A YANG Model for Network and VPN Service Performance Monitoring

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. Three types of VPN service topologies are supported in : "any to any", "hub and spoke", and "hub and spoke disjoint". These VPN topology types can be used to describe how VPN sites communicate with each other. This document defines a YANG Model for both Network Performance Monitoring and VPN Service Performance Monitoring (see Section 2.2.4 of ) that can be used to monitor and manage network Performance on the topology at higher layer or the service topology between VPN sites. The model is designed as an augmentation to the network topology YANG data model defined in .

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here. Tree diagrams used in this document follow the notation defined in .

The module defined in this document is a Network and VPN Service assurance module that can be used to monitor and manage the network performance on the topology at higher layer or the service topology between VPN sites and it is an augmentation to the "ietf-network" and "ietf-network-topology" YANG data model . The performance monitoring data is augmented to service topology as shown in .

+----------------------+ +-----------------------+ |ietf-network | |Network and VPN Service| |ietf-network-topology |<---------|Performance Monitoring | +----------------------+ augments | Model | +-----------------------+

The data model defined in can describe vertical layering relationships between networks. That model can be augmented to cover network/service topologies. illustrates an example of a topology mapping between the VPN service topology and an underlying network:

VPN-SVC 1 VPN-SVC 2 / \ VPN-Service-topology 1 VPN-Service-topology-2 / | \ / | \ Site-1A Site-1B Site1-C Site-2A Site-2B Site-2C Top-Down | | | | | | Service Topology CE CE CE CE CE CE | | | | | | PE PE PE PE PE PE ====|==========|=======|=======|=========|=====|====================== +-------+ | \ / / | Bottom-up | | \ / / | Network | | /\ / | topology | | / \ | | | | | | | | node1 node2 node3 node4 node5 node6 As shown in , two VPN services topologies are both built on top of one common underlying physical network: VPN-SVC 1: supporting "hub-spoke" communications for Customer 1 connecting the customer's access at 3 sites. Site-1A, Site-1B, and Site-1C are connected to PEs that are mapped to nodes 1, 2, and 3 in the underlying physical network. Site-1 A plays the role of hub while Site-2 B and C plays the role of spoke. VPN-SVC 2: supporting "hub-spoke disjoint" communications for Customer 2 connecting the customer's access at 3 sites. Site-2A, Site-2B, and Site-2C are connected to PEs that are mapped to nodes 4, 5, and 6 in the underlying physical network. Site-2 A and B play the role of hub while Site-2 C plays the role of spoke.

An SP must be able to manage the capabilities and characteristics of the network/VPN services when Network connection is established or VPN sites are setup to communicate with each other.

As described in , once the mapping between the VPN Service topology and the underlying physical network has been setup, the performance monitoring data per link in the underlying network can be collected using network performance measurement method such as MPLS Loss and Delay Measurement . The performance monitoring information reflecting the quality of the Network or VPN service such as end to end network performance data between source node and destination node in the network or between VPN sites can be aggregated or calculated using, for example, PCEP solution [RFC8233] [RFC7471] [RFC7810] [RFC8571] or LMAP [RFC8194]. The information can be fed into data source such as the management system or network devices. The measurement interval and report interval associated with these performance data usually depends on configuration parameters.

Some applications such as service-assurance applications, which must maintain a continuous view of operational data and state, can use subscription model 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 to distribute specific telemetry data to target recipients.

To obtain a snapshot of a large amount of performance data from a network element (including network controllers), service-assurance applications may use polling-based methods such as RPC model to fetch performance data on demand.

