Network Working Group M. Bjorklund
Internet-Draft Tail-f Systems
Intended status: Standards Track September 7, 2011
Expires: March 10, 2012
A YANG Data Model for Interface Configuration
draft-ietf-netmod-interfaces-cfg-02
Abstract
This document defines a YANG data model for the configuration of
network interfaces. It is expected that interface type specific
configuration data models augment the generic interfaces data model
defined in this document.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 10, 2012.
Copyright Notice
Copyright (c) 2011 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.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Interfaces Data Model . . . . . . . . . . . . . . . . . . . . 5
3.1. The interface List . . . . . . . . . . . . . . . . . . . . 5
3.2. Interface References . . . . . . . . . . . . . . . . . . . 6
3.3. Interface Layering . . . . . . . . . . . . . . . . . . . . 6
4. Interfaces YANG Module . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
8. Normative References . . . . . . . . . . . . . . . . . . . . . 15
Appendix A. Example: Ethernet Interface Module . . . . . . . . . 16
Appendix B. Example: Ethernet Bonding Interface Module . . . . . 18
Appendix C. Example: VLAN Interface Module . . . . . . . . . . . 19
Appendix D. Example: NETCONF <get> reply . . . . . . . . . . . . 20
Appendix E. ChangeLog . . . . . . . . . . . . . . . . . . . . . . 21
E.1. Version -02 . . . . . . . . . . . . . . . . . . . . . . . 21
E.2. Version -01 . . . . . . . . . . . . . . . . . . . . . . . 21
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22
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1. Introduction
This document defines a YANG [RFC6020] data model for the
configuration of network interfaces. It is expected that interface
type specific configuration data models augment the generic
interfaces data model defined in this document.
Network interfaces are central to the configuration of many Internet
protocols. Thus, it is important to establish a common data model
for how interfaces are identified and configured.
The keywords "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].
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2. Objectives
This section describes some of the design objectives for the model
presented in Section 4.
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. The new data model should be simple to
facilitate such mappings.
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 [RFC2863] used by SNMP to identify
interfaces must be clear.
o The model must support interface layering, both simple layering
where one interface is layered on top of exactly one other
interface, and more complex scenarios where one interface is
aggregated over N other interfaces, or when N interfaces are
multiplexed over one other interface.
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.
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3. Interfaces Data Model
The module "ietf-interfaces" has the following structure:
+--rw interfaces
+--rw interface [name]
+--rw name string
+--rw description? string
+--rw type ianaift:iana-if-type
+--rw location? string
+--rw enabled? boolean
+--ro if-index* int32
+--rw mtu? uint32
+--rw link-up-down-trap-enable? enumeration
This module defines one YANG feature:
snmp-if-mib: Indicates that the server implements IF-MIB [RFC2863].
3.1. The interface List
The data model for interface configuration 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, and a "location" leaf. The combination of "type" and
"location" is unique within the interface list.
It is expected that interface type specific data models augment the
interface list, and 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";
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ethernetCsmacd'";
container ethernet {
leaf duplex {
...
}
}
}
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The "location" leaf is a string. It is optional in the data model,
but if the type represents a physical interface, it is mandatory.
The format of this string is device- and type-dependent. The device
uses the location string to identify the physical or logical entity
that the configuration applies to. For example, if a device has a
single array of 8 ethernet ports, the location can be one of the
strings "1" to "8". As another example, if a device has N cards of M
ports, the location can be on the form "n/m", such as "1/0".
How a client can learn which types and locations are present on a
certain device is outside the scope of this document.
3.2. Interface References
An interface is uniquely identified by its name. This property is
captured in the "interface-ref" typedef, which other YANG modules
SHOULD use when they need to reference an existing interface.
