YANG Data Models for the Application-Layer Traffic Optimization (ALTO) Protocol
draft-ietf-alto-oam-yang-07
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
|
|
|---|---|---|---|
| Authors | Jingxuan Zhang , Dhruv Dhody , Kai Gao , Roland Schott , Qiufang Ma | ||
| Last updated | 2023-05-15 (Latest revision 2023-03-12) | ||
| Replaces | draft-zhang-alto-oam-yang | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | In WG Last Call | |
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| Document shepherd | Mohamed Boucadair | ||
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| Send notices to | mohamed.boucadair@orange.com |
draft-ietf-alto-oam-yang-07
ALTO WG J. Zhang
Internet-Draft Tongji University
Intended status: Standards Track D. Dhody
Expires: 17 November 2023 Huawei Technologies
K. Gao
Sichuan University
R. Schott
Deutsche Telekom
Q. Ma
Huawei
16 May 2023
YANG Data Models for the Application-Layer Traffic Optimization (ALTO)
Protocol
draft-ietf-alto-oam-yang-07
Abstract
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
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the ALTO Working Group
mailing list (alto@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/alto/.
Source for this draft and an issue tracker can be found at
https://github.com/ietf-wg-alto/draft-alto-oam-yang.
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/.
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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 17 November 2023.
Copyright Notice
Copyright (c) 2023 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 to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Acronyms and Abbreviations . . . . . . . . . . . . . . . . . 4
3.1. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Prefixes in Data Node Names . . . . . . . . . . . . . . . 5
3.3. Placeholders in Reference Statements . . . . . . . . . . 5
4. Design Scope and Requirements . . . . . . . . . . . . . . . . 6
4.1. Scope of Data Model for ALTO O&M . . . . . . . . . . . . 6
4.2. Basic Requirements . . . . . . . . . . . . . . . . . . . 6
4.3. Additional Requirements for Extensibility . . . . . . . . 7
4.4. Overview of ALTO O&M Data Model for Reference ALTO
Architecture . . . . . . . . . . . . . . . . . . . . . . 8
5. Design of ALTO O&M Data Model . . . . . . . . . . . . . . . . 9
5.1. Overview of ALTO O&M Data Model . . . . . . . . . . . . . 9
5.2. Data Model for ALTO Client Operation and Management . . . 10
5.3. Data Model for Server-level Operation and Management . . 10
5.3.1. Data Model for ALTO Server Setup . . . . . . . . . . 11
5.3.2. Data Model for Logging Management . . . . . . . . . . 13
5.3.3. Data Model for ALTO-related Management . . . . . . . 13
5.3.4. Data Model for Security Management . . . . . . . . . 14
5.4. Data Model for ALTO Server Configuration Management . . . 14
5.4.1. Data Source Configuration Management . . . . . . . . 14
5.4.2. ALTO Information Resources Configuration
Management . . . . . . . . . . . . . . . . . . . . . 15
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5.4.3. ALTO Information Resource Access Control
Management . . . . . . . . . . . . . . . . . . . . . 18
6. Design of ALTO O&M Statistics Data Model . . . . . . . . . . 19
6.1. Model for ALTO Server Failure Monitoring . . . . . . . . 21
6.2. Model for ALTO-specific Performance Monitoring . . . . . 21
7. ALTO OAM YANG Modules . . . . . . . . . . . . . . . . . . . . 22
7.1. The "ietf-alto" YANG Module . . . . . . . . . . . . . . . 22
7.2. The "ietf-alto-stats" YANG Module . . . . . . . . . . . . 50
8. Security Considerations . . . . . . . . . . . . . . . . . . . 58
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.1. Normative References . . . . . . . . . . . . . . . . . . 60
10.2. Informative References . . . . . . . . . . . . . . . . . 62
Appendix A. Examples of Extending the ALTO O&M Data Model . . . 63
A.1. An Example Module for Extended Server Discovery
Manners . . . . . . . . . . . . . . . . . . . . . . . . . 64
A.2. An Example Module for Extended Client Authentication
Approaches . . . . . . . . . . . . . . . . . . . . . . . 66
A.3. Example Module for Extended Data Sources . . . . . . . . 68
A.4. An Example Module for Information Resource Creation
Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 71
A.5. Example Usage . . . . . . . . . . . . . . . . . . . . . . 74
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 77
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 77
1. 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 [RFC7285]. 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. Section 4.1 illustrates more
details about what is and is not in the scope. Section 4.2 and
Section 4.3 define more concrete requirements for the data model.
The basic structure of this YANG data model is guided by Section 16
of [RFC7285] and [RFC7971]. Although the scope of the YANG data
model in this document mainly focuses on the support of the base ALTO
protocol [RFC7285] and the existing ALTO standard extensions
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(including [RFC8189], [RFC8895], [RFC8896], [RFC9240], [RFC9241], and
[RFC9275]), the design will also be extensible for future standard
extensions (e.g., [I-D.ietf-alto-performance-metrics]).
The detailed design of the data model is illustrated by Section 5 and
Section 6. And some examples of how to extend this data model for
the specific ALTO server implementations are shown in Appendix A.
2. 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 [RFC2119] [RFC8174] 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.
3. Acronyms and Abbreviations
This document uses the following acronyms:
ALTO: Application-Layer Traffic Optimization
CPU: Central Processing Unit
DNS: Domain Name System
HTTP: Hypertext Transfer Protocol
IRR: Internet Routing Registry
OAM: Operations, Administration, and Maintenance (Section 3 of
[RFC6291])
O&M: OAM and Management (Section 3 of [RFC6291])
OAuth: Open Authorization
PID: Provider-defined Identifier in ALTO
TCP: Transmission Control Protocol
TLS: Transport Layer Security
URI: Uniform Resource Identifier
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3.1. Tree Diagrams
The meaning of the symbols in the tree diagrams is defined in
[RFC8340].
3.2. 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 Table 1.
+======+==================+=======================================+
|Prefix| YANG module | Reference |
+======+==================+=======================================+
|yang | ietf-yang-types | [RFC6991] |
+------+------------------+---------------------------------------+
|inet | ietf-inet-types | [RFC6991] |
+------+------------------+---------------------------------------+
|tcp | ietf-tcp-server | [I-D.ietf-netconf-tcp-client-server] |
+------+------------------+---------------------------------------+
|tls | ietf-tls-server | [I-D.ietf-netconf-tls-client-server] |
+------+------------------+---------------------------------------+
|http | ietf-http-server | [I-D.ietf-netconf-http-client-server] |
+------+------------------+---------------------------------------+
Table 1: Prefixes and corresponding YANG modules
3.3. 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
[I-D.ietf-netconf-tcp-client-server]
* FFFF --> the assigned RFC number for
[I-D.ietf-netconf-tls-client-server]
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* GGGG --> the assigned RFC number for
[I-D.ietf-netconf-http-client-server]
* HHHH --> the assigned RFC number for
[I-D.ietf-netconf-netconf-client-server]
* IIII --> the assigned RFC number for
[I-D.ietf-netconf-restconf-client-server]
* XXXX --> the assigned RFC number for this draft
* YYYY --> the assigned RFC number for
[I-D.ietf-alto-performance-metrics]
4. Design Scope and Requirements
4.1. 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 [RFC7921])
4.2. Basic Requirements
Based on discussions and recommendations in [RFC7285] and [RFC7971],
the data model provided by this document satisfies basic requirements
listed in Table 2.
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+======================================+========================+
| Requirement | Reference |
+======================================+========================+
| R1: The data model should support | Section 16.1 of |
| configuration for ALTO server setup. | [RFC7285] |
+--------------------------------------+------------------------+
| R2: The data model should provide | Section 16.2.1 of |
| logging management. | [RFC7285] |
+--------------------------------------+------------------------+
| R3: The data model should provide | Section 16.2.2 of |
| ALTO-related management information. | [RFC7285] |
+--------------------------------------+------------------------+
| R4: The data model should support | Section 16.2.6 of |
| configuration for security policy | [RFC7285] |
| management. | |
+--------------------------------------+------------------------+
| R5-1: The data model should support | Section 16.2.4 of |
| configuration for different data | [RFC7285], Section 3.2 |
| sources. | of [RFC7971] |
+--------------------------------------+------------------------+
| R5-2: The data model should support | Section 16.2.4 of |
| configuration for information | [RFC7285] |
| resource generation algorithms. | |
+--------------------------------------+------------------------+
| R5-3: The data model should support | Section 16.2.4 of |
| configuration for access control at | [RFC7285] |
| information resource level. | |
+--------------------------------------+------------------------+
| R6: The data model should provide | Section 16.2.3 of |
| metrics for server failures. | [RFC7285], Section 3.3 |
| | of [RFC7971] |
+--------------------------------------+------------------------+
| R7: The data model should provide | Section 16.2.5 of |
| performance monitoring for ALTO- | [RFC7285], Section 3.4 |
| specific metrics. | of [RFC7971] |
+--------------------------------------+------------------------+
Table 2: Basic Requirements of Data Model for ALTO O&M.
