]> Tongji University

4800 Cao'An Hwy Shanghai 201804 China jingxuan.n.zhang@gmail.com

Huawei Technologies

Divyashree Techno Park, Whitefield Bangalore Karnataka 560066 India dhruv.ietf@gmail.com

Sichuan University

No.24 South Section 1, Yihuan Road Chengdu Sichuan 610000 China kaigao@scu.edu.cn

Deutsche Telekom

Heinrich-Hertz-Strasse 3-7 Darmstadt 64295 Germany Roland.Schott@telekom.de

Huawei

101 Software Avenue, Yuhua District Nanjing Jiangsu 210012 China maqiufang1@huawei.com

Networks ALTO WG Automation, Service Provisioning, Control, Operation This document defines YANG data models for Operations, Administration, and Maintenance (OAM) & Management of Application-Layer Traffic Optimization (ALTO) Protocol. The operator can use these data models to set up an ALTO server, create, update and remove ALTO information resources, manage the access control, configure server discovery, and collect statistical data. Discussion Venues Discussion of this document takes place on the ALTO Working Group mailing list (alto@ietf.org), which is archived at . Source for this draft and an issue tracker can be found at .

Introduction This document defines a YANG data model for the Operations, Administration, and Maintenance (OAM) & Management of Application-Layer Traffic Optimization (ALTO) Protocol. The basic purpose of this YANG data model is discussed in Section 16 of . The operator can use the data model to set up the ALTO server, create, update and remove ALTO information resources, manage the access control, configure server discovery, and collect statistical data. This document only focuses on the common and implementation-agnostic data model for purposes including deploying an ALTO server/client, operating and managing a running ALTO server/client, functionality/capability configuration of ALTO services, and monitoring ALTO-related performance metrics. Any implementation-specific information is not in the scope of this document. illustrates more details about what is and is not in the scope. and define more concrete requirements for the data model. The basic structure of this YANG data model is guided by Section 16 of and . Although the scope of the YANG data model in this document mainly focuses on the support of the base ALTO protocol and the existing ALTO standard extensions (including , , , , , and {RFC9275}), the design will also be extensible for future standard extensions (e.g., ). The detailed design of the data model is illustrated by and . And some examples of how to extend this data model for the specific ALTO server implementations are shown in .

Requirements Language 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 when, and only when, they appear in all capitals, as shown here. When the words appear in lower case, they are to be interpreted with their natural language meanings.

Acronyms and Abbreviations This document uses the following acronyms:

OAM:

Operations, Administration, and Maintenance (Section 3 of )

O&M:

OAM and Management (Section 3 of )

Tree Diagrams The meaning of the symbols in the tree diagrams is defined in .

Prefixes in Data Node Names In this document, names of data nodes 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 . Prefixes and corresponding YANG modules

Prefix	YANG module	Reference
yang	ietf-yang-types
inet	ietf-inet-types
tcp	ietf-tcp-server
tls	ietf-tls-server
http	ietf-http-server

Placeholders in Reference Statements Note to the RFC Editor: This section is to be removed prior to publication. This document contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Please apply the following replacements:

• DDDD --> the assigned RFC number for
• FFFF --> the assigned RFC number for
• GGGG --> the assigned RFC number for
• HHHH --> the assigned RFC number for
• IIII --> the assigned RFC number for
• XXXX --> the assigned RFC number for this draft
• YYYY --> the assigned RFC number for

Design Scope and Requirements

Scope of Data Model for ALTO O&M The following items are in the scope of the data models specified in this document:

• Deploying an ALTO server/client.
• Operating and managing an ALTO server/client.
• Functionality/capability configuration of ALTO services.
• Monitoring ALTO-related performance metrics.

This document does not define any data model related to specific implementation, including:

• Data structures for how to store/deliver ALTO information resources (e.g., database schema to store a network map).
• Data structures for how to store information collected from data sources. (e.g., database schema to store topology collected from an Interface to the Routing System (I2RS) client )

Basic Requirements Based on discussions and recommendations in and , the data model provided by this document satisfies basic requirements listed in . Basic Requirements of Data Model for ALTO O&M.

Requirement	Reference
R1: The data model should support configuration for ALTO server setup.	Section 16.1 of
R2: The data model should provide logging management.	Section 16.2.1 of
R3: The data model should provide ALTO-related management information.	Section 16.2.2 of
R4: The data model should support configuration for security policy management.	Section 16.2.6 of
R5-1: The data model should support configuration for different data sources.	Section 16.2.4 of , Section 3.2 of
R5-2: The data model should support configuration for information resource generation algorithms.	Section 16.2.4 of
R5-3: The data model should support configuration for access control at information resource level.	Section 16.2.4 of
R6: The data model should provide metrics for server failures.	Section 16.2.3 of , Section 3.3 of
R7: The data model should provide performance monitoring for ALTO-specific metrics.	Section 16.2.5 of , Section 3.4 of

Additional Requirements for Extensibility R8: As the ALTO protocol is extensible, the data model for ALTO O&M should allow for augmentation to support potential future extensions.

Overview of ALTO O&M Data Model for Reference ALTO Architecture shows a reference architecture for the ALTO server implementation and YANG modules that these server components need to implement. The server manager, information resource manager and data source listeners need to implement ietf-alto.yang (see ). The performance monitor and logging and fault manager need to implement ietf-alto-stats.yang (see ). The data broker and algorithm plugins are not in the scope of the data models defined in this document. But user-specified YANG modules can be applied to different algorithm plugins by augmenting the data model defined in this document (see ).

A Reference ALTO Server Architecture and YANG Modules . Algorithm Plugin: . . Data Broker . read . example-ietf-alto-alg.yang . ............... .............................. ^ | write +----------------+ Southbound ++=============++ | Data Source | API || || | Listener: | <==========> || Data Source || | ietf-alto.yang | || || +----------------+ ++=============++ ]]>

Design of ALTO O&M Data Model

Overview of ALTO O&M Data Model The "ietf-alto" module defined in this document is designed to fit all the requirements listed in . As shown in , the top-level container 'alto' in the "ietf-alto" module contains a single 'alto-server' and a list of 'alto-client' that are uniquely identified. The list 'alto-client' defines a list of configurations for other applications to bootstrap an ALTO client. These data nodes can also be used by data sources and information resource creation algorithms that are configured by an ALTO server instance. The container 'alto-server' contains both configuration and operational data of an administrated ALTO server instance.

IETF ALTO Tree Structure /alto/alto-server/auth-client/client-id +--rw data-source* [source-id] | ... +--rw resource* [resource-id] ... ]]>

Data Model for ALTO Client Operation and Management As shown in , the 'alto-client' list contains a list of client-side configurations. 'server-discovery-client' is used to configure how an ALTO client discovers an ALTO server.

IETF ALTO Client Subtree Structure

Data Model for Server-level Operation and Management The ALTO server instance contains a set of data nodes server-level operation and management for ALTO that are shown in . This structure satisfies R1 - R4 in .

IETF ALTO Server Level Subtree Structure

Data Model for ALTO Server Setup To satisfy R1 in , the ALTO server instance contains the basic data nodes for the server setup that are detailed in the following subsections.