This document defines the YANG module "ietf-network-vpn-pm", which has the tree structure described in the following sub-sections.

module: ietf-network-vpn-pm augment /nw:networks/nw:network/nw:network-types: +--rw network-technology-type* identityref augment /nw:networks/nw:network: +--rw vpn-attributes | +--rw vpn-topo? identityref +--rw vpn-summary-statistics | +--rw ipv4 | | +--rw total-routes? uint32 | | +--rw total-active-routes? uint32 | +--rw ipv6 | +--rw total-routes? uint32 | +--rw total-active-routes? uint32 For VPN service performance monitoring, this model defines only the following minimal set of Network level network topology attributes: "network-technology-type": Indicates the network technology type such as L3VPN, L2VPN, ISIS, or OSPF. If the "network-technology-type" is "VPN type" (e.g.,L3VPN, L2VPN), the "vpn-topo" MUST be set. "vpn-topo": The type of VPN service 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). "vpn-summary-statistics": VPN summary statistics, IPv4 statistics, and IPv6 statistics have been specified separately. For network performance monitoring, the attributes of "Network Level" that defined in [RFC8345] do not need to be extended.

augment /nw:networks/nw:network/nw:node: +--rw node-attributes | +--rw node-type? identityref | +--rw site-id? string | +--rw site-role? Identityref The Network and VPN service performance monitoring model defines only the following minimal set of Node level network topology attributes and constraints: "node-type" (Attribute): Indicates the type of the node, such as PE or ASBR. This "node-type" can be used to report performance metric between any two nodes each with specific node-type. "site-id" (Constraint): Uniquely identifies the site within the overall network infrastructure. "site-role" (Constraint): Defines the role of the site in a particular VPN topology.

augment /nw:networks/nw:network/nt:link: +--rw link-type? identityref +--rw low-percentile percentile +--rw high-percentile percentile +--rw middle-percentile percentile +--ro reference-time yang:date-and-time +--ro measurement-interval uint32 +--ro link-telemetry-attributes +--ro loss-statistics | +--ro packet-loss-count? uint32 | +--ro loss-ratio? percentage | +--ro packet-reorder-count? uint32 | +--ro packets-out-of-seq-count? uint32 | +--ro packets-dup-count? uint32 +--ro delay-statistics | +--ro direction? identityref | +--ro unit-value identityref | +--ro min-delay-value? yang:gauge64 | +--ro max-delay-value? yang:gauge64 | +--ro high-delay-percentile? yang:gauge64 | +--ro middle-delay-percentile? yang:gauge64 | +--ro low-delay-percentile? yang:gauge64 +--ro jitter-statistics +--ro unit-value identityref +--ro min-jitter-value? yang:gauge64 +--ro max-jitter-value? yang:gauge64 +--ro low-jitter-percentile? yang:gauge64 +--ro high-jitter-percentile? yang:gauge64 +--ro middle-jitter-percentile? yang:gauge64 augment /nw:networks/nw:network/nw:node/nt:termination-point: +--ro tp-telemetry-attributes +--ro in-octets? uint32 +--ro out-octets? uint32 +--ro inbound-unicast? uint32 +--ro inbound-nunicast? uint32 +--ro inbound-discards? uint32 +--ro inbound-errors? uint32 +--ro in-unknown-protocol? uint32 +--ro outbound-unicast? uint32 +--ro outbound-nunicast? uint32 +--ro outbound-discards? uint32 +--ro outbound-errors? uint32 +--ro outbound-qlen? uint32 The Network and VPN service performance monitoring model defines only the following minimal set of Link level network topology attributes: "link-type" (Attribute): Indicates the type of the link, such as GRE or IP-in-IP. "low-percentile": Indicates low percentile to report. Setting low-percentile into 0.00 indicates the client is not intererested in receiving low percentile. "middle-percentile": Indicates middle percentile to report. Setting middle-percentile into 0.00 indicates the client is not intererested in receiving middle percentile. "high-percentile": Indicates high percentile to report. Setting low-percentile into 0.00 indicates the client is not intererested in receiving high percentile. Loss Statistics: A set of loss statistics attributes that are used to measure end to end loss between VPN sites or between any two network nodes. Delay Statistics: A set of delay statistics attributes that are used to measure end to end latency between VPN sites or between any two network nodes.. Jitter Statistics: A set of 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 Network and VPN service performance monitoring defines the following minimal set of Termination point level network topology attributes: Inbound statistics: A set of inbound statistics attributes that are used to measure the inbound statistics of the termination point, such as "the total number of octets received on the termination point", "The number of inbound packets which were chosen to be discarded", "The number of inbound packets that contained errors", etc. Outbound statistics: A set of outbound statistics attributes that are used to measure the outbound statistics of the termination point, such as "the total number of octets transmitted out of the termination point", "The number of outbound packets which were chosen to be discarded", "The number of outbound packets that contained errors", etc.

