Internet-Draft ALTO OAM YANG July 2021
Zhang, et al. Expires 13 January 2022 [Page]
Workgroup:
ALTO WG
Internet-Draft:
draft-zhang-alto-oam-yang-00
Published:
Intended Status:
Informational
Expires:
Authors:
J. Zhang
Tongji University
D. Dhody
Huawei Technologies
K. Gao
Sichuan University

A Yang Data Model for Operations, Administration, and Maintenance of ALTO Protocol

Abstract

This document defines a YANG data model for the operations and management of Application-Layer Traffic Optimization (ALTO) Protocol. The operator can use the data model to create and update ALTO information resources, manage the access control, configure server-to-server communication and 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/openalto/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/.

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 13 January 2022.

1. Introduction

This document defines a YANG data model for the operations and management of Application-Layer Traffic Optimization (ALTO) Protocol. The basic propose of this YANG data model is discussed in Section 16 of [RFC7285]. The operator can use the data model to create and update ALTO information resources, manage the access control, configure server-to-server communication and server discovery, and collect statistical data.

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 (including [RFC8189], [RFC8895] and [RFC8896]), the design will also be extensible for future standard extensions (e.g., [I-D.ietf-alto-path-vector], [I-D.ietf-alto-unified-props-new], [I-D.ietf-alto-cost-calendar], and [I-D.ietf-alto-performance-metrics]).

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. Terminology

3.1. Tree Diagrams

A simplified graphical representation of the data model is used in this document. The meaning of the symbols in these 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.

Table 1: Prefixes and corresponding YANG modules
Prefix YANG module Reference
yang ietf-yang-types [RFC6991]
inet ietf-inet-types [RFC6991]

4. Objectives

This section describes the design objectives for the YANG data model:

  • The data model should provide intent-based interfaces for administrators to create, update and remove ALTO information resources.

    • The data model should be extensible for new ALTO information resources.
    • The data model should allow developers to augment new APIs for ALTO information resource generation.
  • The data model should support access control at the information resource level.
  • The data model should collect statistics information of the requests to each ALTO information resource.

NOTE: The data model supporting configuration for the ALTO client and the communication between the administrated ALTO server and other ALTO servers will be considered in a future version of the document.

5. Design of ALTO OAM Data Model

5.1. Overview of ALTO OAM Data Model

The ALTO YANG module defined in this document has all the common building blocks for ALTO OAM.

NOTE: So far, the ALTO YANG module only focuses on the ALTO server related configuration. The ALTO client related configuration will be added in a future version of the document.

The container "alto-server" in the ALTO yang module contains all the configured and operational parameters of the adminstrated ALTO server instance.

