RFC 7223
A YANG Data Model for Interface Management
RFC 7223: A YANG Data Model for Interface Management 💖
- Stream: Internet Engineering Task Force (IETF) 🌸
- Request for Comments: 7223
- Category: Standards Track ✨
- Author: M. Bjorklund, Tail-f Systems 🎀
- Date: May 2014
- ISSN: 2070-1721
- Obsoletes/Updates: none listed in the header 🦋
Abstract
okay so this doc defines a YANG model (YANG is the language for describing data models, bestie 💅) for managing network interfaces 🔌. The idea is that interface-type-specific data models will augment this generic interfaces model, so everyone builds on the same base. It covers both the configuration data and the state data, meaning the status info and the counters for statistics 📊.
Status of This Memo
this is an Internet Standards Track document 🔥.
It's a product of the Internet Engineering Task Force (IETF) and represents the consensus of the IETF community 🫶. It got public review and was approved for publication by the Internet Engineering Steering Group (IESG). If you want more on Internet Standards, check Section 2 of RFC 5741 📚.
For the current status, any errata, and how to give feedback, look at http://www.rfc-editor.org/info/rfc7223 🔗.
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) as in effect on the date of publication. Please read these carefully, bestie, because they spell out your rights and restrictions. Code Components pulled out of this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions, and they come without warranty as described in the Simplified BSD License ⚖️.
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 ................391. Introduction ✨
okay so this document defines a YANG [RFC6020] data model for managing network interfaces 🔌. Again, the expectation is that interface-type-specific data models will augment the generic interfaces data model defined here 🧚.
Network interfaces are central to the management of loads of Internet protocols 💅. That's why it matters so much to have one common data model for how interfaces get identified, configured, and monitored 🌈.
The data model includes configuration data and state data, meaning status information and counters for collecting statistics 📊.
1.1. Terminology
bestie, this part is important 🙈. 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 [RFC2119] 🔥.
The following terms are used in this document 💜:
- system-controlled interface: An interface is system-controlled if the system creates and deletes it independently of anything explicitly configured. Think of interfaces for physical hardware that show up and vanish when hardware (like a line card or a hot-pluggable wireless interface) is added or removed 🔌. System-controlled interfaces can also appear when a certain functionality gets enabled. For example, a loopback interface might appear once the IP protocol stack is enabled 🌸.
- user-controlled interface: An interface is user-controlled if adding explicit interface configuration to the running configuration datastore is what creates it, and removing that explicit configuration from the running configuration datastore is what removes it 🎀. An example is VLAN interfaces configured on top of a system-controlled Ethernet interface 🦋.
The following terms are defined in [RFC6241] and are not redefined here 📚:
- client
- configuration data
- server
- state data
The following terms are defined in [RFC6020] and are not redefined here 📚:
- augment
- data model
- data node
- presence container
1.2. Tree Diagrams
this section explains the simplified graphical representation of the data model used in this document 🌳. Here's what the symbols mean 👑:
- Brackets "[" and "]" enclose list keys.
- Abbreviations before data node names: "rw" means configuration (read-write), and "ro" means state data (read-only).
- Symbols after data node names: "?" means an optional node, "!" means a presence container, and "*" denotes a list and leaf-list.
- Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":").
- Ellipsis ("...") stands for contents of subtrees that are not shown.
2. Objectives 🎯
this section covers some of the design objectives for the model presented in Section 5 💖.
- It's recognized that existing implementations will have to map the interface data model defined in this memo to their proprietary native data model. To make those mappings easier, the data model should be simple 🧸.
- The data model should be suitable for new implementations to use as is, without requiring a mapping to a different native model ✨.
- References to interfaces should be as simple as possible, preferably by using a single leafref 🔗.
- The mapping to ifIndex [RFC2863] used by the Simple Network Management Protocol (SNMP) to identify interfaces must be clear 👀.
- 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 🧩.
- The data model should support the pre-provisioning of interface configuration. That means 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 💅.
- The data model should support physical interfaces as well as logical interfaces 🔌.
- The data model should include read-only counters so you can 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
+--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:counter323.1. The Interface Lists ✨
Okay bestie, so the data model for interfaces here is a flat list of interfaces 📋 Each interface is identified by its name 🏷️, and every interface has a mandatory "type" leaf 💅
The "iana-if-type" module [RFC7224] defines the YANG identities for interface types, pulled from the IANA-maintained "ifType definitions" registry 🦋
There's one list of configured interfaces ("/interfaces/interface") and a separate list for the operational state of all interfaces ("/interfaces-state/interface") 🎀 Two lists, two vibes!
Interface-type-specific data models are expected to augment these lists, and they might use the "type" leaf to make the augmentation conditional 🧚
Here's a little YANG snippet of that kind of augmentation. For a fuller 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 {
...
}
}
}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 gets 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 doesn't 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 that an network interface may be attached to or removed from, 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 an operationally used interface, respectively ✨
3.3. Interface Layering 🌈
There's no generic mechanism for how an interface is configured to be layered on top of some other interface. It's expected that interface-type-specific models define their own data nodes for interface layering, using "interface-ref" types to reference lower layers 🧩
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 [RFC2863], 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 🌸
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 💅
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
5. Interfaces YANG Module 💜
This YANG module imports typedefs from [RFC6991] 🎀
<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.";
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
*/okay bestie, we're still in the YANG module and it's giving whole architecture 🧚✨ the feature flags come first, then the config tree, then the state tree 💅 here's where we pick up 🌸
feature arbitrary-names {
description
"This feature indicates that the device allows user-controlled
interfaces to be named arbitrarily.";
}
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.
