Internet-Draft | Network and VPN Service PM YANG | January 2022 |
Wu, et al. | Expires 2 August 2022 | [Page] |
The data model for network topologies defined in RFC 8345 introduces vertical layering relationships between networks that can be augmented to cover network and service topologies. This document defines a YANG module for performance monitoring (PM) of both networks and VPN services that can be used to monitor and manage network performance on the topology at higher layer or the service topology between VPN sites.¶
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[RFC8969] describes a framework for automating service and network management with YANG models. It proposes that the performance measurement telemetry model to be tied with the service, such as Layer 3 VPN and Layer 2 VPN, or network models to monitor the overall network performance or Service Level Agreements (SLA).¶
The performance of VPN services is associated with the performance changes of the underlay network that carries VPN services, such as the delay of the underlay tunnels and the packet loss status of the device interfaces. Additionally, the integration of Layer 2/Layer 3 VPN performance and network performance data enables the orchestrator to subscribe to VPN service performance in a unified manner. Therefore, this document defines a YANG module for both network and VPN service performance monitoring (PM). The module can be used to monitor and manage network performance on the topology level or the service topology between VPN sites, in particular.¶
This document does not introduce new metrics for network performance or mechanisms for measuring network performance, but uses the existing mechanisms and statistics to display the performance monitoring statistics at the network and service layers. All these metrics are defined as unidirectional metrics.¶
The YANG module defined in this document is designed as an augmentation to the network topology YANG model defined in [RFC8345] and draws on relevant YANG types defined in [RFC6991], [RFC8345], [RFC8532], and [I-D.ietf-opsawg-vpn-common].¶
Appendix A provides a set of examples to illustrate the use of the module.¶
The following terms are defined in [RFC7950] and are used in this specification:¶
The terminology for describing YANG data models is found in [RFC7950].¶
The tree diagrams used in this document follow the notation defined in [RFC8340].¶
The following acronyms are used in the document:¶
Models are key for automating network management operations. According to [RFC8969], together with service and network models, performance measurement telemetry models are needed to monitor network performance to meet specific service requirements (typically captured in an SLA).¶
As shown in Figure 1, in the context of layering model architecture described in [RFC8309], the network and VPN service performance monitoring (PM) model can be used to expose a set of performance information to the above layer. Such information can be used by an orchestrator to subscribe to performance data. The network controller will then notify the orchestrator about corresponding parameter changes.¶
Before using the network and VPN service PM model, the mapping between the VPN service topology and the underlying physical network should be set up.¶
The YANG module defined in this document is designed to derive VPN or network level performance data based on lower-level data collected via monitoring counters of the involved devices. The performance monitoring data per link in the underlying network can be collected using a network performance measurement method such as One-Way Active Measurement Protocol (OWAMP) [RFC4656], Two-Way Active Measurement Protocol (TWAMP) [RFC5357], and Multiprotocol Label Switching (MPLS) Loss and Delay Measurement [RFC6374]. The performance monitoring information reflecting the quality of the network or VPN service (e.g., end-to-end network performance data between source node and destination node in the network or between VPN sites) can be computed and aggregated, for example, using the information from the Traffic Engineering Database (TED), [RFC7471] [RFC8570] [RFC8571] or LMAP [RFC8194].¶
The measurement and report intervals that are associated with these performance data usually depend on the configuration of the specific measurement method or collection method or various combinations. This document defines a network-wide measurement interval to align measurement requirements for networks or VPN services.¶
In addition, the amount of performance data collected from the devices can be huge. To avoid receiving a large amount of operational data of VPN instances, VPN interfaces, or tunnels, the network controller can specifically subscribe to metric-specific data using the tagging methods defined in [I-D.ietf-netmod-node-tags].¶
Some applications such as service-assurance applications, which must maintain a continuous view of operational data and state, can use the subscription model specified in[RFC8641] to subscribe to the specific network performance data or VPN service performance data they are interested in, at the data source.¶
