Network Working Group A. Shaikh Internet-Draft Google Intended status: Informational R. Shakir Expires: January 5, 2016 BT K. D'Souza C. Chase AT&T July 4, 2015 Routing Policy Configuration Model for Service Provider Networks draft-shaikh-rtgwg-policy-model-01 Abstract This document defines a YANG data model for configuring and managing routing policies in a vendor-neutral way and based on actual operational practice. The model provides a generic policy framework which can be augmented with protocol-specific policy configuration. 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 January 5, 2016. Copyright Notice Copyright (c) 2015 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 Shaikh, et al. Expires January 5, 2016 [Page 1] Internet-Draft Routing Policy Model July 2015 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. 1. Introduction This document describes a YANG [RFC6020] data model for routing policy configuration based on operational usage and best practices in a variety of service provider networks. The model is intended to be vendor-neutral, in order to allow operators to manage policy configuration in a consistent, intuitive way in heterogeneous environments with routers supplied by multiple vendors. 1.1. Goals and approach This model does not aim to be feature complete -- it is a subset of the policy configuration parameters available in a variety of vendor implementations, but supports widely used constructs for managing how routes are imported, exported, and modified across different routing protocols. The model development approach has been to examine actual policy configurations in use across a number of operator networks. Hence the focus is on enabling policy configuration capabilities and structure that are in wide use. Despite the differences in details of policy expressions and conventions in various vendor implementations, the model reflects the observation that a relatively simple condition- action approach can be readily mapped to several existing vendor implementations, and also gives operators an intuitive and straightforward way to express policy without sacrificing flexibility. A side affect of this design decision is that legacy methods for expressing policies are not considered. Such methods could be added as an augmentation to the model if needed. Consistent with the goal to produce a data model that is vendor neutral, only policy expressions that are deemed to be widely available in existing major implementations are included in the model. Those configuration items that are only available from a single implementation are omitted from the model with the expectation they will be available in separate vendor-provided modules that augment the current model. 2. Model overview The routing policy model is defined in two YANG modules, the main policy module, and an auxiliary module providing additional generic types. The model has three main parts: Shaikh, et al. Expires January 5, 2016 [Page 2] Internet-Draft Routing Policy Model July 2015 o A generic framework to express policies as sets of related conditions and actions. This includes match sets and actions that are useful across many routing protocols. o A structure that allows routing protocol models to add protocol- specific policy conditions and actions though YANG augmentations. There is a complete example of this for BGP [RFC4271] policies in the proposed vendor-neutral BGP data model [I-D.shaikh-idr-bgp-model]. o A reusable grouping for attaching import and export rules in the context of routing configuration for different protocols, VRFs, etc. This also enables creation of policy chains and expressing default policy behavior. These modules make use of the standard Internet types, such as IP addresses, autonomous system numbers, etc., defined in RFC 6991 [RFC6991]. 3. Route policy expression Policies are expressed as a sequence of top-level policy definitions each of which consists of a sequence of policy statements. Policy statements in turn consist of simple condition-action tuples. Conditions may include multiple match or comparison operations, and similarly, actions may effect multiple changes to route attributes, or indicate a final disposition of accepting or rejecting the route. This structure is shown below. +--rw routing-policy +--rw policy-definitions +--rw policy-definition* [name] +--rw name string +--rw statements +--rw statement* [name] +--rw name string +--rw conditions | ... +--rw actions ... 