]> Huawei

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

Huawei

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

Orange

Rennes 35000 France mohamed.boucadair@orange.com

Telefonica

Madrid ES oscar.gonzalezdedios@telefonica.com

Comcast

bin_wen@comcast.com

OPS Area OPSAWG Working Group RFC Request for Comments Internet-Draft VPN Performance Measurement Telemetry 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.

describes a framework for automating service and network management with YANG models. It defines 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 Agreement (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 and draws on relevant YANG types defined in , , , and . provides a set of examples to illustrate the use of the module.

The following terms are defined in and are used in this specification: augment data model data node The terminology for describing YANG data models is found in . The tree diagrams used in this document follow the notation defined in .

The following acronyms are used in the document: Layer 2 Virtual Private Network Layer 3 Virtual Private Network L2VPN Network Model L3VPN Network Model Multiprotocol Label Switching Operations, Administration, and Maintenance One-Way Active Measurement Protocol Provider Edge Performance Monitoring Service Level Agreements Two-Way Active Measurement Protocol Virtual Private LAN Service Virtual Private Network

Models are key for automating network management operations. According to , 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 , in the context of the layering model architecture described in , 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 model, the controller needs to establish complete topology visibility of the network and VPN. For example, the controller can use information from , or VPN instances. Then the controller derives network or VPN level performance data by aggregating (and filtering) lower-level data collected via monitoring counters of the involved devices. The network or VPN performance data can be based on different sources. For example, 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) , Two-Way Active Measurement Protocol (TWAMP) , and Multiprotocol Label Switching (MPLS) Loss and Delay Measurement . 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), or LMAP . 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 .

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 to subscribe to the specific network performance data or VPN service performance data they are interested in, at the data source. For example, network or VPN topology updates may be obtained through on-change notifications . For dynamic-changing PM data, various notifications can be specified to obtain more complete data. A periodic notification can be specified to obtain real-time performance data, a replay notification defined in or can be specified to obtain historical data, or alarm notifications can be specified to get alarms for the metrics which exceed or fall below the performance threshold. The data source can, then, use the network and VPN service assurance model defined in this document and the YANG Push model 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 or a RESTCONF interface. For example, a specified "link-id" of a VPN can be used as a filter in a RESTCONF GET request to retrieve per-link VPN PM data.

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 .

defines a YANG data model for network/service topologies and inventories. The service topology described in 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 : 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. illustrates an example of a topology that maps between the VPN service topology and an underlying network:

As shown in , two VPN services topologies are both built on top of one common underlying physical network: This service topology supports hub-spoke communications for 'customer 1' connecting the customer's access at three sites: 'Site-1A', 'Site-1B', and 'Site-1C'. These sites are connected to nodes that are mapped to node 1 (N1), node 2 (N2), and node 4 (N4) in the underlying physical network. 'Site-1A' plays the role of hub while 'Site-1B' and 'Site-1C' are configured as spoke. This service supports any-to-any communications for 'customer 2' connecting the customer's access at two sites: 'Site-2A' and 'Site-2B'. These sites are connected to nodes that are mapped to nodes 1 (N1) and node 3 (N3)5 in the underlying physical network. 'Site-2A' and 'Site-2B' have 'any-to-any' role. Apart from the association between the VPN topology and the underlay topology, VPN Network PM can also provide the performance status of the underlay network and VPN services. For example, network PM can provide link PM statistics and port statistics. VPN PM can provides statistics on VPN access interfaces, the number of current VRF routes or L2VPN MAC entry of VPN nodes, and performance statistics on the logical point-to-point link between source and destination VPN nodes or between source and destination VPN access interfaces. illustrates an example of VPN PM and the difference between two VPN PM measurement methods. One is the VPN tunnel PM and the other is inter-VPN-access interface PM.

| | | | | | | VPN2+---+---+ +---+---+VPN2 | | TP1| VN1 | Tunnel PM | VN3 |TP2 | | ---+ PE A |==============| PE B +---- | |vpn-access+-------+ +-------+ vpn-access| |-interface| | -interface| | |##############################| | | |inter-vpn-access-interface PM | | | | +-----------------------------------------------------+ | | | | +----+ | TP+-----+ Link +---+ Link +-----+TP | +----+ | CE4+-+----------+ N1 +-------+-N2+-------+ N3 +----------+-+CE5 | +----+ | 1-1+-----+1-2 2-1+---+2-2 3-1+-----+3-2 | +----+ | | | | +-----------------------------------------------------+ Legend: N:node VN:VPN-Node -:Link]]>

