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IETF RFC 7223
Last modified on Wednesday, May 14th, 2014
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Internet Engineering Task Force (IETF) M. Bjorklund
Request for Comments: 7223 Tail-f Systems
Category: Standards Track May 2014
ISSN: 2070-1721
A YANG Data Model for Interface Management
 Abstract
This document defines a YANG data model for the management of network
interfaces. It is expected that interface-type-specific data models
augment the generic interfaces data model defined in this document.
The data model includes configuration data and state data (status
information and counters for the collection of statistics).
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/RFC 7223.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Bjorklund Standards Track PAGE 1 
RFC 7223 YANG Interface Management May 2014
Table of Contents
1. Introduction ....................................................2
1.1. Terminology ................................................3
1.2. Tree Diagrams ..............................................4
2. Objectives ......................................................4
3. Interfaces Data Model ...........................................5
3.1. The Interface Lists ........................................6
3.2. Interface References .......................................7
3.3. Interface Layering .........................................7
4. Relationship to the IF-MIB ......................................8
5. Interfaces YANG Module .........................................11
6. IANA Considerations ............................................26
7. Security Considerations ........................................26
8. Acknowledgments ................................................27
9. References .....................................................27
9.1. Normative References ......................................27
9.2. Informative References ....................................28
Appendix A. Example: Ethernet Interface Module ....................29
Appendix B. Example: Ethernet Bonding Interface Module ............30
Appendix C. Example: VLAN Interface Module ........................31
Appendix D. Example: NETCONF <get> Reply ..........................32
Appendix E. Examples: Interface Naming Schemes ....................35
E.1. Router with Restricted Interface Names .....................35
E.2. Router with Arbitrary Interface Names ......................36
E.3. Ethernet Switch with Restricted Interface Names ............37
E.4. Generic Host with Restricted Interface Names ...............38
E.5. Generic Host with Arbitrary Interface Names ................39
1. Introduction
This document defines a YANG [RFC 6020] data model for the management
of network interfaces. It is expected that interface-type-specific
data models augment the generic interfaces data model defined in this
document.
Network interfaces are central to the management of many Internet
protocols. Thus, it is important to establish a common data model
for how interfaces are identified, configured, and monitored.
The data model includes configuration data and state data (status
information and counters for the collection of statistics).
Bjorklund Standards Track PAGE 2
RFC 7223 YANG Interface Management May 2014
1.1. 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 [RFC 2119].
The following terms are used within this document:
o system-controlled interface: An interface is said to be system-
controlled if the system creates and deletes the interface
independently of what has been explicitly configured. Examples
are interfaces representing physical hardware that appear and
disappear when hardware (e.g., a line card or hot-pluggable
wireless interface) is added or removed. System-controlled
interfaces may also appear if a certain functionality is enabled
(e.g., a loopback interface might appear if the IP protocol stack
is enabled).
o user-controlled interface: An interface is said to be user-
controlled if the creation of the interface is controlled by
adding explicit interface configuration to the running
configuration datastore and the removal of the interface is
controlled by removing explicit interface configuration from the
running configuration datastore. Examples are VLAN interfaces
configured on a system-controlled Ethernet interface.
The following terms are defined in [RFC 6241] and are not redefined
here:
o client
o configuration data
o server
o state data
The following terms are defined in [RFC 6020] and are not redefined
here:
o augment
o data model
o data node
o presence container
Bjorklund Standards Track PAGE 3
RFC 7223 YANG Interface Management May 2014
1.2. Tree Diagrams
A simplified graphical representation of the data model is used in
this document. The meaning of the symbols in these diagrams is as
follows:
o Brackets "[" and "]" enclose list keys.
o Abbreviations before data node names: "rw" means configuration
(read-write), and "ro" means state data (read-only).
o Symbols after data node names: "?" means an optional node, "!"
means a presence container, and "*" denotes a list and leaf-list.
o Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
o Ellipsis ("...") stands for contents of subtrees that are not
shown.
2. Objectives
This section describes some of the design objectives for the model
presented in Section 5.
o It is recognized that existing implementations will have to map
the interface data model defined in this memo to their proprietary
native data model. To facilitate such mappings, the data model
should be simple.
o The data model should be suitable for new implementations to use
as is, without requiring a mapping to a different native model.
o References to interfaces should be as simple as possible,
preferably by using a single leafref.
o The mapping to ifIndex [RFC 2863] used by the Simple Network
Management Protocol (SNMP) to identify interfaces must be clear.
o The model must support interface layering: both (1) simple
layering, where one interface is layered on top of exactly one
other interface, and (2) more complex scenarios, where one
interface results from the aggregation of N other interfaces or
when N interfaces are multiplexed over one other interface.
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RFC 7223 YANG Interface Management May 2014
o The data model should support the pre-provisioning of interface
configuration, i.e., it should be possible to configure an
interface whose physical interface hardware is not present on the
device. It is recommended that devices that support dynamic
addition and removal of physical interfaces also support
pre-provisioning.
o The data model should support physical interfaces as well as
logical interfaces.
o The data model should include read-only counters in order to
gather statistics for sent and received octets and packets,
received packets with errors, and packets that could not be sent
due to errors.