3.1. Defined sets for policy matching The models provides a set of generic sets that can be used for matching in policy conditions. These sets are applicable across multiple routing protocols, and may be further augmented by protocol- specific models which have their own defined sets. The supported defined sets include: Shaikh, et al. Expires January 5, 2016 [Page 3] Internet-Draft Routing Policy Model July 2015 o prefix sets - define a set of IP prefixes, each with an associated CIDR netmask range (or exact length) o neighbor sets - define a set of neighboring nodes by their IP addresses o tag set - define a set of generic tag values that can be used in matches for filtering routes The model structure for defined sets is shown below. +--rw routing-policy +--rw defined-sets +--rw prefix-sets | +--rw prefix-set* [prefix-set-name] | +--rw prefix-set-name string | +--rw prefix* [ip-prefix masklength-range] | +--rw ip-prefix inet:ip-prefix | +--rw masklength-range string +--rw neighbor-sets | +--rw neighbor-set* [neighbor-set-name] | +--rw neighbor-set-name string | +--rw neighbor* [address] | +--rw address inet:ip-address +--rw tag-sets +--rw tag-set* [tag-set-name] +--rw tag-set-name string +--rw tag* [value] +--rw value pt:tag-type 3.2. Policy conditions Policy statements consist of a set of conditions and actions (either of which may be empty). Conditions are used to match route attributes against a defined set (e.g., a prefix set), or to compare attributes against a specific value. Match conditions may be further modified using the match-set-options configuration which allows operators to change the behavior of a match. Three options are supported: o ALL - match is true only if the given value matches all members of the set. o ANY - match is true if the given value matches any member of the set. Shaikh, et al. Expires January 5, 2016 [Page 4] Internet-Draft Routing Policy Model July 2015 o INVERT - match is true if the given value does not match any member of the given set. Not all options are appropriate for matching against all defined sets (e.g., match ALL in a prefix set does not make sense). In the model, a restricted set of match options is used where applicable. Comparison conditions may similarly use options to change how route attributes should be tested, e.g., for equality or inequality, against a given value. While most policy conditions will be added by individual routing protocol models via augmentation, this routing policy model includes several generic match conditions and also the ability to test which protocol or mechanism installed a route (e.g., BGP, IGP, static, etc.). The conditions included in the model are shown below. +--rw routing-policy +--rw policy-definitions +--rw policy-definition* [name] +--rw statements +--rw statement* [name] +--rw conditions +--rw call-policy? +--rw match-prefix-set! | +--rw prefix-set? | +--rw match-set-options? +--rw match-neighbor-set! | +--rw neighbor-set? | +--rw match-set-options? +--rw match-tag-set! | +--rw tag-set? | +--rw match-set-options? +--rw install-protocol-eq? +--rw igp-conditions 3.3. Policy actions When policy conditions are satisfied, policy actions are used to set various attributes of the route being processed, or to indicate the final disposition of the route, i.e., accept or reject. Similar to policy conditions, the routing policy model includes generic actions in addition to the basic route disposition actions. These are shown below. Shaikh, et al. Expires January 5, 2016 [Page 5] Internet-Draft Routing Policy Model July 2015 +--rw routing-policy +--rw policy-definitions +--rw policy-definition* [name] +--rw statements +--rw statement* [name] +--rw actions +--rw (route-disposition)? | +--:(accept-route) | | +--rw accept-route? empty | +--:(reject-route) | +--rw reject-route? empty +--rw igp-actions +--rw set-tag? pt:tag-type 3.4. Policy subroutines Policy 'subroutines' (or nested policies) are supported by allowing policy statement conditions to reference other policy definitions using the call-policy configuration. Called policies apply their conditions and actions before returning to the calling policy statement and resuming evaluation. The outcome of the called policy affects the evaluation of the calling policy. If the called policy results in an accept-route (either explicit or by default), then the subroutine returns an effective boolean true value to the calling policy. For the calling policy, this is equivalent to a condition statement evaluating to a true value and evaluation of the policy continues (see Section 4). Note that the called policy may also modify attributes of the route in its action statements. Similarly, a reject-route action returns false and the calling policy evaluation will be affected accordingly. Note that the called policy may itself call other policies (subject to implementation limitations). The model does not prescribe a nesting depth because this varies among implementations, with some major implementations only supporting a single subroutine, for example. As with any routing policy construction, care must be taken with nested policies to ensure that the effective return value results in the intended behavior. Nested policies are a convenience in many routing policy constructions but creating policies nested beyond a small number of levels (e.g., 2-3) should be discouraged. 