The data source can, then, use the network and VPN service assurance model defined in this document and the YANG Push model [RFC8641] to distribute specific telemetry data to target recipients.¶
To obtain a snapshot of a large amount of performance data from a network topology or VPN network, service-assurance applications may retrieve information using the network and VPN service PM model through a NETCONF [RFC6241] or a RESTCONF [RFC8040] interface.¶
This document defines the YANG module, "ietf-network-vpn-pm", which is an augmentation to the "ietf-network" and "ietf-network-topology".¶
The performance monitoring data augments the service topology as shown in Figure 2.¶
[RFC8345] defines a YANG data model for network/service topologies and inventories. The service topology described in [RFC8345] includes the virtual topology for a service layer above Layer 1 (L1), Layer 2 (L2), and Layer 3 (L3). This service topology has the generic topology elements of node, link, and terminating point. One typical example of a service topology is described in Figure 3 of [RFC8345]: two VPN service topologies instantiated over a common L3 topology. Each VPN service topology is mapped onto a subset of nodes from the common L3 topology.¶
Figure 3 illustrates an example of a topology that maps between the VPN service topology and an underlying network:¶
As shown in Figure 3, two VPN services topologies are both built on top of one common underlying physical network:¶
For network performance monitoring, the container of "networks" in [RFC8345] does not need to be extended.¶
For VPN service performance monitoring, the container "service-type" is defined to indicate the VPN type, e.g., L3VPN or Virtual Private LAN Service (VPLS). The values are taken from [I-D.ietf-opsawg-vpn-common]. When a network topology instance contains the L3VPN or other L2VPN network type, it represents a VPN instance that can perform performance monitoring.¶
The tree in Figure 4 is a part of ietf-network-vpn-pm tree. It defines the following set of network level attributes:¶
The tree in Figure 5 is the node part of ietf-network-vpn-pm tree.¶
For network performance monitoring, a container of "pm-attributes" is augmented to the list of "node" that are defined in [RFC8345]. The "node-type" indicates the device type of Provider Edge (PE), Provider (P) device, or Autonomous System Border Router (ASBR), so that the performance metric between any two nodes each with specific node type can be reported.¶
For VPN service performance monitoring, the model defines the following minimal set of node level network topology attributes:¶
The tree in Figure 6 is the link and termination point (TP) part of ietf-network-vpn-pm tree.¶
The 'links' are classified into two types: topology link defined in [RFC8345] and abstract link of a VPN between PEs.¶
The performance data of a link is a collection of counters that report the performance status.¶
For the data nodes of 'link' depicted in Figure 6, the YANG module defines the following minimal set of link-level performance attributes:¶
For the data nodes of 'termination-point' depicted in Figure 6, the module defines the following minimal set of statistics:¶
The "ietf-network-vpn-pm" module uses types defined in [RFC8345], [RFC6991], [RFC8532], and [I-D.ietf-opsawg-vpn-common].¶
<CODE BEGINS> file "ietf-network-vpn-pm@2021-01-28.yang" module ietf-network-vpn-pm { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"; prefix nvp; import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Types"; } import ietf-vpn-common { prefix vpn-common; reference "RFC CCCC: A Layer 2/3 VPN Common YANG Model."; // RFC Ed.: replace CCCC with actual RFC number and remove // this note. } import ietf-network { prefix nw; reference "RFC 8345: A YANG Data Model for Network Topologies, Section 6.1"; } import ietf-network-topology { prefix nt; reference "RFC 8345: A YANG Data Model for Network Topologies, Section 6.2"; } import ietf-lime-time-types { prefix lime; reference "RFC 8532: Generic YANG Data Model for the Management of Operations, Administration, and Maintenance (OAM) Protocols That Use Connectionless Communications"; } organization "IETF OPSAWG Working Group"; contact "Editor: Qin Wu <bill.wu@huawei.com> Editor: Bo Wu <lana.wubo@huawei.com> Editor: Mohamed Boucadair <mohamed.boucadair@orange.com>"; description "This module defines a model for Network and VPN Service Performance monitoring. Copyright (c) 2022 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices."; // RFC Ed.: update the date below with the date of RFC // publication and remove this note. // RFC Ed.: replace XXXX with actual RFC number and remove // this note. revision 2022-01-28 { description "Initial revision."; reference "RFC XXXX: A YANG Model for Network and VPN Service Performance Monitoring"; } identity node-type { description "Base identity for node type"; } identity pe { base node-type; description "Provider Edge (PE) node type."; reference "RFC 4026: Provider Provisioned Virtual