RTGWG Y. Qu Internet-Draft Futurewei Intended status: Standards Track J. Tantsura Expires: December 9, 2021 Juniper Networks A. Lindem Cisco X. Liu Volta Networks June 7, 2021 A YANG Data Model for Routing Policy draft-ietf-rtgwg-policy-model-28 Abstract This document defines a YANG data model for configuring and managing routing policies in a vendor-neutral way. The model provides a generic routing policy framework which can be extended for specific routing protocols using the YANG 'augment' mechanism. 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 https://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 December 9, 2021. Copyright Notice Copyright (c) 2021 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 (https://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 Qu, et al. Expires December 9, 2021 [Page 1] Internet-Draft Routing Policy Model June 2021 to this document. Code Components extracted from this document must 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Goals and approach . . . . . . . . . . . . . . . . . . . 3 2. Terminology and Notation . . . . . . . . . . . . . . . . . . 3 2.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Prefixes in Data Node Names . . . . . . . . . . . . . . . 5 3. Model overview . . . . . . . . . . . . . . . . . . . . . . . 5 4. Route policy expression . . . . . . . . . . . . . . . . . . . 6 4.1. Defined sets for policy matching . . . . . . . . . . . . 6 4.2. Policy conditions . . . . . . . . . . . . . . . . . . . . 7 4.3. Policy actions . . . . . . . . . . . . . . . . . . . . . 8 4.4. Policy subroutines . . . . . . . . . . . . . . . . . . . 9 5. Policy evaluation . . . . . . . . . . . . . . . . . . . . . . 10 6. Applying routing policy . . . . . . . . . . . . . . . . . . . 10 7. YANG Module and Tree . . . . . . . . . . . . . . . . . . . . 11 7.1. Routing Policy Model Tree . . . . . . . . . . . . . . . . 11 7.2. Routing policy model . . . . . . . . . . . . . . . . . . 12 8. Security Considerations . . . . . . . . . . . . . . . . . . . 33 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 35 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 36 11.1. Normative references . . . . . . . . . . . . . . . . . . 36 11.2. Informative references . . . . . . . . . . . . . . . . . 38 Appendix A. Routing protocol-specific policies . . . . . . . . . 38 Appendix B. Policy examples . . . . . . . . . . . . . . . . . . 41 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 43 1. Introduction This document describes a YANG [RFC7950] 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, to allow operators to manage policy configuration in a consistent way in environments with routers supplied by multiple vendors. The YANG modules in this document conform to the Network Management Datastore Architecture (NMDA) [RFC8342]. Qu, et al. Expires December 9, 2021 [Page 2] Internet-Draft Routing Policy Model June 2021 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 several 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 a familiar and straightforward way to express policy. A side effect of this design decision is that other methods for expressing policies are not considered. 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. Terminology and Notation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. Routing policy: A routing policy defines how routes are imported, exported, modified, and advertised between routing protocol instances or within a single routing protocol instance. Policy chain: A policy chain is a sequence of policy definitions (described in Section 4). They can be referenced from different contexts. Policy statement: Policy statements consist of a set of conditions and actions (either of which may be empty). The following terms are defined in [RFC8342]: Qu, et al. Expires December 9, 2021 [Page 3] Internet-Draft Routing Policy Model June 2021 o client o server o configuration o system state o operational state o intended configuration The following terms are defined in [RFC7950]: o action o augment o container o container with presence o data model o data node o feature o leaf o list o mandatory node o module o schema tree o RPC (Remote Procedure Call) operation 2.1. Tree Diagrams Tree diagrams used in this document follow the notation defined in [RFC8340]. Qu, et al. Expires December 9, 2021 [Page 4] Internet-Draft Routing Policy Model June 2021 2.2. Prefixes in Data Node Names In this document, names of data nodes, actions, and other data model objects are often used without a prefix, as long as it is clear from the context in which YANG module each name is defined. Otherwise, names are prefixed using the standard prefix associated with the corresponding YANG module, as shown in Table 1. +---------+--------------------------------+----------------------+ | Prefix | YANG module | Reference | +---------+--------------------------------+----------------------+ | if | ietf-interfaces | [RFC8343] | | | | | | rt | ietf-routing | [RFC8349] | | | | | | yang | ietf-yang-types | [RFC6991] | | | | | | inet | ietf-inet-types | [RFC6991] | | | | | | if-ext | ietf-if-extensions | [INTF-EXT-YANG] | | | | | | if-flex | ietf-if-flexible-encapsulation | [SUB-INTF-VLAN-YANG] | +---------+--------------------------------+----------------------+ Table 1: Prefixes and Corresponding YANG Modules 3. Model overview The routing policy module has three main parts: o A generic framework is provided 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 is also provided. There is a complete example of this for BGP [RFC4271] policies in the proposed vendor-neutral BGP data model [I-D.ietf-idr-bgp-model]. Appendix A provides an example of how an augmentation for BGP policies might be accomplished. Note that this section is not normative as the BGP model is still evolving. o Finally, a reusable grouping is defined 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. In this document, policy chains are sequences of policy definitions that are applied in order (described in Section 4). Qu, et al. Expires December 9, 2021 [Page 5] Internet-Draft Routing Policy Model June 2021 The module makes use of the standard Internet types, such as IP addresses, autonomous system numbers, etc., defined in RFC 6991 [RFC6991]. 