module: ietf-alto
  +--rw alto-server
     +--rw hostname  inet:host
     +--rw cost-type* [cost-type-name]
     |   +--rw cost-type-name string
     |   +--rw cost-mode      cost-mode
     |   +--rw cost-metric    cost-metric
     |--rw meta* [meta-key]
     |   +--rw meta-key       string
     |   +--rw meta-value     string
     +--rw resource* [resource-id]
     |   +--rw resource-id    resource-id
     |   +--rw resource-type  identityref
     |   +--rw description?   string
     |   +--rw accepted-group* [user-group]
     |   +--rw dependency*    resource-id
     |   |  ...
     |   +--rw (resource-params)
     |      +--:(ird)
     |      |  +--rw alto-ird-params
     |      |     +--rw delegation         inet:uri
     |      +--:(networkmap)
     |      |  +--rw alto-networkmap-params
     |      |     +--rw is-default?        boolean
     |      |     +--rw filtered?          boolean
     |      |     +--rw (algorithm)
     |      +--:(costmap)
     |      |  +--rw alto-costmap-params
     |      |     +--rw filtered?          boolean
     |      |     +--rw cost-type-names*   string
     |      |     +--rw cost-constraints?  boolean
     |      |     +--rw max-cost-types?    uint32 {multi-cost}?
     |      |     +--rw testable-cost-type-names*
     |      |             string {multi-cost}?
     |      |     +--rw calendar?          boolean {cost-calendar}?
     |      |     +--rw (algorithm)
     |      +--:(endpointcost)
     |      |  +--rw alto-endpointcost-params
     |      |     +--rw cost-type* [cost-mode,cost-metric]
     |      |     |  +--rw cost-mode       cost-mode
     |      |     |  +--rw cost-metric     cost-metric
     |      |     +--rw cost-constraints?  boolean
     |      |     +--rw max-cost-types?    uint32 {multi-cost}?
     |      |     +--rw testable-cost-type-names*
     |      |             string {multi-cost}?
     |      |     +--rw calendar?          boolean {cost-calendar}?
     |      |     +--rw (algorithm)
     |      +--:(endpointprop)
     |      |  +--rw alto-endpointprop-params
     |      |     +--rw (algorithm)
     |      +--:(propmap) {propmap}?
     |      |  +--rw alto-propmap-params
     |      |     +--rw (algorithm)
     |      +--:(cdni) {cdni}?
     |      |  +--rw alto-cdni-params
     |      |     +--rw (algorithm)
     |      +--:(update) {incr-update}?
     |         +--rw alto-update-params
     |            +--rw (algorithm)
     +--rw data-source* [source-id]
        +--rw source-id   string
        +--rw source-type identityref
        +--rw (update-policy)
        |  +--:(reactive)
        |  |  +--rw reactive         boolean
        |  +--:(proactive)
        |     +--rw poll-interval    uint32
        +--rw (source-params)
           +--:(internal)
           |  +--rw internal-source-params
           |     +--rw source-path   yang:xpath1.0
           +--:(external)
              +--rw external-source-params
                 +--rw source-uri    inet:uri
                 +--rw query-data?   string

5.2. Meta Information of ALTO Server

The ALTO server instance contains the following basic configurations for the server setup.

The hostname is the name that is used to access the ALTO server. It will be also used in the URI of each information resource provided by the ALTO server.

The cost type list is the registry for the cost types that can be used in the ALTO server.

The meta list contains the customized meta data of the ALTO server. It will be populated into the meta field of the default Information Resource Directory (IRD).

module: ietf-alto
  +--rw alto-server
     +--rw hostname  inet:host
     +--rw cost-type* [cost-type-name]
     |   +--rw cost-type-name string
     |   +--rw cost-mode      cost-mode
     |   +--rw cost-metric    cost-metric
     |--rw meta* [meta-key]
     |   +--rw meta-key       string
     |   +--rw meta-value     string
     ...

5.3. Intent-based Interfaces for ALTO Information Resources Management

The ALTO server instance contains a list of resource entries. Each resource entry contains the configurations of an ALTO information resource (See Section 8.1 of [RFC7285]). The operator of the ALTO server can use this model to create, update, and remove the ALTO information resource.

Each resoruce entry is considered as an intent to create or update an ALTO information resource. Adding a new resource entry will submit an ALTO information resource creation intent to the intent system to create a new ALTO information resource. Updating an existing resource entry will update the corresponding ALTO information resource creation intent. Removing an existing resource entry will remove the corresponding ALTO information resource creation intent and also the created ALTO information resource.

The parameter of the intent interface defined by a resource entry MUST include a unique resource-id and a resource-type.

It can also include an accepted-group node containing a list of user-groups that can access this ALTO information resource.

For some resource-type, the parameter of the intent interface MUST also include the a dependency node containing the resource-id of the dependent ALTO information resources (See Section 9.1.5 of [RFC7285]).

For each type of ALTO information resource, the creation intent MAY also need type-specific parameters. These type-specific parameters include two categories:

  1. One categories of the type-specific parameters are common for the same type of ALTO information resource. They declare the Capabilities of the ALTO information resource (See Section 9.1.3 of [RFC7285]).
  2. The other categories of the type-specific parameters are algorithm-specific. The developer of the ALTO server can implement their own creation altorithms and augment the algorithm node to declare algorithm-specific input parameters.