4.3. 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.
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4.4. Overview of ALTO O&M Data Model for Reference ALTO Architecture
Figure 1 shows a reference architecture for the ALTO server
implementation. It also indicates the 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 (Section 5). The performance monitor and logging and fault
manager need to implement ietf-alto-stats.yang (Section 6).
In practice, an ALTO server may not follow this architecture exactly.
However, to implement the YANG modules defined in this document, an
ALTO server implementation should contain all the server components
above as a minimal implementation.
The data broker and algorithm plugins are not in the scope of the
data models defined in this document. User-specified YANG modules
can be applied to different algorithm plugins by augmenting the data
model defined in this document (Appendix A).
Generally, the ALTO server components shown in Figure 1 have the
following interactions with each others:
* Both the server manager and information resource manager will
report statistics data to performance monitor and logging and
fault manager.
* The algorithm plugins will register callbacks to the corresponding
ALTO information resources upon the configuration; Once an ALTO
information resource is requested, the registered callback
algorithm will be invoked.
* A data source listener will fetch data from the configured data
source using the corresponding data source API in either proactive
mode (polling) or reactive mode (subscription/publication).
* A data source listener will update the preprocessed data to an
optional data broker.
* An algorithm plugin may read data from an optional data broker to
calculate the ALTO information resource.
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+----------------------+ +-----------------+
| Performance Monitor: |<-----| Server Manager: |
| ietf-alto-stats.yang |<-+ +-| ietf-alto.yang |
+----------------------+ | | +-----------------+
report
+----------------------+ | | +-------------------+
| Logging and Fault | +---| Information |
| Manager: |<---+ | Resource Manager: |
| ietf-alto-stats.yang |<-----| ietf-alto.yang |
+----------------------+ +-------------------+
^|
|| callback
|v
............. ..............................
/ \ ------> . Algorithm Plugin: .
. Data Broker . read . example-ietf-alto-alg.yang .
............... ..............................
^
| write
+----------------+ Data Source ++=============++
| Data Source | API || ||
| Listener: | <==========> || Data Source ||
| ietf-alto.yang | || ||
+----------------+ ++=============++
Figure 1: A Reference ALTO Server Architecture and YANG Modules
5. Design of ALTO O&M Data Model
5.1. Overview of ALTO O&M Data Model
The "ietf-alto" module defined in this document is designed to fit
all the requirements listed in Section 4.
As shown in Figure 2, 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.
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module: ietf-alto
+--rw alto!
+--rw alto-client* [client-id] {alto-client}?
| ...
+--rw alto-server {alto-server}?
+...
+--rw auth-client* [client-id]
| ...
+--rw role* [role-name]
| +--rw role-name role-name
| +--rw client* client-ref
+--rw data-source* [source-id]
| ...
+--rw resource* [resource-id]
...
Figure 2: IETF ALTO Tree Structure
5.2. Data Model for ALTO Client Operation and Management
As shown in Figure 3, 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.
module: ietf-alto
+--rw alto!
+--rw alto-client* [client-id] {alto-client}?
| +--rw client-id string
| +--rw server-discovery-client
| +---u alto-server-discovery-client
...
Figure 3: IETF ALTO Client Subtree Structure
5.3. 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 Figure 4. This
structure satisfies R1 - R4 in Section 4.2.
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module: ietf-alto
+--rw alto!
...
+--rw alto-server {alto-server}?
+--rw listen
| +---u alto-server-listen-stack
+--rw server-discovery
| +---u alto-server-discovery
+--rw logging-system
| +---u alto-logging-system
+--rw cost-type* [cost-type-name]
| +--rw cost-type-name cost-type-name
| +--rw cost-mode identityref
| +--rw cost-metric identityref
| +--rw description? string
| +--rw cost-context {performance-metrics}?
| +--rw cost-source identityref
| +--rw parameters
| +--rw (parameters)?
+--rw meta* [meta-key]
| +--rw meta-key meta-key
| +--rw meta-value binary
...
Figure 4: IETF ALTO Server Level Subtree Structure
5.3.1. Data Model for ALTO Server Setup
To satisfy R1 in Section 4.2, the ALTO server instance contains the
basic data nodes for the server setup that are detailed in the
following subsections.
5.3.1.1. ALTO Server Listen Stack
The 'listen' contains all the data nodes for the whole server listen
stack across HTTP, TLS, and TCP layers (Figure 5).
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grouping alto-server:
+-- base-uri? inet:uri
grouping alto-server-listen-stack:
+-- (transport)
+--:(http) {http-listen}?
| +-- http
| +-- tcp-server-parameters
| | +---u tcp:tcp-server-grouping
| +-- http-server-parameters
| | +---u http:http-server-grouping
| +-- alto-server-parameters
| +---u alto-server
+--:(https)
+-- https
+-- tcp-server-parameters
| +---u tcp:tcp-server-grouping
+-- tls-server-parameters
| +---u tls:tls-server-grouping
+-- http-server-parameters
| +---u http:http-server-grouping
+-- alto-server-parameters
+---u alto-server
Figure 5: IETF ALTO Server Groupings Structure
5.3.1.2. ALTO Server Discovery Setup
In practice, for a large-scale network consisting of multiple
administrative domains, the information about the network may be
partitioned and distributed over multiple ALTO servers. That may
require discovery and communication among different ALTO servers.
The "ietf-alto" module provides the configuration for how an ALTO
server can be discovered by another ALTO server or client on demand
(Figure 6). But it does not contain any configuration for the
communication among ALTO servers because the related solution has not
become a standard. Future documents may extend it to fully support
multi-domain scenarios.
grouping alto-server-discovery:
+-- (server-discovery-manner)?
+--:(reverse-dns) {xdom-disc}?
+-- rdns-naptr-records
+-- static-prefix* inet:ip-prefix
+-- dynamic-prefix-source* data-source-ref
Figure 6: IETF ALTO Server Discovery Grouping Structure
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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 [RFC7286] and [RFC8686]. 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
[RFC7286] and [RFC8686], 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.
5.3.2. Data Model for Logging Management
To satisfy R2 in Section 4.2, the ALTO server instance contains the
the logging data nodes shonw in Figure 7.
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.
grouping alto-logging-system:
+-- (logging-system)?
+--:(syslog)
+-- syslog-params
+-- config-file? inet:uri
Figure 7: IETF ALTO Logging System Grouping Structure
A specific server implementation can extend the logging-system node
to add other logging systems.
5.3.3. Data Model for ALTO-related Management
To satisfy R3 in Section 4.2, the data model contains the following
ALTO-related management information (Figure 4):
* The 'cost-type' list is the registry for the cost types that can
be used in the ALTO server.
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* 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).
5.3.4. Data Model for Security Management
To satisfy R4 in Section 4.2, 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.
5.4. Data Model for ALTO Server Configuration Management
5.4.1. Data Source Configuration Management
To satisfy R5-1 in Section 4.2, 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
[RFC7285]).
module: ietf-alto
+--rw alto!
...
+--rw alto-server {alto-server}?
...
+--rw data-source* [source-id]
| +--rw source-id source-id
| +--rw source-type identityref
| +--rw (update-policy)
| | +--:(reactive)
| | | +--rw (publish-mode)?
| | | +--:(on-change)
| | | | +--rw on-change empty
| | | +--:(periodic)
| | | +--rw feed-interval uint32
| | +--:(proactive)
| | +--rw poll-interval uint32
| +--rw (source-params)?
...
Figure 8: IETF ALTO Server Data Source Subtree Structure
As shown in Figure 8, 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.
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* 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 Appendix A.3.