4. Policy evaluation Evaluation of each policy definition proceeds by evaluating its corresponding individual policy statements in order. When a condition statement in a policy statement is satisfied, the corresponding action statement is executed. If the action statement has either accept-route or reject-route actions, evaluation of the Shaikh, et al. Expires January 5, 2016 [Page 6] Internet-Draft Routing Policy Model July 2015 current policy definition stops, and no further policy definitions in the chain are evaluated. If the condition is not satisfied, then evaluation proceeds to the next policy statement. If none of the policy statement conditions are satisfied, then evaluation of the current policy definition stops, and the next policy definition in the chain is evaluated. When the end of the policy chain is reached, the default route disposition action is performed (i.e., reject-route unless an an alternate default action is specified for the chain). 5. Applying routing policy Routing policy is applied by defining and attaching policy chains in various routing contexts. Policy chains are sequences of policy definitions (described in Section 3) that have an associated direction (import or export) with respect to the routing context in which they are defined. The routing policy model defines an apply- policy grouping that can be imported and used by other models. As shown below, it allows definition of import and export policy chains, as well as specifying the default route disposition to be used when no policy definition in the chain results in a final decision. +--rw apply-policy | +--rw config | | +--rw import-policy* | | +--rw default-import-policy? default-policy-type | | +--rw export-policy* | | +--rw default-export-policy? default-policy-type The default policy defined by the model is to reject the route for both import and export policies. An example of using the apply-policy group in another routing model is shown below for BGP. Here, import and export policies are applied in the context of a particular BGP peer group. Note that the policy chains reference policy definitions by name that are defined in the routing policy model. Shaikh, et al. Expires January 5, 2016 [Page 7] Internet-Draft Routing Policy Model July 2015 +--rw bgp! +--rw peer-groups +--rw peer-group* [peer-group-name] +--rw peer-group-name +--rw config | +--rw peer-as? | +--rw local-as? | +--rw peer-type? | +--rw auth-password? | +--rw remove-private-as? | +--rw route-flap-damping? | +--rw send-community? | +--rw description? | +--rw peer-group-name? +--ro state | +--ro peer-as? | +--ro local-as? | +--ro peer-type? | +--ro auth-password? | +--ro remove-private-as? | +--ro route-flap-damping? | +--ro send-community? | +--ro description? | +--ro peer-group-name? | +--ro total-paths? | +--ro total-prefixes? +--rw apply-policy | +--rw config | | +--rw import-policy* | | +--rw default-import-policy? | | +--rw export-policy* | | +--rw default-export-policy? | +--ro state | +--ro import-policy* | +--ro default-import-policy? | +--ro export-policy* | +--ro default-export-policy? ... 6. Routing protocol-specific policies Routing models that require the ability to apply routing policy may augment the routing policy model with protocol or other specific policy configuration. The routing policy model assumes that additional defined sets, conditions, and actions may all be added by other models. Shaikh, et al. Expires January 5, 2016 [Page 8] Internet-Draft Routing Policy Model July 2015 An example of this is shown below, in which the BGP configuration model in [I-D.shaikh-idr-bgp-model] adds new defined sets to match on community values or AS paths. The model similarly augments BGP- specific conditions and actions into the corresponding sections of the routing policy model. +--rw routing-policy +--rw defined-sets +--rw prefix-sets | +--rw prefix-set* [prefix-set-name] | +--rw prefix-set-name | +--rw prefix* [ip-prefix masklength-range] | +--rw ip-prefix | +--rw masklength-range +--rw neighbor-sets | +--rw neighbor-set* [neighbor-set-name] | +--rw neighbor-set-name | +--rw neighbor* [address] | +--rw address +--rw tag-sets | +--rw tag-set* [tag-set-name] | +--rw tag-set-name | +--rw tag* [value] | +--rw value +--rw bgp-pol:bgp-defined-sets +--rw bgp-pol:community-sets | +--rw bgp-pol:community-set* [community-set-name] | +--rw bgp-pol:community-set-name | +--rw bgp-pol:community-member* +--rw bgp-pol:ext-community-sets | +--rw bgp-pol:ext-community-set* [ext-community-set-name] | +--rw bgp-pol:ext-community-set-name | +--rw bgp-pol:ext-community-member* +--rw bgp-pol:as-path-sets +--rw