3. Interfaces Data Model
This document defines the YANG module "ietf-interfaces", which has
the following structure:
+--rw interfaces
| +--rw interface* [name]
| +--rw name string
| +--rw description? string
| +--rw type identityref
| +--rw enabled? boolean
| +--rw link-up-down-trap-enable? enumeration
+--ro interfaces-state
+--ro interface* [name]
+--ro name string
+--ro type identityref
+--ro admin-status enumeration
+--ro oper-status enumeration
+--ro last-change? yang:date-and-time
+--ro if-index int32
+--ro phys-address? yang:phys-address
+--ro higher-layer-if* interface-state-ref
+--ro lower-layer-if* interface-state-ref
+--ro speed? yang:gauge64
+--ro statistics
+--ro discontinuity-time yang:date-and-time
+--ro in-octets? yang:counter64
+--ro in-unicast-pkts? yang:counter64
+--ro in-broadcast-pkts? yang:counter64
+--ro in-multicast-pkts? yang:counter64
+--ro in-discards? yang:counter32
+--ro in-errors? yang:counter32
+--ro in-unknown-protos? yang:counter32
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RFC 7223 YANG Interface Management May 2014
+--ro out-octets? yang:counter64
+--ro out-unicast-pkts? yang:counter64
+--ro out-broadcast-pkts? yang:counter64
+--ro out-multicast-pkts? yang:counter64
+--ro out-discards? yang:counter32
+--ro out-errors? yang:counter32
3.1. The Interface Lists
The data model for interfaces presented in this document uses a flat
list of interfaces. Each interface in the list is identified by its
name. Furthermore, each interface has a mandatory "type" leaf.
The "iana-if-type" module [RFC 7224] defines YANG identities for the
interface types in the IANA-maintained "ifType definitions" registry.
There is one list of configured interfaces ("/interfaces/interface"),
and a separate list for the operational state of all interfaces
("/interfaces-state/interface").
It is expected that interface-type-specific data models augment the
interface lists and possibly use the "type" leaf to make the
augmentation conditional.
As an example of such an interface-type-specific augmentation,
consider this YANG snippet. For a more complete example, see
Appendix A.
import interfaces {
prefix "if";
}
import iana-if-type {
prefix ianaift;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:ethernetCsmacd'";
container ethernet {
leaf duplex {
...
}
}
}
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RFC 7223 YANG Interface Management May 2014
For system-controlled interfaces, the "name" is the device-specific
name of the interface. The 'config false' list
"/interfaces-state/interface" contains all existing interfaces on the
device.
If the device supports arbitrarily named user-controlled interfaces,
the Network Configuration Protocol (NETCONF) server advertises the
"arbitrary-names" feature. If the device does not advertise this
feature, the names of user-controlled interfaces MUST match the
device's naming scheme. How a client can learn the naming scheme of
such devices is outside the scope of this document. See Appendices
E.1 and E.2 for examples.
When a system-controlled interface is created by the system, the
system tries to apply the interface configuration in "/interfaces/
interface" with the same name as the new interface. If no such
interface configuration is found, or if the configured type does not
match the real interface type, the system creates the interface
without applying explicit configuration.
When a user-controlled interface is created, the configuration
determines the name of the interface.
Depending on the operating system and the physical attachment point
to which a network interface may be attached or removed, it may be
impossible for an implementation to provide predictable and
consistent names for system-controlled interfaces across insertion/
removal cycles as well as in anticipation of initial insertion. The
ability to provide configurations for such interfaces is therefore
dependent on the implementation and cannot be assumed in all cases.
3.2. Interface References
An interface is identified by its name, which is unique within the
server. This property is captured in the "interface-ref" and
"interface-state-ref" typedefs, which other YANG modules SHOULD use
when they need to reference a configured interface or operationally
used interface, respectively.
3.3. Interface Layering
There is no generic mechanism for how an interface is configured to
be layered on top of some other interface. It is expected that
interface-type-specific models define their own data nodes for
interface layering by using "interface-ref" types to reference
lower layers.
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RFC 7223 YANG Interface Management May 2014
Below is an example of a model with such nodes. For a more complete
example, see Appendix B.
import interfaces {
prefix "if";
}
import iana-if-type {
prefix ianaift;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:ieee8023adLag'";
leaf-list slave-if {
type if:interface-ref;
must "/if:interfaces/if:interface[if:name = current()]"
+ "/if:type = 'ianaift:ethernetCsmacd'" {
description
"The type of a slave interface must be
'ethernetCsmacd'.";
}
}
// other bonding config params, failover times, etc.
}
While the interface layering is configured in interface-type-specific
models, two generic state data leaf-lists, "higher-layer-if" and
"lower-layer-if", represent a read-only view of the interface
layering hierarchy.
4. Relationship to the IF-MIB
If the device implements the IF-MIB [RFC 2863], each entry in the "/
interfaces-state/interface" list is typically mapped to one ifEntry.
The "if-index" leaf MUST contain the value of the corresponding
ifEntry's ifIndex.
In most cases, the "name" of an "/interfaces-state/interface" entry
is mapped to ifName. The IF-MIB allows two different ifEntries to
have the same ifName. Devices that support this feature and also
support the data model defined in this document cannot have a 1-1
mapping between the "name" leaf and ifName.
The configured "description" of an "interface" has traditionally been
mapped to ifAlias in some implementations. This document allows this
mapping, but implementers should be aware of the differences in the
value space and persistence for these objects. See the YANG module
definition of the leaf "description" in Section 5 for details.