For network performance monitoring, the container of "networks" in 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 . 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 is a part of ietf-network-vpn-pm tree. It defines the following set of network level attributes: Refers to an identifier of VPN service defined in ). This identifier is used to correlate the performance status with the network service configuration. Indicates the type of the VPN topology. This model supports "any-to-any", "Hub and Spoke" (where Hubs can exchange traffic), and "Hub and Spoke disjoint" (where Hubs cannot exchange traffic) that are taken from . These VPN topology types can be used to describe how VPN sites communicate with each other.

The tree in 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 . The container includes the following attributes: Indicates the device type of Provider Edge (PE), Provider (P) device, or Autonomous System Border Router (ASBR) as defined in and , so that the performance metric between any two nodes each with specific node type can be reported. Lists a set of IPv4 statistics, IPv6 statistics, and MAC statistics. The detailed statistics are specified separately. For VPN service performance monitoring, the model defines one attribute: Defines the role in a particular VPN service topology. The roles are taken from (e.g., any-to-any-role, spoke-role, hub-role).

The tree in 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 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 , the YANG module defines the following minimal set of link-level performance attributes: The module supports reporting delay and jitter metric by percentile values. By default, low percentile (10th percentile), intermediate percentile (50th percentile), high percentile (90th percentile) are used. Setting a percentile to 0.00 indicates the client is not interested in receiving particular percentile. If all percentile nodes are set to 0.00, this represents that no percentile related nodes will be reported for a given performance metric (e.g., one-way delay, one-way delay variation) and only peak/min values will be reported. For example, a client can inform the server that it is interested in receiving only high percentiles. Then for a given link, at a given "start-time", "end-time" and “measurement-interval", the 'high-delay-percentile' and 'high-jitter-percentile' will be reported. An example to illustrate the use of percentiles is provided in . Indicates the performance monitoring source. The data for the topology link can be based, e.g., on BGP-LS . The statistics of the VPN abstract links can be collected based upon VPN OAM mechanisms, e.g.,OAM mechanisms referenced in , or Ethernet service OAM referenced in . Alternatively, the data can be based upon the underlay technology OAM mechanisms, for example, Generic Routing Encapsulation (GRE) tunnel OAM. Specifies the performance measurement interval, in seconds. Indicates the start time of the performance measurement for link statistics. Indicates the end time of the performance measurement for link statistics. Indicates the timestamp when the counters are obtained. A set of one-way loss statistics attributes that are used to measure end to end loss between VPN sites or between any two network nodes. The exact loss value or the loss percentage can be reported. A set of one-way delay statistics attributes that are used to measure end to end latency between VPN sites or between any two network nodes. The peak/min values or percentile values can be reported. A set of one-way IP Packet Delay Variation statistics attributes that are used to measure end to end jitter between VPN sites or between any two network nodes. The peak/min values or percentile values can be reported. Lists performance measurement statistics for the topology link or the abstract underlay link between VPN PEs with given "class-id" names. The list is defined separately from "one-way-pm-statistics", which is used to collect generic metrics for unspecified "class-id" names. Indicates the VPN performance type, which can be inter-vpn-access-interface PM or VPN underlay-tunnel PM. These two methods are common VPN measurement methods. The inter-VPN-access-interface PM is to monitor the performance of logical point-to-point connections between a source and a destination VPN access interfaces. And the underlay-tunnel PM is to monitor the performance of underlay tunnels of VPNs. The inter-VPN-access-interface PM includes PE-PE monitoring. Therefore, only one of the two methods is needed , and the model defines "choice" to indicate these two methods, which also allows other methods to be extended. Indicates the abstract link protocol-type of a VPN, such as GRE or IP-in-IP. The leaf refers to an identifier of the "underlay-transport" defined in , which describes the transport technology to carry the traffic of the VPN service. For the data nodes of 'termination-point' depicted in , the module defines the following minimal set of statistics: A set of inbound statistics attributes that are used to measure the inbound statistics of the termination point, such as received packets, received packets with errors, etc. A set of outbound statistics attributes that are used to measure the outbound statistics of the termination point, such as sent packets, packets that could not be sent due to errors, etc. Lists counters of the VPN network access defined in or . When multiple VPN network accesses are created using the same physical port, finer-grained metrics can be monitored. If a TP is associated with only a single VPN, this list is not required.