5.4.2. ALTO Information Resources Configuration Management
To satisfy R5-2 and R-3, the ALTO server instance contains a list of
'resource' entries (Figure 9). Each resource entry contains the
configurations of an ALTO information resource (See Section 8.1 of
[RFC7285]). The operator of the ALTO server can use this model to
create, update, and remove the ALTO information resources.
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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.
module: ietf-alto
+--rw alto!
...
+--rw alto-server {alto-server}?
...
+--rw resource* [resource-id]
+--rw resource-id resource-id
+--rw resource-type identityref
+--rw description? string
+--rw accepted-role* role-ref
+--rw dependency* resource-ref
+--rw alto-ird-params
| +--rw delegation inet:uri
+--rw alto-networkmap-params
| +--rw is-default? boolean
| +--rw filtered? boolean
| +---u algorithm
+--rw alto-costmap-params
| +--rw filtered? boolean
| +---u filter-costmap-cap
| +---u algorithm
+--rw alto-endpointcost-params
| +---u filter-costmap-cap
| +---u algorithm
+--rw alto-endpointprop-params
| +--rw prop-type* endpoint-property
| +---u algorithm
+--rw alto-propmap-params {propmap}?
| +---u algorithm
+--rw alto-cdni-params {cdni}?
| +---u algorithm
+--rw alto-update-params {incr-update}?
| +---u algorithm
+--rw resource-limits
+--rw notify-res-mem-limit? uint64
+--rw notify-upd-stream-limit? uint64
{incr-update}?
notifications:
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+---n alto-resource-event {alto-server}?
+--ro resource-id resource-ref
+--ro notify-res-mem-threshold? uint64
+--ro notify-upd-stream-threshold? uint64 {incr-update}?
grouping filter-costmap-cap:
+-- cost-type-name* cost-type-ref
+-- cost-constraints? boolean
+-- max-cost-types? uint32 {multi-cost}?
+-- testable-cost-type-name* cost-type-ref {multi-cost}?
+-- calendar-attributes {cost-calendar}?
+-- cost-type-name* cost-type-ref
+-- time-interval-size decimal64
+-- number-of-intervals uint32
grouping algorithm:
+-- (algorithm)
Figure 9: IETF ALTO Resource Subtree Structure
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 Section 5.4.3 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 [RFC7285]).
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
[RFC7285]).
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.
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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
Section 5.4.1). An example of extending the algorithm node for a
specific type of resource is included in Appendix A.4.
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 [RFC7285]).
Each resource entry may also set thresholds of memory usage and
active update streams (if "incr-update" feature is enabled). Table 3
describes limits that, once exceeded, will trigger notifications to
be generated:
+=========================+========================================+
| Notification Threshold | Description |
+=========================+========================================+
| notify-res-mem-limit | Used to notify high memory utilization |
| | of the resource configured to an ALTO |
| | server instance. When exceeded, an |
| | alto-resource-event will be generated. |
+-------------------------+----------------------------------------+
| notify-upd-stream-limit | Used to notify a high number of active |
| | update streams that are serviced by an |
| | update resource configured to an ALTO |
| | server instance. When exceeded, an |
| | alto-resource-event will be generated. |
+-------------------------+----------------------------------------+
Table 3: Notification Thresholds.
5.4.3. ALTO Information Resource Access Control Management
As per Section 15.5.2 of [RFC7285], 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 Figure 10.
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module: ietf-alto
+--rw alto!
...
+--rw alto-server {alto-server}?
...
+--rw auth-client* [client-id]
| +--rw client-id string
| +--rw (authentication)?
| +--:(http)
| | +--rw http-auth-client
| | {http-listen,http:client-auth-supported,
| | http:local-users-supported}?
| | +--rw user-id http-user-id-ref
| +--:(https)
| +--rw https-auth-client
| {http:client-auth-supported,
| http:local-users-supported}?
| | +--rw user-id https-user-id-ref
+--rw role* [role-name]
| +--rw role-name role-name
| +--rw client* client-ref
...
Figure 10: IETF ALTO Client Authentication Subtree Structure
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.
6. 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
(Figure 11).
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module: ietf-alto-stats
augment /alto:alto/alto:alto-server:
+--rw server-level-monitor-config
| +--rw time-window-size? uint32
+--ro server-level-stats
+---u server-level-stats
augment /alto:alto/alto:alto-server/alto:resource:
+--ro resource-level-stats
+---u resource-level-stats
grouping server-level-stats:
+-- discontinuity-time? yang:timestamp
+-- last-report-time? yang:timestamp
+-- num-total-req? yang:counter64
+-- num-total-succ? yang:counter64
+-- num-total-fail? yang:counter64
+-- num-total-last-req? yang:gauge64
+-- num-total-last-succ? yang:gauge64
+-- num-total-last-fail? yang:gauge64
grouping network-map-stats:
+-- num-map-pid? yang:gauge64
grouping prop-map-stats:
+-- num-map-entry? yang:gauge64
grouping cdni-stats:
+-- num-base-obj? yang:gauge64
grouping upd-stream-stats:
+-- num-upd-stream? yang:gauge64
+-- num-upd-msg-total? yang:gauge64
+-- num-upd-msg-max? yang:gauge64
+-- num-upd-msg-min? yang:gauge64
+-- num-upd-msg-avg? yang:gauge64
+-- num-upd-msg-total-last? yang:gauge64
+-- num-upd-msg-max-last? yang:gauge64
+-- num-upd-msg-min-last? yang:gauge64
+-- num-upd-msg-avg-last? yang:gauge64
grouping resource-level-stats:
+-- discontinuity-time? yang:timestamp
+-- last-report-time? yang:timestamp
+-- num-res-upd? yang:counter64
+-- res-mem-size? uint64
+-- res-enc-size? uint64
+-- num-res-req? yang:counter64
+-- num-res-succ? yang:counter64
+-- num-res-fail? yang:counter64
+-- num-res-last-req? yang:gauge64
+-- num-res-last-succ? yang:gauge64
+-- num-res-last-fail? yang:gauge64
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+-- network-map-stats
| +---u network-map-stats
+-- endpoint-prop-stats
| +---u prop-map-stats
+-- property-map-stats
| +---u prop-map-stats
+-- cdni-stats
| +---u cdni-stats
+-- upd-stream-stats
Figure 11: IETF ALTO Statistics Structure
6.1. Model for ALTO Server Failure Monitoring
To satisfy R6 in Section 4.2, the "ietf-alto-stats" module contains
statistics that indicates server failures (Figure 11).
More specifically, num-total-* and num-total-last-* provides server-
level failure counters; num-res-* and num-res-last-* provides
information resource-level failure counters.
6.2. Model for ALTO-specific Performance Monitoring
To satisfy R7 in Section 4.2,the "ietf-alto-stats" module also
contains statistics for ALTO-specific performance metrics
(Figure 11).
More specifically, this data model contains the following measurement
information of "system and service performance" suggested by
[RFC7285] and [RFC7971]:
* 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 [RFC7285] and
[RFC7971], 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 [RFC9240] and [RFC9241])
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* num-upd-stream and num-upd-msg-* provides statistics for update
streams and messages (for [RFC8189])
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 [RFC7971] are
not contained in this data model:
* Total amount and distribution of traffic
* Application performance
7. ALTO OAM YANG Modules
7.1. The "ietf-alto" YANG Module
<CODE BEGINS> file "ietf-alto@2023-02-23.yang"
module ietf-alto {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-alto";
prefix alto;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types, Section 4";
}
import ietf-tcp-server {
prefix tcp;
reference
"RFC DDDD: YANG Groupings for TCP Clients and TCP Servers";
}
import ietf-tls-server {
prefix tls;
reference
"RFC FFFF: YANG Groupings for TLS Clients and TLS Servers";
}
import ietf-http-server {
prefix http;
reference
"RFC GGGG: YANG Groupings for HTTP Clients and HTTP Servers";
}
organization
"IETF ALTO Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/alto/about/>
WG List: <alto@ietf.org>";
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description
"This YANG module defines a set of configured and operational
parameters of an 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 alto-client {
description
"Indicates that the implementation embeds an ALTO client
instance.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol";
}
feature alto-server {
description
"Indicates that the implementation embeds an ALTO server
instance.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol";
}
feature http-listen {
description
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"The 'http-listen' feature is only used for test deployment.