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RFC 7223 YANG Interface Management May 2014
The IF-MIB also defines the writable object ifPromiscuousMode. Since
this object typically is not implemented as a configuration object by
SNMP agents, it is not mapped to the "ietf-interfaces" module.
The ifMtu object from the IF-MIB is not mapped to the
"ietf-interfaces" module. It is expected that interface-type-
specific YANG modules provide interface-type-specific MTU leafs by
augmenting the "ietf-interfaces" model.
There are a number of counters in the IF-MIB that exist in two
versions: one with 32 bits and one with 64 bits. The 64-bit versions
were added to support high-speed interfaces with a data rate greater
than 20,000,000 bits/second. Today's implementations generally
support such high-speed interfaces, and hence only 64-bit counters
are provided in this data model. Note that NETCONF and SNMP may
differ in the time granularity in which they provide access to the
counters. For example, it is common that SNMP implementations cache
counter values for some time.
The objects ifDescr and ifConnectorPresent from the IF-MIB are not
mapped to the "ietf-interfaces" module.
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RFC 7223 YANG Interface Management May 2014
The following tables list the YANG data nodes with corresponding
objects in the IF-MIB.
+--------------------------------------+----------------------------+
| YANG data node in /interfaces- | IF-MIB object |
| state/interface | |
+--------------------------------------+----------------------------+
| name | ifName |
| type | ifType |
| admin-status | ifAdminStatus |
| oper-status | ifOperStatus |
| last-change | ifLastChange |
| if-index | ifIndex |
| link-up-down-trap-enable | ifLinkUpDownTrapEnable |
| phys-address | ifPhysAddress |
| higher-layer-if and lower-layer-if | ifStackTable |
| speed | ifSpeed and ifHighSpeed |
| discontinuity-time | ifCounterDiscontinuityTime |
| in-octets | ifHCInOctets |
| in-unicast-pkts | ifHCInUcastPkts |
| in-broadcast-pkts | ifHCInBroadcastPkts |
| in-multicast-pkts | ifHCInMulticastPkts |
| in-discards | ifInDiscards |
| in-errors | ifInErrors |
| in-unknown-protos | ifInUnknownProtos |
| out-octets | ifHCOutOctets |
| out-unicast-pkts | ifHCOutUcastPkts |
| out-broadcast-pkts | ifHCOutBroadcastPkts |
| out-multicast-pkts | ifHCOutMulticastPkts |
| out-discards | ifOutDiscards |
| out-errors | ifOutErrors |
+--------------------------------------+----------------------------+
YANG State Data Nodes and Related IF-MIB Objects
+-----------------------------------------+---------------+
| YANG data node in /interfaces/interface | IF-MIB object |
+-----------------------------------------+---------------+
| description | ifAlias |
+-----------------------------------------+---------------+
YANG Config Data Nodes and Related IF-MIB Objects
Bjorklund Standards Track PAGE 10
RFC 7223 YANG Interface Management May 2014
5. Interfaces YANG Module
This YANG module imports typedefs from [RFC 6991].
<CODE BEGINS> file "ietf-interfaces@2014-05-08.yang"
module ietf-interfaces {
namespace "urn:ietf:params:xml:ns:yang:ietf-interfaces";
prefix if;
import ietf-yang-types {
prefix yang;
}
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
WG Chair: Thomas Nadeau
<mailto:tnadeau@lucidvision.com>
WG Chair: Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>
Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>";
description
"This module contains a collection of YANG definitions for
managing network interfaces.
Copyright (c) 2014 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 7223; see
the RFC itself for full legal notices.";
Bjorklund Standards Track PAGE 11
RFC 7223 YANG Interface Management May 2014
revision 2014-05-08 {
description
"Initial revision.";
reference
"RFC 7223: A YANG Data Model for Interface Management";
}
/*
* Typedefs
*/
typedef interface-ref {
type leafref {
path "/if:interfaces/if:interface/if:name";
}
description
"This type is used by data models that need to reference
configured interfaces.";
}
typedef interface-state-ref {
type leafref {
path "/if:interfaces-state/if:interface/if:name";
}
description
"This type is used by data models that need to reference
the operationally present interfaces.";
}
/*
* Identities
*/
identity interface-type {
description
"Base identity from which specific interface types are
derived.";
}
/*
* Features
*/
feature arbitrary-names {
description
"This feature indicates that the device allows user-controlled
interfaces to be named arbitrarily.";
}
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RFC 7223 YANG Interface Management May 2014
feature pre-provisioning {
description
"This feature indicates that the device supports
pre-provisioning of interface configuration, i.e., it is
possible to configure an interface whose physical interface
hardware is not present on the device.";
}
feature if-mib {
description
"This feature indicates that the device implements
the IF-MIB.";
reference
"RFC 2863: The Interfaces Group MIB";
}
/*
* Configuration data nodes
*/
container interfaces {
description
"Interface configuration parameters.";
list interface {
key "name";
description
"The list of configured interfaces on the device.
The operational state of an interface is available in the
/interfaces-state/interface list. If the configuration of a
system-controlled interface cannot be used by the system
(e.g., the interface hardware present does not match the
interface type), then the configuration is not applied to
the system-controlled interface shown in the
/interfaces-state/interface list. If the configuration
of a user-controlled interface cannot be used by the system,
the configured interface is not instantiated in the
/interfaces-state/interface list.";
leaf name {
type string;
description
"The name of the interface.