Private Network (VPN) Terminology"; } identity p { base node-type; description "Provider router node type."; reference "RFC 4026: Provider Provisioned Virtual Private Network (VPN) Terminology"; } identity asbr { base node-type; description "Autonomous System Border Router (ASBR) node type."; reference "RFC 4364: BGP/MPLS IP Virtual Private Networks (VPNs)"; } identity pm-source-type { description "Base identity from which specific performance monitoring mechanism types are derived."; } identity pm-source-bgpls { base pm-source-type; description "Indicates BGP-LS as the performance monitoring metric source"; reference "RFC 8571: BGP - Link State (BGP-LS) Advertisement of IGP Traffic Engineering Performance Metric Extensions"; } identity pm-source-owamp { base pm-source-type; description "Indicates One-Way Active Measurement Protocol(OWAMP) as the performance monitoring metric source."; reference "RFC 4656: A One-Way Active Measurement Protocol (OWAMP)"; } identity pm-source-twamp { base pm-source-type; description "Indicates Two-Way Active Measurement Protocol(TWAMP) as the performance monitoring metric source."; reference "RFC 5357: A Two-Way Active Measurement Protocol (TWAMP)"; } identity pm-source-y-1731 { base pm-source-type; description "Indicates Ethernet OAM Y.1731 as the performance monitoring metric source."; reference "ITU-T Y.1731: Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks"; } typedef percentage { type decimal64 { fraction-digits 5; range "0..100"; } description "Percentage."; } typedef percentile { type decimal64 { fraction-digits 2; range "0..100"; } description "The percentile is a value between 0 and 100, e.g. 10.00, 99.90 ,99.99 etc.. For example, for a given one-way delay measurement, if the percentile is set to 95.00 and the 95th percentile one-way delay is 2 milliseconds, then the 95 percent of the sample value is less than or equal to 2 milliseconds."; } grouping vpn-summary-statistics { description "VPN Statistics grouping used for network topology augmentation."; container vpn-summary-statistics { config false; description "Container for VPN summary statistics."; container ipv4 { leaf maximum-routes { type uint32; description "Indicates the maximum number of IPv4 routes for the VPN."; } leaf total-active-routes { type uint32; description "Indicates total active IPv4 routes for the VPN."; } description "IPv4-specific parameters."; } container ipv6 { leaf maximum-routes { type uint32; description "Indicates the maximum number of IPv6 routes for the VPN."; } leaf total-active-routes { type uint32; description "Indicates total active IPv6 routes for the VPN."; } description "IPv6-specific parameters."; } container mac-num { leaf mac-num-limit { type uint32; description "Maximum number of MAC addresses."; } leaf total-active-mac-num { type uint32; description "Total active MAC entries for the VPN."; } description "MAC statistics."; } } } grouping link-loss-statistics { description "Grouping for per link error statistics."; container loss-statistics { description "Link loss summarized information. By default, one way measurement protocol (e.g., OWAMP) is used to measure one-way packet loss."; reference "RFC 4656: A One-way Active Measurement Protocol (OWAMP)"; leaf packet-loss-count { type yang:counter64; description "Total received packet drops count."; } leaf loss-ratio { type percentage; description "Loss ratio of the packets. Express as percentage of packets lost with respect to packets sent."; } } } grouping link-delay-statistics { description "Grouping for per link delay statistics."; container delay-statistics { description "Link delay summarized information. By default, one way measurement protocol (e.g., OWAMP) is used to measure delay."; reference "RFC 4656: A One-way Active Measurement Protocol (OWAMP)"; leaf unit-value { type identityref { base lime:time-unit-type; } default "lime:milliseconds"; description "Time units, where the options are s, ms, ns, etc."; } leaf min-delay-value { type yang:gauge64; description "Minimum observed one-way delay."; } leaf max-delay-value { type yang:gauge64; description "Maximum observed one-way delay."; } leaf low-delay-percentile { type yang:gauge64; description "Low percentile of observed one-way delay with specific measurement method."; } leaf intermediate-delay-percentile { type yang:gauge64; description "Intermediate percentile of observed one-way delay with specific measurement method."; } leaf high-delay-percentile { type yang:gauge64; description "High percentile of observed one-way delay with specific measurement method."; } } } grouping link-jitter-statistics { description "Grouping for per link jitter statistics."; container jitter-statistics { description "Link jitter summarized information. By default, jitter is measured using one-way IP Packet Delay Variation (IPDV)."; reference "RFC 3393: IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)"; leaf unit-value { type identityref { base lime:time-unit-type; } default "lime:milliseconds"; description "Time units, where the options are s, ms, ns, etc."; } leaf