ALTO Server Listen Stack The 'listen' contains all the data nodes for the whole server listen stack across HTTP, TLS, and TCP layers ().

IETF ALTO Server Groupings Structure

ALTO Server Discovery Setup In practice, multiple ALTO servers can be deployed for scalability. That may require communication among different ALTO servers. The "ietf-alto" module does not contain any configuration for the communication between peer ALTO servers. Instead, it provides the configuration for how an ALTO server can be discovered by another ALTO server on demand ().

IETF ALTO Server Discovery Grouping Structure /alto-server/data-source/source-id ]]>

The 'server-discovery' node provides configuration for the discovery of ALTO servers using a variety of mechanisms. The initial version of the "ietf-alto" module only defines the 'reverse-dns' case that is used to configure DNS NAPTR records for ALTO server discovery, which is sugested by and . It configures a set of endpoints that can be served by this ALTO server. The node contains two leaf lists. The 'static' list contains a list of manually configured endpoints. The dynamic list points to a list of data sources to retrieve the endpoints dynamically. As suggested by and , the IP prefixes of the endpoints configured by both static and dynamic lists will be translated into DNS NAPTR resource records for server discovery. The server-discovery-manner choice can be augmented by the future modules to support other mechanisms.

Data Model for Logging Management To satisfy R2 in , the ALTO server instance contains the the logging data nodes shonw in . The 'logging-system' data node provides configuration to select a logging system to capture log messages generated by an ALTO server. By default, 'syslog' is the only supported logging system. When selecting 'syslog', the related configuration is delegated to the configuration file of the syslog server.

IETF ALTO Logging System Grouping Structure

A specific server implementation can extend the logging-system node to add other logging systems.

Data Model for ALTO-related Management To satisfy R3 in , the data model contains the following ALTO-related management information ():

• The 'cost-type' list is the registry for the cost types that can be used in the ALTO server.
• The 'meta' list contains the customized meta data of the ALTO server. It is populated into the meta field of the default Information Resource Directory (IRD).

Data Model for Security Management To satisfy R4 in , the data model leverages HTTP and TLS to provide basic security management for an ALTO server. All the related configurations are covered by the server listen stack.

Data Model for ALTO Server Configuration Management

Data Source Configuration Management To satisfy R5-1 in , the ALTO server instance contains a list of 'data-source' entries to subscribe the data sources from which ALTO information resources are derived (Section 16.2.4 of ).

IETF ALTO Server Data Source Subtree Structure

As shown in , a 'data-source' list entry includes:

• A unique `source-id' for resource creation algorithms to reference.
• The 'source-type' attribute to declare the type of the data source.
• The 'update-policy' to specify how to get the data update from the data source.
• The 'source-params' to specify where and how to query the data.

The update policy can be either reactive or proactive. For the reactive update, the ALTO server reactively waits the data source for pushing updates. For the proactive update, the ALTO server has to proactively fetch the data source periodically. To use the reactive update, two publish modes are supported:

• If the 'on-change' attribute is present, the data source is expected to push the update as soon as the data source changes.
• Otherwise, if the 'feed-interval' attribute is present, the data source is expected to push the updates periodically. The value of 'feed-interval' specifies the interval of pushing the data change updates in milliseconds. If 'feed-interval' is zero, the data source is expected to work in the 'on-change' mode.

To use the proactive update, the poll-interval attribute MUST be present. The value of poll-interval specifies the interval of fetching the data in milliseconds. If poll-interval is zero, the ALTO server will not fetch the data source. The data-source/source-params node can be augmented for different types of data sources. This data model only includes common configuration parameters for an ALTO server to correctly interact with a data source. The implementation-specific parameters of any certain data source can be augmented in another module. An example is included in .

ALTO Information Resources Configuration Management To satisfy R5-2 and R-3, the ALTO server instance contains a list of 'resource' entries (). Each resource entry contains the configurations of an ALTO information resource (See Section 8.1 of ). The operator of the ALTO server can use this model to create, update, and remove the ALTO information resources. Each resource entry provides configurations defining how to create or update an ALTO information resource. Adding a new resource entry notifies the ALTO server to create a new ALTO information resource. Updating an existing resource entry notifies the ALTO server to update the generation parameters (e.g., capabilities and the creation algorithm) of an existing ALTO information resource. Removing an existing resource entry will remove the corresponding ALTO information resource.

IETF ALTO Resource Subtree Structure /alto/alto-server/role/role-name +--rw dependency* | -> /alto/alto-server/resource/resource-id +--rw (resource-params)? +--:(ird) | +--rw alto-ird-params | +--rw delegation inet:uri +--:(networkmap) | +--rw alto-networkmap-params | +--rw is-default? boolean | +--rw filtered? boolean | +---u algorithm +--:(costmap) | +--rw alto-costmap-params | +--rw filtered? boolean | +---u filter-costmap-cap | +---u algorithm +--:(endpointcost) | +--rw alto-endpointcost-params | +---u endpoint-cost-cap | +---u algorithm +--:(endpointprop) | +--rw alto-endpointprop-params | +--rw prop-types* string | +---u algorithm +--:(propmap) {propmap}? | +--rw alto-propmap-params | +---u algorithm +--:(cdni) {cdni}? | +--rw alto-cdni-params | +---u algorithm +--:(update) {incr-update}? +--rw alto-update-params +---u algorithm grouping filter-costmap-cap: +-- cost-type-names* string +-- cost-constraints? boolean +-- max-cost-types? uint32 {multi-cost}? +-- testable-cost-type-names* string {multi-cost}? +-- calendar-attributes {cost-calendar}? +-- cost-type-names* string +-- time-interval-size decimal64 +-- number-of-intervals uint32 grouping endpoint-cost-cap: +---u filter-costmap-cap grouping algorithm: +-- (algorithm) ]]>

A 'resource' list entry MUST include a unique 'resource-id' and a 'resource-type'. It may also include an accepted-role node containing a list of role-names that is used by role-based access control for this ALTO information resource. See for details of information resource access control. For some resource-type, the resource entry may also include a dependency node containing the resource-id of the dependent ALTO information resources (Section 9.1.5 of ). For each type of ALTO information resource, the resource entry may also need type-specific parameters. These type-specific parameters include two categories:

1. One category of the type-specific parameters is common for the same type of ALTO information resource. They declare the Capabilities of the ALTO information resource (Section 9.1.3 of ).
2. The other category of the type-specific parameters is algorithm-specific. The developer of the ALTO server can implement their own creation algorithms and augment the algorithm node to declare algorithm-specific input parameters.

Except for the ird resource, all the other types of resource entries have an augmented algorithm node. The augmented algorithm node can reference data sources subscribed by the data-source entries (See ). An example of extending the algorithm node for a specific type of resource is included in . The developer does not have to customize the creation algorithm of the ird resource. The default ird resource will be created automatically based on all the added resource entries. The delegated ird resource will be created as a static ALTO information resource (Section 9.2.4 of ).