This feature shouldn't be used in the production
deployment.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 8.3.5 ";
}
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";
}
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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
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 8.1 ";
}
identity source-type {
description
"Base identity for type of data source. A data source
indicates the origin from which the ALTO information
resources are derived.";
}
identity cost-metric {
description
"The cost metric indicates what the cost represents.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6.1.1";
}
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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
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6.1.2
RFC 9274: A Cost Mode Registry for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
identity cost-source {
description
"The cost source indicates the high-level type of the
data source.";
reference
"RFC YYYY: ALTO Performance Cost Metrics, Section 3.1";
}
// Identities for ALTO information resources
identity ird {
base resource-type;
description
"Identity for information resource directory.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 9";
}
identity network-map {
base resource-type;
description
"Identity for network map.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 5";
}
identity cost-map {
base resource-type;
description
"Identity for cost map.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6";
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}
identity endpoint-prop {
base resource-type;
description
"Identity for endpoint property service.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 11.4.1";
}
identity endpoint-cost {
base resource-type;
description
"Identity for endpoint cost service.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 11.5.1";
}
identity property-map {
base resource-type;
description
"Identity for property map.";
reference
"RFC 9240: An ALTO Extension: Entity Property Maps";
}
identity cdni {
base resource-type;
description
"Identity for Content Delivery Network Interconnection (CDNI)
advertisement service.";
reference
"RFC 9241: Content Delivery Network Interconnection (CDNI)
Request Routing: CDNI Footprint and Capabilities
Advertisement using ALTO";
}
identity update {
base resource-type;
description
"Identity for update stream service.";
reference
"RFC 8895: Application-Layer Traffic Optimization (ALTO)
Incremental Updates Using Server-Sent Events
(SSE)";
}
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// Identities for cost mode
identity numerical {
base cost-mode;
description
"This mode indicates that it is safe to perform numerical
operations";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6.1.2.1";
}
identity ordinal {
base cost-mode;
description
"This mode indicates that the cost values in a cost map
represent ranking";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6.1.2.2";
}
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.";
reference
"RFC 9275: An Extension for Application-Layer Traffic
Optimization (ALTO): Path Vector, Section 6.5.2";
}
// 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.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 6.1.1.1";
}
identity ane-path {
if-feature "path-vector";
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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.";
reference
"RFC 9275: An Extension for Application-Layer Traffic
Optimization (ALTO): Path Vector, Section 6.5.1";
}
identity delay-ow {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 4.1";
}
identity delay-rt {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 4.2";
}
identity delay-variation {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 4.3";
}
identity lossrate {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 4.4";
}
identity hopcount {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 4.5";
}
identity tput {
if-feature "performance-metrics";
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base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 5.1";
}
identity bw-residual {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 5.2";
}
identity bw-available {
if-feature "performance-metrics";
base cost-metric;
description
"RFC YYYY: ALTO Performance Cost Metrics, Section 5.3";
}
// 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
"RFC YYYY: ALTO Performance Cost Metrics, Section 3.1";
}
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
"RFC YYYY: ALTO Performance Cost Metrics, Section 3.1";
}
identity estimation {
if-feature "performance-metrics";
base cost-source;
description
"The 'estimation' category indicates that the metric value is
computed through an estimation process.";
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reference
"RFC YYYY: ALTO Performance Cost Metrics, Section 3.1";
}
// Typedefs
typedef resource-id {
type string {
length "1..64";
pattern '[0-9a-zA-Z\-:@_]*';
}
description
"Type for a resource ID that are used to reference an ALTO
information resource.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 9.1.1";
}
typedef cost-type-name {
type string {
length "1..max";
}
description
"Type for the name of a single CostType that can be
referenced by other ALTO information resources.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 9.2.2";
}
typedef meta-key {
type string {
length "1..max";
}
description
"Type for a custom meta key of an ALTO server.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 8.4.1";
}
typedef endpoint-property {
type union {
type resource-specific-endpoint-property;
type global-endpoint-property;
}
description
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"Type for an endpoint property.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 10.8";
}
typedef resource-specific-endpoint-property {
type string {
length "1..97";
pattern '[0-9a-zA-Z\-:@_]*\.[0-9a-zA-Z\-:_]*';
}
description
"Type for a resource-specific endpoint property.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 10.8.1";
}
typedef global-endpoint-property {
type string {
length "1..32";
pattern '[0-9a-zA-Z\-:_]*';
}
description
"Type for a global endpoint property.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 10.8.2";
}
typedef source-id {
type string {
length "1..max";
pattern '[0-9a-zA-Z\-:@_]*';
}
description
"Type for a data source ID that are used to reference a data
source.";
}
typedef role-name {
type string {
length "1..max";
pattern '[0-9a-zA-Z\-:@_]*';
}
description
"Type for a name of a role for role-based access control.";
}
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// Typedefs for referencing purposes
typedef cost-type-ref {
type leafref {
path "/alto:alto/alto:alto-server/alto:cost-type"
+ "/alto:cost-type-name";
}
description
"Type to reference a cost type name.";
}
typedef data-source-ref {
type leafref {
path "/alto:alto/alto:alto-server/alto:data-source"
+ "/alto:source-id";
}
description
"Type to reference a data source identifier.";
}
typedef http-user-id-ref {
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";
}
description
"Type to reference an HTTP client user id.";
}
typedef https-user-id-ref {
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";
}
description
"Type to reference an HTTPS client user id.";
}
typedef resource-ref {
type leafref {
path "/alto:alto/alto:alto-server/alto:resource"
+ "/alto:resource-id";
}
description
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"Type to reference a resource identifier.";
}
typedef role-ref {
type leafref {
path "/alto:alto/alto:alto-server/alto:role"
+ "/alto:role-name";
}
description
"Type to reference a role.";
}
typedef client-ref {
type leafref {
path "/alto:alto/alto:alto-server/alto:auth-client"
+ "/alto:client-id";
}
description
"Type to reference an authenticated client.";
}
// Groupings
grouping filter-costmap-cap {
description
"This grouping defines a data model for
FilteredCostMapCapabilities.";
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 11.3.2.4";
leaf-list cost-type-name {
type cost-type-ref;
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";
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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-name {
if-feature "multi-cost";
type cost-type-ref;
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
"RFC 8896: Application-Layer Traffic Optimization (ALTO)
Cost Calendar, Section 4.1";
leaf-list cost-type-name {
type cost-type-ref;
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.";
}
}
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}
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.";
}
reference
"RFC XXXX: YANG Data Models for the Application-Layer Traffic
Optimization (ALTO) Protocol, Section 5.4.2";
}
grouping alto-server {
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 {
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" {
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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;
}
}
}
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 {
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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 alto-server-discovery {
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 method {
description
"Selects among available server discovery methods.";
case reverse-dns {
if-feature "xdom-disc";
description
"Configures 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 data-source-ref;
description
"Dynamic IP prefixes collected from data sources.";
}
}
}
}
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}
grouping alto-server-discovery-client {
description
"Grouping for configuration of how a client can discover
an ALTO server.";
choice method {
description
"Selects among available server discovery methods.";
case reverse-dns {
if-feature "xdom-disc";
description
"Uses reverse DNS lookup to discover an ALTO server.";
reference
"RFC 8686: Application-Layer Traffic Optimization (ALTO)
Cross-Domain Server Discovery.";
container rdns-params {
description
"Defines a set of parameters for reverse DNS
lookups.";
leaf-list dns-server {
type inet:host;
description
"Provides a DNS server list for reverse DNS lookup.";
}
}
}
}
}
grouping alto-logging-system {
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
"Provides a set of syslog parameters.";
leaf config-file {
type inet:uri {
pattern 'file:.*';
}
description
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"Indicates 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. A single device can implement either alto-client or
alto-server. No need to implement both.";
list alto-client {
if-feature 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 {
description
"Specifies a set of parameters for ALTO server discovery.";
uses alto-server-discovery-client;
}
}
container alto-server {
if-feature 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;
}
container server-discovery {
description
"Configures how the ALTO server to be discovered by
others.";
uses alto-server-discovery;
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}
container logging-system {
description
"Configure logging system to capture log messages
generated by the ALTO server.";
uses alto-logging-system;
}
list cost-type {
key "cost-type-name";
description
"Mapping between name and referenced cost type.";
leaf cost-type-name {
type cost-type-name;
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
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"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
