A YANG Data Model for
Layer 2 Network TopologiesHuaweiNo. 156 Beiqing Rd.Huawei CampusBeijing100095Chinajie.dong@huawei.comHuaweiNo. 156 Beiqing Rd.Huawei CampusBeijing100095Chinaweixiugang@huawei.comHuawei101 Software AvenueYuhua DistrictNanjing210012Chinabill.wu@huawei.comOrangeRennes 35000Francemohamed.boucadair@orange.comTecent38 Haidian StYinke BuildingHaidian DistrictBeijing100080Chinaandersliu@tencent.comVxLANVLANQinQProvider Backbone BridgingEthernetVPLSThis document defines a YANG data model for Layer 2 network
topologies. In particular, this data model augments the generic network
and network topology data models with topology
attributes that are specific to Layer 2.Introduction defines the YANG data models of the abstract (generic) network
and network topology. Such models can be augmented with
technology-specific details to build more specific topology models.This document defines the YANG data model for Layer 2 (L2) network
topologies by augmenting the generic network () and network topology () data models with
L2-specific topology attributes. An
example is provided in .There are multiple applications for such a data model. For example,
within the context of Interface to the Routing System (I2RS), nodes
within the network can use the data model to capture their understanding
of the overall network topology and expose it to a network controller. A
network controller can then use the instantiated topology data to
compare and reconcile its own view of the network topology with that of
the network elements that it controls. Alternatively, nodes within the
network may compare and reconcile this understanding either among
themselves or with the help of a controller. Beyond the network element
and the immediate context of I2RS itself, a network controller might
even use the data model to represent its view of the topology that it
controls and expose it to external applications. Further use cases where
the data model can be applied are described in .This document uses the common YANG types defined in and adopts the Network Management Datastore
Architecture (NMDA) .Terminology
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.
The terminology for describing YANG modules is defined in . The meanings of the symbols used in the tree diagram
are defined in .Layer 2 Topology ModelThe Layer 2 network topology YANG module is designed to be generic
and applicable to Layer 2 networks built with different Layer 2
technologies. It can be used to describe both the physical and the
logical (virtual) Layer 2 network topologies.The relationship between the Layer 2 topology module and the generic
network and network topology module is shown in . In
order to represent a Layer 2 network topology, the generic network and
topology models are augmented with L2-specific information, such as
the identifiers, identities (e.g., Provider Backbone Bridging , QinQ , or Virtual eXtensible Local Area Network (VXLAN)
), attributes, and states of the Layer 2
networks, nodes, links, and termination points. Some of the information
may be collected via Link Layer Discovery Protocol (LLDP) or other Layer 2 protocols, and some of them may
be locally configured.Layer 2 Topology YANG Module StructureThe structure of the "ietf-l2-topology" YANG module is depicted in
the following tree diagram: /nw:networks/network/node/nt:termination-point/tp-id
+--rw vxlan {VXLAN}?
+--rw vni-id? vni
notifications:
+---n l2-node-event
| +--ro event-type? l2-network-event-type
| +--ro node-ref?
-> /nw:networks/network[nw:network-id=current()
/../network-ref]/node/node-id
| +--ro network-ref? -> /nw:networks/network/network-id
| +--ro l2-topology!
| +--ro l2-node-attributes
| +--ro name? string
| +--ro flags* node-flag-type
| +--ro bridge-id* uint64
| +--ro management-address* inet:ip-address
| +--ro management-mac? yang:mac-address
| +--ro management-vlan? string
+---n l2-link-event
| +--ro event-type? l2-network-event-type
| +--ro link-ref?
-> /nw:networks/network[nw:network-id=current()
/../network-ref]/nt:link/link-id
| +--ro network-ref? -> /nw:networks/network/network-id
| +--ro l2-topology!
| +--ro l2-link-attributes
| +--ro name? string
| +--ro flags* link-flag-type
| +--ro rate? uint64
| +--ro delay? uint32
| +--ro auto-nego? boolean
| +--ro duplex? duplex-mode
+---n l2-termination-point-event
+--ro event-type? l2-network-event-type
+--ro tp-ref?
-> /nw:networks/network[nw:network-id=current()
/../network-ref]/node[nw:node-id=current()
/../node-ref]/nt:termination-point/tp-id
+--ro node-ref?