4. 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 ... 4.1. Defined sets for policy matching The model provides a collection of generic sets that can be used for matching in policy conditions. These sets are applicable for route selection across multiple routing protocols. They may be further augmented by protocol-specific models which have their own defined sets. The defined sets include: o prefix sets - Each prefix set defines a set of IP prefixes, each with an associated IP prefix and netmask range (or exact length). o neighbor sets - Each neighbor set defines a set of neighboring nodes by their IP addresses. A neighbor set is used for selecting routes based on the neighbors advertising the routes. o tag set - Each tag set defines a set of generic tag values that can be used in matches for filtering routes. The model structure for defined sets is shown below. Qu, et al. Expires December 9, 2021 [Page 6] Internet-Draft Routing Policy Model June 2021 +--rw routing-policy +--rw defined-sets | +--rw prefix-sets | | +--rw prefix-set* [name] | | +--rw name string | | +--rw mode? enumeration | | +--rw prefixes | | +--rw prefix-list* [ip-prefix mask-length-lower | | mask-length-upper] | | +--rw ip-prefix inet:ip-prefix | | +--rw mask-length-lower uint8 | | +--rw mask-length-upper uint8 | +--rw neighbor-sets | | +--rw neighbor-set* [name] | | +--rw name string | | +--rw address* inet:ip-address | +--rw tag-sets | +--rw tag-set* [name] | +--rw name string | +--rw tag-value* tag-type 4.2. 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. The default action is to reject-route. Match conditions may be further modified using the match-set-options configuration which allows network 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. 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. Qu, et al. Expires December 9, 2021 [Page 7] Internet-Draft Routing Policy Model June 2021 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 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 name string +--rw statements +--rw statement* [name] +--rw conditions | +--rw call-policy? | +--rw source-protocol? | +--rw match-interface | | +--rw interface? | | +--rw subinterface? | +--rw match-prefix-set | | +--rw prefix-set? | | +--rw match-set-options? | +--rw match-neighbor-set | | +--rw neighbor-set? | +--rw match-tag-set | | +--rw tag-set? | | +--rw match-set-options? | +--rw match-route-type* identityref 4.3. 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. Qu, et al. Expires December 9, 2021 [Page 8] Internet-Draft Routing Policy Model June 2021 +--rw routing-policy +--rw policy-definitions +--rw policy-definition* [name] +--rw statements +--rw statement* [name] +--rw actions +--rw policy-result? policy-result-type +--rw set-metric | +--rw metric-modification? | | metric-modification-type | +--rw metric? uint32 +--rw set-metric-type | +--rw metric-type? identityref +--rw set-route-level | +--rw route-level? identityref +--rw set-preference? uint16 +--rw set-tag? tag-type +--rw set-application-tag? tag-type 4.4. 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, 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 5). 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. When the end of the subroutine policy statements is reached, the default route disposition action is returned (i.e., Boolean false for reject- route). Consequently, a subroutine cannot explicitly accept or reject a route. Rather, the called policy returns Boolean true if its outcome is accept-route or Boolean false if its outcome is reject-route. Route acceptance or rejection is solely determined by the top-level policy. 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. For example, an implementation may only support a single level of subroutine recursion. As with any routing policy construction, care must be taken with nested policies to ensure that the effective Qu, et al. Expires December 9, 2021 [Page 9] Internet-Draft Routing Policy Model June 2021 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) is discouraged. Also, implementations MUST validate to ensure that there is no recursion amongst nested routing policies. 5. Policy evaluation Evaluation of each policy definition proceeds by evaluating its individual policy statements in order that they are defined. When all the condition statements in a policy statement are satisfied, the corresponding action statements are executed. If the actions include either accept-route or reject-route actions, evaluation of the current policy definition stops, and no further policy statement is evaluated. If there are multiple policies in the policy chain, subsequent policies are not evaluated. Policy chains are sequences of policy definitions (as described in . (Section 4)). If the conditions are 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 alternate default action is specified for the chain). Note that the route's pre-policy attributes are always used for testing policy statement conditions. In other words, if actions modify the policy application-specific attributes, those modifications are not used for policy statement conditions. 6. 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 4). They can be referenced from different contexts. For example, a policy chain could be associated with a routing protocol and used to control its interaction with its protocol peers. Or it could be used to control the interaction between a routing protocol and the local routing information base. A policy chain has an associated direction (import or export), with respect to the context in which it is referenced. 