The "ietf-network-vpn-pm" module uses types defined in , , , and .

file "ietf-network-vpn-pm@2021-04-08.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 9181: A Common YANG Data Model for Layer 2 and Layer 3 VPNs."; } 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 (Operations and Management Area Working Group)"; contact "WG Web: WG List: Editor: Bo Wu Editor: Mohamed Boucadair Editor: Qin Wu Author: Oscar Gonzalez de Dios Author: Bin Wen "; 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 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."; // 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 2022-04-08 { 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 entry-summary { description "Entry summary grouping used for network topology augmentation."; container entry-summary { config false; description "Container for VPN or network entry summary."; 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 "One-way link loss summarized information."; reference "RFC 4656: A One-way Active Measurement Protocol (OWAMP) ITU-T Y.1731: Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks"; 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 "One-way link delay summarized information."; reference "RFC 4656: A One-way Active Measurement Protocol (OWAMP) ITU-T Y.1731: Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks"; 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 "One-way link jitter summarized information."; reference "RFC 3393: IP Packet Delay Variation Metric for IP Performance Metrics (IPPM) RFC 4656: A One-way Active Measurement Protocol (OWAMP) ITU-T Y.1731: Operations, administration and maintenance (OAM) functions and mechanisms for Ethernet-based networks"; 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:gauge64; description "Minimum observed one-way jitter."; } leaf max-jitter-value { type yang:gauge64; description "Maximum observed one-way jitter."; } leaf low-jitter-percentile { type yang:gauge64; description "Low percentile of observed one-way jitter."; } leaf intermediate-jitter-percentile { type yang:gauge64; description "Intermediate percentile of observed one-way jitter."; } leaf high-jitter-percentile { type yang:gauge64; 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 inbound non-unicast (i.e., broadcast or multicast) packets."; } leaf inbound-discards { type yang:counter64; description "The number of inbound packets that were chosen to be discarded even though no errors had been detected. Possible reasons for discarding such a packet could be to free up buffer space, not enough buffer for too much data, etc."; } 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. Possible reasons for discarding such a packet could be to free up buffer space, not enough buffer for too much data, etc."; } 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."; uses entry-summary; } } 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."; } } 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 { range "1..max"; } 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; } list one-way-pm-statistics-per-class { 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/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."; choice vpn-pm-type { description "The VPN PM type of this logical point-to-point unidirectional VPN link."; case inter-vpn-access-interface { leaf inter-vpn-access-interface { type empty; description "This is a placeholder for inter-vpn-access-interface PM. There is no technology to be defined."; } } case underlay-tunnel { 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."; } } } } 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; } } } ]]>

The YANG modules defined in this document MAY be accessed via the RESTCONF protocol or NETCONF protocol . 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) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The NETCONF access control model 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: "/nw:networks/nw:network/nw:network-types" “/nw:networks/nw:network/nvp:vpn-pm-attributes” “/nw:networks/nw:network/nw:node/nvp:pm-attributes” /nw:networks/nw:network/nt:link/nvp:pm-attributes" /nw:networks/nw:network/nw:node/nt:termination-point/nvp:pm-statistics" 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: “/nw:networks/nw:network/nw:node/nvp:pm-attributes/nvp:vpn-summary-statistics": Unauthorized access to this subtree can disclose the operational state information of VPN instances. “/nw:networks/nw:network/nt:link/nvp:pm-attributes/nvp:one-way-pm-statistics": Unauthorized access to this subtree can disclose the operational state information of network links or VPN abstract links. “/nw:networks/nw:network/nw:node/nt:termination-point/nvp:pm-statistics": Unauthorized access to this subtree can disclose the operational state information of network termination points or VPN network accesses.

This document requests IANA to register the following URI in the "ns" subregistry within the "IETF XML Registry" :

This document requests IANA to register the following YANG module in the "YANG Module Names" subregistry within the "YANG Parameters" registry.

Thanks to Joe Clarke, Adrian Farrel, Tom Petch, 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:

The example shown in 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 , illustrates an VPN PM instance example in which a client uses RESTCONF 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.