min-jitter-value { type yang:gauge32; description "Minimum observed one-way jitter."; } leaf max-jitter-value { type yang:gauge32; description "Maximum observed one-way jitter."; } leaf low-jitter-percentile { type yang:gauge32; description "Low percentile of observed one-way jitter."; } leaf intermediate-jitter-percentile { type yang:gauge32; description "Intermediate percentile of observed one-way jitter."; } leaf high-jitter-percentile { type yang:gauge32; description "High percentile of observed one-way jitter."; } } } grouping tp-svc-telemetry { leaf reference-time { type yang:date-and-time; config false; description "Indicates the time when the statistics are collected."; } leaf inbound-octets { type yang:counter64; description "The total number of octets received on the interface, including framing characters."; } leaf inbound-unicast { type yang:counter64; description "The total number of inbound unicast packets."; } leaf inbound-nunicast { type yang:counter64; description "The total number of non-unicast (i.e., broadcast or multicast) packets."; } leaf inbound-discards { type yang:counter32; description "The number of inbound packets that were chosen to be discarded even though no errors had been detected. One possible reason for discarding such a packet could be to free up buffer space"; } leaf inbound-errors { type yang:counter64; description "The number of inbound packets that contained errors."; } leaf inbound-unknown-protocol { type yang:counter64; description "The number of packets received via the interface which were discarded because of an unknown or unsupported protocol."; } leaf outbound-octets { type yang:counter64; description "The total number of octets transmitted out of the interface, including framing characters."; } leaf outbound-unicast { type yang:counter64; description "The total number of outbound unicast packets."; } leaf outbound-nunicast { type yang:counter64; description "The total number of outbound non unicast (i.e., broadcast or multicast) packets."; } leaf outbound-discards { type yang:counter64; description "The number of outbound packets which were chosen to be discarded even though no errors had been detected to prevent their being transmitted. One possible reason for discarding such a packet could be to free up buffer space."; } leaf outbound-errors { type yang:counter64; description "The number of outbound packets that contained errors."; } description "Grouping for interface service telemetry."; } augment "/nw:networks/nw:network/nw:network-types" { description "Defines the service topologies types."; container service-type { presence "Indicates network service topology."; leaf service-type { type identityref { base vpn-common:service-type; } description "The presence identifies the network service type, e.g., L3VPN, VPLS, etc."; } description "Container for VPN service type."; } } augment "/nw:networks/nw:network" { when 'nw:network-types/nvp:service-type' { description "Augments only for VPN Network topology."; } description "Augments the network with service topology attributes"; container vpn-pm-attributes { leaf vpn-id { type vpn-common:vpn-id; description "VPN identifier."; } leaf vpn-service-topology { type identityref { base vpn-common:vpn-topology; } description "VPN service topology, e.g., hub-spoke, any-to-any, hub-spoke-disjoint."; } description "Container for VPN topology attributes."; } } augment "/nw:networks/nw:network/nw:node" { description "Augments the network node with other general attributes."; container pm-attributes { leaf node-type { type identityref { base node-type; } description "Node type, e.g., PE, P, ASBR."; } description "Container for node attributes."; } } augment "/nw:networks/nw:network/nw:node/pm-attributes" { when '../../nw:network-types/nvp:service-type' { description "Augments only for VPN node attributes."; } description "Augments the network node with VPN specific attributes."; leaf role { type identityref { base vpn-common:role; } default "vpn-common:any-to-any-role"; description "Role of the node in the VPN."; } uses vpn-summary-statistics; } augment "/nw:networks/nw:network/nt:link" { description "Augments the network topology link with performance monitoring attributes."; container pm-attributes { description "Container for PM attributes."; leaf low-percentile { type percentile; default "10.00"; description "Low percentile to report. Setting low-percentile into 0.00 indicates the client is not interested in receiving low percentile."; } leaf intermediate-percentile { type percentile; default "50.00"; description "Intermediate percentile to report. Setting intermediate-percentile into 0.00 indicates the client is not interested in receiving intermediate percentile."; } leaf high-percentile { type percentile; default "95.00"; description "High percentile to report. Setting high-percentile into 0.00 indicates the client is not interested in receiving high percentile."; } leaf measurement-interval { type uint32; units "seconds"; default "60"; description "Indicates the time interval to perform PM measurement."; } leaf