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. Qu, et al. Expires December 9, 2021 [Page 10] Internet-Draft Routing Policy Model June 2021 +--rw apply-policy | +--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. 7. YANG Module and Tree 7.1. Routing Policy Model Tree The tree of the routing policy model is shown below. module: ietf-routing-policy rw routing-policy +--rw defined-sets | +--rw prefix-sets | | +--rw prefix-set* [name mode] | | +--rw name string | | +--rw mode enumeration | | +--rw prefixes | | +--rw prefix-list* [ip-prefix mask-length-lower | | mask-length-upper] | | +--rw ip-prefix inet:ip-prefix | | +--rw mask-length-lower uint8 | | +--rw mask-length-upper uint8 | +--rw neighbor-sets | | +--rw neighbor-set* [name] | | +--rw name string | | +--rw address* inet:ip-address | +--rw tag-sets | +--rw tag-set* [name] | +--rw name string | +--rw tag-value* tag-type +--rw policy-definitions +--rw policy-definition* [name] +--rw name string +--rw statements +--rw statement* [name] +--rw name string +--rw conditions | +--rw call-policy? -> ../../../../../.. | /policy-definitions | /policy-definition/name | +--rw source-protocol? identityref | +--rw match-interface Qu, et al. Expires December 9, 2021 [Page 11] Internet-Draft Routing Policy Model June 2021 | | +--rw interface? -> /if:interfaces/interface | | /name | | +--rw subinterface? -> /if:interfaces/interface | | /if-ext:encapsulation | | /if-flex:flexible/match | | /dot1q-vlan-tagged | | /outer-tag/vlan-id | +--rw match-prefix-set | | +--rw prefix-set? -> ../../../../../../.. | | /defined-sets/prefix-sets | | /prefix-set/name | | +--rw match-set-options? match-set-options-type | +--rw match-neighbor-set | | +--rw neighbor-set? -> ../../../../../../.. | | /defined-sets/neighbor-sets | | /neighbor-set/name | +--rw match-tag-set | | +--rw tag-set? -> ../../../../../../.. | | /defined-sets/tag-sets | | /tag-set/name | | +--rw match-set-options? match-set-options-type | +--rw match-route-type* identityref +--rw actions +--rw policy-result? policy-result-type +--rw set-metric | +--rw metric-modification? metric-modification-type | +--rw metric? uint32 +--rw set-metric-type | +--rw metric-type? identityref +--rw set-route-level | +--rw route-level? identityref +--rw set-preference? uint16 +--rw set-tag? tag-type +--rw set-application-tag? tag-type 7.2. Routing policy model The following RFCs are not referenced in the document text but are referenced in the ietf-routing-policy.yang module: [RFC2328], [RFC3101], [RFC5130], [RFC5302], [RFC6991], and [RFC8343]. file "ietf-routing-policy@2021-06-07.yang" module ietf-routing-policy { yang-version "1.1"; namespace "urn:ietf:params:xml:ns:yang:ietf-routing-policy"; prefix rt-pol; Qu, et al. Expires December 9, 2021 [Page 12] Internet-Draft Routing Policy Model June 2021 import ietf-inet-types { prefix "inet"; reference "RFC 6991: Common YANG Data Types"; } import ietf-yang-types { prefix "yang"; reference "RFC 6991: Common YANG Data Types"; } import ietf-interfaces { prefix "if"; reference "RFC 8343: A YANG Data Model for Interface Management (NMDA Version)"; } import ietf-routing { prefix "rt"; reference "RFC 8349: A YANG Data Model for Routing Management (NMDA Version)"; } import ietf-if-extensions { prefix "if-ext"; reference "RFC YYYY: Common Interface Extension YANG Data Models. Please replace YYYY with published RFC number for draft-ietf-netmod-intf-ext-yang."; } import ietf-if-flexible-encapsulation { prefix "if-flex"; reference "RFC ZZZZ: Sub-interface VLAN YANG Data Models. Please replace ZZZZ with published RFC number for draft-ietf-netmod-sub-intf-vlan-model."; } organization "IETF RTGWG - Routing Area Working Group"; contact "WG Web: WG List: Editor: Yingzhen Qu Jeff Tantsura Acee Lindem Qu, et al. Expires December 9, 2021 [Page 13] Internet-Draft Routing Policy Model June 2021 Xufeng Liu "; description "This module describes a YANG model for routing policy 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, modified and advertised across different routing protocol instances or within a single routing protocol instance. This module is intended to be used in conjunction with routing protocol configuration modules (e.g., BGP) defined in other models. This YANG module conforms to the Network Management Datastore Architecture (NMDA), as described in RFC 8342. Copyright (c) 2021 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices. The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; reference "RFC XXXX: A YANG Data Model for Routing Policy."; revision "2021-06-07" { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for Routing Policy Management."; } /* Identities */ Qu, et al. Expires December 9, 2021 [Page 14] Internet-Draft Routing Policy Model June 2021 identity metric-type { description "Base identity for route metric types."; } identity ospf-type-1-metric { base metric-type; description "Identity for the OSPF type 1 external metric types. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-type-2-metric { base metric-type; description "Identity for the OSPF type 2 external metric types. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity isis-internal-metric { base metric-type; description "Identity for the IS-IS internal metric types. It is only applicable to IS-IS routes."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity isis-external-metric { base metric-type; description "Identity for the IS-IS external metric types. It is only applicable to IS-IS routes."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity route-level { description "Base identity for route import level."; } Qu, et al. Expires December 9, 2021 [Page 15] Internet-Draft Routing Policy Model June 2021 identity ospf-normal { base route-level; description "Identity for OSPF importation into normal areas It is only applicable to routes imported into the OSPF protocol."