"RFC 7285: Application-Layer Traffic Optimization
(ALTO) Protocol, Section 8.4.1";
leaf meta-key {
type meta-key;
description
"Custom meta key";
}
leaf meta-value {
type binary;
mandatory true;
description
"Custom meta value encoded with the base64 encoding
schema. The encoded value must be a valid JSON
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. If no authentication method is
configured, the client must be ignored.";
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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 http-user-id-ref;
mandatory true;
description
"Reference of the user-id for the authenticated
HTTP 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 https-user-id-ref;
mandatory true;
description
"Reference of the user-id for the authenticated
HTTPS 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 client-ref;
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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 source-id;
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
"Indicates an on-change subscription.";
}
}
case periodic {
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description
"The data source is requested to periodically
publish an update.";
leaf feed-interval {
type uint32;
units "seconds";
mandatory true;
description
"Specifies the duration of time that should
occur between periodic push updates, in units
of seconds. If it is set to zero, it is
equivalent to the on-change mode.";
}
}
}
}
case proactive {
description
"Configuration for the data source listener to
proactively pull data from the data source.";
leaf poll-interval {
type uint32;
units "seconds";
mandatory true;
description
"Polling interval in seconds for proactive mode. If
it is set to zero, the data source listener will
never pull data periodically. The data can still
be pulled when an algorithm plugin of an
information resource calls this data source
listener. This can be useful for some on-demand
settings.";
}
}
}
choice source-params {
description
"Data source specific configuration.";
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol,
Section 5.4.1";
}
}
list resource {
key "resource-id";
description
"ALTO information resources to be defined";
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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 role-ref;
description
"Roles allowed to access this information resource.";
}
leaf-list dependency {
type resource-ref;
description
"A list of dependent information resources.";
}
container alto-ird-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:ird")';
description
"IRD-specific configuration.";
leaf delegation {
type inet:uri;
mandatory true;
description
"Upstream IRD to be delegated.";
}
}
container alto-networkmap-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:network-map")';
description
"Filtered Network Map specific configuration.";
reference
"RFC 7285: Application-Layer Traffic Optimization
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(ALTO) Protocol, Sections 11.2.1 and
11.3.1";
leaf is-default {
type boolean;
description
"Sets whether this is the default network map.";
}
leaf filtered {
type boolean;
default false;
description
"Configures whether filtered network map is
supported.";
}
uses algorithm;
}
container alto-costmap-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:cost-map")';
description
"Filtered Cost Map specific configuration.";
reference
"RFC 7285: Application-Layer Traffic Optimization
(ALTO) Protocol, Sections 11.2.2 and
11.3.2";
leaf filtered {
type boolean;
description
"Configures whether filtered cost map is supported.";
}
uses filter-costmap-cap;
uses algorithm;
}
container alto-endpointcost-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:endpoint-cost")';
description
"Endpoint Cost Service specific configuration.";
reference
"RFC 7285: Application-Layer Traffic Optimization
(ALTO) Protocol, Section 11.5";
uses filter-costmap-cap;
uses algorithm;
}
container alto-endpointprop-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:endpoint-prop")';
description
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"Endpoint Cost Service specific configuration.";
reference
"RFC 7285: Application-Layer Traffic Optimization
(ALTO) Protocol, Section 11.5";
leaf-list prop-type {
type endpoint-property;
min-elements 1;
description
"Supported endpoint properties.";
}
uses algorithm;
}
container alto-propmap-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:property-map")';
if-feature "propmap";
description
"(Filtered) Entity Property Map specific
configuration.";
reference
"RFC 9240: An ALTO Extension: Entity Property Maps";
uses algorithm;
}
container alto-cdni-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:cdni")';
if-feature "cdni";
description
"CDNi specific configuration.";
reference
"RFC 9241: Content Delivery Network Interconnection
(CDNI) Request Routing: CDNI Footprint and
Capabilities Advertisement using ALTO";
uses algorithm;
}
container alto-update-params {
when 'derived-from-or-self(../resource-type,'
+ '"alto:update")';
if-feature "incr-update";
description
"Incremental Updates specific configuration.";
reference
"RFC 8895: Application-Layer Traffic Optimization
(ALTO) Incremental Updates Using Server-Sent
Events (SSE)";
uses algorithm;
}
container resource-limits {
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description
"Sets resource limits.";
leaf notify-res-mem-limit {
type uint64;
units "bytes";
description
"Notification of resource memory usage.
Notification must be generated when the defined
threshold is reached.";
}
leaf notify-upd-stream-limit {
when 'derived-from-or-self(../../resource-type,'
+ '"alto:update")';
if-feature "incr-update";
type uint64;
description
"Notification of number of active update streams.
Notification must be generated when the defined
threshold is reached.";
}
}
}
}
}
// Notifications
notification alto-resource-event {
if-feature alto-server;
description
"Notifications must be generated when notify-res-mem-limit
and/or notify-upd-stream-limit thresholds are reached.";
leaf resource-id {
type resource-ref;
mandatory true;
description
"Resource identifier.";
}
leaf notify-res-mem-threshold {
type uint64;
units "bytes";
description
"The notify-res-mem-limit threshold has been fired.";
}
leaf notify-upd-stream-threshold {
if-feature "incr-update";
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type uint64;
description
"The notify-upd-stream-limit threshold has been fired.";
}
}
}
<CODE ENDS>
7.2. The "ietf-alto-stats" YANG Module
<CODE BEGINS> file "ietf-alto-stats@2023-02-23.yang"
module ietf-alto-stats {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-alto-stats";
prefix alto-stats;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types, Section 3";
}
import ietf-alto {
prefix alto;
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
organization
"IETF ALTO Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/alto/about/>
WG List: <alto@ietf.org>";
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
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(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";
}
// Groupings
grouping server-level-stats {
description
"This grouping defines statistics for server-level
monitoring.";
leaf discontinuity-time {
type yang:timestamp;
description
"The time on the most recent occasion at which the ALTO
server suffered a discontinuity. This must be initialized
when the ALTO server is configured or rebooted.";
}
leaf last-report-time {
type yang:timestamp;
description
"The time on the most recent occasion at which the
statistics were reported.";
}
leaf num-total-req {
type yang:counter64;
description
"The total number of ALTO requests received by the ALTO
server.";
}
leaf num-total-succ {
type yang:counter64;
description
"The total number of successful responses sent by the ALTO
server.";
}
leaf num-total-fail {
type yang:counter64;
description
"The total number of failed responses sent by the ALTO
server.";
}
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leaf num-total-last-req {
type yang:gauge64;
description
"The total number of ALTO requests received by the ALTO
server within the last time window. The duration of the
time window is configured by time-window-size parameter.";
}
leaf num-total-last-succ {
type yang:gauge64;
description
"The total number of successful responses sent by the ALTO
server within the last time window. The duration of the
time window is configured by time-window-size parameter.";
}
leaf num-total-last-fail {
type yang:gauge64;
description
"The total number of failed responses sent by the ALTO
server within the last time window. The duration of the
time window is configured by time-window-size parameter.";
}
}
grouping network-map-stats {
description
"This grouping defines resource-specific statstics for the
network map service only.";
leaf num-map-pid {
type yang:gauge64;
description
"Number of PIDs contained in the network map.";
}
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
Protocol, Section 5";
}
grouping prop-map-stats {
description
"This grouping defines resource-specific statstics for the
endpoint property or property map service only.";
leaf num-map-entry {
type yang:gauge64;
description
"Number of ALTO entities contained in the property map.";
}
reference
"RFC 7285: Application-Layer Traffic Optimization (ALTO)
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Protocol, Section 11.4.1
RFC 9240: An ALTO Extension: Entity Property Maps";
}
grouping cdni-stats {
description
"This grouping defines resource-specific statstics for the
CDNI advertisement service only.";
leaf num-base-obj {
type yang:gauge64;
description
"Number of base CDNi advertisement objects contained in the
CDNI resource.";
}
reference
"RFC 9241: Content Delivery Network Interconnection (CDNI)
Request Routing: CDNI Footprint and Capabilities
Advertisement using ALTO";
}
grouping upd-stream-stats {
description
"This grouping defines resource-specific statstics for the
update stream service only.";
leaf num-upd-stream {
type yang:gauge64;
description
"Number of active update streams connected to the update
stream service.";
}
leaf num-upd-msg-total {
type yang:gauge64;
description
"Total number of update messages sent to all the active
update streams.";
}
leaf num-upd-msg-max {
type yang:gauge64;
description
"The maximum value over the total number of update messages
sent to each active update stream. Assume there are 3
active update streams A, B, and C with 4, 3, and 2 update
messages sent to them respectively, the value of this
metric is 4. After a while, if there is no new update
message sent to any update stream, but the update stream A
is closed, then the value of this metric is updated to
3.";
}
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leaf num-upd-msg-min {
type yang:gauge64;
description
"The minimum value over the total number of update messages
sent to each active update stream. The procedure is similar
to num-msg-max.";
}
leaf num-upd-msg-avg {
type yang:gauge64;
description
"The average value over the total number of update messages
sent to each active update stream. The procedure is similar
to num-msg-max.";
}
leaf num-upd-msg-total-last {
type yang:gauge64;
description
"Total number of update messages sent to all the active
update streams within the last time window. The duration
of the time window is configured by time-window-size
parameter.";
}
leaf num-upd-msg-max-last {
type yang:gauge64;
description
"The maximum value over the number of update messages sent
to each active update stream within the last time window.