-> /nw:networks/network[nw:network-id=current()
/../network-ref]/node/node-id
+--ro network-ref? -> /nw:networks/network/network-id
+--ro l2-topology!
+--ro l2-termination-point-attributes
+--ro interface-name? string
+--ro mac-address? yang:mac-address
+--ro port-number* uint32
+--ro unnumbered-id* uint32
+--ro encapsulation-type? identityref
+--ro outer-tag? dot1q-types:vid-range-type {VLAN}?
+--ro outer-tpid? dot1q-types:dot1q-tag-type {QinQ}?
+--ro inner-tag? dot1q-types:vid-range-type {VLAN}?
+--ro inner-tpid? dot1q-types:dot1q-tag-type {QinQ}?
+--ro lag? boolean
+--ro member-link-tp*
-> /nw:networks/network/node/nt:termination-point/tp-id
+--ro vxlan {VXLAN}?
+--ro vni-id? vni
]]>The Layer 2 Topology YANG module augments the "ietf-network" and
"ietf-network-topology" YANG modules as follows:
A new network type "l2-network-type" is introduced. This is
represented by a container object and is inserted under the
"network-types" container of the generic "ietf-network" module
defined in .
Additional network attributes are introduced in a grouping
"l2-network-attributes", which augments the "network" list of the
"ietf-network" module. The attributes include the Layer 2 network name
and a set of flags. Each type of flag is represented by a separate
identity.
Additional data objects for Layer 2 nodes are introduced by
augmenting the "node" list of the generic "ietf-network" module.
New objects include the Layer 2 node identifier, management address,
management MAC address, management VLAN, and a set of flags.
Additional data objects for Layer 2 termination points are
introduced by augmenting the "termination-point" list of the
"ietf-network-topology" module defined in .
New objects include the interface name, encapsulation type,
lag support indication, and attributes that are specific to
the Layer 2 termination point type.
Links in the "ietf-network-topology" module are augmented as well
with a set of Layer 2 parameters, allowing to associate a link with
a name, a set of Layer 2 link attributes, and flags.
Some optional Layer 2 technology-specific attributes are
introduced in this module as Layer 2 features because these
attributes may be useful to expose to above services/applications.
Note that learning or configuring advanced
Layer 2 technology-specific attributes is not within the scope of
the Layer
2 Topology YANG module; dedicated YANG modules should be used
instead (e.g., ).
Layer 2 Topology YANG ModuleThis module uses types defined in , , , and . It also references , , , and
.
WG List:
Editor: Jie Dong
Editor: Xiugang Wei
Editor: Qin Wu
Editor: Mohamed Boucadair
Editor: Anders Liu
";
description
"This module defines a basic model for the Layer 2 topology
of a network.
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 8944; see
the RFC itself for full legal notices.";
revision 2020-11-15 {
description
"Initial revision.";
reference
"RFC 8944: A YANG Data Model for Layer 2 Network Topologies";
}
feature VLAN {
description
"Enables VLAN tag support as defined in IEEE 802.1Q.";
reference
"IEEE Std 802.1Q-2014: Bridges and Bridged Networks";
}
feature QinQ {
description
"Enables QinQ double tag support as defined in IEEE 802.1ad.";
reference
"IEEE Std 802.1ad: Provider Bridges";
}
feature VXLAN {
description
"Enables VXLAN support as defined in RFC 7348.";
reference
"RFC 7348: Virtual eXtensible Local Area Network (VXLAN):
A Framework for Overlaying Virtualized Layer 2
Networks over Layer 3 Networks";
}
identity flag-identity {
description
"Base type for flags.";
}
identity eth-encapsulation-type {
base ianaift:iana-interface-type;
description
"Base identity from which specific Ethernet
encapsulation types are derived.";
reference
"RFC 7224: IANA Interface Type YANG Module";
}
identity ethernet {
base eth-encapsulation-type;
description
"Native Ethernet encapsulation.";
}
identity vlan {
base eth-encapsulation-type;
description
"VLAN encapsulation.";
}
identity qinq {
base eth-encapsulation-type;
description
"QinQ encapsulation.";
}
identity pbb {
base eth-encapsulation-type;
description
"Provider Backbone Bridging (PBB) encapsulation.