This example shows the way for a client to subscribe for the Performance monitoring information between node A and node B in the L3 network topology built on top of the underlying network . The performance monitoring parameter that the client is interested in is end to end loss attribute.

<rpc netconf:message-id="101" xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0"> <establish-subscription xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"> <stream-subtree-filter> <networks xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topo"> <network> <network-id>l3-network</network-id> <network-technology-type xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> L3VPN </network-technology-type> <node> <node-id>A</node-id> <node-attributes xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> <node-type>pe</node-type> </node-attribtues> <termination-point xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology"> <tp-id>1-0-1</tp-id> <tp-telemetry-attributes xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> <in-octets>100</in-octets> <out-octets>150</out-octets> </tp-telemetry-attributes> </termination-point> </node> <node> <node-id>B</node-id> <node-attributes xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> <node-type>pe</node-type> </node-attribtues> <termination-point xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology"> <tp-id>2-0-1</tp-id> <tp-telemetry-attributes xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> <in-octets>150</in-octets> <out-octets>100</out-octets> </tp-telemetry-attributes> </termination-point> </node> <link xmlns="urn:ietf:params:xml:ns:yang:ietf-network-topology"> <link-id>A-B</link-id> <source> <source-node>A</source-node> </source> <destination> <dest-node>B</dest-node> </destination> <link-type>mpls-te</link-type> <link-telemetry-attributes xmlns="urn:ietf:params:xml:ns:yang:ietf-network-vpn-pm"> <loss-statistics> <packet-loss-count>100</packet-loss-count> </loss-statistics> </link-telemetry-attributes> </link> </network> </networks> </stream-subtree-filter> <period xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push:1.0">500</period> </establish-subscription> </rpc>

This example shows the way for the client to use RPC model to fetch performance data on demand, e.g., the client requests "packet-loss-count" between PE1 in site 1 and PE2 in site 2 belonging to the same VPN1.

This module uses types defined in , and .

