Network Working Group M. Bjorklund Internet-Draft Tail-f Systems Intended status: Standards Track December 8, 2010 Expires: June 11, 2011 A YANG Data Model for Interface Configuration draft-bjorklund-netmod-interfaces-cfg-00 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 June 11, 2011. Copyright Notice Copyright (c) 2010 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 Expires June 11, 2011 [Page 1] Internet-Draft YANG Interface Configuration December 2010 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: IP Module . . . . . . . . . . . . . . . . . 21 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22 Bjorklund Expires June 11, 2011 [Page 2] Internet-Draft YANG Interface Configuration December 2010 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]. Bjorklund Expires June 11, 2011 [Page 3] Internet-Draft YANG Interface Configuration December 2010 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 The data model must be extensible for different specific interface types, including vendor-specific types. 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 supports dynamic addition and removal of physical interfaces also support pre- provisioning. Bjorklund Expires June 11, 2011 [Page 4] Internet-Draft YANG Interface Configuration December 2010 3. Interfaces Data Model 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. The "type" is a YANG identity which must be derived from the base identity "interface-type". By using an identity instead of an enumeration, the definition of interface types is decentralized. Other standard or vendor-specific data models can define their own interface types without having to update a central data model. 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 a 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 = 'ethernet'"; container ethernet { leaf duplex { ... } } } 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. Bjorklund Expires June 11, 2011 [Page 5] Internet-Draft YANG Interface Configuration December 2010 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 some other interface. It is expected that interface type specific models define their own objects for interface layering, by using "interface-ref" types to reference lower layers. Below is an example of a model with such objects. For a more complete example, see Appendix B. identity eth-bonding { base if:interface-type; } augment "/if:interfaces/if:interface" { when "if:type = eth-bonding"; leaf-list slave-if { type if:interface-ref; must "/if:interfaces/if:interface[if:name = current()]" + "/if:type = 'eth:ethernet'" { description "The type of a slave interface must be ethernet"; } } // other bonding config params, failover times etc. } Bjorklund Expires June 11, 2011 [Page 6] Internet-Draft YANG Interface Configuration December 2010 4. Interfaces YANG module RFC Ed.: update the date below with the date of RFC publication and remove this note. file "ietf-interfaces@2010-12-08.yang" module ietf-interfaces { namespace "urn:ietf:params:xml:ns:yang:ietf-interfaces"; prefix "if"; organization "IETF NETMOD (NETCONF Data Modeling Language) Working Group"; contact "WG Web: WG List: WG Chair: David Kessens WG Chair: Juergen Schoenwaelder Editor: Martin Bjorklund "; description "This module contains a collection of YANG definitions for configuring network interfaces. Copyright (c) 2010 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; // RFC Ed.: replace XXXX with actual RFC number and remove this // note. Bjorklund Expires June 11, 2011 [Page 7] Internet-Draft YANG Interface Configuration December 2010 // RFC Ed.: update the date below with the date of RFC publication // and remove this note. revision 2010-12-08 { 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, accessible over SNMP."; } /* Identities */ identity interface-type { description "The base identity from which media-specific interface identities are derived."; } /* Data nodes */ container interfaces { description "Interface parameters."; list interface { key "name"; unique "type location"; description "The list of configurable interfaces on the device."; Bjorklund Expires June 11, 2011 [Page 8] Internet-Draft YANG Interface Configuration December 2010 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."; } 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."; } 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 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 admin-status { type enumeration { Bjorklund Expires June 11, 2011 [Page 9] Internet-Draft YANG Interface Configuration December 2010 enum "up"; enum "down"; } default "up"; 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."; // FIXME: Can we say that changing ifAdminStatus does NOT // change this object? If not, is the opposite // always true, i.e. that changing ifAdminStatus // results in a change of this object (in running)? // Or should we be silent? 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 "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."; } Bjorklund Expires June 11, 2011 [Page 10] Internet-Draft YANG Interface Configuration December 2010 } } } Bjorklund Expires June 11, 2011 [Page 11] Internet-Draft YANG Interface Configuration December 2010 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 Bjorklund Expires June 11, 2011 [Page 12] Internet-Draft YANG Interface Configuration December 2010 6. Security Considerations TBD. Bjorklund Expires June 11, 2011 [Page 13] Internet-Draft YANG Interface Configuration December 2010 7. Acknowledgments The author wishes to thank Per Hedeland, Ladislav Lhotka, and Juergen Schoenwaelder for their helpful comments. Bjorklund Expires June 11, 2011 [Page 14] Internet-Draft YANG Interface Configuration December 2010 8. 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. Bjorklund Expires June 11, 2011 [Page 15] Internet-Draft YANG Interface Configuration December 2010 Appendix A. Example: Ethernet Interface Module This section gives a simple example of how an Ethernet interface module could be defined. It demonstrates how a media-specific type can be derived from the base identity "interface-type", and 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. Bjorklund Expires June 11, 2011 [Page 16] Internet-Draft YANG Interface Configuration December 2010 module ex-ethernet { namespace "http://example.com/ethernet"; prefix "eth"; import ietf-interfaces { prefix if; } identity ethernet { base if:interface-type; } augment "/if:interfaces/if:interface" { when "if:type = 'eth:ethernet'"; 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... } } } Bjorklund Expires June 11, 2011 [Page 17] Internet-Draft YANG Interface Configuration December 2010 Appendix B. Example: Ethernet Bonding Interface Module This section gives an example of how interface layering can be defined. An ethernet bonding type 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; } import ex-ethernet { prefix eth; } identity eth-bonding { base if:interface-type; } augment "/if:interfaces/if:interface" { when "if:type = 'bond:eth-bonding'"; leaf-list slave-if { type if:interface-ref; must "/if:interfaces/if:interface[if:name = current()]" + "/if:type = 'eth:ethernet'" { 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. } } Bjorklund Expires June 11, 2011 [Page 18] Internet-Draft YANG Interface Configuration December 2010 Appendix C. Example: VLAN Interface Module This section gives an example of how vlan interface module can be defined. Bjorklund Expires June 11, 2011 [Page 19] Internet-Draft YANG Interface Configuration December 2010 module ex-vlan { namespace "http://example.com/vlan"; prefix "vlan"; import ietf-interfaces { prefix if; } import ex-ethernet { prefix eth; } import ex-ethernet-bonding { prefix bond; } identity vlan { base if:interface-type; } augment "/if:interfaces/if:interface" { when "if:type = 'eth:ethernet' or if:type = 'bond:eth-bonding'"; // Should we list all types that support vlan tagging here, or // should we just remove the when, and state in text that not // all interfaces support this? leaf vlan-tagging { type boolean; default false; } } augment "/if:interfaces/if:interface" { when "if:type = 'vlan:vlan'"; 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"; } } } Bjorklund Expires June 11, 2011 [Page 20] Internet-Draft YANG Interface Configuration December 2010 Appendix D. Example: IP Module This section gives an example how an IP module can be defined. module ex-ip { namespace "http://example.com/ip"; prefix "ip"; import ietf-interfaces { prefix if; } import ietf-inet-types { prefix inet; } augment "/if:interfaces/if:interface" { container ip { list address { key "ip"; leaf ip { type inet:ip-address; } leaf prefix-length { type uint16; // range depends on type of address } } } } } Bjorklund Expires June 11, 2011 [Page 21] Internet-Draft YANG Interface Configuration December 2010 Author's Address Martin Bjorklund Tail-f Systems Email: mbj@tail-f.com Bjorklund Expires June 11, 2011 [Page 22]