A device MAY restrict the allowed values for this leaf,
possibly depending on the type of the interface.
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RFC 7223 YANG Interface Management May 2014
For system-controlled interfaces, this leaf is the
device-specific name of the interface. The 'config false'
list /interfaces-state/interface contains the currently
existing interfaces on the device.
If a client tries to create configuration for a
system-controlled interface that is not present in the
/interfaces-state/interface list, the server MAY reject
the request if the implementation does not support
pre-provisioning of interfaces or if the name refers to
an interface that can never exist in the system. A
NETCONF server MUST reply with an rpc-error with the
error-tag 'invalid-value' in this case.
If the device supports pre-provisioning of interface
configuration, the 'pre-provisioning' feature is
advertised.
If the device allows arbitrarily named user-controlled
interfaces, the 'arbitrary-names' feature is advertised.
When a configured user-controlled interface is created by
the system, it is instantiated with the same name in the
/interface-state/interface list.";
}
leaf description {
type string;
description
"A textual description of the interface.
A server implementation MAY map this leaf to the ifAlias
MIB object. Such an implementation needs to use some
mechanism to handle the differences in size and characters
allowed between this leaf and ifAlias. The definition of
such a mechanism is outside the scope of this document.
Since ifAlias is defined to be stored in non-volatile
storage, the MIB implementation MUST map ifAlias to the
value of 'description' in the persistently stored
datastore.
Specifically, if the device supports ':startup', when
ifAlias is read the device MUST return the value of
'description' in the 'startup' datastore, and when it is
written, it MUST be written to the 'running' and 'startup'
datastores. Note that it is up to the implementation to
Bjorklund Standards Track PAGE 14
RFC 7223 YANG Interface Management May 2014
decide whether to modify this single leaf in 'startup' or
perform an implicit copy-config from 'running' to
'startup'.
If the device does not support ':startup', ifAlias MUST
be mapped to the 'description' leaf in the 'running'
datastore.";
reference
"RFC 2863: The Interfaces Group MIB - ifAlias";
}
leaf type {
type identityref {
base interface-type;
}
mandatory true;
description
"The type of the interface.
When an interface entry is created, a server MAY
initialize the type leaf with a valid value, e.g., if it
is possible to derive the type from the name of the
interface.
If a client tries to set the type of an interface to a
value that can never be used by the system, e.g., if the
type is not supported or if the type does not match the
name of the interface, the server MUST reject the request.
A NETCONF server MUST reply with an rpc-error with the
error-tag 'invalid-value' in this case.";
reference
"RFC 2863: The Interfaces Group MIB - ifType";
}
leaf enabled {
type boolean;
default "true";
description
"This leaf contains the configured, desired state of the
interface.
Systems that implement the IF-MIB use the value of this
leaf in the 'running' datastore to set
IF-MIB.ifAdminStatus to 'up' or 'down' after an ifEntry
has been initialized, as described in RFC 2863.
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Changes in this leaf in the 'running' datastore are
reflected in ifAdminStatus, but if ifAdminStatus is
changed over SNMP, this leaf is not affected.";
reference
"RFC 2863: The Interfaces Group MIB - ifAdminStatus";
}
leaf link-up-down-trap-enable {
if-feature if-mib;
type enumeration {
enum enabled {
value 1;
}
enum disabled {
value 2;
}
}
description
"Controls whether linkUp/linkDown SNMP notifications
should be generated for this interface.
If this node is not configured, the value 'enabled' is
operationally used by the server for interfaces that do
not operate on top of any other interface (i.e., there are
no 'lower-layer-if' entries), and 'disabled' otherwise.";
reference
"RFC 2863: The Interfaces Group MIB -
ifLinkUpDownTrapEnable";
}
}
}
/*
* Operational state data nodes
*/
container interfaces-state {
config false;
description
"Data nodes for the operational state of interfaces.";
list interface {
key "name";
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RFC 7223 YANG Interface Management May 2014
description
"The list of interfaces on the device.
System-controlled interfaces created by the system are
always present in this list, whether they are configured or
not.";
leaf name {
type string;
description
"The name of the interface.
A server implementation MAY map this leaf to the ifName
MIB object. Such an implementation needs to use some
mechanism to handle the differences in size and characters
allowed between this leaf and ifName. The definition of
such a mechanism is outside the scope of this document.";
reference
"RFC 2863: The Interfaces Group MIB - ifName";
}
leaf type {
type identityref {
base interface-type;
}
mandatory true;
description
"The type of the interface.";
reference
"RFC 2863: The Interfaces Group MIB - ifType";
}
leaf admin-status {
if-feature if-mib;
type enumeration {
enum up {
value 1;
description
"Ready to pass packets.";
}
enum down {
value 2;
description
"Not ready to pass packets and not in some test mode.";
}
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enum testing {
value 3;
description
"In some test mode.";
}
}
mandatory true;
description
"The desired state of the interface.