<CODE BEGINS> file "ietf-network-vpn-pm@2020-04-17.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-network { prefix nw; reference "Section 6.1 of RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-network-topology { prefix nt; reference "Section 6.2 of RFC 8345: A YANG Data Model for Network Topologies"; } import ietf-l3vpn-svc { prefix l3vpn-svc; reference "RFC 8299: YANG Data Model for L3VPN Service Delivery"; } 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 BESS Working Group"; contact "Editor: Qin Wu <bill.wu@huawei.com> Editor: Mohamed Boucadair <mohamed.boucadair@orange.com>"; description "This module defines a model for the VPN Service Performance monitoring. Copyright (c) 2020 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 (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2019-04-17 { description "Initial revision."; reference "RFC XXXX: A YANG Model for Network and VPN Service Performance Monitoring"; } identity network-type { description "Base type for Overlay network topology."; } identity l3vpn { base network-type; description "Identity for layer3 VPN network type."; } identity l2vpn { base network-type; description "Identity for layer2 VPN network type."; } identity ospf { base network-type; description "Identity for OSPF network type."; } identity isis { base network-type; description "Identity for ISIS network type."; } identity node-type { description "Base identity for node type"; } identity pe { base node-type; description "Identity for PE type"; } identity ce { base node-type; description "Identity for CE type"; } identity asbr { base node-type; description "Identity for ASBR type"; } identity p { base node-type; description "Identity for P type"; } identity link-type { description "Base identity for link type, e.g.,GRE, MPLS TE, VXLAN."; } identity gre { base link-type; description "Base identity for GRE Tunnel."; } identity VXLAN { base link-type; description "Base identity for VXLAN Tunnel."; } identity ip-in-ip { base link-type; description "Base identity for IP in IP Tunnel."; } identity direction { description "Base Identity for measurement direction including one way measurement and two way measurement."; } identity one-way { base direction; description "Identity for one way measurement."; } identity two-way { base direction; description "Identity for two way measurement."; } typedef percentage { type decimal64 { fraction-digits 5; range "0..100"; } description "Percentage."; } typedef percentile { type decimal64 { fraction-digits 2; } description "The nth percentile of a set of data is the value at which n percent of the data is below it."; } grouping vpn-summary-statistics { description "VPN Statistics grouping used for network topology augmentation."; container vpn-summary-statistics { description "Container for VPN summary statistics."; container ipv4 { leaf total-routes { type uint32; description "Total routes in the RIB from all protocols."; } leaf total-active-routes { type uint32; description "Total active routes in the RIB."; } description "IPv4-specific parameters."; } container ipv6 { leaf total-routes { type uint32; description "Total routes in the RIB from all protocols."; } leaf total-active-routes { type uint32; description "Total active routes in the RIB."; } description "IPv6-specific parameters."; } } } grouping link-error-statistics { description "Grouping for per link error statistics."; container loss-statistics { description "Per link loss statistics."; leaf packet-loss-count { type uint32 { range "0..4294967295"; } default "0"; description "Total received packet drops count. The value of count will be set to zero (0) on creation and will thereafter increase monotonically until it reaches a maximum value of 2^32-1 (4294967295 decimal), when it wraps around and starts increasing again from zero."; } leaf loss-ratio { type percentage; description "Loss ratio of the packets. Express as percentage of packets lost with respect to packets sent."; } leaf packet-reorder-count { type uint32 { range "0..4294967295"; } default "0"; description "Total received packet reordered count. The value of count will be set to zero (0) on creation and will thereafter increase monotonically until it reaches a maximum value of 2^32-1 (4294967295 decimal), when it wraps around and starts increasing again from zero."; } leaf packets-out-of-seq-count { type uint32 { range "0..4294967295"; } description "Total received out of sequence count. The value of count will be set to zero (0) on creation and will thereafter increase monotonically until it reaches a maximum value of 2^32-1 (4294967295 decimal), when it wraps around and starts increasing again from zero.."; } leaf packets-dup-count { type uint32 { range "0..4294967295"; } description "Total received packet duplicates count. The value of count will be set to zero (0) on creation and will thereafter increase monotonically until it reaches a maximum value of 2^32-1 (4294967295 decimal), when it wraps around and starts increasing again from zero."; } } } grouping link-delay-statistics { description "Grouping for per link delay statistics"; container delay-statistics { description "Link delay summarised information. By default, one way measurement protocol (e.g., OWAMP) is used to measure delay."; leaf direction { type identityref { base direction; } default "one-way"; description "Define measurement direction including one way measurement and two way measurement."; } 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 delay value observed."; } leaf max-delay-value { type yang:gauge64; description "Maximum delay value observed."; } leaf low-delay-percentile { type yang:gauge64; description "Low percentile of the delay observed with specific measurement method."; } leaf middle-delay-percentile { type yang:gauge64; description "Middle percentile of the delay observed with specific measurement method."; } leaf high-delay-percentile { type yang:gauge64; description "High percentile of the delay observed with specific measurement method."; } } } grouping link-jitter-statistics { description "Grouping for per link jitter statistics"; container jitter-statistics { description "Link jitter summarised information. By default, jitter