The procedure is similar to num-msg-max, but only count
the update messages within the last time window. The
duration of the time window is configured by
time-window-size parameter.";
}
leaf num-upd-msg-min-last {
type yang:gauge64;
description
"The minimal value over the number of update messages sent
to each active update stream within the last time window.
The procedure is similar to num-msg-max, but only count
the update messages within the last time window. The
duration of the time window is configured by
time-window-size parameter.";
}
leaf num-upd-msg-avg-last {
type yang:gauge64;
description
"The average value over the number of update messages sent
to each active update stream within the last time window.
The procedure is similar to num-msg-max, but only count
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the update messages within the last time window. The
duration of the time window is configured by
time-window-size parameter.";
}
reference
"RFC 8895: Application-Layer Traffic Optimization (ALTO)
Incremental Updates Using Server-Sent Events
(SSE)";
}
grouping resource-level-stats {
description
"This grouping defines statistics for resource-level
monitoring.";
leaf discontinuity-time {
type yang:timestamp;
description
"The time on the most recent occasion at which the ALTO
service providing the information resource suffered a
discontinuity. This must be initialized when the ALTO
information resource is configured or the ALTO server is
rebooted.";
}
leaf last-report-time {
type yang:timestamp;
description
"The time on the most recent occasion at which the
statistics are reported.";
}
leaf num-res-upd {
type yang:counter64;
description
"The number of version updates since the information
resource was created.";
}
leaf res-mem-size {
type uint64;
units "bytes";
description
"Memory size utilized by the information resource.";
}
leaf res-enc-size {
type uint64;
units "bytes";
description
"Size of JSON encoded data of the information resource.";
}
leaf num-res-req {
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type yang:counter64;
description
"The total number of ALTO requests to this information
resource.";
}
leaf num-res-succ {
type yang:counter64;
description
"The total number of successful responses for requests to
this information resource.";
}
leaf num-res-fail {
type yang:counter64;
description
"The total number of failed responses for requests to this
information resource.";
}
leaf num-res-last-req {
type yang:gauge64;
description
"The number of ALTO requests to this information resource
within the last time window. The duration of the time
window is configured by time-window-size parameter.";
}
leaf num-res-last-succ {
type yang:gauge64;
description
"The number of successful responses for requests to this
information resource within the last time window. The
duration of the time window is configured by
time-window-size parameter.";
}
leaf num-res-last-fail {
type yang:gauge64;
description
"The number of failed responses for requests to this
information resource within the last time window. The
duration of the time window is configured by
time-window-size parameter.";
}
container network-map-stats {
when 'derived-from-or-self(../../alto:resource-type,'
+ '"alto:network-map")';
description
"Resource-specific statistics for network map
service only.";
uses network-map-stats;
}
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container endpoint-prop-stats {
when 'derived-from-or-self(../../alto:resource-type,'
+ '"alto:endpoint-prop")';
description
"Resource-specific statistics for endpoint property
service only.";
uses prop-map-stats;
}
container property-map-stats {
when 'derived-from-or-self(../../alto:resource-type,'
+ '"alto:property-map")';
description
"Resource-specific statistics for entity property map
service only.";
uses prop-map-stats;
}
container cdni-stats {
when 'derived-from-or-self(../../alto:resource-type,'
+ '"alto:cdni")';
description
"Resource-specific statistics for CDNI advertisement
service only.";
uses cdni-stats;
}
container upd-stream-stats {
when 'derived-from-or-self(../../alto:resource-type,'
+ '"alto:update")';
description
"Resource-specific statistics for update stream service
only.";
uses upd-stream-stats;
}
}
// Augment modules to add statistics
augment "/alto:alto/alto:alto-server" {
description
"Augmenting statistics and configuration parameters for
server-level monitoring.";
container server-level-monitor-config {
description
"Configuration parameters for server-level monitoring.";
leaf time-window-size {
type uint32;
units "seconds";
default "300";
description
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"Duration of the time window within that the statistics
are reported.";
}
}
container server-level-stats {
config false;
description
"Top-level statistics for the whole ALTO server.";
uses server-level-stats;
}
}
augment "/alto:alto/alto:alto-server/alto:resource" {
description
"Augmenting statistics and configuration parameters for
resource-level monitoring.";
container resource-level-stats {
config false;
description
"Common statistics for each information resource.";
uses resource-level-stats;
}
}
}
<CODE ENDS>
8. 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 [RFC6241] and RESTCONF [RFC8040]. Both of these
protocols have mandatory-to-implement secure transport layers (e.g.,
SSH, TLS) with mutual authentication.
The Network Access Control Model (NACM) [RFC8341] 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 modules 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 in network environments. The NACM "default-deny-write"
extension has not been set for any data nodes defined in these
modules.
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However, there are a number of writable data nodes defined in these
YANG modules that are considered vulnerable in network environments.
Write operations to these data nodes without proper protection can
have a negative effect. These are the data nodes and their
vulnerable:
feed-interval: A malicious client could attempt to set a very low/
large value to this node. Setting a very low value could attack
the data source. And setting a very large value would lead to
maintaining stale data in the ALTO server.
poll-interval: A malicious client could attempt to set a very low/
large value to this node. Setting a very low value could attack
the data source. And setting a very large value would lead to
maintaining stale data in the ALTO server.
The "ietf-alto" supports an HTTP listen mode to cover cases where the
ALTO server stack does not handle the TLS termination itself, but is
handled by a separate component. Special care should be considered
when such mode is enabled. Note that the default listen mode is
"https".
Also, please be aware that these modules include choice nodes that
can be augmented by other extended modules. The augmented data nodes
may be considered sensitive or vulnerable in some network
environments. For instance, an augmented case of the "source-params"
choice in "data-source" may include authentication information about
how to access a data source including private network information.
The "yang-datastore" case in Appendix A.3 is such an example. The
"restconf" and "netconf" nodes in it may reveal the access to a
private YANG datastore. Thus, those extended modules may have the
NACM extension "default-deny-all" set.
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.
9. IANA Considerations
This document registers the following URIs in the "IETF XML Registry"
[RFC3688]:
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URI: urn:ietf:params:xml:ns:yang:ietf-alto
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-alto-stats
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
This document registers the following two YANG modules in the "YANG
Module Names" registry [RFC6020]:
Name: ietf-alto
Namespace: urn:ietf:params:xml:ns:yang:ietf-alto
Prefix: alto
Maintained by IANA: N
Reference: [RFC XXXX]
Name: ietf-alto-stats
Namespace: urn:ietf:params:xml:ns:yang:ietf-alto-stats
Prefix: alto-stats
Maintained by IANA: N
Reference: [RFC XXXX]
10. References
10.1. Normative References
[I-D.ietf-netconf-http-client-server]
Watsen, K., "YANG Groupings for HTTP 1.1/2.0 Clients and
HTTP Servers", Work in Progress, Internet-Draft, draft-
ietf-netconf-http-client-server-13, 17 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
http-client-server-13>.
[I-D.ietf-netconf-netconf-client-server]
Watsen, K., "NETCONF Client and Server Models", Work in
Progress, Internet-Draft, draft-ietf-netconf-netconf-
client-server-29, 17 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
netconf-client-server-29>.
[I-D.ietf-netconf-restconf-client-server]
Watsen, K., "RESTCONF Client and Server Models", Work in
Progress, Internet-Draft, draft-ietf-netconf-restconf-
client-server-29, 17 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
restconf-client-server-29>.