The PBB functions are developed in IEEE 802.1ah.";
}
identity trill {
base eth-encapsulation-type;
description
"Transparent Interconnection of Lots of Links (TRILL)
encapsulation.";
}
identity vpls {
base eth-encapsulation-type;
description
"Ethernet Virtual Private LAN Service (VPLS)
interface encapsulation.";
}
identity vxlan {
base eth-encapsulation-type;
description
"VXLAN Media Access Control (MAC) in UDP encapsulation.";
reference
"RFC 7348: Virtual eXtensible Local Area Network (VXLAN):
A Framework for Overlaying Virtualized Layer 2
Networks over Layer 3 Networks";
}
typedef vni {
type uint32 {
range "0..16777215";
}
description
"VXLAN Network Identifier or VXLAN Segment ID.
It allows up to 16 M VXLAN segments to coexist
within the same administrative domain.
The use of value '0' is implementation specific.";
reference
"RFC 7348: Virtual eXtensible Local Area Network (VXLAN):
A Framework for Overlaying Virtualized Layer 2
Networks over Layer 3 Networks";
}
typedef l2-flag-type {
type identityref {
base flag-identity;
}
description
"Base type for L2 flags. One example of L2 flag
type is trill, which represents the trill topology
type.";
}
typedef node-flag-type {
type identityref {
base flag-identity;
}
description
"Node flag attributes. The physical node can be
one example of a node flag attribute.";
}
typedef link-flag-type {
type identityref {
base flag-identity;
}
description
"Link flag attributes. One example of a link flag
attribute is the pseudowire.";
}
typedef l2-network-event-type {
type enumeration {
enum addition {
value 0;
description
"A Layer 2 node or link or termination-point
has been added.";
}
enum removal {
value 1;
description
"A Layer 2 node or link or termination-point
has been removed.";
}
enum update {
value 2;
description
"A Layer 2 node or link or termination-point
has been updated.";
}
}
description
"Layer 2 network event type for notifications.";
}
typedef duplex-mode {
type enumeration {
enum full-duplex {
description
"Indicates full-duplex mode.";
}
enum half-duplex {
description
"Indicates half-duplex mode.";
}
}
description
"Indicates the type of the duplex mode.";
}
grouping l2-network-type {
description
"Indicates the topology type to be L2.";
container l2-topology {
presence "Indicates L2 Network Topology.";
description
"The presence of the container node indicates
L2 Network Topology.";
}
}
grouping l2-topology-attributes {
description
"L2 topology scope attributes.";
container l2-topology-attributes {
description
"Contains L2 topology attributes.";
leaf name {
type string;
description
"Name of the topology.";
}
leaf-list flags {
type l2-flag-type;
description
"Topology flags.";
}
}
}
grouping l2-node-attributes {
description
"L2 node attributes.";
container l2-node-attributes {
description
"Contains L2 node attributes.";
leaf name {
type string;
description
"Node name.";
}
leaf-list flags {
type node-flag-type;
description
"Node flags. It can be used to indicate
node flag attributes.";
}
leaf-list bridge-id {
type string {
pattern '[0-9a-fA-F]{2}(:[0-9a-fA-F]{2}){7}';
}
description
"This is the bridge identifier represented as a
hexadecimal 8-octet string. It has 4 bits of
priority, 12 bits of Multiple Spanning Tree
Instance Identifier (MSTI-ID), and the base bridge
identifier. There may be multiple for each
spanning tree instance.";
reference
"RFC 7727: Spanning Tree Protocol (STP) Application of
the Inter-Chassis Communication Protocol
(ICCP)";
}
leaf-list management-address {
type inet:ip-address;
description
"IP address used for management purpose.";
}
leaf management-mac {
type yang:mac-address;
description
"This is a MAC address used for the bridge management.
It can be the Bridge Base VLAN ID (VID), interface
MAC address, or other. ";
}
leaf management-vlan {
type string;
description
"This is a VLAN that supports the management address.
The actual VLAN ID type and value would be a member of
this VLAN.";
}
}
}
grouping l2-link-attributes {
description
"L2 link attributes.";
container l2-link-attributes {
description
"Contains L2 link attributes.";
leaf name {
type string;
description
"Link name.";
}
leaf-list flags {
type link-flag-type;
description
"Link flags. It can be used to indicate
link flag attributes.";
}
leaf rate {
type uint64;
units "Kbps";
description
"Link rate. It specifies bandwidth requirements
associated with the specific link. The link
contains a source and a destination.";
}
leaf delay {
type uint32;
units "microseconds";
description
"Unidirectional link delay in
microseconds.";
}
leaf auto-nego {
type boolean;
default "true";
description
"Set to true if auto-negotiation is supported.