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-nssa-only { base route-level; description "Identity for the OSPF Not-So-Stubby Area (NSSA) area importation. It is only applicable to routes imported into the OSPF protocol."; reference "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option"; } identity ospf-normal-nssa { base route-level; description "Identity for OSPF importation into both normal and NSSA areas, it is only applicable to routes imported into the OSPF protocol."; reference "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option"; } identity isis-level-1 { base route-level; description "Identity for IS-IS Level 1 area importation. It is only applicable to routes imported into the IS-IS protocol."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity isis-level-2 { base route-level; description "Identity for IS-IS Level 2 area importation. It is only applicable to routes imported into the IS-IS protocol."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; Qu, et al. Expires December 9, 2021 [Page 16] Internet-Draft Routing Policy Model June 2021 } identity isis-level-1-2 { base route-level; description "Identity for IS-IS Level 1 and Level 2 area importation. It is only applicable to routes imported into the IS-IS protocol."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity proto-route-type { description "Base identity for route type within a protocol."; } identity isis-level-1-type { base proto-route-type; description "Identity for IS-IS Level 1 route type. It is only applicable to IS-IS routes."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity isis-level-2-type { base proto-route-type; description "Identity for IS-IS Level 2 route type. It is only applicable to IS-IS routes."; reference "RFC 5302 - Domain-Wide Prefix Distribution with Two-Level IS-IS"; } identity ospf-internal-type { base proto-route-type; description "Identity for OSPF intra-area or inter-area route type. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-external-type { Qu, et al. Expires December 9, 2021 [Page 17] Internet-Draft Routing Policy Model June 2021 base proto-route-type; description "Identity for OSPF external type 1/2 route type. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-external-t1-type { base ospf-external-type; description "Identity for OSPF external type 1 route type. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-external-t2-type { base ospf-external-type; description "Identity for OSPF external type 2 route type. It is only applicable to OSPF routes."; reference "RFC 2328 - OSPF Version 2"; } identity ospf-nssa-type { base proto-route-type; description "Identity for OSPF NSSA type 1/2 route type. It is only applicable to OSPF routes."; reference "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option"; } identity ospf-nssa-t1-type { base ospf-nssa-type; description "Identity for OSPF NSSA type 1 route type. It is only applicable to OSPF routes."; reference "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option"; } identity ospf-nssa-t2-type { base ospf-nssa-type; description "Identity for OSPF NSSA type 2 route type. Qu, et al. Expires December 9, 2021 [Page 18] Internet-Draft Routing Policy Model June 2021 It is only applicable to OSPF routes."; reference "RFC 3101: The OSPF Not-So-Stubby Area (NSSA) Option"; } identity bgp-internal { base proto-route-type; description "Identity for routes learned from internal BGP (IBGP). It is only applicable to BGP routes."; reference "RFC 4271: A Border Gateway Protocol 4 (BGP-4)"; } identity bgp-external { base proto-route-type; description "Identity for routes learned from external BGP (EBGP). It is only applicable to BGP routes."; reference "RFC 4271: A Border Gateway Protocol 4 (BGP-4)"; } /* Type Definitions */ 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 route disposition in a policy chain. This typedef is used in the default import and export policy."; } typedef policy-result-type { type enumeration { enum accept-route { description "Policy accepts the route."; } Qu, et al. Expires December 9, 2021 [Page 19] Internet-Draft Routing Policy Model June 2021 enum reject-route { description "Policy rejects the route."; } } description "Type used to specify route disposition in a policy chain."; } 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 hexadecimal integer."; reference "RFC 2328 - OSPF Version 2 RFC 5130 - A Policy Control Mechanism in IS-IS Using Administrative Tags"; } 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."; Qu, et al. Expires December 9, 2021 [Page 20] Internet-Draft Routing Policy Model June 2021 } typedef metric-modification-type { type enumeration { enum set-metric { description "Set the metric to the specified value."; } enum add-metric { description "Add the specified value to the existing metric. If the result would overflow the maximum metric (0xffffffff), set the metric to the maximum."; } enum subtract-metric { description "Subtract the specified value from the existing metric. If the result would be less than 0, set the metric to 0."; } } description "Type used to specify how to set the metric given the specified value."; } /* Groupings */ grouping prefix { description "Configuration data for a prefix definition. The combination of mask-length-lower and mask-length-upper define a range for the mask length, or single 'exact' length if mask-length-lower and mask-length-upper are equal. Example: 192.0.2.0/24 through 192.0.2.0/26 would be expressed as prefix: 192.0.2.0/24, mask-length-lower=24, mask-length-upper=26 Example: 192.0.2.0/24 (an exact match) would be expressed as prefix: 192.0.2.0/24, mask-length-lower=24, mask-length-upper=24 Example: 2001:DB8::/32 through 