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[I-D.ietf-netconf-tcp-client-server]
Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients
and TCP Servers", Work in Progress, Internet-Draft, draft-
ietf-netconf-tcp-client-server-16, 17 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
tcp-client-server-16>.
[I-D.ietf-netconf-tls-client-server]
Watsen, K., "YANG Groupings for TLS Clients and TLS
Servers", Work in Progress, Internet-Draft, draft-ietf-
netconf-tls-client-server-33, 17 April 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
tls-client-server-33>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/rfc/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/rfc/rfc6020>.
[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,
<https://www.rfc-editor.org/rfc/rfc6241>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/rfc/rfc6991>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<https://www.rfc-editor.org/rfc/rfc7285>.
[RFC7286] Kiesel, S., Stiemerling, M., Schwan, N., Scharf, M., and
H. Song, "Application-Layer Traffic Optimization (ALTO)
Server Discovery", RFC 7286, DOI 10.17487/RFC7286,
November 2014, <https://www.rfc-editor.org/rfc/rfc7286>.
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[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8189] Randriamasy, S., Roome, W., and N. Schwan, "Multi-Cost
Application-Layer Traffic Optimization (ALTO)", RFC 8189,
DOI 10.17487/RFC8189, October 2017,
<https://www.rfc-editor.org/rfc/rfc8189>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/rfc/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/rfc/rfc8341>.
[RFC8686] Kiesel, S. and M. Stiemerling, "Application-Layer Traffic
Optimization (ALTO) Cross-Domain Server Discovery",
RFC 8686, DOI 10.17487/RFC8686, February 2020,
<https://www.rfc-editor.org/rfc/rfc8686>.
[RFC8895] Roome, W. and Y. Yang, "Application-Layer Traffic
Optimization (ALTO) Incremental Updates Using Server-Sent
Events (SSE)", RFC 8895, DOI 10.17487/RFC8895, November
2020, <https://www.rfc-editor.org/rfc/rfc8895>.
[RFC8896] Randriamasy, S., Yang, R., Wu, Q., Deng, L., and N.
Schwan, "Application-Layer Traffic Optimization (ALTO)
Cost Calendar", RFC 8896, DOI 10.17487/RFC8896, November
2020, <https://www.rfc-editor.org/rfc/rfc8896>.
10.2. Informative References
[I-D.ietf-alto-performance-metrics]
Wu, Q., Yang, Y. R., Lee, Y., Dhody, D., Randriamasy, S.,
and L. M. Contreras, "ALTO Performance Cost Metrics", Work
in Progress, Internet-Draft, draft-ietf-alto-performance-
metrics-28, 21 March 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-alto-
performance-metrics-28>.
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[RFC6291] Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
D., and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", BCP 161, RFC 6291,
DOI 10.17487/RFC6291, June 2011,
<https://www.rfc-editor.org/rfc/rfc6291>.
[RFC7921] Atlas, A., Halpern, J., Hares, S., Ward, D., and T.
Nadeau, "An Architecture for the Interface to the Routing
System", RFC 7921, DOI 10.17487/RFC7921, June 2016,
<https://www.rfc-editor.org/rfc/rfc7921>.
[RFC7971] Stiemerling, M., Kiesel, S., Scharf, M., Seidel, H., and
S. Previdi, "Application-Layer Traffic Optimization (ALTO)
Deployment Considerations", RFC 7971,
DOI 10.17487/RFC7971, October 2016,
<https://www.rfc-editor.org/rfc/rfc7971>.
[RFC8346] Clemm, A., Medved, J., Varga, R., Liu, X.,
Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model
for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346,
March 2018, <https://www.rfc-editor.org/rfc/rfc8346>.
[RFC9240] Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
Gao, "An Extension for Application-Layer Traffic
Optimization (ALTO): Entity Property Maps", RFC 9240,
DOI 10.17487/RFC9240, July 2022,
<https://www.rfc-editor.org/rfc/rfc9240>.
[RFC9241] Seedorf, J., Yang, Y., Ma, K., Peterson, J., and J. Zhang,
"Content Delivery Network Interconnection (CDNI) Footprint
and Capabilities Advertisement Using Application-Layer
Traffic Optimization (ALTO)", RFC 9241,
DOI 10.17487/RFC9241, July 2022,
<https://www.rfc-editor.org/rfc/rfc9241>.
[RFC9275] Gao, K., Lee, Y., Randriamasy, S., Yang, Y., and J. Zhang,
"An Extension for Application-Layer Traffic Optimization
(ALTO): Path Vector", RFC 9275, DOI 10.17487/RFC9275,
September 2022, <https://www.rfc-editor.org/rfc/rfc9275>.
Appendix A. 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.
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* The authentication choice of each auth-client.
* The data-source choice.
* The algorithm choice of the resource-params of each resource.
A.1. 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.
module example-vendor-alto-server-discovery {
yang-version 1.1;
namespace "https://example.com/ns/vendor-alto-server-discovery";
prefix vendor-alto-disc;
import ietf-alto {
prefix alto;
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
organization
"Example, Inc.";
contact
"Example, Inc.
Customer Service
E-mail: alto-oam-yang@example.com";
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description
"This module contains a collection of vendor-specific cases of
server discovery mechanisms for ALTO.";
revision 2023-02-28 {
description
"Version 1.0";
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
augment "/alto:alto/alto:alto-server/alto:server-discovery"
+ "/alto:method" {
description
"Examples of server discovery mechanisms provided by the ALTO
server.";
case internet-routing-registry {
description
"Update descr attributes of an aut-num class in an Internet
Routing Registry (IRR) database for ALTO server discovery
using Routing Policy Specification Language (RPSL).";
reference
"RFC 2622: Routing Policy Specification Language (RPSL).";
container irr-params {
description
"Configuration parameters for IRR database.";
leaf aut-num {
type inet:as-number;
description
"The Autonomous System (AS) number to be updated.";
}
}
}
case peeringdb {
description
"Update metadata of a network record in PeeringDB database
for ALTO server discovery using PeeringDB lookup.";
container peeringdb-params {
description
"Configuration parameters for PeeringDB database.";
leaf org-id {
type uint32;
description
"Specifies an identifier that refers to the org object
of the organization record in PeeringDB.";
}
}
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}
}
augment "/alto:alto/alto:alto-client"
+ "/alto:server-discovery/alto:method" {
description
"Examples of server discovery mechanisms used by an ALTO
client.";
case internet-routing-registry {
description
"Use IRR to discover an ALTO server.";
reference
"RFC 2622: Routing Policy Specification Language (RPSL).";
container irr-params {
description
"Configuration for IRR query using RPSL.";
leaf whois-server {
type inet:host;
description
"Whois server for an IRR query using RPSL.";
}
}
}
case peeringdb {
description
"Use PeeringDB to discover an ALTO server.";
container peeringdb-params {
description
"Configuration for PeeringDB queries.";
leaf peeringdb-endpoint {
type inet:uri;
description
"Endpoint of PeeringDB API server.";
}
}
}
}
}
A.2. 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.
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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.
module example-vendor-alto-auth {
yang-version 1.1;
namespace "https://example.com/ns/vendor-alto-auth";
prefix vendor-alto-auth;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-alto {
prefix alto;
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
organization
"Example, Inc.";
contact
"Example, Inc.
Customer Service
E-mail: alto-oam-yang@example.com";
description
"This module contains a collection of vendor-specific cases of
client authentication approaches for ALTO.";
revision 2023-02-28 {
description
"Version 1.0";
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
augment "/alto:alto/alto:alto-server/alto:auth-client"
+ "/alto:authentication" {
description
"Example of extended ALTO client authentication approaches.";
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case oauth2 {
description
"Example of authentication by a third-party OAuth 2.0
server.";
container oauth2 {
description
"Parameters for authentication by a third-party OAuth 2.0
server.";
leaf oauth2-server {
type inet:uri;
description
"The URI to the authorization server.";
}
}
}
}
}
A.3. 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.
module example-vendor-alto-data-source {
yang-version 1.1;
namespace "https://example.com/ns/vendor-alto-data-source";
prefix vendor-alto-ds;
import ietf-alto {
prefix alto;
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
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import ietf-datastores {
prefix ds;
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
import ietf-yang-push {
prefix yp;
reference
"RFC 8641: Subscription to YANG Notifications for Datastore
Updates";
}
import ietf-netconf-client {
prefix ncc;
reference
"RFC HHHH: NETCONF Client and Server Models";
}
import ietf-restconf-client {
prefix rcc;
reference
"RFC IIII: YANG Groupings for RESTCONF Clients and RESTCONF
Servers";
}
organization
"Example, Inc.";
contact
"Example, Inc.