Set to false if auto-negotiation is not supported.";
}
leaf duplex {
type duplex-mode;
description
"Exposes the duplex mode, full-duplex or half-duplex.";
}
}
}
grouping l2-termination-point-attributes {
description
"L2 termination point attributes.";
container l2-termination-point-attributes {
description
"Containing L2 termination point attributes.";
leaf interface-name {
type string;
description
"Name of the interface. The name can (but does not
have to) correspond to an interface reference of a
containing node's interface, i.e., the path name of a
corresponding interface data node on the containing
node is reminiscent of data type interface-ref defined
in RFC 8343. It should be noted that data type
interface-ref of RFC 8343 cannot be used directly,
as this data type is used to reference an interface
in a datastore of a single node in the network, not
to uniquely reference interfaces across a network.";
}
leaf mac-address {
type yang:mac-address;
description
"Interface MAC address for logical link control.";
}
leaf-list port-number {
type uint32;
description
" List of port numbers of the bridge ports for which each
entry contains bridge management information.";
}
leaf-list unnumbered-id {
type uint32;
description
"List of unnumbered interface identifiers.
The unnumbered interface identifier will correspond to
the ifIndex value of the interface, i.e., the ifIndex
value of the ifEntry that represents the interface in
implementations where the Interfaces Group MIB
(RFC 2863) is supported.";
}
leaf encapsulation-type {
type identityref {
base eth-encapsulation-type;
}
description
"Encapsulation type of this
termination point.";
}
leaf outer-tag {
if-feature "VLAN";
type dot1q-types:vid-range-type;
description
"The outermost VLAN tag. It may include a list of VLAN
Ids or nonoverlapping VLAN ranges.";
}
leaf outer-tpid {
if-feature "QinQ";
type dot1q-types:dot1q-tag-type;
description
"Identifies a specific 802.1Q tag type of outermost VLAN
tag.";
}
leaf inner-tag {
if-feature "VLAN";
type dot1q-types:vid-range-type;
description
"The inner VLAN tag. It may include a list of VLAN
Ids or nonoverlapping VLAN ranges.";
}
leaf inner-tpid {
if-feature "QinQ";
type dot1q-types:dot1q-tag-type;
description
"Identifies a specific 802.1Q tag type of inner VLAN tag.";
}
leaf lag {
type boolean;
default "false";
description
"Defines whether lag is supported or not.
When it is set to true, the lag is supported.";
}
leaf-list member-link-tp {
when "../lag = 'true'" {
description
"Relevant only when the lag interface is supported.";
}
type leafref {
path "/nw:networks/nw:network/nw:node"
+ "/nt:termination-point/nt:tp-id";
}
description
"List of member link termination points associated with
specific L2 termination point.";
}
container vxlan {
when "derived-from-or-self(../encapsulation-type, "
+ "'l2t:vxlan')" {
description
"Only applies when the type of the Ethernet
encapsulation is 'vxlan'.";
}
if-feature "VXLAN";
leaf vni-id {
type vni;
description
"VXLAN Network Identifier (VNI).";
}
description
"Vxlan encapsulation type.";
}
}
}
augment "/nw:networks/nw:network/nw:network-types" {
description
"Introduces new network type for L2 topology.";
uses l2-network-type;
}
augment "/nw:networks/nw:network" {
when '/nw:networks/nw:network/nw:network-types/l2t:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Configuration parameters for the L2 network
as a whole.";
uses l2-topology-attributes;
}
augment "/nw:networks/nw:network/nw:node" {
when '/nw:networks/nw:network/nw:network-types/l2t:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Configuration parameters for L2 at the node
level.";
uses l2-node-attributes;
}
augment "/nw:networks/nw:network/nt:link" {
when '/nw:networks/nw:network/nw:network-types/l2t:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Augments L2 topology link information.";
uses l2-link-attributes;
}
augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
when '/nw:networks/nw:network/nw:network-types/l2t:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Augments L2 topology termination point information.";
uses l2-termination-point-attributes;
}
notification l2-node-event {
description
"Notification event for L2 node.";
leaf event-type {
type l2-network-event-type;
description
"Event type.";
}
uses nw:node-ref;
uses l2-network-type;
uses l2-node-attributes;
}
notification l2-link-event {
description
"Notification event for L2 link.";
leaf event-type {
type l2-network-event-type;
description
"Event type.";
}
uses nt:link-ref;
uses l2-network-type;
uses l2-link-attributes;
}
notification l2-termination-point-event {
description
"Notification event for L2 termination point.";
leaf event-type {
type l2-network-event-type;
description
"Event type.";
}
uses nt:tp-ref;
uses l2-network-type;
uses l2-termination-point-attributes;
}
}
]]>IANA ConsiderationsIANA has registered the following URIs in the
"ns" subregistry within "The IETF XML Registry" :
These modules are not maintained by IANA.Security ConsiderationsThe YANG modules specified in this document define a schema for data
that is designed to be accessed via network management protocols, such as
Network Configuration Protocol (NETCONF) or RESTCONF .