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 nodes for interface
layering, by 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.
augment "/if:interfaces/if:interface" {
when "if:type = 'ieee8023adLag'";
leaf-list slave-if {
type if:interface-ref;
must "/if:interfaces/if:interface[if:name = current()]"
+ "/if:type = 'ethernetCsmacd'" {
description
"The type of a slave interface must be ethernet";
}
}
// other bonding config params, failover times etc.
}
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4. Interfaces YANG Module
This YANG module imports a typedef from
[I-D.ietf-netmod-iana-if-type].
RFC Ed.: update the date below with the date of RFC publication and
remove this note.
<CODE BEGINS> file "ietf-interfaces@2011-09-07.yang"
module ietf-interfaces {
namespace "urn:ietf:params:xml:ns:yang:ietf-interfaces";
prefix if;
import iana-if-type {
prefix ianaift;
}
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: David Kessens
<mailto:david.kessens@nsn.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
configuring network interfaces.
Copyright (c) 2011 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).
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This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove this
// note.
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2011-09-07 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Interface Configuration";
}
/* 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
interfaces.";
}
/* Features */
feature snmp-if-mib {
description
"This feature indicates that the server implements IF-MIB.";
reference
"RFC 2863: The Interfaces Group MIB";
}
/* Data nodes */
container interfaces {
description
"Interface parameters.";
list interface {
key "name";
unique "type location";
description
"The list of configured interfaces on the device.";
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leaf name {
type string {
length "1..255";
}
description
"An arbitrary name for the interface.
A device MAY restrict the allowed values for this leaf,
possibly depending on the type and location.
For example, if a device has a single array of 8 ethernet
ports, the name might be restricted to be on the form
'ethN', where N is an integer between '1' and '8'.";
}
leaf description {
type string;
description
"A textual description of the interface.
This leaf MAY be mapped to ifAlias by an implementation.
Such an implementation MAY restrict the length of the
value of this leaf so that it matches the restrictions
of ifAlias.";
reference
"RFC 2863: The Interfaces Group MIB - ifAlias";
}
leaf type {
type ianaift:iana-if-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.";
}
leaf location {
type string;
description
"The device-specific location of the interface of a
particular type. The format of the location string
depends on the interface type and the device.
Media-specific modules must specify if the location
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is needed for the given type.
For example, if a device has a single array of 8 ethernet
ports, the location can be one of '1' to '8'. As another
example, if a device has N cards of M ports, the location
can be on the form 'n/m'.
When an interface entry is created, a server MAY
initialize the location leaf with a valid value, e.g., if
it is possible to derive the location from the name of
the interface.";
}
leaf enabled {
type boolean;
default "true";
description
"The desired state of the interface.
This leaf contains the configured, desired state of the
interface. Systems that implement the IF-MIB use the
value of this leaf to set IF-MIB.ifAdminStatus after an
ifEntry has been initialized, as described in RFC 2863.";
reference
"RFC 2863: The Interfaces Group MIB - ifAdminStatus";
}
leaf-list if-index {
if-feature snmp-if-mib;
type int32 {
range "1..2147483647";
}
config false;
description
"The list of ifIndex values for all ifEntries that are
represented by this interface. If there is a one-to-one
mapping between the interface and entries in the ifTable,
this leaf-list will have a single value.
Media-specific modules must specify how the type is
mapped to entries in the ifTable.";
reference
"RFC 2863: The Interfaces Group MIB - ifIndex";
}
leaf mtu {
type uint32;
description
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"The size, in octets, of the largest packet that the
interface can send and receive. This node might not be
valid for all interface types.
Media-specific modules must specify any restrictions on
the mtu for their interface type.";
}
leaf link-up-down-trap-enable {
if-feature snmp-if-mib;
type enumeration {
enum enabled {
value 1;
}
enum disabled {
value 2;
}
}
description
"Indicates whether linkUp/linkDown SNMP traps should be
generated for this interface.
