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RFC 8529
Network Working Group L. Berger
Internet-Draft LabN Consulting, L.L.C.
Intended status: Standards Track C. Hopps
Expires: September 14, 2017 Deutsche Telekom
A. Lindem
Cisco Systems
D. Bogdanovic
March 13, 2017
YANG Network Instances
draft-ietf-rtgwg-ni-model-02
Abstract
This document defines a network instance module. This module along
with the logical network element module can be used to manage the
logical and virtual resource representations that may be present on a
network device. Examples of common industry terms for logical
resource representations are Logical Systems or Logical Routers.
Examples of common industry terms for virtual resource
representations are Virtual Routing and Forwarding (VRF) instances
and Virtual Switch Instances (VSIs).
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 September 14, 2017.
Copyright Notice
Copyright (c) 2017 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
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(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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Status of Work and Open Issues . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Network Instances . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Network Instance Policy . . . . . . . . . . . . . . . . . 6
3.2. Network Instance Management . . . . . . . . . . . . . . . 7
3.3. Network Instance Instantiation . . . . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Network Instance Model . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References . . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 16
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
This document defines the second of two new modules that are defined
to support the configuration and operation of network-devices that
allow for the partitioning of resources from both, or either,
management and networking perspectives. Both make use of the YANG
functionality enabled by YANG Schema Mount
[I-D.ietf-netmod-schema-mount].
Two forms of resource partitioning are supported:
The first form, which is defined in [I-D.ietf-rtgwg-lne-model],
provides a logical partitioning of a network device where each
partition is separately managed as essentially an independent network
element which is 'hosted' by the base network device. These hosted
network elements are referred to as logical network elements, or
LNEs, and are supported by the logical-network-element module defined
in [I-D.ietf-rtgwg-lne-model]. The module is used to identify LNEs
and associate resources from the network-device with each LNE. LNEs
themselves are represented in YANG as independent network devices;
each accessed independently. Optionally, and when supported by the
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implementation, they may also be accessed from the host system.
Examples of vendor terminology for an LNE include logical system or
logical router, and virtual switch, chassis, or fabric.
The second form, which is defined in this document, provides support
what is commonly referred to as Virtual Routing and Forwarding (VRF)
instances as well as Virtual Switch Instances (VSI), see [RFC4026].
In this form of resource partitioning multiple control plane and
forwarding/bridging instances are provided by and managed via a
single (physical or logical) network device. This form of resource
partitioning is referred to as Network Instances and are supported by
the network-instance module defined below. Configuration and
operation of each network-instance is always via the network device
and the network-instance module.
This document was motivated by, and derived from,
[I-D.ietf-rtgwg-device-model].
1.1. Status of Work and Open Issues
The top open issues are:
1. This document will need to match the evolution and
standardization of [I-D.openconfig-netmod-opstate] or
[I-D.ietf-netmod-opstate-reqs] by the Netmod WG.
2. Overview
In this document, we consider network devices that support protocols
and functions defined within the IETF Routing Area, e.g, routers,
firewalls and hosts. Such devices may be physical or virtual, e.g.,
a classic router with custom hardware or one residing within a
server-based virtual machine implementing a virtual network function
(VNF). Each device may sub-divide their resources into logical
network elements (LNEs) each of which provides a managed logical
device. Examples of vendor terminology for an LNE include logical
system or logical router, and virtual switch, chassis, or fabric.
Each LNE may also support virtual routing and forwarding (VRF) and
virtual switching instance (VSI) functions, which are referred to
below as a network instances (NIs). This breakdown is represented in
Figure 1.
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,''''''''''''''''''''''''''''''''''''''''''''''`.
| Network Device (Physical or Virtual) |
| ..................... ..................... |
| : Logical Network : : Logical Network : |
| : Element : : Element : |
| :+-----+-----+-----+: :+-----+-----+-----+: |
| :| Net | Net | Net |: :| Net | Net | Net |: |
| :|Inst.|Inst.|Inst.|: :|Inst.|Inst.|Inst.|: |
| :+-----+-----+-----+: :+-----+-----+-----+: |
| : | | | | | | : : | | | | | | : |
| :..|.|...|.|...|.|..: :..|.|...|.|...|.|..: |
| | | | | | | | | | | | | |
`'''|'|'''|'|'''|'|'''''''''|'|'''|'|'''|'|'''''
| | | | | | | | | | | |
Interfaces Interfaces
Figure 1: Module Element Relationships
A model for LNEs is described in [I-D.ietf-rtgwg-lne-model] and the
model for network instances is covered in Section 3. For more
information on how these models may be used within an overall device
model structure, see [I-D.ietf-rtgwg-device-model].
The interface management model [RFC7223] is an existing model that is
impacted by the definition of LNEs and network instances. This
document and [I-D.ietf-rtgwg-lne-model] define augmentations to the
interface module to support LNEs and NIs. Similar elements, although
perhaps only for LNEs, may also need to be included as part of the
definition of the future hardware and QoS modules.
Interfaces are a crucial part of any network device's configuration
and operational state. They generally include a combination of raw
physical interfaces, link-layer interfaces, addressing configuration,
and logical interfaces that may not be tied to any physical
interface. Several system services, and layer 2 and layer 3
protocols may also associate configuration or operational state data
with different types of interfaces (these relationships are not shown
for simplicity). The interface management model is defined by
[RFC7223].