bgp-pol:as-path-set* [as-path-set-name] +--rw bgp-pol:as-path-set-name +--rw bgp-pol:as-path-set-member* 7. Security Considerations Routing policy configuration has a significant impact on network operations, and as such any related model carries potential security risks. YANG data models are generally designed to be used with the NETCONF protocol over an SSH transport. This provides an authenticated and secure channel over which to transfer configuration and operational data. Note that use of alternate transport or data encoding (e.g., Shaikh, et al. Expires January 5, 2016 [Page 9] Internet-Draft Routing Policy Model July 2015 JSON over HTTPS) would require similar mechanisms for authenticating and securing access to configuration data. Most of the data elements in the policy model could be considered sensitive from a security standpoint. Unauthorized access or invalid data could cause major disruption. 8. IANA Considerations This YANG data model and the component modules currently use a temporary ad-hoc namespace. If and when it is placed on redirected for the standards track, an appropriate namespace URI will be registered in the IETF XML Registry" [RFC3688]. The routing policy YANG modules will be registered in the "YANG Module Names" registry [RFC6020]. 9. YANG modules The routing policy model is described by the YANG modules in the sections below. 9.1. Routing policy model file routing-policy.yang module routing-policy { yang-version "1"; // namespace namespace "http://openconfig.net/yang/routing-policy"; prefix "rpol"; // import some basic types import ietf-inet-types { prefix inet; } import policy-types {prefix pt; } // meta organization "OpenConfig working group"; contact "OpenConfig working group netopenconfig@googlegroups.com"; description "This module describes a YANG model for routing policy Shaikh, et al. Expires January 5, 2016 [Page 10] Internet-Draft Routing Policy Model July 2015 configuration. It is a limited subset of all of the policy configuration parameters available in the variety of vendor implementations, but supports widely used constructs for managing how routes are imported, exported, and modified across different routing protocols. This module is intended to be used in conjunction with routing protocol configuration models (e.g., BGP) defined in other modules. Route policy expression: Policies are expressed as a set of top-level policy definitions, each of which consists of a sequence of policy statements. Policy statements consist of simple condition-action tuples. Conditions may include mutiple match or comparison operations, and similarly actions may be multitude of changes to route attributes or a final disposition of accepting or rejecting the route. Route policy evaluation: Policy definitions are referenced in routing protocol configurations using import and export configuration statements. The arguments are members of an ordered list of named policy definitions which comprise a policy chain, and optionally, an explicit default policy action (i.e., reject or accept). Evaluation of each policy definition proceeds by evaluating its corresponding individual policy statements in order. When a condition statement in a policy statement is satisfied, the corresponding action statement is executed. If the action statement has either accept-route or reject-route actions, policy evaluation of the current policy definition stops, and no further policy definitions in the chain are evaluated. If the condition is not satisfied, then evaluation proceeds to the next policy statement. If none of the policy statement conditions are satisfied, then evaluation of the current policy definition stops, and the next policy definition in the chain is evaluated. When the end of the policy chain is reached, the default route disposition action is performed (i.e., reject-route unless an an alternate default action is specified for the chain). Policy 'subroutines' (or nested policies) are supported by allowing policy statement conditions to reference another policy definition which applies conditions and actions from the referenced policy before returning to the calling policy statement and resuming evaluation. If the called policy results in an accept-route (either explicit or by default), then Shaikh, et al. Expires January 5, 2016 [Page 11] Internet-Draft Routing Policy Model July 2015 the subroutine returns an effective true value to the calling policy. Similarly, a reject-route action returns false. If the subroutine returns true, the calling policy continues to evaluate the remaining conditions (using a modified route if the subroutine performed any changes to the route)."; revision "2015-05-15" { description "Initial revision"; reference "TBD"; } // typedef statements typedef default-policy-type { type enumeration { enum ACCEPT-ROUTE { description "default policy to accept the route"; } enum REJECT-ROUTE { description "default policy to reject the route"; } } description "type used to specify default route disposition in a policy chain"; } // grouping statements grouping generic-defined-sets { description "Data definitions for pre-defined sets of attributes used in policy match conditions. These sets are generic and can be used in matching conditions in different routing protocols."; container prefix-sets { description "Enclosing container for defined prefix sets for matching"; list prefix-set { key prefix-set-name; description "List of the defined prefix sets"; leaf prefix-set-name { Shaikh, et al. Expires January 5, 2016 [Page 12] Internet-Draft Routing Policy Model July 2015 type string; description "name / label of the prefix set -- this is used to reference the set in match conditions"; } list prefix { key "ip-prefix masklength-range"; description "List of prefix expressions that are part of the set"; leaf ip-prefix { type inet:ip-prefix; mandatory true; description "The prefix member in CIDR notation -- while the prefix may be either IPv4 or IPv6, most implementations require all members of the prefix set to be the same address family. Mixing address types in the same prefix set is likely to cause an error."; } leaf masklength-range { type string { pattern '^([0-9]+\.\.[0-9]+)|exact$'; } description "Defines a range for the masklength, or 'exact' if the prefix has an exact length. Example: 10.3.192.0/21 through 10.3.192.0/24 would be expressed as prefix: 10.3.192.0/21, masklength-range: 21..24. Example: 10.3.192.0/21 would be expressed as prefix: 10.3.192.0/21, masklength-range: exact"; } } } } container neighbor-sets { description "Enclosing container for defined neighbor sets for matching"; list neighbor-set { key neighbor-set-name; Shaikh, et al. Expires January 5, 2016 [Page 13] Internet-Draft Routing Policy Model July 2015 description "Definitions for neighbor sets"; leaf neighbor-set-name { type string; description "name / label of the neighbor set -- this is used to reference the set in match conditions"; } list neighbor { key "address"; description "list of addresses that are part of the neighbor set"; leaf address { type inet:ip-address; description "IP address of the neighbor set member"; } } } } container tag-sets { description "Enclosing container for defined tag sets for matching"; list tag-set { key tag-set-name; description "Definitions for tag sets"; leaf tag-set-name { type string; description "name / label of the tag set -- this is used to reference the set in match conditions"; } list tag { key "value"; description "list of tags that are part of the tag set"; leaf value { type pt:tag-type; description Shaikh, et al. Expires January 5, 2016 [Page 14] Internet-Draft Routing Policy Model July 2015 "Value of the tag set member"; } } } } } grouping local-generic-conditions { description "Condition statement definitions for consideration of a local characteristic of a route"; leaf install-protocol-eq { type identityref { base pt:install-protocol-type; } description "Condition to check the protocol / method used to install which installed the route into the local routing table"; } } grouping match-set-options-group { description "Grouping containing options relating to how a particular set should be matched"; leaf match-set-options { type pt:match-set-options-type; description "Optional parameter that governs the behaviour of the match operation"; } } grouping match-set-options-restricted-group { description "Grouping for a restricted set of match operation modifiers"; leaf match-set-options { type pt:match-set-options-restricted-type; description "Optional parameter that governs the behaviour of the match operation. This leaf only supports matching on ANY member of the set or inverting the match. Matching on ALL is not supported)"; } } Shaikh, et al. Expires January 5, 2016 [Page 15] Internet-Draft Routing Policy Model July 2015 grouping generic-conditions { description "Condition statement definitions for checking membership in a generic defined set"; container match-prefix-set { presence "The presence of this container indicates that the routes should match the prefix-set referenced."; description "Match a referenced prefix-set according to the logic defined in the match-set-options leaf"; leaf prefix-set { type leafref { path "/routing-policy/defined-sets/prefix-sets/" + "prefix-set/prefix-set-name"; //TODO: require-instance should be added when it's //supported in YANG 1.1 //require-instance true; } description "References a defined prefix set"; } uses match-set-options-restricted-group; } container match-neighbor-set { presence "The presence of this container indicates that the routes should match the neighbour set referenced"; description "Match a referenced