ALTO Information Resource Access Control Management As per Section 15.5.2 of , the "ietf-alto" module also defines authentication and authorization related configuration to employ access control at the information resource level. The ALTO server returns the IRD to the ALTO client based on its authentication information. The information resource access control is supported using the structure shown in .

IETF ALTO Client Authentication Subtree Structure /alto/alto-server/auth-client/client-id ... ]]>

The above structure can be used to configure the role-based access control:

• auth-client declares a list of ALTO clients that can be authenticated by the internal or external authorization server. This basic model only includes authentication approach directly provided by the HTTP server, but the operators or future documents can augment the authentication choice for different authentication mechanisms.
• role defines a list of roles for access control. Each role contains a list of authenticated ALTO clients. Each client can be assigned to multiple roles. The role-name can be referenced by the accepted-role list of a resource. For a given authenticated ALTO client, if one of the roles containing it is allowed to access a resource, this client is allowed to access the resource.

Design of ALTO O&M Statistics Data Model The "ietf-alto-stats" module augments the "ietf-alto" module to include statistics at the ALTO server and information resource level ().

IETF ALTO Statistics Structure

Model for ALTO Server Failure Monitoring To satisfy R6 in , the "ietf-alto-stats" module contains statistics that indicates server failures (). More specifically, num-total-* and num-total-last-* provides server-level failure counters; num-res-* provides information resource-level failure counters.

Model for ALTO-specific Performance Monitoring To satisfy R7 in ,the "ietf-alto-stats" module also contains statistics for ALTO-specific performance metrics (). More specifically, this data model contains the following measurement information of "system and service performance" suggested by and :

• Requests and responses for each information resource
• CPU and memory utilization
• ALTO map updates
• Number of PIDs
• ALTO map sizes

Besides the above measurement information suggested by and , the "ietf-alto-stats" module also contains useful measurement information for other ALTO extensions:

• num-map-entry and num-base-obj provides measurement for number of generic ALTO entities (for and )
• num-upd-sess and num-event-* provides statistics for update sessions and events (for )

The "ietf-alto-stats" module only focuses on the performance metrics that can be directly measured at the ALTO server. The following metrics for "measurement of the impact" suggested by are not contained in this data model:

• Total amount and distribution of traffic
• Application performance

ALTO OAM YANG Modules

The "ietf-alto" YANG Module WG List: "; description "This YANG module defines all the configured and operational parameters of the administrated ALTO server instance. Copyright (c) 2023 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 Revised 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 (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices."; revision 2023-02-23 { description "Initial Version."; reference "RFC XXXX: YANG Data Models for the Application-Layer Traffic Optimization (ALTO) Protocol"; } // Features feature http-listen { description "The 'http-listen' feature is only used for test deployment. This feature shouldn't be used in the production deployment."; reference "Section 8.3.5 of RFC 7285"; } feature xdom-disc { description "Indicates support of cross-domain server discovery."; reference "RFC 8686: Application-Layer Traffic Optimization (ALTO) Cross-Domain Server Discovery"; } feature multi-cost { description "Indicates support of multi-cost extension."; reference "RFC 8189: Multi-Cost Application-Layer Traffic Optimization (ALTO)"; } feature incr-update { description "Indicates support of incremental update extension."; reference "RFC 8895: Application-Layer Traffic Optimization (ALTO) Incremental Updates Using Server-Sent Events (SSE)"; } feature cost-calendar { description "Indicates support of cost calendar extension."; reference "RFC 8896: Application-Layer Traffic Optimization (ALTO) Cost Calendar"; } feature propmap { description "Indicates support of entity property map extension."; reference "RFC 9240: An ALTO Extension: Entity Property Maps"; } feature cdni { description "Indicates support of CDNi extension."; reference "RFC 9241: Content Delivery Network Interconnection (CDNI) Request Routing: CDNI Footprint and Capabilities Advertisement using ALTO"; } feature path-vector { description "Indicates support of path vector extension."; reference "RFC 9275: An Extension for Application-Layer Traffic Optimization (ALTO): Path Vector"; } feature performance-metrics { description "Indicates support of performance metrics extension."; reference "RFC YYYY: ALTO Performance Cost Metrics"; } // Base identities identity resource-type { description "Base identity for type of information resource."; reference "Section 8.1 of RFC 7285"; } identity source-type { description "Base identity for type of data source. A data source indicates the origin from which the ALTO information resources is derived."; } identity cost-metric { description "The cost metric indicates what the cost represents."; reference "Section 6.1.1 of RFC 7285"; } identity cost-mode { description "The cost mode indicates how costs should be interpreted. Specifically, the cost mode attribute indicates whether indicated costs should be interpreted as numerical values or ordinal rankings."; reference "Section 6.1.2 of RFC 7285"; } identity cost-source { description "Theh cost source indicates the high-level type of the data source."; reference "Section 3.1 of RFC YYYY"; } // Identities for ALTO information resources identity ird { base resource-type; description "Identity for information resource directory."; } identity network-map { base resource-type; description "Identity for network map."; reference "Section 5 of RFC 7285"; } identity cost-map { base resource-type; description "Identity for cost map."; reference "Section 6 of RFC 7285"; } identity endpoint-cost { base resource-type; description "Identity for endpoint cost service."; reference "Section 11.5.1 of RFC 7285"; } identity endpoint-prop { base resource-type; description "Identity for endpoint property service."; } identity property-map { base resource-type; description "Identity for property map."; } identity cdni { base resource-type; description "Identity for Content Delivery Network Interconnection (CDNI) advertisement service."; } identity update { base resource-type; description "Identity for update stream service."; } // Identities for cost mode identity numerical { base cost-mode; description "This mode indicates that it is safe to perform numerical operations"; } identity ordinal { base cost-mode; description "This mode indicates that the cost values in a cost map represent ranking"; } identity array { if-feature "path-vector"; base cost-mode; description "This mode indicates that every cost value in the response body of a (Filtered) Cost Map or an Endpoint Cost Service is interpreted as a JSON array."; } // Identities for cost metrics identity routingcost { base cost-metric; description "This metric conveys a generic measure for the cost of routing traffic from a source to a destination."; } identity ane-path { if-feature "path-vector"; base cost-metric; description "This metric indicates that the value of such a cost type conveys an array of Abstract Network Element (ANE) names, where each ANE name uniquely represents an ANE traversed by traffic from a source to a destination."; } identity delay-ow { if-feature "performance-metrics"; base cost-metric; description "Section 4.1 of RFC YYYY"; } identity delay-rt { if-feature "performance-metrics"; base cost-metric; description "Section 4.2 of RFC YYYY"; } identity delay-variation { if-feature "performance-metrics"; base cost-metric; description "Section 4.3 of RFC YYYY"; } identity lossrate { if-feature "performance-metrics"; base cost-metric; description "Section 4.4 of RFC YYYY"; } identity hopcount { if-feature "performance-metrics"; base cost-metric; description "Section 4.5 of RFC YYYY"; } identity tput { if-feature "performance-metrics"; base cost-metric; description "Section 5.1 of RFC YYYY"; } identity bw-residual { if-feature "performance-metrics"; base cost-metric; description "Section 5.2 of RFC YYYY"; } identity bw-available { if-feature "performance-metrics"; base cost-metric; description "Section 5.3 of RFC YYYY"; } // Identities for cost sources identity nominal { if-feature "performance-metrics"; base cost-source; description "The 'nominal' category indicates that the metric value is statically configured by the underlying devices."; reference "Section 3.1 of RFC YYYY"; } identity sla { if-feature "performance-metrics"; base cost-source; description "The 'sla' category indicates that the metric value is derived from some commitment which this document refers to as service-level agreement (SLA)."; reference "Section 3.1 of RFC YYYY"; } identity estimation { if-feature "performance-metrics"; base cost-source; description "The 'estimation' category indicates that the metric value is computed through an estimation process."; reference "Section 3.1 of RFC YYYY"; } typedef resource-id { type string { length "1..64"; pattern '[0-9a-zA-Z\-:@_]*'; } description "Format of Resource ID"; reference "Section 9.1.1 of RFC 7285"; } typedef role-name { type string; description "Name of a role for role-based access control."; } // Groupings grouping filter-costmap-cap { description "This grouping defines a data model for FilteredCostMapCapabilities."; reference "Section 11.3.2.4 of RFC 7285"; leaf-list cost-type-names { type string; min-elements 1; description "Supported cost types."; } leaf cost-constraints { type boolean; default false; description "If set to true, then the ALTO server allows cost constraints to be included in requests to the corresponding URI."; } leaf max-cost-types { if-feature "multi-cost"; type uint32; default "0"; description "If present with value N greater than 0, this resource understands the multi-cost extensions and can return a multi-cost map with any combination of N or fewer cost types in the 'cost-type-names' list."; } leaf-list testable-cost-type-names { if-feature "multi-cost"; type string; description "If present, the resource allows constraint tests, but only on the cost type names in this array."; } container calendar-attributes { if-feature "cost-calendar"; description "Configuration for CalendarAttributes."; reference "Section 4.1 of RFC 8896"; leaf-list cost-type-names { type string; min-elements 1; description "An array of one or more elements indicating the cost type names in the IRD entry to which the values of 'time-interval-size' and 'number-of-intervals' apply."; } leaf time-interval-size { type decimal64 { fraction-digits 4; } units "seconds"; mandatory true; description "The duration of an ALTO Calendar time interval."; } leaf number-of-intervals { type uint32 { range "1..max"; } mandatory true; description "A strictly positive integer (greater or equal to 1) that indicates the number of values of the Cost Calendar array."; } } } grouping endpoint-cost-cap { description "This grouping defines EndpointCostCapabilities as the same as FilteredCostMapCapabilities defined by the grouping filter-costmap-cap."; reference "Section 11.5.1.4 of RFC 7285"; uses filter-costmap-cap; } grouping algorithm { description "This grouping defines the base data model for information resource creation algorithm."; choice algorithm { mandatory true; description "Information resource creation algorithm to be augmented."; } } grouping alto-server-grouping { description "A reuseable grouping for configuring an ALTO server without any consideration for how underlying transport sessions are established."; leaf base-uri { type inet:uri; description "The base URI for the ALTO server."; } } grouping alto-server-listen-stack-grouping { description "A reuseable grouping for configuring an ALTO server 'listen' protocol stack for a single connection."; choice transport { mandatory true; description "Selects between available transports."; case http { if-feature "http-listen"; container http { description "Configures ALTO server stack assuming that TLS-termination is handled externally."; container tcp-server-parameters { description "A wrapper around the TCP server parameters to avoid name collisions."; uses tcp:tcp-server-grouping { refine "local-port" { default "80"; description "The RESTCONF server will listen on the IANA- assigned well-known port value for 'http' (80) if no value is specified."; } } } container http-server-parameters { description "A wrapper around the HTTP server parameters to avoid name collisions."; uses http:http-server-grouping; } container alto-server-parameters { description "A wrapper around the ALTO server parameters to avoid name collisiions."; uses alto-server-grouping; } } } case https { container https { description "Configures ALTO server stack assuming that TLS-termination is handled internally."; container tcp-server-parameters { description "A wrapper around the TCP server parameters to avoid name collisions."; uses tcp:tcp-server-grouping { refine "local-port" { default "443"; description "The ALTO server will listen on the IANA- assigned well-known port value for 'https' (443) if no value is specified."; } } } container tls-server-parameters { description "A wrapper around the TLS server parameters to avoid name collisions."; uses tls:tls-server-grouping; } container