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 Network Configuration Access Control Model (NACM) 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.The Layer 2 topology module defines information that can be
configurable in certain instances, for example, in the case of virtual
topologies that can be created by client applications. In such cases, a
malicious client could introduce topologies that are undesired.
Specifically, a malicious client could attempt to remove or add a node,
a link, or a termination point by creating or deleting corresponding
elements in the node, link, and termination point lists, respectively.
In the case of a topology that is learned, the server will automatically
prohibit such misconfiguration attempts. In the case of a topology that
is configured, i.e., whose origin is "intended", the undesired
configuration could become effective and be reflected in the operational
state datastore , leading to
disruption of services provided
via this topology. For those reasons, it is important that the NACM is
vigorously applied to prevent topology misconfiguration by unauthorized
clients.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:
l2-network-attributes:
A malicious client could attempt to
sabotage the configuration of any of the contained attributes, such
as the name or the flag data nodes.
l2-node-attributes:
A malicious client could attempt to sabotage
the configuration of important node attributes, such as the name or
the management-address.
l2-link-attributes:
A malicious client could attempt to sabotage
the configuration of important link attributes, such as the rate or
the delay data nodes.
l2-termination-point-attributes:
A malicious client could attempt
to sabotage the configuration of important termination point
attributes (e.g., 'maximum-frame-size').
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. In particular, the YANG module for
Layer 2 topology may expose sensitive information, for example, the MAC
addresses of devices or VLAN/VXLAN identifiers. Unrestricted use of such
information can lead to privacy violations. For example, listing MAC
addresses in a network allows monitoring of devices and their movements.
Location information can be derived from MAC addresses of network
devices, bypassing protection of location information by the Operating
System.ReferencesNormative ReferencesInformative ReferencesIEEE Standard for Local and metropolitan area networks -
Station and Media Access Control Connectivity DiscoveryIEEEIEEE Standard for Local and metropolitan area
networks--Bridges and Bridged Networks--Amendment 30: YANG Data
ModelIEEEIEEE Standard for Local and Metropolitan Area
Networks--Virtual Bridged Local Area Networks--Amendment 4:
Provider BridgesIEEEIEEE Standard for Local and metropolitan area networks --
Virtual Bridged Local Area Networks Amendment 7: Provider Backbone
BridgesIEEEIEEE Standard for Local and metropolitan area
networks--Bridges and Bridged NetworksIEEECompanion YANG Module for Non-NMDA-Compliant ImplementationsThe YANG module ietf-l2-topology defined in this document augments
two modules, "ietf-network" and "ietf-network-topology", that are
designed to be used in conjunction with implementations that support the
Network Management Datastore Architecture (NMDA) defined in . In order to allow implementations
to use the model
even in cases when NMDA is not supported, a set of companion modules
have been defined that represent a state model of networks and network
topologies, "ietf-network-state" and "ietf-network-topology-state",
respectively.In order to be able to use the model for Layer 2 topologies defined
in this document in conjunction with non-NMDA-compliant implementations,
a corresponding companion module is defined that represents the
operational state of Layer 2 network topologies. The module
"ietf-l2-topology-state" mirrors the module "ietf-l2-topology" defined
in . However, it augments "ietf-network-state"
and "ietf-network-topology-state" (instead of "ietf-network" and
"ietf-network-topology") and all its data nodes are
nonconfigurable.The companion module "ietf-l2-topology" SHOULD NOT be supported by
implementations that support NMDA. It is for this reason that this
module is defined in the informative appendix.As the structure of this module mirrors that of its underlying
modules, the YANG tree is not depicted separately.