This leaf has the same read semantics as ifAdminStatus.";
reference
"RFC 2863: The Interfaces Group MIB - ifAdminStatus";
}
leaf oper-status {
type enumeration {
enum up {
value 1;
description
"Ready to pass packets.";
}
enum down {
value 2;
description
"The interface does not pass any packets.";
}
enum testing {
value 3;
description
"In some test mode. No operational packets can
be passed.";
}
enum unknown {
value 4;
description
"Status cannot be determined for some reason.";
}
enum dormant {
value 5;
description
"Waiting for some external event.";
}
enum not-present {
value 6;
description
"Some component (typically hardware) is missing.";
}
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enum lower-layer-down {
value 7;
description
"Down due to state of lower-layer interface(s).";
}
}
mandatory true;
description
"The current operational state of the interface.
This leaf has the same semantics as ifOperStatus.";
reference
"RFC 2863: The Interfaces Group MIB - ifOperStatus";
}
leaf last-change {
type yang:date-and-time;
description
"The time the interface entered its current operational
state. If the current state was entered prior to the
last re-initialization of the local network management
subsystem, then this node is not present.";
reference
"RFC 2863: The Interfaces Group MIB - ifLastChange";
}
leaf if-index {
if-feature if-mib;
type int32 {
range "1..2147483647";
}
mandatory true;
description
"The ifIndex value for the ifEntry represented by this
interface.";
reference
"RFC 2863: The Interfaces Group MIB - ifIndex";
}
leaf phys-address {
type yang:phys-address;
description
"The interface's address at its protocol sub-layer. For
example, for an 802.x interface, this object normally
contains a Media Access Control (MAC) address. The
interface's media-specific modules must define the bit
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RFC 7223 YANG Interface Management May 2014
and byte ordering and the format of the value of this
object. For interfaces that do not have such an address
(e.g., a serial line), this node is not present.";
reference
"RFC 2863: The Interfaces Group MIB - ifPhysAddress";
}
leaf-list higher-layer-if {
type interface-state-ref;
description
"A list of references to interfaces layered on top of this
interface.";
reference
"RFC 2863: The Interfaces Group MIB - ifStackTable";
}
leaf-list lower-layer-if {
type interface-state-ref;
description
"A list of references to interfaces layered underneath this
interface.";
reference
"RFC 2863: The Interfaces Group MIB - ifStackTable";
}
leaf speed {
type yang:gauge64;
units "bits/second";
description
"An estimate of the interface's current bandwidth in bits
per second. For interfaces that do not vary in
bandwidth or for those where no accurate estimation can
be made, this node should contain the nominal bandwidth.
For interfaces that have no concept of bandwidth, this
node is not present.";
reference
"RFC 2863: The Interfaces Group MIB -
ifSpeed, ifHighSpeed";
}
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RFC 7223 YANG Interface Management May 2014
container statistics {
description
"A collection of interface-related statistics objects.";
leaf discontinuity-time {
type yang:date-and-time;
mandatory true;
description
"The time on the most recent occasion at which any one or
more of this interface's counters suffered a
discontinuity. If no such discontinuities have occurred
since the last re-initialization of the local management
subsystem, then this node contains the time the local
management subsystem re-initialized itself.";
}
leaf in-octets {
type yang:counter64;
description
"The total number of octets received on the interface,
including framing characters.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifHCInOctets";
}
leaf in-unicast-pkts {
type yang:counter64;
description
"The number of packets, delivered by this sub-layer to a
higher (sub-)layer, that were not addressed to a
multicast or broadcast address at this sub-layer.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifHCInUcastPkts";
}
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leaf in-broadcast-pkts {
type yang:counter64;
description
"The number of packets, delivered by this sub-layer to a
higher (sub-)layer, that were addressed to a broadcast
address at this sub-layer.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB -
ifHCInBroadcastPkts";
}
leaf in-multicast-pkts {
type yang:counter64;
description
"The number of packets, delivered by this sub-layer to a
higher (sub-)layer, that were addressed to a multicast
address at this sub-layer. For a MAC-layer protocol,
this includes both Group and Functional addresses.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB -
ifHCInMulticastPkts";
}
leaf in-discards {
type yang:counter32;
description
"The number of inbound packets that were chosen to be
discarded even though no errors had been detected to
prevent their being deliverable to a higher-layer
protocol. One possible reason for discarding such a
packet could be to free up buffer space.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
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reference
"RFC 2863: The Interfaces Group MIB - ifInDiscards";
}
leaf in-errors {
type yang:counter32;
description
"For packet-oriented interfaces, the number of inbound
packets that contained errors preventing them from being
deliverable to a higher-layer protocol. For character-
oriented or fixed-length interfaces, the number of
inbound transmission units that contained errors
preventing them from being deliverable to a higher-layer
protocol.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifInErrors";
}
leaf in-unknown-protos {
type yang:counter32;
description
"For packet-oriented interfaces, the number of packets
received via the interface that were discarded because
of an unknown or unsupported protocol. For
character-oriented or fixed-length interfaces that
support protocol multiplexing, the number of
transmission units received via the interface that were
discarded because of an unknown or unsupported protocol.