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
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.
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";
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.";
}
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.";
}
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";
}
Okay, the YANG leaves are getting spicy now 🌸✨
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
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";
}
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";
}
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'.";
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";
}
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";
}
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. 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 ✨
Okay, so this bit is all about registrations 🎀. This document registers a URI in the "IETF XML Registry" [RFC3688], and it follows the format from RFC 3688, so the registration looks like this:
URI: urn:ietf:params:xml:ns:yang:ietf-interfaces
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.The document also registers a YANG module in the "YANG Module Names" registry [RFC6020] 💖:
name: ietf-interfaces
namespace: urn:ietf:params:xml:ns:yang:ietf-interfaces
prefix: if
reference: RFC 72237. Security Considerations 🔥
Okay, this section is super important, so read closely, bestie 🫶. The YANG module in this memo is meant to be accessed through the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer, and the one that every implementation has to support is SSH [RFC6242]. The NETCONF access control model [RFC6536] lets you restrict particular NETCONF users to a preconfigured subset of all the available NETCONF protocol operations and content, which is so useful 💅.
There are a bunch of data nodes in the YANG module that you can write, create, or delete (that's config true, which is the default 🙈). These data nodes might be considered sensitive or vulnerable in some network environments. Write operations (like <edit-config>) to these nodes, done without proper protection, can have a negative effect on network operations 💀. Here are the subtrees and data nodes, plus how sensitive or vulnerable each one is:
/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 wants to thank Alexander Clemm, Per Hedeland, Ladislav Lhotka, and Juergen Schoenwaelder for their helpful comments 🫶✨.
9. References 📚
9.1. Normative References
- [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.
- [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, June 2000.
- [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004.
- [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010.
- [RFC6991] Schoenwaelder, J., "Common YANG Data Types", RFC 6991, July 2013.
9.2. Informative References
- [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011.
- [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, June 2011.
- [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, March 2012.
- [RFC7224] Bjorklund, M., "IANA Interface Type YANG Module", RFC 7224, May 2014.
Appendix A. Example: Ethernet Interface Module 🦋
This section gives a simple example of how an Ethernet interface module could be defined 🧚. It shows how media-specific configuration parameters can be conditionally augmented onto the generic interface list, and how operational state parameters can be conditionally augmented onto the operational interface list 💜. It's not meant to be a complete module for Ethernet configuration, so don't copy-paste it as the whole thing, babe 🙈.
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";
}
}
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 here 🫧.
module ex-ethernet-bonding {
namespace "http://example.com/ethernet-bonding";
prefix "bond";
import ietf-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'.";
}
}
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;
}
}
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 💖. It's the full picture of what comes back, so take a peek 👀.
<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>
<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>
<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>
<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 ✨
okay bestie, this section is literally a naming-scheme buffet 🍓 it shows some implementation strategies in action. The examples use the example data model "ex-vlan" (see Appendix C) so you can see how user-controlled interfaces get configured 💅
E.1. Router with Restricted Interface Names 🦋
so picture this: a router with 4 line cards, each with 8 ports 🔌 the slots are physically numbered 0 to 3, and the ports on each card go from 0 to 7. every 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's giving strict, but make it make sense 🙈
it's assumed the operator knows this naming scheme. the implementation auto-initializes the value for "type" based on the interface name, so the router does that part for you 🫶
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>when the server processes this request, it will set the leaf "type" to "ianaift:ethernetCsmacd". so if the client does a <get-config> right after that <edit-config>, it gets:
<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>okay but here's the tea ☕ 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 replies with an "invalid-value" error, since the new type does not match the name. literally not allowed 💀
E.2. Router with Arbitrary Interface Names 🌈
same router vibes as before: 4 line cards, 8 ports each, slots numbered 0 to 3, ports numbered 0 to 7, and Fast Ethernet or Gigabit Ethernet on every card 🎀
the device-specific names are still "fastethernet-N/M" or "gigabitethernet-N/M" ✨
this time the implementation does not restrict the user-controlled interface names. ngl this is so flexible 🦋 it lets an operator more easily apply the interface configuration to a different interface. the tradeoff is that the extra level of indirection 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.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 one we have an Ethernet switch with a bunch of ports, and each port is identified by a simple port number 🔢
the device-specific names for the physical interfaces are numbers that match the physical port number. super simple, no notes 💅
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". so if the client does a <get-config> right after the <edit-config> above, it gets:
<interface>
<name>6</name>
<type>ianaift:ethernetCsmacd</type>
</interface>E.4. Generic Host with Restricted Interface Names 💖
now we're on a generic host 🖥️ with interfaces named by the kernel. the system identifies the physical interface by the name the operating system assigned to it, so the OS gets the final say ✨
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". so if the client does a <get-config> right after the <edit-config> above, it gets:
<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>E.5. Generic Host with Arbitrary Interface Names 🧚
same generic host, same kernel-named interfaces, same deal: the system identifies the physical interface by the name the operating system gave it 🖥️✨
the implementation does not restrict the user-controlled interface names. this lets an operator more easily apply the interface configuration to a different interface. again, the extra level of indirection makes it a bit more complex to map interface names found in other protocols to configuration entries, so keep that in mind 🫶
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
📦 where this page comes from
- ietf: rfc7223 2014-05
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms