proxy-parameters {

    leaf out-interface-name {
      mandatory true;
      type string;
      description
        "Interface name on which the packet sent to the service endpoint";
    }

    leaf in-interface-name {
      mandatory true;
      type string;
      description
        "Interface name on which the packet received from the service endpoint";
    }
  }

  grouping mpls-packet-cache-info {
    description
      "MPLS Label stack";

    list mpls-sids {
      key "index";

      leaf index {
        type uint8 {
          range "1..16";
        }
        description
          "cache index - MPLS Label stack index";
      }

      leaf mpls-label {
        mandatory true;
        type rt-types:mpls-label;
        description
          "MPLS Label value.";
      }
    }
  }

  grouping srv6-packet-cache-info {
    description
      "SRv6 SID stack";

    leaf ipv6-source-address {
      type inet:ipv6-address;
      description
        "IPv6 source address that needs in the case if SRv6.";
    }
    list srv6-sids {
      key "index";

      leaf index {
        type uint8 {
          range "1..16";
        }
        description
          "cache index - SRv6 SID index";
      }

      leaf srv6-sid {
        mandatory true;
        type srv6-types:srv6-sid;
        description
          "SRv6 SID.";
      }
    }
  }

  grouping service-proxy-packet-cache-info {
    description
      "SRv6 Proxy header cache";

    container packet-cache-info {

      choice cache-type {
        mandatory true;
        case mpls {

          when "/rt:routing/sr:segment-routing
                /sr-svc-pgm:service-programming
                /sr-svc-pgm:service-program
                /sr-svc-pgm:service-programming-info
                /sr-svc-pgm:dataplane = 'mpls'";

          uses mpls-packet-cache-info;
        }
        case srv6 {

          when "/rt:routing/sr:segment-routing/sr-svc-pgm:service-programming
            /sr-svc-pgm:service-program
            /sr-svc-pgm:service-programming-info
            /sr-svc-pgm:dataplane = 'srv6'";

          uses srv6-packet-cache-info;
        }
      }
    }
  }

  grouping static-service-proxy {
    container static-proxy {
      when "/rt:routing/sr:segment-routing/sr-svc-pgm:service-programming
            /sr-svc-pgm:service-program
            /sr-svc-pgm:service-programming-info
            /sr-svc-pgm:behaviour = 'static-proxy'";
      description
        "Parameters related to static service proxy";

      leaf inner-packet-type {
        mandatory true;
        type identityref {
          base sr-svc-pgm-types:service-proxy-inner-pkt-type;
        }
        description
          "Defines the expected inner packet type";
      }

      leaf next-hop {
        when "(../inner-packet-type = 'IPv4' or ../inner-packet-type = 'IPv6')";
        type yang:mac-address;
        description
          "Nexthop Ethernet address for inner packet type IPv4/IPv6";
      }
      uses service-proxy-parameters;
      uses service-proxy-packet-cache-info;
    }
  }

  grouping dynamic-service-proxy {
    container dynamic-proxy {
      when "/rt:routing/sr:segment-routing/sr-svc-pgm:service-programming
            /sr-svc-pgm:service-program
            /sr-svc-pgm:service-programming-info
            /sr-svc-pgm:behaviour = 'dynamic-proxy'";
      description
        "Parameters related to dynamic service proxy";
      uses service-proxy-parameters;
    }
  }

  grouping masquerading-service-parameters {

    leaf next-hop {
      type yang:mac-address;
      description
        "Nexthop Ethernet address";
    }
    uses service-proxy-parameters;
  }

  grouping masquerading-service-proxy {
    container masquerading-proxy {
      description
        "Parameters related to masquerading service proxy";

      when "/rt:routing/sr:segment-routing
            /sr-svc-pgm:service-programming
            /sr-svc-pgm:service-program
            /sr-svc-pgm:service-programming-info
            /sr-svc-pgm:dataplane = 'srv6' and /rt:routing
            /sr:segment-routing/sr-svc-pgm:service-programming
            /sr-svc-pgm:service-program
            /sr-svc-pgm:service-programming-info
            /sr-svc-pgm:behaviour = 'Masquerading-proxy'";

      uses masquerading-service-parameters;
    }
  }

  grouping service-proxy-programming {
    container service-proxy {

      choice proxy-type {
        mandatory true;
        case static {
          uses static-service-proxy;
        }
        case dynamic {
          uses dynamic-service-proxy;
        }
        case masquerading {
          uses masquerading-service-proxy;
        }
      }
    }