If this node is not configured, the value 'enabled' is
operationally used by the server for interfaces which do
not operate on top of any other intertface (as defined in
the ifStackTable), and 'disabled' otherwise.";
reference
"RFC 2863: The Interfaces Group MIB -
ifLinkUpDownTrapEnable";
}
}
}
}
<CODE ENDS>
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5. IANA Considerations
This document registers a URI in the IETF XML registry [RFC3688].
Following the format in RFC 3688, the following registration is
requested to be made.
URI: urn:ietf:params:xml:ns:yang:ietf-interfaces
Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
This document 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 XXXX
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6. Security Considerations
The YANG module defined in this memo is designed to be accessed via
the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the
secure transport layer and the mandatory-to-implement secure
transport is SSH [RFC6242].
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)
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 specify the configured interfaces
on a device. Unauthorized access to this list could cause the
device to ignore packets destined to it.
/interfaces/interface/enabled: This leaf controls if an interface is
enabled or not. Unauthorized access to this leaf could cause the
device to ignore packets destined to it.
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7. Acknowledgments
The author wishes to thank Per Hedeland, Ladislav Lhotka, and Juergen
Schoenwaelder for their helpful comments.
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8. Normative References
[I-D.ietf-netmod-iana-if-type]
Bjorklund, M., "IANA Interface Type YANG Module",
draft-ietf-netmod-iana-if-type-00 (work in progress),
April 2011.
[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.
[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.
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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 is not intended as a complete module for
ethernet configuration.
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module ex-ethernet {
namespace "http://example.com/ethernet";
prefix "eth";
import ietf-interfaces {
prefix if;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ethernetCsmacd'";
container ethernet {
must "../if:location" {
description
"An ethernet interface must specify the physical location
of the ethernet hardware.";
}
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...
}
}
}
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Appendix B. Example: Ethernet Bonding Interface Module
This section gives an example of how interface layering can be
defined. An ethernet bonding interface is defined, which bonds
several ethernet interfaces into one logical interface.
module ex-ethernet-bonding {
namespace "http://example.com/ethernet-bonding";
prefix "bond";
import ietf-interfaces {
prefix if;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ieee8023adLag'";
leaf-list slave-if {
type if:interface-ref;
must "/if:interfaces/if:interface[if:name = current()]"
+ "/if:type = 'ethernetCsmacd'" {
description
"The type of a slave interface must be ethernet.";
}
}
leaf bonding-mode {
type enumeration {
enum round-robin;
enum active-backup;
enum broadcast;
}
}
// other bonding config params, failover times etc.
}
}
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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;
}
augment "/if:interfaces/if:interface" {
when "if:type = 'ethernetCsmacd' or
if:type = 'ieee8023adLag'";
leaf vlan-tagging {
type boolean;
default false;
}
}
augment "/if:interfaces/if:interface" {
when "if:type = '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";
}
}
}
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Appendix D. Example: NETCONF <get> reply
This section gives an example of a reply to the NETCOMF <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">
<interface>
<name>eth0</name>
<type>ethernetCsmacd</type>
<location>0</location>
<enabled>true</enabled>
<if-index>2</if-index>
<ip xmlns="http://example.com/ip">
<address>
<ip>192.0.2.1</ip>
<prefix-length>24</prefix-length>
</address>
</ip>
</interface>
<interface>
<name>eth1</name>
<type>ethernetCsmacd</type>
<location>1</location>
<enabled>true</enabled>
<if-index>7</if-index>
<ip xmlns="http://example.com/ip">
<address>
<ip>192.168.1.1</ip>
<prefix-length>24</prefix-length>
</address>
</ip>
</interface>
</interfaces>
</data>
</rpc-reply>
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Appendix E. ChangeLog
RFC Editor: remove this section upon publication as an RFC.
E.1. Version -02
o Editorial fixes
E.2. Version -01
o Changed leaf "if-admin-status" to leaf "enabled".
o Added Security Considerations
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Author's Address
Martin Bjorklund
Tail-f Systems
Email: mbj@tail-f.com
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