http-server-parameters { description "A wrapper around the HTTP server parameters to avoid name collisions."; uses http:http-server-grouping; } container alto-server-parameters { description "A wrapper around the ALTO server parameters to avoid name collisions."; uses alto-server-grouping; } } } } } grouping alto-server-discovery-grouping { description "Grouping for the configuration of how to set up server discovery for clients or other ALTO servers to discovery the URI of this ALTO server."; choice server-discovery-manner { description "Selects among available server discovery manners."; case reverse-dns { if-feature "xdom-disc"; description "Configure DNS NAPTR records for cross-domain ALTO server discovery using reverse DNS lookup."; reference "RFC 8686: Application-Layer Traffic Optimization (ALTO) Cross-Domain Server Discovery."; container rdns-naptr-records { description "Configuration parameters for DNS NAPTR records."; leaf-list static-prefix { type inet:ip-prefix; description "Specifies a list of static IP prefixes."; } leaf-list dynamic-prefix-source { type leafref { path "/alto:alto/alto:alto-server/alto:data-source" + "/alto:source-id"; } description "Dynamic IP prefixes collected from data sources."; } } } } } grouping alto-server-discovery-client-grouping { description "Grouping for configuration of how a client can discover another ALTO server."; choice server-discovery-client-manner { description "Selects among available server discovery manners."; case reverse-dns { if-feature "xdom-disc"; description "Use reverse DNS lookup to discover an ALTO server."; reference "RFC 8686: Application-Layer Traffic Optimization (ALTO) Cross-Domain Server Discovery."; container rdns-params { description "Configuration for reverse DNS lookups."; leaf-list dns-server { type inet:host; description "DNS server list for reverse DNS lookup."; } } } } } grouping alto-logging-system-grouping { description "Grouping for configuration of logging system used by the ALTO server."; choice logging-system { description "Selects among available logging systems."; case syslog { description "Specifies syslog as the logging system."; container syslog-params { description "Configuration parameters for syslog."; leaf config-file { type inet:uri { pattern 'file:.*'; } default "file:/etc/syslog.conf"; description "The file location of the syslog configuration."; } } } } } // Top-level container container alto { presence "The ALTO service is enabled"; description "Indicates a set of parameters for both ALTO clients and servers."; list alto-client { key "client-id"; description "The ALTO client configuration."; leaf client-id { type string; description "A unique identifier of a client that can be referenced by a data source or a resource creation algorithm to communicate with other ALTO servers."; } container server-discovery-client { description "Configuration of how to discover an ALTO server."; uses alto-server-discovery-client-grouping; } } container alto-server { description "The ALTO server instance configuration."; container listen { description "Configure the ALTO server to listen for ALTO clients."; uses alto-server-listen-stack-grouping; } container server-discovery { description "Configure how the ALTO server to be discovered by others."; uses alto-server-discovery-grouping; } container logging-system { description "Configure logging system to capture log messages generated by the ALTO server."; uses alto-logging-system-grouping; } list cost-type { key "cost-type-name"; description "Mapping between name and referenced cost type."; leaf cost-type-name { type string; description "The name to reference a cost type."; } leaf cost-mode { type identityref { base cost-mode; } mandatory true; description "The referenced cost mode."; } leaf cost-metric { type identityref { base cost-metric; } mandatory true; description "The referenced cost metric."; } leaf description { type string; description "A human-readable description fo the 'cost-mode' and 'cost-metric'."; } container cost-context { if-feature "performance-metrics"; description "Context of how the metric is obtained."; leaf cost-source { type identityref { base cost-source; } mandatory true; description "The referenced cost source."; } container parameters { description "Additional computation parameters for the cost source."; choice parameters { description "Cases of parameters to be augmented."; } } } } list meta { key "meta-key"; description "Mapping of custom meta information"; reference "Section 8.4.1 of RFC 7285."; leaf meta-key { type string; description "Custom meta key"; } leaf meta-value { type string; mandatory true; description "Custom meta value"; } } list auth-client { key "client-id"; description "List of authenticated ALTO clients."; leaf client-id { type string; description "Identifier to reference an ALTO client."; } choice authentication { description "Choice of authentication methods to identify this ALTO client."; case http { description "The client is authenticated by the HTTP server."; container http-auth-client { if-feature "http-listen"; if-feature "http:client-auth-supported"; if-feature "http:local-users-supported"; description "Parameters of the authenticated HTTP client."; leaf user-id { type leafref { path "/alto:alto/alto:alto-server/alto:listen" + "/alto:http/alto:http-server-parameters" + "/alto:client-authentication/alto:users" + "/alto:user/alto:user-id"; } mandatory true; description "Reference of the user-id for the authenticated client."; } } } case https { description "The client is authenticated by the HTTP server."; container https-auth-client { if-feature "http:client-auth-supported"; if-feature "http:local-users-supported"; description "Parameters of the authenticated HTTPS client."; leaf user-id { type leafref { path "/alto:alto/alto:alto-server/alto:listen" + "/alto:https/alto:http-server-parameters" + "/alto:client-authentication/alto:users" + "/alto:user/alto:user-id"; } mandatory true; description "Reference of the user-id for the authenticated client."; } } } } } list role { key "role-name"; description "List of roles for access control."; leaf role-name { type role-name; description "Name of a role for access control."; } leaf-list client { type leafref { path "/alto:alto/alto:alto-server/alto:auth-client" + "/alto:client-id"; } description "List of authenticated ALTO clients assigned to the role."; } } list data-source { key "source-id"; description "List of subscribed data sources."; leaf source-id { type string; description "Data source id that can be referenced by information resource creation algorithms."; } leaf source-type { type identityref { base source-type; } mandatory true; description "Identify the type of the data source."; } choice update-policy { mandatory true; description "Policy to get updates from data sources."; case reactive { description "Configuration for the data source listener to reactively subscribe data and wait for updates published by the data source."; choice publish-mode { description "Configuration for when the data source publish an update."; case on-change { description "The data source is requested to publish an update once the data has a change."; leaf on-change { type empty; mandatory true; description "Indicate an on-change subscription."; } } case periodic { description "The data source is requested to periodically publish an update."; leaf feed-interval { type uint32; mandatory true; description "Duration of time that should occur between periodic push updates, in units of seconds."; } } } } case proactive { description "Configuration for the data source listener to proactively pull data from the data source."; leaf poll-interval { type uint32; mandatory true; description "Polling interval in seconds for proactive mode."; } } } choice source-params { description "Data source specific configuration."; } } list resource { key "resource-id"; description "ALTO information resources to be defined"; leaf resource-id { type resource-id; description "resource-id to be defined."; } leaf resource-type { type identityref { base resource-type; } mandatory true; description "identityref to be defined."; } leaf description { type string; description "The optional description for this information resource."; } leaf-list accepted-role { type leafref { path "/alto:alto/alto:alto-server/alto:role" + "/alto:role-name"; } description "Roles allowed to access this information resource."; } leaf-list dependency { type leafref { path "/alto:alto/alto:alto-server/alto:resource" + "/alto:resource-id"; } description "A list of dependent information resources."; } choice resource-params { description "Resource-specific configuration."; case ird { when 'derived-from-or-self(resource-type, "alto:ird")'; container alto-ird-params { description "IRD-specific configuration."; leaf delegation { type inet:uri; mandatory true; description "Upstream IRD to be delegated."; } } } case networkmap { when 'derived-from-or-self(resource-type,' + '"alto:network-map")'; container alto-networkmap-params { description "(Filtered) Network Map specific configuration."; reference "Section 11.2.1 and Section 11.3.1 of RFC 7285."; leaf is-default { type boolean; description "Set whether this is the default network map."; } leaf filtered { type boolean; default false; description "Configure whether filtered network map is supported."; } uses algorithm; } } case costmap { when 'derived-from-or-self(resource-type,' + '"alto:cost-map")'; container alto-costmap-params { description "(Filtered) Cost Map specific configuration."; reference "Sections 11.2.2 and 11.3.2 of RFC 7285."; leaf filtered { type boolean; description "Configure whether filtered cost map is supported."; } uses filter-costmap-cap; uses algorithm; } } case endpointcost { when 'derived-from-or-self(resource-type,' + '"alto:endpoint-cost")'; container alto-endpointcost-params { description "Endpoint Cost Service specific configuration."; reference "Section 11.5 of RFC 7285"; uses endpoint-cost-cap; uses algorithm; } } case endpointprop { when 'derived-from-or-self(resource-type,' + '"alto:endpoint-prop")'; container alto-endpointprop-params { description "Endpoint Cost Service specific configuration."; reference "Section 11.5 of RFC 7285"; leaf-list prop-types { type string; min-elements 1; description "Supported endpoint properties."; } uses algorithm; } } case propmap { when 'derived-from-or-self(resource-type,' + '"alto:property-map")'; if-feature "propmap"; container alto-propmap-params { description "(Filtered) Entity Property Map specific configuration."; uses algorithm; } } case cdni { when 'derived-from-or-self(resource-type, "alto:cdni")'; if-feature "cdni"; container alto-cdni-params { description "CDNi specific configuration."; uses algorithm; } } case update { when 'derived-from-or-self(resource-type,' + '"alto:update")'; if-feature "incr-update"; container alto-update-params { description "Incremental Updates specific configuration."; uses algorithm; } } } } } } } ]]>