For any interface that does not support protocol
multiplexing, this counter is not present.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifInUnknownProtos";
}
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leaf out-octets {
type yang:counter64;
description
"The total number of octets transmitted out of the
interface, including framing characters.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifHCOutOctets";
}
leaf out-unicast-pkts {
type yang:counter64;
description
"The total number of packets that higher-level protocols
requested be transmitted, and that were not addressed
to a multicast or broadcast address at this sub-layer,
including those that were discarded or not sent.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifHCOutUcastPkts";
}
leaf out-broadcast-pkts {
type yang:counter64;
description
"The total number of packets that higher-level protocols
requested be transmitted, and that were addressed to a
broadcast address at this sub-layer, including those
that were discarded or not sent.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB -
ifHCOutBroadcastPkts";
}
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leaf out-multicast-pkts {
type yang:counter64;
description
"The total number of packets that higher-level protocols
requested be transmitted, and that were addressed to a
multicast address at this sub-layer, including those
that were discarded or not sent. For a MAC-layer
protocol, this includes both Group and Functional
addresses.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB -
ifHCOutMulticastPkts";
}
leaf out-discards {
type yang:counter32;
description
"The number of outbound packets that 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.
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifOutDiscards";
}
leaf out-errors {
type yang:counter32;
description
"For packet-oriented interfaces, the number of outbound
packets that could not be transmitted because of errors.
For character-oriented or fixed-length interfaces, the
number of outbound transmission units that could not be
transmitted because of errors.
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RFC 7223 YANG Interface Management May 2014
Discontinuities in the value of this counter can occur
at re-initialization of the management system, and at
other times as indicated by the value of
'discontinuity-time'.";
reference
"RFC 2863: The Interfaces Group MIB - ifOutErrors";
}
}
}
}
}
<CODE ENDS>
6. IANA Considerations
This document registers a URI in the "IETF XML Registry" [RFC 3688].
Following the format in RFC 3688, the following registration has been
made.
URI: urn:ietf:params:xml:ns:yang:ietf-interfaces
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
This document registers a YANG module in the "YANG Module Names"
registry [RFC 6020].
name: ietf-interfaces
namespace: urn:ietf:params:xml:ns:yang:ietf-interfaces
prefix: if
reference: RFC 7223
7. Security Considerations
The YANG module defined in this memo is designed to be accessed via
the NETCONF protocol [RFC 6241]. The lowest NETCONF layer is the
secure transport layer and the mandatory-to-implement secure
transport is SSH [RFC 6242]. The NETCONF access control model
[RFC 6536] provides the means to restrict access for particular
NETCONF users to a pre-configured subset of all available NETCONF
protocol operations and content.
There are a number of data nodes defined in the YANG module which 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>)
Bjorklund Standards Track PAGE 26
RFC 7223 YANG Interface Management May 2014
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:
/interfaces/interface: This list specifies the configured interfaces
on a device. Unauthorized access to this list could cause the
device to ignore packets it should receive and process.
/interfaces/interface/enabled: This leaf controls whether an
interface is enabled or not. Unauthorized access to this leaf
could cause the device to ignore packets it should receive and
process.
8. Acknowledgments
The author wishes to thank Alexander Clemm, Per Hedeland, Ladislav
Lhotka, and Juergen Schoenwaelder for their helpful comments.
9. References
9.1. Normative References
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group
MIB", RFC 2863, June 2000.
[RFC 3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC 6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC 6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991,
July 2013.
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RFC 7223 YANG Interface Management May 2014
9.2. Informative References
[RFC 6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)",
RFC 6241, June 2011.
[RFC 6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, June 2011.
[RFC 6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
March 2012.
[RFC 7224] Bjorklund, M., "IANA Interface Type YANG Module",
RFC 7224, May 2014.
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RFC 7223 YANG Interface Management May 2014
Appendix A. Example: Ethernet Interface Module
This section gives a simple example of how an Ethernet interface
module could be defined. It demonstrates how media-specific
configuration parameters can be conditionally augmented to the
generic interface list. It also shows how operational state
parameters can be conditionally augmented to the operational
interface list. The example is not intended as a complete module for
Ethernet configuration.
module ex-ethernet {
namespace "http://example.com/ethernet";
prefix "eth";
import ietf-interfaces {
prefix if;
}
import iana-if-type {
prefix ianaift;
}
// configuration parameters for Ethernet interfaces
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:ethernetCsmacd'";
container ethernet {
choice transmission-params {
case auto {
leaf auto-negotiate {
type empty;
}
}
case manual {
leaf duplex {
type enumeration {
enum "half";
enum "full";
}
}
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leaf speed {
type enumeration {
enum "10Mb";
enum "100Mb";
enum "1Gb";
enum "10Gb";
}
}
}
}
// other Ethernet-specific params...
}
}
// operational state parameters for Ethernet interfaces
augment "/if:interfaces-state/if:interface" {
when "if:type = 'ianaift:ethernetCsmacd'";
container ethernet {
leaf duplex {
type enumeration {
enum "half";
enum "full";
}
}
// other Ethernet-specific params...
}
}
}
Appendix B. Example: Ethernet Bonding Interface Module
This section gives an example of how interface layering can be
defined. An Ethernet bonding interface that bonds several Ethernet
interfaces into one logical interface is defined.
module ex-ethernet-bonding {
namespace "http://example.com/ethernet-bonding";
prefix "bond";
import ietf-interfaces {
prefix if;
}
import iana-if-type {
prefix ianaift;
}
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RFC 7223 YANG Interface Management May 2014
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:ieee8023adLag'";
leaf-list slave-if {
type if:interface-ref;
must "/if:interfaces/if:interface[if:name = current()]"
+ "/if:type = 'ianaift:ethernetCsmacd'" {
description
"The type of a slave interface must be 'ethernetCsmacd'.";
}
}
leaf bonding-mode {
type enumeration {
enum round-robin;
enum active-backup;
enum broadcast;
}
}
// other bonding config params, failover times, etc.