Customer Service
E-mail: alto-oam-yang@example.com";
description
"This module contains a collection of vendor-specific cases of
data sources for ALTO.";
revision 2023-02-28 {
description
"Version 1.0";
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
identity yang-datastore {
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base alto:source-type;
description
"Identity for data source of YANG-based datastore.";
}
identity protocol-type {
description
"Base identity for protocol type.";
}
identity netconf {
base protocol-type;
description
"Identity for NETCONF protocol.";
}
identity restconf {
base protocol-type;
description
"Identity for RESTCONF protocol.";
}
augment "/alto:alto/alto:alto-server/alto:data-source"
+ "/alto:source-params" {
description
"Example of data source for YANG datastore.";
case yang-datastore {
when 'derived-from-or-self(alto:source-type,'
+ '"yang-datastore")';
description
"Example data source for local or remote YANG datastore.";
container yang-datastore-source-params {
description
"YANG datastore specific configuration.";
leaf datastore {
type ds:datastore-ref;
mandatory true;
description
"Reference of the datastore from which to get data.";
}
list target-paths {
key name;
description
"XML Path Language (XPath) to subscribed YANG datastore
node or subtree.";
leaf name {
type string;
description
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"Name of the supported XPath or subtree filters.";
}
uses yp:selection-filter-types;
}
leaf protocol {
type identityref {
base protocol-type;
}
description
"Indicates the protocol that is used to access the YANG
datastore.";
}
container restconf {
uses rcc:restconf-client-app-grouping {
when 'derived-from-or-self(../protocol, "restconf")';
}
description
"Parameters for the RESTCONF endpoint of the YANG
datastore.";
}
container netconf {
uses ncc:netconf-client-app-grouping {
when 'derived-from-or-self(../protocol, "netconf")';
}
description
"Parameters for the NETCONF endpoint of the YANG
datastore.";
}
}
}
}
}
A.4. 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.
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module: example-vendor-alto-alg
augment /alto:alto/alto:alto-server/alto:resource
/alto:alto-networkmap-params/alto:algorithm:
+--:(l3-unicast-cluster)
+--rw l3-unicast-cluster-algorithm
+--rw l3-unicast-topo
| +--rw source-datastore alto:data-source-ref
| +--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 Appendix A.3) subscribed in the data-source list (See
Section 5.4.1). The referenced target path in the corresponding
yang-datastore data source is assumed for an IETF layer 3 unicast
topology defined in [RFC8346]. 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 Section 5.4.1).
module example-vendor-alto-alg {
yang-version 1.1;
namespace "https://example.com/ns/vendor-alto-alg";
prefix vendor-alto-alg;
import ietf-alto {
prefix alto;
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
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import ietf-datastores {
prefix ietf-datastores;
reference
"RFC 8342: Network Management Datastore Architecture (NMDA)";
}
import example-vendor-alto-data-source {
prefix alto-ds;
}
organization
"Example, Inc.";
contact
"Example, Inc.
Customer Service
E-mail: alto-oam-yang@example.com";
description
"This module contains a collection of vendor-specific cases of
information resource creation algorithms for ALTO.";
revision 2023-02-28 {
description
"Version 1.0";
reference
"RFC XXXX: YANG Data Models for the Application-Layer
Traffic Optimization (ALTO) Protocol";
}
augment "/alto:alto/alto:alto-server/alto:resource"
+ "/alto:alto-networkmap-params/alto:algorithm" {
description
"Example of a network map creation algorithm.";
case l3-unicast-cluster {
description
"Example algorithm translating a Layer 3 unicast topology
of Interface to the Routing System (I2RS) to an ALTO
network map.";
container l3-unicast-cluster-algorithm {
description
"Parameters for l3-unicast-cluster algorithm.";
container l3-unicast-topo {
leaf source-datastore {
type alto:data-source-ref;
must 'deref(.)/../alto-ds:yang-datastore-source-params'
+ '/alto-ds:datastore '
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+ '= "ietf-datastores:operational"'
{
error-message
"The referenced YANG datastore MUST be
operational";
}
mandatory true;
description
"The data source to YANG datastore.";
}
leaf topo-name {
type leafref {
path '/alto:alto/alto:alto-server/alto:data-source'
+ '[alto:source-id'
+ ' = current()/../source-datastore]'
+ '/alto-ds:yang-datastore-source-params'
+ '/alto-ds:target-paths/alto-ds:name';
}
description
"The name of the IETF Layer 3 unicast topology.";
}
description
"The data source info to an IETF Layer 3 unicast
topology.";
}
leaf depth {
type uint32;
description
"The depth of the clustering.";
}
}
}
}
}
A.5. 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).
=============== NOTE: '\' line wrapping per RFC 8792 ================
{
"ietf-alto:alto": {
"alto-server": {
"listen": {
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"https": {
"tcp-server-parameters": {
"local-address": "0.0.0.0"
},
"alto-server-parameters": {},
"http-server-parameters": {
"server-name": "alto.example.com",
"client-authentication": {
"users": {
"user": [
{
"user-id": "alice",
"basic": {
"user-id": "alice",
"password": "$0$p8ssw0rd"
}
}
]
}
}
},
"tls-server-parameters": {
"server-identity": {}
}
}
},
"server-discovery": {
"example-vendor-alto-server-discovery:irr-params": {
"aut-num": 64496
}
},
"auth-client": [
{
"client-id": "alice",
"https-auth-client": {
"user-id": "alice"
}
},
{
"client-id": "bob",
"example-vendor-alto-auth:oauth2": {
"oauth2-server": "https://auth.example.com/login"
}
}
],
"role": [
{
"role-name": "group0",
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"client": [
"alice",
"bob"
]
}
],
"data-source": [
{
"source-id": "test-yang-ds",
"source-type": "example-vendor-alto-data-source:yang-\
datastore",
"feed-interval": 30,
"example-vendor-alto-data-source:yang-datastore-source-\
params": {
"datastore": "ietf-datastores:operational",
"target-paths": [
{
"name": "network-topology",
"datastore-xpath-filter": "/network-topology:network\
-topology/topology[topology-id=bgp-example-ipv4-topology]"
}
],
"protocol": "restconf",
"restconf": {
"listen": {
"endpoint": [
{
"name": "example restconf server",
"https": {
"tcp-server-parameters": {
"local-address": "172.17.0.2"
},
"http-client-parameters": {
"client-identity": {
"basic": {
"user-id": "carol",
"cleartext-password": "secret"
}
}
}
}
}
]
}
}
}
}
],
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"resource": [
{
"resource-id": "default-network-map",
"resource-type": "network-map",
"accepted-role": [
"group0"
],
"alto-networkmap-params": {
"is-default": true,
"example-vendor-alto-alg:l3-unicast-cluster-algorithm": {
"l3-unicast-topo": {
"source-datastore": "test-yang-ds",
"topo-name": "network-topology"
},
"depth": 2
}
}
}
]
}
}
}
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 Adrian Farrel, Jordi Ros Giralt,
Luis M. Contreras, and Qiao Xiang for their thorough reviews,
shepherding, and valuable feedback.
Thanks to Dan Romascanu for the opsdir review, Andy Bierman for the
yangdoctors review, and Spencer Dawkins for the tsvart review.
Authors' Addresses
Jingxuan Jensen Zhang
Tongji University
4800 Cao'An Hwy
Shanghai
201804
China
Email: jingxuan.n.zhang@gmail.com
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
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Bangalore 560066
Karnataka
India
Email: dhruv.ietf@gmail.com
Kai Gao
Sichuan University
No.24 South Section 1, Yihuan Road
Chengdu
Sichuan, 610000
China
Email: kaigao@scu.edu.cn
Roland Schott
Deutsche Telekom
Ida-Rhodes-Straße 2
64295 Darmstadt
Germany
Email: Roland.Schott@telekom.de
Qiufang Ma
Huawei
101 Software Avenue, Yuhua District
Nanjing
Jiangsu, 210012
China
Email: maqiufang1@huawei.com
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