  }

  augment "/rt:routing/sr:segment-routing/
           sr-svc-pgm:service-programming/
           sr-svc-pgm:service-program/
           sr-svc-pgm:service-programming-info/
           sr-svc-pgm:sr-services" {
    description
      "Augmenting the segment-routing bindings to add SR-unaware
       service programming";

    uses service-proxy-programming;
  }

  grouping static-mpls-service-proxy-programming {
    container static-mpls-service-proxy {

      choice proxy-type {
        mandatory true;
        case static {
          uses static-service-proxy;
        }
        case dynamic {
          uses dynamic-service-proxy;
        }
      }
    }

  }

  augment "/rt:routing/sr:segment-routing/
           sr-mpls:sr-mpls/sr-mpls:bindings/
           sr-svc-pgm:mpls-static-service-programming/
           sr-svc-pgm:service-program/
           sr-svc-pgm:service-programming-info/
           sr-svc-pgm:sr-services" {
    uses static-mpls-service-proxy-programming;
  }

}


            
             ]]>




    

	
	  The YANG module specified in this document defines a schema for data that
	  is designed to be accessed via network management protocols such as
	  NETCONF  or RESTCONF .
	  The lowest NETCONF layer is the secure transport 
	  layer, and the mandatory-to-implement secure transport is Secure Shell (SSH)
	  . The lowest RESTCONF layer is HTTPS, and the
	  mandatory-to-implement secure transport is TLS .
	

	
	  The Network Configuration Access Control Model (NACM) 
	provides the means to restrict access for particular NETCONF or RESTCONF users to a
	preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.
	

	
	  There are a number of data nodes defined in this YANG module that are writable/creatable/
	  deletable (i.e., config true, which is the default). These data nodes may be considered
	  sensitive or vulnerable in some network environments. Write operations (e.g., edit-config)
	  to these data nodes without proper protection can have a negative effect on network
	  operations.
	

	
	  Some of the readable data nodes in this YANG module may be considered sensitive or
	  vulnerable in some network environments. It is thus important to control read access
	  (e.g., via get, get-config, or notification) to these data nodes. 
	


	 It goes without saying that this specification also inherits the security
	considerations captured in the SRv6 specification document
	.
	
	      
    
    
      	
    

       This document requests the registration of the following URIs in the IETF
      "XML registry" : 
      
	URI
	Registrant
	XML
	
	 urn:ietf:params:xml:ns:yang:ietf-service-function-types 
	 The IESG 
	 N/A 

	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-types
	 The IESG 
	 N/A 

	     
	
	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming
	 The IESG 
	 N/A 

	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-proxy
	 The IESG 
	 N/A 
	
      
      
      
       This document requests the registration of the following YANG modules in the
      "YANG Module Names" registry : 

      
	 Name 
	 Namespace 
	 Prefix 
	 Reference 

	 ietf-service-function-types 
	 urn:ietf:params:xml:ns:yang:ietf-service-function-types 
	 service-function-types 
	 This document 

	       

	 ietf-sr-service-programming-types 
	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-types 
	 ietf-sr-service-programming-types 
	 This document 

	       

	 ietf-sr-service-programming 
	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming 
	 ietf-sr-service-programming 
	 This document 

	       
	
	 ietf-sr-service-programming-proxy 
	 urn:ietf:params:xml:ns:yang:ietf-sr-service-programming-proxy 
	 ietf-sr-service-programming-proxy 
	 This document 
      
      
       -- RFC Editor: Replace "This document" with the document RFC number at time of publication,
      and remove this note.
      
      
    
         
    
       The authors would like to acknowledge Francois Clad, Ketan Talaulikar, and 
          Darren Dukes for their review of some of the contents in this document.