neighbor set according to the logic defined in the match-set-options-leaf"; leaf neighbor-set { type leafref { path "/routing-policy/defined-sets/neighbor-sets/" + "neighbor-set/neighbor-set-name"; //TODO: require-instance should be added when it's //supported in YANG 1.1 //require-instance true; } description "References a defined neighbor set"; } uses match-set-options-restricted-group; } Shaikh, et al. Expires January 5, 2016 [Page 16] Internet-Draft Routing Policy Model July 2015 container match-tag-set { presence "The presence of this container indicates that the routes should match the tag-set referenced"; description "Match a referenced tag set according to the logic defined in the match-options-set leaf"; leaf tag-set { type leafref { path "/routing-policy/defined-sets/tag-sets/tag-set" + "/tag-set-name"; //TODO: require-instance should be added when it's //supported in YANG 1.1 //require-instance true; } description "References a defined tag set"; } uses match-set-options-restricted-group; } uses local-generic-conditions; } grouping igp-generic-conditions { description "grouping for IGP policy conditions"; } grouping igp-conditions { description "grouping for IGP-specific policy conditions"; container igp-conditions { description "Policy conditions for IGP attributes"; uses igp-generic-conditions; } } grouping generic-actions { description "Definitions for common set of policy action statements that manage the disposition or control flow of the policy"; choice route-disposition { Shaikh, et al. Expires January 5, 2016 [Page 17] Internet-Draft Routing Policy Model July 2015 description "Select the final disposition for the route, either accept or reject."; leaf accept-route { type empty; description "accepts the route into the routing table"; } leaf reject-route { type empty; description "rejects the route"; } } } grouping igp-actions { description "grouping for IGP-specific policy actions"; container igp-actions { description "Actions to set IGP route attributes; these actions apply to multiple IGPs"; leaf set-tag { type pt:tag-type; description "Set the tag value for OSPF or IS-IS routes."; } } } container routing-policy { description "top-level container for all routing policy configuration"; container defined-sets { description "Predefined sets of attributes used in policy match statements"; uses generic-defined-sets; // uses bgp-defined-sets; // don't see a need for IGP-specific defined sets at this point // e.g., for OSPF, IS-IS, etc. } container policy-definitions { description Shaikh, et al. Expires January 5, 2016 [Page 18] Internet-Draft Routing Policy Model July 2015 "Enclosing container for the list of top-level policy definitions"; list policy-definition { key name; description "List of top-level policy definitions, keyed by unique name. These policy definitions are expected to be referenced (by name) in policy chains specified in import/ export configuration statements."; leaf name { type string; description "Name of the top-level policy definition -- this name is used in references to the current policy"; } container statements { description "Enclosing container for policy statements"; list statement { key name; // TODO: names of policy statements within a policy defn // should be optional, however, YANG requires a unique id // for lists; not sure that a compound key works either; // need to investigate further. ordered-by user; description "Policy statements group conditions and actions within a policy definition. They are evaluated in the order specified (see the description of policy evaluation at the top of this module."; leaf name { type string; description "name of the policy statement"; } container conditions { description "Condition statements for this policy statement"; leaf call-policy { Shaikh, et al. Expires January 5, 2016 [Page 19] Internet-Draft Routing Policy Model July 2015 type leafref { path "/rpol:routing-policy/" + "rpol:policy-definitions/" + "rpol:policy-definition/rpol:name"; //TODO: require-instance should be added when it's //supported in YANG 1.1 //require-instance true; } description "Applies the statements from the specified policy definition and then returns control the current policy statement. Note that the called policy may itself call other policies (subject to implementation limitations). This is intended to provide a policy 'subroutine' capability. The called policy should contain an explicit or a default route disposition that returns an effective true (accept-route) or false (reject-route), otherwise the behavior may be ambiguous and implementation dependent"; } uses generic-conditions; uses igp-conditions; } container actions { description "Action statements for this policy statement"; uses generic-actions; uses igp-actions; } } } } } } grouping apply-policy-config { description "Configuration data for routing policies"; leaf-list import-policy { type leafref { path "/rpol:routing-policy/rpol:policy-definitions/" + "rpol:policy-definition/rpol:name"; //TODO: require-instance should be added when it's Shaikh, et al. Expires January 5, 2016 [Page 20] Internet-Draft Routing Policy Model July 2015 //supported in YANG 1.1 //require-instance true; } ordered-by user; description "list of policy names in sequence to be applied on receiving a routing update in the current context, e.g., for the current peer group, neighbor, address family, etc."; } leaf default-import-policy { type default-policy-type; default REJECT-ROUTE; description "explicitly set a default policy if no policy definition in the import policy chain is satisfied."; } leaf-list export-policy { type leafref { path "/rpol:routing-policy/rpol:policy-definitions/" + "rpol:policy-definition/rpol:name"; //TODO: require-instance should be added when it's //supported in YANG 1.1 //require-instance true; } ordered-by user; description "list of policy names in sequence to be applied on sending a routing update in the current context, e.g., for the current peer group, neighbor, address family, etc."; } leaf default-export-policy { type default-policy-type; default REJECT-ROUTE; description "explicitly set a default policy if no policy definition in the export policy chain is satisfied."; } } grouping apply-policy-state { description "Operational state associated with routing policy"; Shaikh, et al. Expires January 5, 2016 [Page 21] Internet-Draft Routing Policy Model July 2015 //TODO: identify additional state data beyond the intended //policy configuration. } grouping apply-policy-group { description "Top level container for routing policy applications. This grouping is intended to be used in routing models where needed."; container apply-policy { description "Anchor point for routing policies in the model. Import and export policies are with respect to the local routing table, i.e., export (send) and import (receive), depending on the context."; container config { description "Policy configuration data."; uses apply-policy-config; } container state { config false; description "Operational state for routing policy"; uses apply-policy-config; uses apply-policy-state; } } } } 9.2. Routing policy types file policy-types.yang module policy-types { yang-version "1"; // namespace namespace "http://openconfig.net/yang/policy-types"; Shaikh, et al. Expires January 5, 2016 [Page 22] Internet-Draft Routing Policy Model July 2015 prefix "ptypes"; // import some basic types import ietf-yang-types { prefix yang; } // meta organization "OpenConfig working group"; contact "OpenConfig working group netopenconfig@googlegroups.com"; description "This module contains general data definitions for use in routing policy. It can be imported by modules that contain protocol- specific policy conditions and actions."; revision "2015-05-15" { description "Initial revision"; reference "TBD"; } // identity statements identity attribute-comparison { description "base type for supported comparison operators on route attributes"; } identity attribute-eq { base attribute-comparison; description "== comparison"; } identity attribute-ge { base attribute-comparison; description ">= comparison"; } identity attribute-le { base attribute-comparison; description "<= comparison"; } Shaikh, et al. Expires January 5, 2016 [Page 23] Internet-Draft Routing Policy Model July 2015 typedef match-set-options-type { type enumeration { enum ANY { description "match is true if given value matches any member of the defined set"; } enum ALL { description "match is true if given value matches all members of the defined set"; } enum INVERT { description "match is true if given value does not match any member of the defined set"; } } default ANY; description "Options that govern the behavior of a match statement. The default behavior is ANY, i.e., the given value matches any of the members of the defined set"; } typedef match-set-options-restricted-type { type enumeration { enum ANY { description "match is true if given value matches any member of the defined set"; } enum INVERT { description "match is true if given value does not match any member of the defined set"; } } default ANY; description "Options that govern the behavior of a match statement. The default behavior is ANY, i.e., the given value matches any of the members of the defined set. Note this type is a restricted version of the match-set-options-type."; //TODO: restriction on enumerated types is only allowed in //YANG 1.1. Until then, we will require this additional type } grouping attribute-compare-operators { description "common definitions for comparison operations in condition statements"; leaf operator { Shaikh, et al. Expires January 5, 2016 [Page 24] Internet-Draft