}
}
Appendix C. Example: VLAN Interface Module
This section gives an example of how a VLAN interface module can be
defined.
module ex-vlan {
namespace "http://example.com/vlan";
prefix "vlan";
import ietf-interfaces {
prefix if;
}
import iana-if-type {
prefix ianaift;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:ethernetCsmacd' or
if:type = 'ianaift:ieee8023adLag'";
leaf vlan-tagging {
type boolean;
default false;
}
}
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RFC 7223 YANG Interface Management May 2014
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:l2vlan'";
leaf base-interface {
type if:interface-ref;
must "/if:interfaces/if:interface[if:name = current()]"
+ "/vlan:vlan-tagging = 'true'" {
description
"The base interface must have VLAN tagging enabled.";
}
}
leaf vlan-id {
type uint16 {
range "1..4094";
}
must "../base-interface" {
description
"If a vlan-id is defined, a base-interface must
be specified.";
}
}
}
}
Appendix D. Example: NETCONF <get> Reply
This section gives an example of a reply to the NETCONF <get> request
for a device that implements the example data models above.
<rpc-reply
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
message-id="101">
<data>
<interfaces
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type"
xmlns:vlan="http://example.com/vlan">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>false</enabled>
</interface>
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<interface>
<name>eth1</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
<vlan:vlan-tagging>true</vlan:vlan-tagging>
</interface>
<interface>
<name>eth1.10</name>
<type>ianaift:l2vlan</type>
<enabled>true</enabled>
<vlan:base-interface>eth1</vlan:base-interface>
<vlan:vlan-id>10</vlan:vlan-id>
</interface>
<interface>
<name>lo1</name>
<type>ianaift:softwareLoopback</type>
<enabled>true</enabled>
</interface>
</interfaces>
<interfaces-state
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<admin-status>down</admin-status>
<oper-status>down</oper-status>
<if-index>2</if-index>
<phys-address>00:01:02:03:04:05</phys-address>
<statistics>
<discontinuity-time>
2013-04-01T03:00:00+00:00
</discontinuity-time>
<!-- counters now shown here -->
</statistics>
</interface>
<interface>
<name>eth1</name>
<type>ianaift:ethernetCsmacd</type>
<admin-status>up</admin-status>
<oper-status>up</oper-status>
<if-index>7</if-index>
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<phys-address>00:01:02:03:04:06</phys-address>
<higher-layer-if>eth1.10</higher-layer-if>
<statistics>
<discontinuity-time>
2013-04-01T03:00:00+00:00
</discontinuity-time>
<!-- counters now shown here -->
</statistics>
</interface>
<interface>
<name>eth1.10</name>
<type>ianaift:l2vlan</type>
<admin-status>up</admin-status>
<oper-status>up</oper-status>
<if-index>9</if-index>
<lower-layer-if>eth1</lower-layer-if>
<statistics>
<discontinuity-time>
2013-04-01T03:00:00+00:00
</discontinuity-time>
<!-- counters now shown here -->
</statistics>
</interface>
<!-- This interface is not configured -->
<interface>
<name>eth2</name>
<type>ianaift:ethernetCsmacd</type>
<admin-status>down</admin-status>
<oper-status>down</oper-status>
<if-index>8</if-index>
<phys-address>00:01:02:03:04:07</phys-address>
<statistics>
<discontinuity-time>
2013-04-01T03:00:00+00:00
</discontinuity-time>
<!-- counters now shown here -->
</statistics>
</interface>
<interface>
<name>lo1</name>
<type>ianaift:softwareLoopback</type>
<admin-status>up</admin-status>
<oper-status>up</oper-status>
<if-index>1</if-index>
<statistics>
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RFC 7223 YANG Interface Management May 2014
<discontinuity-time>
2013-04-01T03:00:00+00:00
</discontinuity-time>
<!-- counters now shown here -->
</statistics>
</interface>
</interfaces-state>
</data>
</rpc-reply>
Appendix E. Examples: Interface Naming Schemes
This section gives examples of some implementation strategies.
The examples make use of the example data model "ex-vlan" (see
Appendix C) to show how user-controlled interfaces can be configured.
E.1. Router with Restricted Interface Names
In this example, a router has support for 4 line cards, each with 8
ports. The slots for the cards are physically numbered from 0 to 3,
and the ports on each card from 0 to 7. Each card has Fast Ethernet
or Gigabit Ethernet ports.
The device-specific names for these physical interfaces are
"fastethernet-N/M" or "gigabitethernet-N/M".
The name of a VLAN interface is restricted to the form
"<physical-interface-name>.<subinterface-number>".
It is assumed that the operator is aware of this naming scheme. The
implementation auto-initializes the value for "type" based on the
interface name.
The NETCONF server does not advertise the "arbitrary-names" feature
in the <hello> message.