is measured using IP Packet Delay Variation (IPDV)."; 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 jitter value observed."; } leaf max-jitter-value { type yang:gauge64; description "Maximum jitter value observed."; } leaf low-jitter-percentile { type yang:gauge64; description "Low percentile of the jitter observed."; } leaf middle-jitter-percentile { type yang:gauge64; description "Middle percentile of the jitter observed."; } leaf high-jitter-percentile { type yang:gauge64; description "High percentile of the jitter observed."; } } } grouping tp-svc-telemetry { leaf in-octets { type uint32; description "The total number of octets received on the interface, including framing characters."; } leaf inbound-unicast { type uint32; description "Inbound unicast packets were received, and delivered to a higher layer during the last period."; } leaf inbound-nunicast { type uint32; description "The number of non-unicast (i.e., subnetwork- broadcast or subnetwork-multicast) packets delivered to a higher-layer protocol."; } leaf inbound-discards { type uint32; description "The number of inbound packets which were chosen to be discarded even though no errors had been detected to prevent their being deliverable to a higher-layer protocol."; } leaf inbound-errors { type uint32; description "The number of inbound packets that contained errors preventing them from being deliverable to a higher-layer protocol."; } leaf outbound-errors { type uint32; description "The number of outbound packets that contained errors preventing them from being deliverable to a higher-layer protocol."; } leaf in-unknown-protocol { type uint32; description "The number of packets received via the interface which were discarded because of an unknown or unsupported protocol."; } leaf out-octets { type uint32; description "The total number of octets transmitted out of the interface, including framing characters."; } leaf outbound-unicast { type uint32; description "The total number of packets that higher-level protocols requested be transmitted to a subnetwork-unicast address, including those that were discarded or not sent."; } leaf outbound-nunicast { type uint32; description "The total number of packets that higher-level protocols requested be transmitted to a non- unicast (i.e., a subnetwork-broadcast or subnetwork-multicast) address, including those that were discarded or not sent."; } leaf outbound-discards { type uint32; 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-qlen { type uint32; description " Length of the queue of the interface from where the packet is forwarded out. The queue depth could be the current number of memory buffers used by the queue and a packet can consume one or more memory buffers thus constituting device-level information."; } description "Grouping for interface service telemetry."; } augment "/nw:networks/nw:network/nw:network-types" { description "Augment the network-types with service topologyies types"; leaf-list network-technology-type { type identityref { base network-type; } description "Identify the network technology type, e.g., L3VPN, L2VPN, ISIS, OSPF."; } } augment "/nw:networks/nw:network" { description "Augment the network with service topology attributes"; container vpn-topo-attributes { leaf vpn-topology { type identityref { base l3vpn-svc:vpn-topology; } description "VPN service topology, e.g., hub-spoke, any-to-any, hub-spoke-disjoint"; } description "Container for vpn topology attributes."; } uses vpn-summary-statistics; } augment "/nw:networks/nw:network/nw:node" { description "Augment the network node with overlay topology attributes"; container node-attributes { leaf node-type { type identityref { base node-type; } description "Node type, e.g., PE, P, ASBR."; } leaf site-id { type string; description "Associated vpn site"; } leaf site-role { type identityref { base l3vpn-svc:site-role; } default "l3vpn-svc:any-to-any-role"; description "Role of the site in the VPN."; } description "Container for overlay topology attributes."; } } augment "/nw:networks/nw:network/nt:link" { description "Augment the network topology link with overlay topology attributes"; leaf link-type { type identityref { base link-type; } description "Link type, e.g., GRE,VXLAN, IP in IP."; } leaf low-percentile { type percentile; default 10.00; description "Low percentile to report.Setting low-percentile into 0.00 indicates the client is not intererested in receiving low percentile."; } leaf middle-percentile { type percentile; default 50.00; description "Middle percentile to report.Setting middle-percentile into 0.00 indicates the client is not intererested in receiving middle percentile."; } leaf high-percentile { type percentile; default 90.00; description "High percentile to report."; } leaf reference-time { type yang:date-and-time; description "The time that the current Measurement Interval started.Setting high-percentile into 0.00 indicates the client is not intererested in receiving high percentile."; } leaf measurement-interval { type uint32; units "seconds"; default 60; description "Interval to calculate performance metric."; } container link-telemetry-attributes { config false; uses link-error-statistics; uses link-delay-statistics; uses link-jitter-statistics; description "Container for service telemetry attributes."; } } augment "/nw:networks/nw:network/nw:node/nt:termination-point" { description "Augment the network topology termination point with vpn service attributes"; container tp-telemetry-attributes { config false; uses tp-svc-telemetry; description "Container for termination point service telemetry attributes."; } } } <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 [RFC5246]. The NETCONF access control model [RFC6536] 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 and data nodes and their sensitivity/vulnerability: /nw:networks/nw:network/svc-topo:svc-telemetry-attributes /nw:networks/nw:network/nw:node/svc-topo:node-attributes

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

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 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

Michale Wang Huawei Email:wangzitao@huawei.com Roni Even Huawei Email: ron.even.tlv@gmail.com