start-time { type yang:date-and-time; config false; description "The time that the current measurement started."; } leaf end-time { type yang:date-and-time; config false; description "The time that the current measurement ended."; } leaf pm-source { type identityref { base pm-source-type; } config false; description "The OAM tool used to collect the PM data."; } container one-way-pm-statistics { config false; description "Container for link telemetry attributes."; uses link-loss-statistics; uses link-delay-statistics; uses link-jitter-statistics; } } } augment "/nw:networks/nw:network/nt:link/pm-attributes" { when '../../nw:network-types/nvp:service-type' { description "Augments only for VPN Network topology."; } description "Augments the network topology link with VPN service performance monitoring attributes."; leaf vpn-underlay-transport-type { type identityref { base vpn-common:protocol-type; } config false; description "The leaf indicates the underlay transport type of a VPN service, e.g., GRE, LDP, etc."; } list vpn-one-way-pm-statistics { key "class-id"; config false; description "The list of PM data based on class of service."; leaf class-id { type string; description "The class-id is used to identify the class of service. This identifier is internal to the administration."; } uses link-loss-statistics; uses link-delay-statistics; uses link-jitter-statistics; } } augment "/nw:networks/nw:network/nw:node/nt:termination-point" { description "Augments the network topology termination point with performance monitoring attributes."; container pm-statistics { config false; description "Container for termination point PM attributes."; uses tp-svc-telemetry; } } augment "/nw:networks/nw:network/nw:node" + "/nt:termination-point/pm-statistics" { when '../../../nw:network-types/nvp:service-type' { description "Augments only for VPN Network topology."; } description "Augments the network topology termination-point with VPN service performance monitoring attributes"; list vpn-network-access { key "network-access-id"; description "The list of PM based on VPN network accesses."; leaf network-access-id { type vpn-common:vpn-id; description "References to an identifier for the VPN network access, e.g. L3VPN or VPLS."; } uses tp-svc-telemetry; } } } <CODE ENDS>¶
The YANG modules defined in this document MAY be accessed via the RESTCONF protocol [RFC8040] or NETCONF protocol [RFC6241]. The lowest RESTCONF or NETCONF layer requires that the transport-layer protocol provides both data integrity and confidentiality, see Section 2 in [RFC8040] and [RFC6241]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].¶
The NETCONF access control model [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees with the write operation that can be exploited to impact the network monitoring:¶
Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. The nodes reveals the quality of a service that is operated by an operator. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability:¶
This document requests IANA to register the following URI in the "ns" subregistry within the "IETF XML Registry" [RFC3688]:¶
URI: urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace.¶
This document requests IANA to register the following YANG module in the "YANG Module Names" subregistry [RFC6020] within the "YANG Parameters" registry.¶
Name: ietf-network-vpn-pm Namespace: urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm Maintained by IANA: N Prefix: nvp Reference: RFC XXXX (RFC Ed.: replace XXXX with actual RFC number and remove this note.)¶
Thanks to Joe Clarke, Adrian Farrel, Greg Mirsky, Roque Gagliano, Erez Segev, and Dhruv Dhody for reviewing and providing important input to this document.¶
The following authors contributed significantly to this document:¶
Michale Wang Huawei Email:wangzitao@huawei.com Roni Even Huawei Email: ron.even.tlv@gmail.com Change Liu China Unicom Email: liuc131@chinaunicom.cn Honglei Xu China Telecom Email: xuhl.bri@chinatelecom.cn¶
The example shown in Figure 7 illustrates how a client subscribes to the performance monitoring information between nodes ('node-id') A and B in the L3 network topology. The performance monitoring parameter that the client is interested in is end-to-end loss.¶
This example, depicted in Figure 8, illustrates an VPN PM instance example in which a client uses RESTCONF [RFC8040] to fetch the performance data of the link and TP belonged to "VPN1".¶
The following shows an example of a percentile measurement for a VPN link.¶
{ "ietf-network-topology:link":[ { "link-id":"vpn1-link1", "source":{ "source-node":"vpn-node1" }, "destination":{ "dest-node":"vpn-node3" }, "ietf-network-vpn-pm:pm-attributes":{ "low-percentile":"20.00", "middle-percentile":"50.00", "high-percentile":"90.00", "one-way-pm-statistics:delay-statistics":{ "unit-values":"lime:milliseconds", "min-delay-value":"43", "max-delay-value":"99", "low-delay-percentile":"64", "middle-delay-percentile":"77", "high-delay-percentile":"98" }, "ietf-network-vpn-pm:vpn-underlay-transport-type": "ietf-vpn-common:gre", } } ] }¶