Routing Policy Model July 2015 type identityref { base attribute-comparison; } description "type of comparison to be performed"; } leaf value { type uint32; description "value to compare with the community count"; } } typedef tag-type { type union { type uint32; type yang:hex-string; } description "type for expressing route tags on a local system, including IS-IS and OSPF; may be expressed as either decimal or hexidecimal integer"; reference "RFC 2178 OSPF Version 2 RFC 5130 A Policy Control Mechanism in IS-IS Using Administrative Tags"; } identity install-protocol-type { description "Base type for protocols which can install prefixes into the RIB"; } identity BGP { base install-protocol-type; description "BGP"; reference "RFC 4271"; } identity ISIS { base install-protocol-type; description "IS-IS"; reference "ISO/IEC 10589"; } identity OSPF { base install-protocol-type; Shaikh, et al. Expires January 5, 2016 [Page 25] Internet-Draft Routing Policy Model July 2015 description "OSPFv2"; reference "RFC 2328"; } identity OSPF3 { base install-protocol-type; description "OSPFv3"; reference "RFC 5340"; } identity STATIC { base install-protocol-type; description "Locally-installed static route"; } identity DIRECTLY-CONNECTED { base install-protocol-type; description "A directly connected route"; } identity LOCAL-AGGREGATE { base install-protocol-type; description "Locally defined aggregate route"; } } 10. Policy examples Below we show an example of XML-encoded configuration data using the routing policy and BGP models to illustrate both how policies are defined, and also how they can be applied. Note that the XML has been simplified for readability. prefix-set-A 192.0.2.0/24 24..32 10.0.0.0/16 Shaikh, et al. Expires January 5, 2016 [Page 26] Internet-Draft Routing Policy Model July 2015 16..32 192.168.0.0/19 19..24 cust-tag1 10 export-tagged-BGP term-0 OSPF3 cust-tag1 65517 Shaikh, et al. Expires January 5, 2016 [Page 27] Internet-Draft Routing Policy Model July 2015 PG1 65518 EXTERNAL export-tagged-BGP 11. References 11.1. Normative references [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2014. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, July 2013. [RFC3688] Mealling, M., "The IETF XML Registry", RFC 3688, January 2004. 11.2. Informative references [I-D.shaikh-idr-bgp-model] Shaikh, A., Shakir, R., Patel, K., Hares, S., D'Souza, K., Bansal, D., Clemm, A., Alex, A., Jethanandani, M., and X. Liu, "BGP Model for Service Provider Networks", draft- shaikh-idr-bgp-model-02 (work in progress), June 2015. [I-D.openconfig-netmod-opstate] Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling of Operational State Data in YANG", draft-openconfig- netmod-opstate-00 (work in progress), March 2015. Shaikh, et al. Expires January 5, 2016 [Page 28] Internet-Draft Routing Policy Model July 2015 Appendix A. Acknowledgements The authors are grateful for valuable contributions to this document and the associated models from: Ebben Aires, Luyuan Fang, Josh George, Acee Lindem, Stephane Litkowski, Ina Minei, Carl Moberg, Eric Osborne, Steve Padgett, Juergen Schoenwaelder, Jim Uttaro, and Russ White. Appendix B. Change summary B.1. Changes between revisions -00 and -01 The -01 revision of the policy model reflects a number of changes to the data model based on additional operator, reviewer, and implementor feedback. o Modified the apply-policy container to use the pattern for modeling operational state described in [I-D.openconfig-netmod-opstate]. o Updated prefix lists to use ip-prefix type and masklength range to better enable range-checking and validation. Added an 'exact' option to the masklength range. o Changed accept / reject route to be within a choice statement. o Added enclosing containers to lists. o Minor changes to leaf-lists in defined sets definitions; also to apply-policy container structure. o Added second type of match-options set to handle restricted case of only ANY | INVERT (i.e., without ALL). The restricted enumerated type is now associated with the appropriate types of sets. o Moved install-protocol-type identity to policy-types module. o Removed require-instance statements from leafrefs pending availability in YANG 1.1. o Fixed discrepancies in the example shown in the document, and simplified the example. Shaikh, et al. Expires January 5, 2016 [Page 29] Internet-Draft Routing Policy Model July 2015 Authors' Addresses Anees Shaikh Google 1600 Amphitheatre Pkwy Mountain View, CA 94043 US Email: aashaikh@google.com Rob Shakir BT pp. C3L, BT Centre 81, Newgate Street London EC1A 7AJ UK Email: rob.shakir@bt.com URI: http://www.bt.com/ Kevin D'Souza AT&T 200 S. Laurel Ave Middletown, NJ US Email: kd6913@att.com Chris Chase AT&T 9505 Arboretum Blvd Austin, TX US Email: chase@labs.att.com Shaikh, et al. Expires January 5, 2016 [Page 30]