Except for the ird resource, all the other types of resource entries have augmented algorithm node. The augmented algorithm node can reference data sources subscribed by the data-source entries (See Section 5.4).

The developer cannot 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 (See Section 9.2.4 of [RFC7285]).

module: ietf-alto
  +--rw alto-server
     ...
     +--rw resource* [resource-id]
     |   +--rw resource-id    resource-id
     |   +--rw resource-type  identityref
     |   +--rw description?   string
     |   +--rw accepted-group* [user-group]
     |   +--rw dependency*    resource-id
     |   |  ...
     |   +--rw (resource-params)
     |      +--:(ird)
     |      |  +--rw alto-ird-params
     |      |     +--rw delegation         inet:uri
     |      +--:(networkmap)
     |      |  +--rw alto-networkmap-params
     |      |     +--rw is-default?        boolean
     |      |     +--rw filtered?          boolean
     |      |     +--rw (algorithm)
     |      +--:(costmap)
     |      |  +--rw alto-costmap-params
     |      |     +--rw filtered?          boolean
     |      |     +--rw cost-type-names*   string
     |      |     +--rw cost-constraints?  boolean
     |      |     +--rw max-cost-types?    uint32 {multi-cost}?
     |      |     +--rw testable-cost-type-names*
     |      |             string {multi-cost}?
     |      |     +--rw calendar?          boolean {cost-calendar}?
     |      |     +--rw (algorithm)
     |      +--:(endpointcost)
     |      |  +--rw alto-endpointcost-params
     |      |     +--rw cost-type* [cost-mode,cost-metric]
     |      |     |  +--rw cost-mode       cost-mode
     |      |     |  +--rw cost-metric     cost-metric
     |      |     +--rw cost-constraints?  boolean
     |      |     +--rw max-cost-types?    uint32 {multi-cost}?
     |      |     +--rw testable-cost-type-names*
     |      |             string {multi-cost}?
     |      |     +--rw calendar?          boolean {cost-calendar}?
     |      |     +--rw (algorithm)
     |      +--:(endpointprop)
     |      |  +--rw alto-endpointprop-params
     |      |     +--rw (algorithm)
     |      +--:(propmap) {propmap}?
     |      |  +--rw alto-propmap-params
     |      |     +--rw (algorithm)
     |      +--:(cdni) {cdni}?
     |      |  +--rw alto-cdni-params
     |      |     +--rw (algorithm)
     |      +--:(update) {incr-update}?
     |         +--rw alto-update-params
     |            +--rw (algorithm)
     ...

5.3.1. Information Resource Creation Algorithm Example

The following example shows how the developer can augment a creation algorithm for the network map resource.

  augment /alto:alto-server/alto:resource/alto:resource-params
            /alto:networkmap/alto:alto-networkmap-params
            /alto:algorithm:
    +--rw l3-unicast-cluster-algorithm
       +--rw l3-unicast-topo
       |       -> /alto:alto-server/data-source/source-id
       +--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 refers to the source id of a data source node subscribed in the data-source list (See Section 5.4). The corresponding data source is assumed to be an internel data source (See Section 5.4.1) 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.

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).

5.4. Data Sources

The ALTO server instance contains a list of data-source entries to subscribe the data sources from which ALTO information resources are derived (See Section 16.2.4 of [RFC7285]).

A data-source entry MUST include:

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

The update policy can be either reactive or proactive. For the reactive update, the ALTO server gets the update as soon as the data source changes. For the proactive update, the ALTO server has to proactively fetch the data source periodically.

To use the reactive update, the reactive attribute MUST be set true. To use the proactive update, the poll-interval attribute MUST be greater than zero. The value of poll-interval specifies the interval of fetching the data in milliseconds. If reactive is false or poll-interval is zero, the ALTO server will not update the data source.