The "ietf-alto-stats" YANG Module WG List: "; description "This YANG module defines a set of statistics of an ALTO server instance. Copyright (c) 2023 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 Revised 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 (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices."; revision 2023-02-23 { description "Initial Version."; reference "RFC XXXX: A YANG Data Model for Operations, Administration, and Maintenance of ALTO Protocol."; } augment "/alto:alto/alto:alto-server" { description "Top-level statistics for the whole ALTO server."; leaf num-total-req { type yang:counter64; config false; description "The total number of ALTO requests received by the ALTO server."; } leaf num-total-succ { type yang:counter64; config false; description "The total number of successful responses sent by the ALTO server."; } leaf num-total-fail { type yang:counter64; config false; description "The total number of failed responses sent by the ALTO server."; } leaf num-total-last-req { type yang:counter64; config false; description "The total number of ALTO requests received by the server within the last 5 minutes."; } leaf num-total-last-succ { type yang:counter64; config false; description "The total number of successful responses sent by the ALTO server within the last 5 minutes."; } leaf num-total-last-fail { type yang:counter64; config false; description "The total number of failed responses sent by the ALTO server within the last 5 minutes."; } } augment "/alto:alto/alto:alto-server/alto:resource" { description "Common statistics for each information resource."; leaf num-res-upd { type yang:counter64; config false; description "The number of version updates since the information resource was created."; } leaf res-mem-size { type yang:counter64; units "bytes"; config false; description "Memory size utilized by the information resource."; } leaf res-enc-size { type yang:counter64; units "bytes"; config false; description "Size of JSON encoded data of the information resource."; } leaf num-res-req { type yang:counter64; config false; description "The number of ALTO requests to this information resource."; } leaf num-res-succ { type yang:counter64; config false; description "The number of successful responses for requests to this information resource."; } leaf num-res-fail { type yang:counter64; config false; description "The total number of failed responses for requests to this information resource."; } } augment "/alto:alto/alto:alto-server/alto:resource" + "/alto:resource-params/alto:networkmap" + "/alto:alto-networkmap-params" { description "Augmented statistics for network maps only."; leaf num-map-pid { type yang:counter64; config false; description "Number of PIDs contained by the network map."; } } augment "/alto:alto/alto:alto-server/alto:resource" + "/alto:resource-params/alto:propmap" + "/alto:alto-propmap-params" { description "Augmented statistics for property maps only."; leaf num-map-entry { type yang:counter64; config false; description "Number of ALTO entities contained by the property map."; } } augment "/alto:alto/alto:alto-server/alto:resource" + "/alto:resource-params/alto:cdni" + "/alto:alto-cdni-params" { description "Augmented statistics for CDNi resources only."; leaf num-base-obj { type yang:counter64; config false; description "Number of base CDNi advertisement objects contained by the CDNi resource."; } } augment "/alto:alto/alto:alto-server/alto:resource" + "/alto:resource-params/alto:update" + "/alto:alto-update-params" { description "Augmented statistics for incremental updates only."; leaf num-upd-sess { type yang:counter64; config false; description "Number of sessions connected to the incremental update service."; } leaf num-event-total { type yang:counter64; config false; description "Total number of update events sent to all the connected clients."; } leaf num-event-max { type yang:counter64; config false; description "The maximum number of update events sent to the connected clients."; } leaf num-event-min { type yang:counter64; config false; description "The minimum number of update events sent to the connected clients."; } leaf num-event-avg { type yang:gauge64; config false; description "The average number of update events sent by the ALTO server to the connected clients."; } } } ]]>