2001:DB8::/64 would be expressed as prefix: 2001:DB8::/32, Qu, et al. Expires December 9, 2021 [Page 21] Internet-Draft Routing Policy Model June 2021 mask-length-lower=32, mask-length-upper=64"; leaf ip-prefix { type inet:ip-prefix; mandatory true; description "The IP prefix represented as an IPv6 or IPv4 network number followed by a prefix length with an intervening slash character as a delimiter. All members of the prefix-set MUST be of the same address family as the prefix-set mode."; } leaf mask-length-lower { type uint8 { range "0..128"; } description "Mask length range lower bound. It MUST NOT be less than the prefix length defined in ip-prefix."; } leaf mask-length-upper { type uint8 { range "1..128"; } must "../mask-length-upper >= ../mask-length-lower" { error-message "The upper bound MUST NOT be less" + "than lower bound."; } description "Mask length range upper bound. It MUST NOT be less than lower bound."; } } grouping match-set-options-group { description "Grouping containing options relating to how a particular set will be matched."; leaf match-set-options { type match-set-options-type; description "Optional parameter that governs the behavior of the match operation."; } } Qu, et al. Expires December 9, 2021 [Page 22] Internet-Draft Routing Policy Model June 2021 grouping match-set-options-restricted-group { description "Grouping for a restricted set of match operation modifiers."; leaf match-set-options { type match-set-options-type { 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."; } } description "Optional parameter that governs the behavior of the match operation. This leaf only supports matching on 'any' member of the set or 'invert' the match. Matching on 'all' is not supported."; } } grouping match-interface-condition { description "This grouping provides interface match condition."; container match-interface { leaf interface { type leafref { path "/if:interfaces/if:interface/if:name"; } description "Reference to a base interface. If a reference to a subinterface is required, this leaf MUST be specified to indicate the base interface."; } leaf subinterface { type leafref { path "/if:interfaces/if:interface/if-ext:encapsulation" + "/if-flex:flexible/if-flex:match" + "/if-flex:dot1q-vlan-tagged" + "/if-flex:outer-tag/if-flex:vlan-id"; } description Qu, et al. Expires December 9, 2021 [Page 23] Internet-Draft Routing Policy Model June 2021 "Reference to a subinterface -- this requires the base interface to be specified using the interface leaf in this container. If only a reference to a base interface is required, this leaf MUST NOT be set."; } description "Container for interface match conditions"; } } grouping match-route-type-condition { description "This grouping provides route-type match condition"; leaf-list match-route-type { type identityref { base proto-route-type; } description "Condition to check the protocol-specific type of route. This is normally used during route importation to select routes or to set protocol specific attributes based on the route type."; } } grouping prefix-set-condition { description "This grouping provides prefix-set conditions."; container match-prefix-set { leaf prefix-set { type leafref { path "../../../../../../../defined-sets/" + "prefix-sets/prefix-set/name"; } description "References a defined prefix set."; } uses match-set-options-restricted-group; description "Match a referenced prefix-set according to the logic defined in the match-set-options leaf."; } } Qu, et al. Expires December 9, 2021 [Page 24] Internet-Draft Routing Policy Model June 2021 grouping neighbor-set-condition { description "This grouping provides neighbor-set conditions."; container match-neighbor-set { leaf neighbor-set { type leafref { path "../../../../../../../defined-sets/neighbor-sets/" + "neighbor-set/name"; require-instance true; } description "References a defined neighbor set."; } description "Match a referenced neighbor set according to the logic defined in the match-set-options-leaf."; } } grouping tag-set-condition { description "This grouping provides tag-set conditions."; container match-tag-set { leaf tag-set { type leafref { path "../../../../../../../defined-sets/tag-sets" + "/tag-set/name"; require-instance true; } description "References a defined tag set."; } uses match-set-options-group; description "Match a referenced tag set according to the logic defined in the match-options-set leaf."; } } grouping apply-policy-import { description "Grouping for applying import policies."; leaf-list import-policy { Qu, et al. Expires December 9, 2021 [Page 25] Internet-Draft Routing Policy Model June 2021 type leafref { path "/rt-pol:routing-policy/rt-pol:policy-definitions/" + "rt-pol:policy-definition/rt-pol:name"; require-instance true; } ordered-by user; description "List of policy names in sequence to be applied on receiving redistributed routes from another routing protocol or 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."; } } grouping apply-policy-export { description "Grouping for applying export policies."; leaf-list export-policy { type leafref { path "/rt-pol:routing-policy/rt-pol:policy-definitions/" + "rt-pol:policy-definition/rt-pol:name"; require-instance true; } ordered-by user; description "List of policy names in sequence to be applied on redistributing routes from one routing protocol to another or 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 Qu, et al. Expires December 9, 2021 [Page 26] Internet-Draft Routing Policy Model June 2021 in the export policy chain is satisfied."; } } 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."; uses apply-policy-import; uses apply-policy-export; } } container routing-policy { description "Top-level container for all routing policy."; container defined-sets { description "Predefined sets of attributes used in policy match statements."; container