The target of the data source can be either internal or external.

module: ietf-alto
  +--rw alto-server
     ...
     +--rw data-source* [source-id]
        +--rw source-id   string
        +--rw source-type identityref
        +--rw (update-policy)
        |  +--:(reactive)
        |  |  +--rw reactive         boolean
        |  +--:(proactive)
        |     +--rw poll-interval    uint32
        +--rw (source-params)
           +--:(internal)
           |  +--rw internal-source-params
           |     +--rw source-path   yang:xpath1.0
           +--:(external)
              +--rw external-source-params
                 +--rw source-uri    inet:uri
                 +--rw query-data?   string

5.4.1. Internal Data Source

The internal-source-params is used to subscribe the internel data source which is located in the same YANG model-driven data store supplying the current ALTO OAM data model. The source-path is used to specify the XPath of the data source node.

5.4.2. External Data Source

The external-source-params is sued to subscribe the external data source which is located in other database systems, e.g., an SNMP server, a prometheus monitor, or a SQL database. The source-uir is used to establish the connection with the external data source. The query-data is used to speficify the potential query expression.

7. References

7.1. Normative References

[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC6991]
Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/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, , <https://www.rfc-editor.org/info/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, , <https://www.rfc-editor.org/info/rfc7286>.
[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, , <https://www.rfc-editor.org/info/rfc7971>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8189]
Randriamasy, S., Roome, W., and N. Schwan, "Multi-Cost Application-Layer Traffic Optimization (ALTO)", RFC 8189, DOI 10.17487/RFC8189, , <https://www.rfc-editor.org/info/rfc8189>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <https://www.rfc-editor.org/info/rfc8340>.
[RFC8571]
Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric Extensions", RFC 8571, DOI 10.17487/RFC8571, , <https://www.rfc-editor.org/info/rfc8571>.
[RFC8686]
Kiesel, S. and M. Stiemerling, "Application-Layer Traffic Optimization (ALTO) Cross-Domain Server Discovery", RFC 8686, DOI 10.17487/RFC8686, , <https://www.rfc-editor.org/info/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, , <https://www.rfc-editor.org/info/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, , <https://www.rfc-editor.org/info/rfc8896>.

7.2. Informative References

[I-D.ietf-alto-cost-calendar]
Randriamasy, S., Yang, R., Wu, Q., Deng, L., and N. Schwan, "Application-Layer Traffic Optimization (ALTO) Cost Calendar", Work in Progress, Internet-Draft, draft-ietf-alto-cost-calendar-21, , <https://www.ietf.org/archive/id/draft-ietf-alto-cost-calendar-21.txt>.
[I-D.ietf-alto-path-vector]
Gao, K., Lee, Y., Randriamasy, S., Yang, Y. R., and J. J. Zhang, "ALTO Extension: Path Vector", Work in Progress, Internet-Draft, draft-ietf-alto-path-vector-14, , <https://www.ietf.org/archive/id/draft-ietf-alto-path-vector-14.txt>.
[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-16, , <https://www.ietf.org/archive/id/draft-ietf-alto-performance-metrics-16.txt>.
[I-D.ietf-alto-unified-props-new]
Roome, W., Randriamasy, S., Yang, Y. R., Zhang, J. J., and K. Gao, "ALTO Extension: Entity Property Maps", Work in Progress, Internet-Draft, draft-ietf-alto-unified-props-new-17, , <https://www.ietf.org/archive/id/draft-ietf-alto-unified-props-new-17.txt>.
[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, , <https://www.rfc-editor.org/info/rfc8346>.

Appendix A. The Full ALTO OAM Data Model

TODO: The complete tree diagram and YANG modules will be updated soon.

Authors' Addresses

Jingxuan Jensen Zhang
Tongji University
4800 Cao'An Hwy
Shanghai
201804
China
Dhruv Dhody
Huawei Technologies
Divyashree Techno Park, Whitefield
Bangalore 560066
Karnataka
India
Kai Gao
Sichuan University
No.24 South Section 1, Yihuan Road
Chengdu
610000
China