WG List:
Editor: Jie Dong
Editor: Xiugang Wei
Editor: Qin Wu
Editor: Mohamed Boucadair
Editor: Anders Liu
";
description
"This module defines a model for Layer 2 Network Topology
state, representing topology that either is learned or
results from applying topology that has been configured per
the 'ietf-l2-topology' model, mirroring the
corresponding data nodes in this model.
This model mirrors 'ietf-l2-topology' but contains only
read-only state data. The model is not needed when the
underlying implementation infrastructure supports the
Network Management Datastore Architecture (NMDA).
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 8944; see
the RFC itself for full legal notices.";
revision 2020-11-15 {
description
"Initial revision.";
reference
"RFC 8944: A YANG Data Model for Layer 2 Network Topologies";
}
/*
* Data nodes
*/
augment "/nw-s:networks/nw-s:network/nw-s:network-types" {
description
"Introduces a new network type for L2 topology.";
uses l2t:l2-network-type;
}
augment "/nw-s:networks/nw-s:network" {
when 'nw-s:network-types/l2t-s:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Configuration parameters for the L2 network
as a whole.";
uses l2t:l2-topology-attributes;
}
augment "/nw-s:networks/nw-s:network/nw-s:node" {
when '../nw-s:network-types/l2t-s:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Configuration parameters for L2 at the node
level.";
uses l2t:l2-node-attributes;
}
augment "/nw-s:networks/nw-s:network/nt-s:link" {
when '../nw-s:network-types/l2t-s:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Augments L2 topology link information.";
uses l2t:l2-link-attributes;
}
augment "/nw-s:networks/nw-s:network/nw-s:node/"
+ "nt-s:termination-point" {
when '../../nw-s:network-types/l2t-s:l2-topology' {
description
"Augmentation parameters apply only for networks
with L2 topology.";
}
description
"Augments L2 topology termination point information.";
uses l2t:l2-termination-point-attributes;
}
/*
* Notifications
*/
notification l2-node-event {
description
"Notification event for L2 node.";
leaf event-type {
type l2t:l2-network-event-type;
description
"Event type.";
}
uses nw-s:node-ref;
uses l2t:l2-network-type;
uses l2t:l2-node-attributes;
}
notification l2-link-event {
description
"Notification event for an L2 link.";
leaf event-type {
type l2t:l2-network-event-type;
description
"Event type.";
}
uses nt-s:link-ref;
uses l2t:l2-network-type;
uses l2t:l2-link-attributes;
}
notification l2-termination-point-event {
description
"Notification event for L2 termination point.";
leaf event-type {
type l2t:l2-network-event-type;
description
"Event type.";
}
uses nt-s:tp-ref;
uses l2t:l2-network-type;
uses l2t:l2-termination-point-attributes;
}
}
]]>An ExampleThis section contains an example of an instance data tree in JSON
encoding . The example instantiates
"ietf-l2-topology" for the topology that is depicted in the following
diagram. There are three nodes: D1, D2, and D3. D1 has three termination
points: 1-0-1, 1-2-1, and 1-3-1. D2 has three termination points as
well: 2-1-1, 2-0-1, and 2-3-1. D3 has two termination points: 3-1-1 and
3-2-1. For termination point 1-0-1, it provides lag support and has two
member link termination points: 1-0-1-1 and 1-0-1-2. In addition, there are
six links, two between each pair of nodes with one going in each
direction.A Network Topology Example| | 1-0-1 | |---------------->| | 2-1-1 | |
1-0-1-2 | | 1-2-1 | |<----------------| | 2-0-1 | |
<--------> \-/ 1-3-1 \-/ \-/ 2-3-1 \-/
| /----\ | | /----\ |
+---| |---+ +---| |---+
\----/ \----/
A | A |
| | | |
| | | |
| | +------------+ | |
| | | D3 | | |
| | /-\ /-\ | |
| +----->| | 3-1-1 | |-------+ |
+---------| | 3-2-1 | |<---------+
\-/ \-/
| |
+------------+
]]>The corresponding instance data tree is depicted below:AcknowledgementsThe authors would like to acknowledge the comments and suggestions
received from , , , , , , , , , , , and .Many thanks to for the
yang-doctors review.