prefix-sets { description "Data definitions for a list of IPv4 or IPv6 prefixes which are matched as part of a policy."; list prefix-set { key "name mode"; description "List of the defined prefix sets"; leaf name { type string; description "Name of the prefix set -- this is used as a label to reference the set in match conditions."; } Qu, et al. Expires December 9, 2021 [Page 27] Internet-Draft Routing Policy Model June 2021 leaf mode { type enumeration { enum ipv4 { description "Prefix set contains IPv4 prefixes only."; } enum ipv6 { description "Prefix set contains IPv6 prefixes only."; } } description "Indicates the mode of the prefix set, in terms of which address families (IPv4, IPv6, or both) are present. The mode provides a hint, all prefixes MUST be of the indicated type. The device MUST validate that all prefixes and reject the configuration if there is a discrepancy."; } container prefixes { description "Container for the list of prefixes in a policy prefix list. Since individual prefixes do not have unique actions, the order in which the prefix in prefix-list are matched has no impact on the outcome and is left to the implementation. A given prefix-set condition is satisfied if the input prefix matches any of the prefixes in the prefix-set."; list prefix-list { key "ip-prefix mask-length-lower mask-length-upper"; description "List of prefixes in the prefix set."; uses prefix; } } } } container neighbor-sets { description "Data definition for a list of IPv4 or IPv6 neighbors which can be matched in a routing policy."; list neighbor-set { key "name"; Qu, et al. Expires December 9, 2021 [Page 28] Internet-Draft Routing Policy Model June 2021 description "List of defined neighbor sets for use in policies."; leaf name { type string; description "Name of the neighbor set -- this is used as a label to reference the set in match conditions."; } leaf-list address { type inet:ip-address; description "List of IP addresses in the neighbor set."; } } } container tag-sets { description "Data definitions for a list of tags which can be matched in policies."; list tag-set { key "name"; description "List of tag set definitions."; leaf name { type string; description "Name of the tag set -- this is used as a label to reference the set in match conditions."; } leaf-list tag-value { type tag-type; description "Value of the tag set member."; } } } } container policy-definitions { description "Enclosing container for the list of top-level policy definitions."; Qu, et al. Expires December 9, 2021 [Page 29] Internet-Draft Routing Policy Model June 2021 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 or 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"; 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 the current policy statement."; leaf call-policy { type leafref { path "../../../../../../" + "rt-pol:policy-definitions/" + "rt-pol:policy-definition/rt-pol:name"; require-instance true; } description "Applies the statements from the specified policy Qu, et al. Expires December 9, 2021 [Page 30] Internet-Draft Routing Policy Model June 2021 definition and then returns control to 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."; } leaf source-protocol { type identityref { base rt:control-plane-protocol; } description "Condition to check the protocol / method used to install the route into the local routing table."; } uses match-interface-condition; uses prefix-set-condition; uses neighbor-set-condition; uses tag-set-condition; uses match-route-type-condition; } container actions { description "Top-level container for policy action statements."; leaf policy-result { type policy-result-type; default reject-route; description "Select the final disposition for the route, either accept or reject."; } container set-metric { leaf metric-modification { type metric-modification-type; description "Indicates how to modify the metric."; } leaf metric { type uint32; description Qu, et al. Expires December 9, 2021 [Page 31] Internet-Draft Routing Policy Model June 2021 "Metric value to set, add, or subtract."; } description "Set the metric for the route."; } container set-metric-type { leaf metric-type { type identityref { base metric-type; } description "Route metric type."; } description "Set the metric type for the route."; } container set-route-level { leaf route-level { type identityref { base route-level; } description "Route import level."; } description "Set the level for importation or exportation of routes."; } leaf set-preference { type uint16; description "Set the preference for the route. It is also known as 'administrative distance', allows for selecting the preferred route among routes with the same destination prefix. A smaller value is more preferred."; } leaf set-tag { type tag-type; description "Set the tag for the route."; } leaf set-application-tag { type tag-type; description "Set the application tag for the route. The application-specific tag is an additional tag that can be used by applications that require Qu, et al. Expires December 9, 2021 [Page 32] Internet-Draft Routing Policy Model June 2021 semantics and/or policy different from that of the tag. For example, the tag is usually automatically advertised in OSPF AS-External Link State Advertisements (LSAs) while this application-specific tag is not advertised implicitly."; } } } } } } } } 8. Security Considerations 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 [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446]. The NETCONF Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a pre- configured 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. These are the subtrees and data nodes and their sensitivity/vulnerability: /routing-policy /routing-policy/defined-sets/prefix-sets -- Modification to prefix-sets could result in a Denial-of-Service (DoS) attack. An attacker may try to modify