Security Considerations The "ietf-alto" and "ietf-alto-stats" YANG modules define data nodes that are designed to be accessed via YANG based management protocols, such as NETCONF and RESTCONF . Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication. The Network Access Control Model (NACM) provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. None of the readable data nodes in these YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in these module. None of the writable data nodes in these YANG modules are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in these modules. These modules use groupings defined in other RFCs that define data nodes that do set the NACM "default-deny-all" and "default-deny-write" extensions.

IANA Considerations This document registers the following URIs in the "IETF XML Registry" : This document registers the following two YANG modules in the "YANG Module Names" registry :

References Normative References In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. Applications using the Internet already have access to some topology information of Internet Service Provider (ISP) networks. For example, views to Internet routing tables at Looking Glass servers are available and can be practically downloaded to many network application clients. What is missing is knowledge of the underlying network topologies from the point of view of ISPs. In other words, what an ISP prefers in terms of traffic optimization -- and a way to distribute it. The Application-Layer Traffic Optimization (ALTO) services defined in this document provide network information (e.g., basic network location structure and preferences of network paths) with the goal of modifying network resource consumption patterns while maintaining or improving application performance. The basic information of ALTO is based on abstract maps of a network. These maps provide a simplified view, yet enough information about a network for applications to effectively utilize them. Additional services are built on top of the maps. This document describes a protocol implementing the ALTO services. Although the ALTO services would primarily be provided by ISPs, other entities, such as content service providers, could also provide ALTO services. Applications that could use the ALTO services are those that have a choice to which end points to connect. Examples of such applications are peer-to-peer (P2P) and content delivery networks. The goal of Application-Layer Traffic Optimization (ALTO) is to provide guidance to applications that have to select one or several hosts from a set of candidates capable of providing a desired resource. ALTO is realized by a client-server protocol. Before an ALTO client can ask for guidance, it needs to discover one or more ALTO servers. This document specifies a procedure for resource-consumer-initiated ALTO server discovery, which can be used if the ALTO client is embedded in the resource consumer. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document describes the key chain YANG data model. Key chains are commonly used for routing protocol authentication and other applications requiring symmetric keys. A key chain is a list containing one or more elements containing a Key ID, key string, send/accept lifetimes, and the associated authentication or encryption algorithm. By properly overlapping the send and accept lifetimes of multiple key chain elements, key strings and algorithms may be gracefully updated. By representing them in a YANG data model, key distribution can be automated. The Application-Layer Traffic Optimization (ALTO) protocol, specified in RFC 7285, defines several services that return various metrics describing the costs between network endpoints. This document defines a new service that allows an ALTO Client to retrieve several cost metrics in a single request for an ALTO filtered cost map and endpoint cost map. In addition, it extends the constraints to further filter those maps by allowing an ALTO Client to specify a logical combination of tests on several cost metrics. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. The goal of Application-Layer Traffic Optimization (ALTO) is to provide guidance to applications that have to select one or several hosts from a set of candidates capable of providing a desired resource. ALTO is realized by a client-server protocol. Before an ALTO client can ask for guidance, it needs to discover one or more ALTO servers that can provide suitable guidance. In some deployment scenarios, in particular if the information about the network topology is partitioned and distributed over several ALTO servers, it may be necessary to discover an ALTO server outside of the ALTO client's own network domain, in order to get appropriate guidance. This document details applicable scenarios, itemizes requirements, and specifies a procedure for ALTO cross-domain server discovery. Technically, the procedure specified in this document takes one IP address or prefix and a U-NAPTR Service Parameter (typically, "ALTO:https") as parameters. It performs DNS lookups (for NAPTR resource records in the "in-addr.arpa." or "ip6.arpa." trees) and returns one or more URIs of information resources related to that IP address or prefix. The Application-Layer Traffic Optimization (ALTO) protocol (RFC 7285) provides network-related information, called network information resources, to client applications so that clients can make informed decisions in utilizing network resources. This document presents a mechanism to allow an ALTO server to push updates to ALTO clients to achieve two benefits: (1) updates can be incremental, in that if only a small section of an information resource changes, the ALTO server can send just the changes and (2) updates can be immediate, in that the ALTO server can send updates as soon as they are available. This document is an extension to the base Application-Layer Traffic Optimization (ALTO) protocol. It extends the ALTO cost information service so that applications decide not only 'where' to connect but also 'when'. This is useful for applications that need to perform bulk data transfer and would like to schedule these transfers during an off-peak hour, for example. This extension introduces the ALTO Cost Calendar with which an ALTO Server exposes ALTO cost values in JSON arrays where each value corresponds to a given time interval. The time intervals, as well as other Calendar attributes, are specified in the Information Resources Directory and ALTO Server responses. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. Watsen Networks Hochschule Esslingen - University of Applied Sciences This document defines three YANG 1.1 modules to support the configuration of TCP clients and TCP servers. The modules include basic parameters of a TCP connection relevant for client or server applications, as well as client configuration required for traversing proxies. The modules can be used either standalone or in conjunction with configuration of other stack protocol layers. Watsen Networks This document defines three YANG 1.1 modules: the first defines features and groupings common to both TLS clients and TLS servers, the second defines a grouping for a generic TLS client, and the third defines a grouping for a generic TLS server. Editorial Note (To be removed by RFC Editor) This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements: * AAAA --> the assigned RFC value for draft-ietf-netconf-crypto- types * BBBB --> the assigned RFC value for draft-ietf-netconf-trust- anchors * CCCC --> the assigned RFC value for draft-ietf-netconf-keystore * DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client- server * FFFF --> the assigned RFC value for this draft Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: * 2022-12-12 --> the publication date of this draft The "Relation to other RFCs" section Section 1.1 contains the text "one or more YANG modules" and, later, "modules". This text is sourced from a file in a context where it is unknown how many modules a draft defines. The text is not wrong as is, but it may be improved by stating more directly how many modules are defined. The "Relation to other RFCs" section Section 1.1 contains a self- reference to this draft, along with a corresponding Informative Reference in the Appendix. The following Appendix section is to be removed prior to publication: * Appendix B. Change Log Watsen Networks This document defines two YANG modules: the first defines a minimal grouping for configuring an HTTP client, and the second defines a minimal grouping for configuring an HTTP server. It is intended that these groupings will be used to help define the configuration for simple HTTP-based protocols (not for complete web servers or browsers). Editorial Note (To be removed by RFC Editor) This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements (note: not all may be present): * AAAA --> the assigned RFC value for draft-ietf-netconf-crypto- types * DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client- server * FFFF --> the assigned RFC value for draft-ietf-netconf-tls-client- server * GGGG --> the assigned RFC value for this draft Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: * 2022-12-12 --> the publication date of this draft The "Relation to other RFCs" section Section 1.1 contains the text "one or more YANG modules" and, later, "modules". This text is sourced from a file in a context where it is unknown how many modules a draft defines. The text is not wrong as is, but it may be improved by stating more directly how many modules are defined. The "Relation to other RFCs" section Section 1.1 contains a self- reference to this draft, along with a corresponding Informative Reference in the Appendix. The following Appendix section is to be removed prior to publication: * Appendix A. Change Log Watsen Networks This document defines two YANG modules, one module to configure a NETCONF client and the other module to configure a NETCONF server. Both modules support both the SSH and TLS transport protocols, and support both standard NETCONF and NETCONF Call Home connections. Editorial Note (To be removed by RFC Editor) This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements (note: not all may be present): * AAAA --> the assigned RFC value for draft-ietf-netconf-crypto- types * BBBB --> the assigned RFC value for draft-ietf-netconf-trust- anchors * CCCC --> the assigned RFC value for draft-ietf-netconf-keystore * DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client- server * EEEE --> the assigned RFC value for draft-ietf-netconf-ssh-client- server * FFFF --> the assigned RFC value for draft-ietf-netconf-tls-client- server * GGGG --> the assigned RFC value for draft-ietf-netconf-http- client-server * HHHH --> the assigned RFC value for this draft Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: * 2022-12-12 --> the publication date of this draft The "Relation to other RFCs" section Section 1.1 contains the text "one or more YANG modules" and, later, "modules". This text is sourced from a file in a context where it is unknown how many modules a draft defines. The text is not wrong as is, but it may be improved by stating more directly how many modules are defined. The "Relation to other RFCs" section Section 1.1 contains a self- reference to this draft, along with a corresponding Informative Reference in the Appendix. The following Appendix section is to be removed prior to publication: * Appendix A. Change Log Watsen Networks This document defines two YANG modules, one module to configure a RESTCONF client and the other module to configure a RESTCONF server. Both modules support the TLS transport protocol with both standard RESTCONF and RESTCONF Call Home connections. Editorial Note (To be removed by RFC Editor) This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements (note: not all may be present): * AAAA --> the assigned RFC value for draft-ietf-netconf-crypto- types * BBBB --> the assigned RFC value for draft-ietf-netconf-trust- anchors * CCCC --> the assigned RFC value for draft-ietf-netconf-keystore * DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client- server * EEEE --> the assigned RFC value for draft-ietf-netconf-ssh-client- server * FFFF --> the assigned RFC value for draft-ietf-netconf-tls-client- server * GGGG --> the assigned RFC value for draft-ietf-netconf-http- client-server * HHHH --> the assigned RFC value for draft-ietf-netconf-netconf- client-server * IIII --> the assigned RFC value for this draft Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: * 2022-12-12 --> the publication date of this draft The "Relation to other RFCs" section Section 1.1 contains the text "one or more YANG modules" and, later, "modules". This text is sourced from a file in a context where it is unknown how many modules a draft defines. The text is not wrong as is, but it may be improved by stating more directly how many modules are defined. The "Relation to other RFCs" section Section 1.1 contains a self- reference to this draft, along with a corresponding Informative Reference in the Appendix. The following Appendix section is to be removed prior to publication: * Appendix A. Change Log Informative References RPSL allows a network operator to be able to specify routing policies at various levels in the Internet hierarchy; for example at the Autonomous System (AS) level. At the same time, policies can be specified with sufficient detail in RPSL so that low level router configurations can be generated from them. RPSL is extensible; new routing protocols and new protocol features can be introduced at any time. [STANDARDS-TRACK] This document describes the IETF architecture for a standard, programmatic interface for state transfer in and out of the Internet routing system. It describes the high-level architecture, the building blocks of this high-level architecture, and their interfaces, with particular focus on those to be standardized as part of the Interface to the Routing System (I2RS). Many Internet applications are used to access resources such as pieces of information or server processes that are available in several equivalent replicas on different hosts. This includes, but is not limited to, peer-to-peer file sharing applications. The goal of Application-Layer Traffic Optimization (ALTO) is to provide guidance to applications that have to select one or several hosts from a set of candidates capable of providing a desired resource. This memo discusses deployment-related issues of ALTO. It addresses different use cases of ALTO such as peer-to-peer file sharing and Content Delivery Networks (CDNs) and presents corresponding examples. The document also includes recommendations for network administrators and application designers planning to deploy ALTO, such as recommendations on how to generate ALTO map information. Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. This document defines a YANG data model for Layer 3 network topologies. This document describes a mechanism that allows subscriber applications to request a continuous and customized stream of updates from a YANG datastore. Providing such visibility into updates enables new capabilities based on the remote mirroring and monitoring of configuration and operational state. This document specifies an extension to the base Application-Layer Traffic Optimization (ALTO) Protocol that generalizes the concept of "endpoint properties", which have been tied to IP addresses so far, to entities defined by a wide set of objects. Further, these properties are presented as maps, similar to the network and cost maps in the base ALTO Protocol. While supporting the endpoints and related Endpoint Property Service defined in RFC 7285, the ALTO Protocol is extended in two major directions. First, from endpoints restricted to IP addresses to entities covering a wider and extensible set of objects; second, from properties for specific endpoints to entire entity property maps. These extensions introduce additional features that allow entities and property values to be specific to a given information resource. This is made possible by a generic and flexible design of entity and property types. The Content Delivery Networks Interconnection (CDNI) framework in RFC 6707 defines a set of protocols to interconnect CDNs to achieve multiple goals, including extending the reach of a given CDN. A CDNI Request Routing Footprint & Capabilities Advertisement interface (FCI) is needed to achieve the goals of a CDNI. RFC 8008 defines the FCI semantics and provides guidelines on the FCI protocol, but the exact protocol is not specified. This document defines a new Application-Layer Traffic Optimization (ALTO) service, called "CDNI Advertisement Service", that provides an implementation of the FCI, following the guidelines defined in RFC 8008. This document is an extension to the base Application-Layer Traffic Optimization (ALTO) protocol. It extends the ALTO cost map and ALTO property map services so that an application can decide to which endpoint(s) to connect based not only on numerical/ordinal cost values but also on fine-grained abstract information regarding the paths. This is useful for applications whose performance is impacted by specific components of a network on the end-to-end paths, e.g., they may infer that several paths share common links and prevent traffic bottlenecks by avoiding such paths. This extension introduces a new abstraction called the "Abstract Network Element" (ANE) to represent these components and encodes a network path as a vector of ANEs. Thus, it provides a more complete but still abstract graph representation of the underlying network(s) for informed traffic optimization among endpoints. Huawei Yale University Samsung Huawei Nokia Bell Labs Telefonica The cost metric is a basic concept in Application-Layer Traffic Optimization (ALTO), and different applications may use different types of cost metrics. Since the ALTO base protocol (RFC 7285) defines only a single cost metric (namely, the generic "routingcost" metric), if an application wants to issue a cost map or an endpoint cost request in order to identify a resource provider that offers better performance metrics (e.g., lower delay or loss rate), the base protocol does not define the cost metric to be used. This document addresses this issue by extending the specification to provide a variety of network performance metrics, including network delay, delay variation (a.k.a, jitter), packet loss rate, hop count, and bandwidth. There are multiple sources (e.g., estimation based on measurements or service-level agreement) to derive a performance metric. This document introduces an additional "cost-context" field to the ALTO "cost-type" field to convey the source of a performance metric. At first glance, the acronym "OAM" seems to be well-known and well-understood. Looking at the acronym a bit more closely reveals a set of recurring problems that are revisited time and again. This document provides a definition of the acronym "OAM" (Operations, Administration, and Maintenance) for use in all future IETF documents that refer to OAM. There are other definitions and acronyms that will be discussed while exploring the definition of the constituent parts of the "OAM" term. This memo documents an Internet Best Current Practice.