An operator can configure a physical interface by sending an
<edit-config> containing:
<interface nc:operation="create">
<name>fastethernet-1/0</name>
</interface>
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RFC 7223 YANG Interface Management May 2014
When the server processes this request, it will set the leaf "type"
to "ianaift:ethernetCsmacd". Thus, if the client performs a
<get-config> right after the <edit-config> above, it will get:
<interface>
<name>fastethernet-1/0</name>
<type>ianaift:ethernetCsmacd</type>
</interface>
The client can configure a VLAN interface by sending an <edit-config>
containing:
<interface nc:operation="create">
<name>fastethernet-1/0.10005</name>
<type>ianaift:l2vlan</type>
<vlan:base-interface>fastethernet-1/0</vlan:base-interface>
<vlan:vlan-id>5</vlan:vlan-id>
</interface>
If the client tries to change the type of the physical interface with
an <edit-config> containing:
<interface nc:operation="merge">
<name>fastethernet-1/0</name>
<type>ianaift:tunnel</type>
</interface>
then the server will reply with an "invalid-value" error, since the
new type does not match the name.
E.2. Router with Arbitrary Interface Names
In this example, a router has support for 4 line cards, each with 8
ports. The slots for the cards are physically numbered from 0 to 3,
and the ports on each card from 0 to 7. Each card has Fast Ethernet
or Gigabit Ethernet ports.
The device-specific names for these physical interfaces are
"fastethernet-N/M" or "gigabitethernet-N/M".
The implementation does not restrict the user-controlled interface
names. This allows an operator to more easily apply the interface
configuration to a different interface. However, the additional
level of indirection also makes it a bit more complex to map
interface names found in other protocols to configuration entries.
The NETCONF server advertises the "arbitrary-names" feature in the
<hello> message.
Bjorklund Standards Track PAGE 36
RFC 7223 YANG Interface Management May 2014
Physical interfaces are configured as in Appendix E.1.
An operator can configure a VLAN interface by sending an
<edit-config> containing:
<interface nc:operation="create">
<name>acme-interface</name>
<type>ianaift:l2vlan</type>
<vlan:base-interface>fastethernet-1/0</vlan:base-interface>
<vlan:vlan-id>5</vlan:vlan-id>
</interface>
If necessary, the operator can move the configuration named
"acme-interface" over to a different physical interface with an
<edit-config> containing:
<interface nc:operation="merge">
<name>acme-interface</name>
<vlan:base-interface>fastethernet-1/1</vlan:base-interface>
</interface>
E.3. Ethernet Switch with Restricted Interface Names
In this example, an Ethernet switch has a number of ports, each
identified by a simple port number.
The device-specific names for the physical interfaces are numbers
that match the physical port number.
An operator can configure a physical interface by sending an
<edit-config> containing:
<interface nc:operation="create">
<name>6</name>
</interface>
When the server processes this request, it will set the leaf "type"
to "ianaift:ethernetCsmacd". Thus, if the client performs a
<get-config> right after the <edit-config> above, it will get:
<interface>
<name>6</name>
<type>ianaift:ethernetCsmacd</type>
</interface>
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E.4. Generic Host with Restricted Interface Names
In this example, a generic host has interfaces named by the kernel.
The system identifies the physical interface by the name assigned by
the operating system to the interface.
The name of a VLAN interface is restricted to the form
"<physical-interface-name>:<vlan-number>".
The NETCONF server does not advertise the "arbitrary-names" feature
in the <hello> message.
An operator can configure an interface by sending an <edit-config>
containing:
<interface nc:operation="create">
<name>eth8</name>
</interface>
When the server processes this request, it will set the leaf "type"
to "ianaift:ethernetCsmacd". Thus, if the client performs a
<get-config> right after the <edit-config> above, it will get:
<interface>
<name>eth8</name>
<type>ianaift:ethernetCsmacd</type>
</interface>
The client can configure a VLAN interface by sending an <edit-config>
containing:
<interface nc:operation="create">
<name>eth8:5</name>
<type>ianaift:l2vlan</type>
<vlan:base-interface>eth8</vlan:base-interface>
<vlan:vlan-id>5</vlan:vlan-id>
</interface>
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RFC 7223 YANG Interface Management May 2014
E.5. Generic Host with Arbitrary Interface Names
In this example, a generic host has interfaces named by the kernel.
The system identifies the physical interface by the name assigned by
the operating system to the interface.
The implementation does not restrict the user-controlled interface
names. This allows an operator to more easily apply the interface
configuration to a different interface. However, the additional
level of indirection also makes it a bit more complex to map
interface names found in other protocols to configuration entries.
The NETCONF server advertises the "arbitrary-names" feature in the
<hello> message.
Physical interfaces are configured as in Appendix E.4.
An operator can configure a VLAN interface by sending an
<edit-config> containing:
<interface nc:operation="create">
<name>acme-interface</name>
<type>ianaift:l2vlan</type>
<vlan:base-interface>eth8</vlan:base-interface>
<vlan:vlan-id>5</vlan:vlan-id>
</interface>
If necessary, the operator can move the configuration named
"acme-interface" over to a different physical interface with an
<edit-config> containing:
<interface nc:operation="merge">
<name>acme-interface</name>
<vlan:base-interface>eth3</vlan:base-interface>
</interface>
Author's Address
Martin Bjorklund
Tail-f Systems
EMail: mbj@tail-f.com
Bjorklund Standards Track PAGE 39
RFC TOTAL SIZE: 70537 bytes
PUBLICATION DATE: Wednesday, May 14th, 2014
LEGAL RIGHTS: The IETF Trust (see BCP 78)
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