prefix-sets and redirect or drop traffic. Redirection of traffic could be used as part of a more elaborate attack to either collect sensitive information or masquerade a service. Additionally, a control-plane DoS attack Qu, et al. Expires December 9, 2021 [Page 33] Internet-Draft Routing Policy Model June 2021 could be accomplished by allowing a large number of routes to be leaked into a routing protocol domian (e.g., BGP). /routing-policy/defined-sets/neighbor-sets -- Modification to the neighbor-sets could be used to mount a DoS attack or more elaborate attack as with prefix-sets. For example, a DoS attack could be mounted by changing the neighbor-set from which routes are accepted. /routing-policy/defined-sets/tag-sets -- Modification to the tag- sets could be used to mount a DoS attack. Routes with certain tags might be redirected or dropped. The implications are similar to prefix-sets and neighbor-sets. However, the attack may be more difficult to detect as the routing policy usage of route tags and intent must be understood to recognize the breach. Conversely, the implications of prefix-set or neighbor set modification are easier to recognize. /routing-policy/policy-definitions /routing-policy/policy-definitions/policy-definition /statements/statement/conditions -- Modification to the conditions could be used to mount a DoS attack or other attack. An attacker may change a policy condition and redirect or drop traffic. As with prefix-sets, neighbor-sets, or tag-sets, traffic redirection could be used as part of a more elaborate attack. /routing-policy/policy-definitions/policy-definition /statements/statement/actions -- Modification to actions could be used to mount a DoS attack or other attack. Traffic may be redirected or dropped. As with prefix-sets, neighbor-sets, or tag-sets, traffic redirection could be used as part of a more elaborate attack. Additionally, route attributes may be changed to mount a second-level attack that is more difficult to detect. Some of the readable data nodes in the 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. These are the subtrees and data nodes and their sensitivity/vulnerability: /routing-policy/defined-sets/prefix-sets -- Knowledge of these data nodes can be used to ascertain which local prefixes are suspectable to a Denial-of-Service (DoS) attack. /routing-policy/defined-sets/prefix-sets -- Knowledge of these data nodes can be used to ascertain local neighbors against whom to mount a Denial-of-Service (DoS) attack. Qu, et al. Expires December 9, 2021 [Page 34] Internet-Draft Routing Policy Model June 2021 /routing-policy/policy-definitions/policy-definition /statements/ -- Knowledge of these data nodes can be used to attack the local router with a Denial-of-Service (DoS) attack. Additionally, policies and their attendant conditions and actions should be considered proprietary and disclosure could be used to ascertain partners, customers, and supplies. Furthermore, the policies themselves could represent intellectual property and disclosure could diminish their corresponding business advantage. Routing policy configuration has a significant impact on network operations, and, as such, any related model carries potential security risks. Unauthorized access or invalid data could cause major disruption. 9. IANA Considerations This document registers a URI in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registration is requested to be made: URI: urn:ietf:params:xml:ns:yang:ietf-routing-policy Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. This document registers a YANG module in the YANG Module Names registry [RFC6020]. name: ietf-routing-policy namespace: urn:ietf:params:xml:ns:yang:ietf-routing-policy prefix: rt-pol reference: RFC XXXX 10. Acknowledgements The routing policy module defined in this document is based on the OpenConfig route policy model. The authors would like to thank to OpenConfig for their contributions, especially Anees Shaikh, Rob Shakir, Kevin D'Souza, and Chris Chase. The authors are grateful for valuable contributions to this document and the associated models from: Ebben Aires, Luyuan Fang, Josh George, Stephane Litkowski, Ina Minei, Carl Moberg, Eric Osborne, Steve Padgett, Juergen Schoenwaelder, Jim Uttaro, Russ White, and John Heasley. Thanks to Mahesh Jethanandani, John Scudder, Chris Bower and Tom Petch for their reviews and comments. Qu, et al. Expires December 9, 2021 [Page 35] Internet-Draft Routing Policy Model June 2021 11. References 11.1. Normative references [INTF-EXT-YANG] Wilton, R., Ball, D., tapsingh@cisco.com, t., and S. Sivaraj,, "Common Interface Extension YANG Data Models", 2019, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/RFC2328, April 1998, . [RFC3101] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option", RFC 3101, DOI 10.17487/RFC3101, January 2003, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, DOI 10.17487/RFC4271, January 2006, . [RFC5130] Previdi, S., Shand, M., Ed., and C. Martin, "A Policy Control Mechanism in IS-IS Using Administrative Tags", RFC 5130, DOI 10.17487/RFC5130, February 2008, . [RFC5302] Li, T., Smit, H., and T. Przygienda, "Domain-Wide Prefix Distribution with Two-Level IS-IS", RFC 5302, DOI 10.17487/RFC5302, October 2008, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . Qu, et al. Expires December 9, 2021 [Page 36] Internet-Draft Routing Policy Model June 2021 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, . [RFC8343] Bjorklund, M., "A YANG Data Model for Interface Management", RFC 8343, DOI 10.17487/RFC8343, March 2018, . [RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for Routing Management (NMDA Version)", RFC 8349, DOI 10.17487/RFC8349, March 2018, . Qu, et al. Expires December 9, 2021 [Page 37] Internet-Draft Routing Policy Model June 2021 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . [SUB-INTF-VLAN-YANG] Wilton, R., Ball, D., tapsingh@cisco.com, t., and S. Sivaraj, "Sub-interface VLAN YANG Data Model", 2019, . 