Examples of Extending the ALTO O&M Data Model Developers and operators can also extend the ALTO O&M data model to align with their own implementations. Specifically, the following nodes of the data model can be augmented:

• The server-discovery-manner choice of the server-discovery.
• The authentication choice of each auth-client.
• The data-source choice.
• The algorithm choice of the resource-params of each resource.

An Example Module for Extended Server Discovery Manners The base data model defined by ietf-alto.yang only includes a reverse DNS based server discovery manner. The following example module demonstrates how additional server discovery manners can be augmented into the base data model. The case internet-routing-registry allows the ALTO server to update the server URI to the attribute of the corresponding aut-num class in IRR. The case peeringdb allows the ALTO server to update the server URI to the org object of the organization record in PeeringDB.

An Example Module for Extended Client Authentication Approaches The base data model "ietf-alto" only includes the client authentication approaches directly provided by the HTTP server. However, an implementation may authenticate clients in different ways. For example, an implementation may delegate the authentication to a third-party OAuth 2.0 server. The following example module demonstrates how additional client authentication approaches can enrich the base data model. In this example, the oauth2 case includes the URI to a third-party OAuth 2.0 based authorization server that the ALTO server can redirect to for the client authentication.

Example Module for Extended Data Sources The base data model defined by ietf-alto.yang does not include any choice cases for specific data sources. The following example module demonstrates how a implementation-specific data source can be augmented into the base data model. The yang-datastore case is used to import the YANG data from a YANG model-driven datastore. It includes:

• datastore to indicate which datastore is fetched.
• target-paths to specify the list of nodes or subtrees in the datastore.
• protocol to indicate which protocol is used to access the datastore. Either restconf or netconf can be used.

An Example Module for Information Resource Creation Algorithm The base data model "ietf-alto" does not include any choices cases for information resource creation algorithms. But developers may augment the "ietf-alto" module with definitions for custom creation algorithms for different information resources. The following example module demonstrates the parameters of a network map creation algorithm that translates an IETF layer 3 unicast topology into a network map. /alto:alto/alto-server/data-source/source-id | +--rw topo-name? leafref +--rw depth? uint32 ]]> This example defines a creation algorithm called l3-unicast-cluster-algorithm for the network map resource. It takes two algorithm-specific parameters:

'l3-unicast-topo':

This parameter contains information referring to the target path name of an operational yang-datastore data source node (See ) subscribed in the data-source list (See ). The referenced target path in the corresponding yang-datastore data source is assumed for an IETF layer 3 unicast topology defined in . The algorithm uses the topology data from this data source to compute the ALTO network map resource. 'source-datastore' refers to the 'source-id' of the operational yang-datastore data source node, and 'topo-name' refers to the 'name' of the target path in the source datastore.

'depth':

This optional parameter sets the depth of the clustering algorithm. For example, if the depth sets to 1, the algorithm will generate PID for every l3-node in the topology.

The creation algorithm can be reactively called once the referenced data source updates. Therefore, the ALTO network map resource can be updated dynamically. The update of the reference data source depends on the used update-policy (See ).

Example Usage This section presents a complete example showing how the base data model and all the vendor extended models above are used to set up an ALTO server and configure corresponding components (e.g., data source listener, information resource, access control).

Acknowledgements The authors thank Qin Wu for the help with drafting the initial version of the YANG modules. Big thanks also to ALTO WG chairs (Mohamed Boucadair and Qin Wu) and all the directorate reviewers (Adrian Farrel, Jordi Ros Giralt, and Qiao Xiang) for their thorough reviews, shepherding, and valuable feedback.