11.2. Informative references [I-D.ietf-idr-bgp-model] Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP YANG Model for Service Provider Networks", draft-ietf-idr- bgp-model-10 (work in progress), November 2020. Appendix A. 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. The example below provides an illustration of how another data model can augment parts of this routing policy data model. It uses specific examples from draft-ietf-idr-bgp-model-09 to show in a concrete manner how the different pieces fit together. This example is not normative with respect to [I-D.ietf-idr-bgp-model]. The model similarly augments BGP-specific conditions and actions in the corresponding sections of the routing policy model. In the example below, the XPath prefix "bp:" specifies import from the ietf-bgp- policy sub-module and the XPath prefix "bt:" specifies import from the ietf-bgp-types sub-module [I-D.ietf-idr-bgp-model]. module: ietf-routing-policy +--rw routing-policy +--rw defined-sets | +--rw prefix-sets | | +--rw prefix-set* [name] | | +--rw name string | | +--rw mode? enumeration | | +--rw prefixes | | +--rw prefix-list* [ip-prefix mask-length-lower | | mask-length-upper] | | +--rw ip-prefix inet:ip-prefix | | +--rw mask-length-lower uint8 Qu, et al. Expires December 9, 2021 [Page 38] Internet-Draft Routing Policy Model June 2021 | | +--rw mask-length-upper uint8 | +--rw neighbor-sets | | +--rw neighbor-set* [name] | | +--rw name string | | +--rw address* inet:ip-address | +--rw tag-sets | | +--rw tag-set* [name] | | +--rw name string | | +--rw tag-value* tag-type | +--rw bp:bgp-defined-sets | +--rw bp:community-sets | | +--rw bp:community-set* [name] | | +--rw bp:name string | | +--rw bp:member* union | +--rw bp:ext-community-sets | | +--rw bp:ext-community-set* [name] | | +--rw bp:name string | | +--rw bp:member* union | +--rw bp:as-path-sets | +--rw bp:as-path-set* [name] | +--rw bp:name string | +--rw bp:member* string +--rw policy-definitions +--rw policy-definition* [name] +--rw name string +--rw statements +--rw statement* [name] +--rw name string +--rw conditions | +--rw call-policy? | +--rw source-protocol? identityref | +--rw match-interface | | +--rw interface? | | +--rw subinterface? | +--rw match-prefix-set | | +--rw prefix-set? prefix-set/name | | +--rw match-set-options? match-set-options-type | +--rw match-neighbor-set | | +--rw neighbor-set? | +--rw match-tag-set | | +--rw tag-set? | | +--rw match-set-options? match-set-options-type | +--rw match-route-type* identityref | +--rw bp:bgp-conditions | +--rw bp:med-eq? uint32 | +--rw bp:origin-eq? bt:bgp-origin-attr-type | +--rw bp:next-hop-in* inet:ip-address-no-zone | +--rw bp:afi-safi-in* identityref Qu, et al. Expires December 9, 2021 [Page 39] Internet-Draft Routing Policy Model June 2021 | +--rw bp:local-pref-eq? uint32 | +--rw bp:route-type? enumeration | +--rw bp:community-count | +--rw bp:as-path-length | +--rw bp:match-community-set | | +--rw bp:community-set? | | +--rw bp:match-set-options? | +--rw bp:match-ext-community-set | | +--rw bp:ext-community-set? | | +--rw bp:match-set-options? | +--rw bp:match-as-path-set | +--rw bp:as-path-set? | +--rw bp:match-set-options? +--rw actions +--rw policy-result? policy-result-type +--rw set-metric | +--rw metric-modification? | +--rw metric? uint32 +--rw set-metric-type | +--rw metric-type? identityref +--rw set-route-level | +--rw route-level? identityref +--rw set-preference? uint16 +--rw set-tag? tag-type +--rw set-application-tag? tag-type +--rw bp:bgp-actions +--rw bp:set-route-origin?bt:bgp-origin-attr-type +--rw bp:set-local-pref? uint32 +--rw bp:set-next-hop? bgp-next-hop-type +--rw bp:set-med? bgp-set-med-type +--rw bp:set-as-path-prepend | +--rw bp:repeat-n? uint8 +--rw bp:set-community | +--rw bp:method? enumeration | +--rw bp:options? | +--rw bp:inline | | +--rw bp:communities* union | +--rw bp:reference | +--rw bp:community-set-ref? +--rw bp:set-ext-community +--rw bp:method? enumeration +--rw bp:options? +--rw bp:inline | +--rw bp:communities* union +--rw bp:reference +--rw bp:ext-community-set-ref? Qu, et al. Expires December 9, 2021 [Page 40] Internet-Draft Routing Policy Model June 2021 Appendix B. Policy examples Below we show examples of XML-encoded configuration data using the routing policy and BGP models to illustrate both how policies are defined, and how they can be applied. Note that the XML has been simplified for readability. The following example shows how prefix-set and tag-set can be defined. The policy condition is to match a prefix-set and a tag- set, and the action is to accept routes that match the condition. prefix-set-A ipv4 192.0.2.0/24 24 32 198.51.100.0/24 24 32 prefix-set-B ipv6 2001:DB8::/32 32 64 cust-tag1 Qu, et al. Expires December 9, 2021 [Page 41] Internet-Draft Routing Policy Model June 2021 10 export-tagged-BGP term-0 prefix-set-A cust-tag1 accept-route In the following example, all routes in the RIB that have been learned from OSPF advertisements corresponding to OSPF intra-area and inter-area route types should get advertised into ISIS level-2 advertisements. Qu, et al. Expires December 9, 2021 [Page 42] Internet-Draft Routing Policy Model June 2021 export-all-OSPF-prefixes-into-ISIS-level-2 term-0 ospf-internal-type isis-level-2 accept-route Authors' Addresses Yingzhen Qu Futurewei 2330 Central Expressway Santa Clara CA 95050 USA Email: yingzhen.qu@futurewei.com Jeff Tantsura Juniper Networks Email: jefftant.ietf@gmail.com Qu, et al. Expires December 9, 2021 [Page 43] Internet-Draft Routing Policy Model June 2021 Acee Lindem Cisco 301 Midenhall Way Cary, NC 27513 US Email: acee@cisco.com Xufeng Liu Volta Networks Email: xufeng.liu.ietf@gmail.com Qu, et al. Expires December 9, 2021 [Page 44]