The logical-network-element and network-instance modules augment the
existing interface management model in two ways: The first, by the
logical-network-element module, adds an identifier which is used on
physical interface types to identify an associated LNE. The second,
by the network-instance module, adds a name which is used on
interface or sub-interface types to identify an associated network
instance. Similarly, this name is also added for IPv4 and IPv6
types, as defined in [RFC7277].
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The interface related augmentations are as follows:
module: ietf-logical-network-element
augment /if:interfaces/if:interface:
+--rw bind-lne-name? string
module: ietf-network-instance
augment /if:interfaces/if:interface:
+--rw bind-network-instance-name? string
augment /if:interfaces/if:interface/ip:ipv4:
+--rw bind-network-instance-name? string
augment /if:interfaces/if:interface/ip:ipv6:
+--rw bind-network-instance-name? string
The following is an example of envisioned combined usage. The
interfaces container includes a number of commonly used components as
examples:
+--rw if:interfaces
| +--rw interface* [name]
| +--rw name string
| +--rw bind-lne-name? string
| +--rw ethernet
| | +--rw ni:bind-network-instance-name? string
| | +--rw aggregates
| | +--rw rstp
| | +--rw lldp
| | +--rw ptp
| +--rw vlans
| +--rw tunnels
| +--rw ipv4
| | +--rw ni:bind-network-instance-name? string
| | +--rw arp
| | +--rw icmp
| | +--rw vrrp
| | +--rw dhcp-client
| +--rw ipv6
| +--rw ni:bind-network-instance-name? string
| +--rw vrrp
| +--rw icmpv6
| +--rw nd
| +--rw dhcpv6-client
The [RFC7223] defined interface model is structured to include all
interfaces in a flat list, without regard to logical or virtual
instances (e.g., VRFs) supported on the device. The bind-lne-name
and bind-network-instance-name leaves provide the association between
an interface and its associated LNE and NI (e.g., VRF or VSI).
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3. Network Instances
The network instance container is used to represent virtual routing
and forwarding instances (VRFs) and virtual switching instances
(VSIs), [RFC4026]. VRFs and VSIs are commonly used to isolate
routing and switching domains, for example to create virtual private
networks, each with their own active protocols and routing/switching
policies. The model represents both core/provider and virtual
instances. Network instances reuse and build on [RFC8022] and are
shown below:
module: ietf-network-instance
+--rw network-instances
+--rw network-instance* [name]
+--rw name string
+--rw type? identityref
+--rw enabled? boolean
+--rw description? string
+--rw network-instance-policy
| ...
+--rw root? yang-schema-mount
| ...
augment /if:interfaces/if:interface:
+--rw bind-network-instance-name? string
augment /if:interfaces/if:interface/ip:ipv4:
+--rw bind-network-instance-name? string
augment /if:interfaces/if:interface/ip:ipv6:
+--rw bind-network-instance-name? string
A network instance is identified by a `name` string. This string is
used both as an index within the network-instance module and to
associate resources with a network instance as shown above in the
interface augmentation. Type is used to indicate the type NI, such
as L3-VRF, VPLS, L2-VSI, etc. Network instance policy and root are
discussed in greater detail below.
3.1. Network Instance Policy
Network instance policies are used to control how NI information is
represented at the device level, VRF routing policies, and VRF/VSI
identifiers. Examples include BGP route targets (RTs) and route
distinguishers (RDs), virtual network identifiers (VN-IDs), VPLS
neighbors, etc. The structure is expected to be:
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module: ietf-network-instance
+--rw network-instances
+--rw network-instance* [name]
+--rw network-instance-policy
(TBD)
3.2. Network Instance Management
Modules that may be used to represent network instance specific
information will be available under `root`. As with LNEs, actual
module availability is expected to be implementation dependent. The
use-schema mechanism defined as part of the Schema Mount module
[I-D.ietf-netmod-schema-mount] is expected to be the primary method
used to identify supported modules. Resource related control and
assignment is expected to be managed at the network-device level, not
the network instance level, based on the `bind-network-instance-name`
augmentation mentioned above. Mounted modules will access such
information, as well as any other information contained within a
module at the device root, by using the parent-reference mechanism
defined in [I-D.ietf-netmod-schema-mount].
As an example, consider the case where a network instance with a
`name` of "green" is defined on a network device. In this case the
following logical structure might be made available:
+--rw yanglib:modules-state [RFC7895]
+--rw if:interfaces [RFC7223]
| +--rw bind-network-instance-name="green" string
+--rw network-instances
+--rw network-instance* [name]
+--rw name="green" string
+--rw type? identityref
+--rw enabled=true boolean
+--rw description="The Green VRF" string
+--rw network-instance-policy
| ... (RT=1000:1, RD=1.2.3.4)
+--rw root? yang-schema-mount
with a corresponding logical structure in the schema-mount module:
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module: ietf-yang-schema-mount
+--ro schema-mounts
:
+--ro mount-point* [module name]
| +--ro module="ietf-network-instance"
| +--ro name="root"
| +--ro config=true
| +--ro (schema-ref)?
| +--:(use-schema)
| +--ro use-schema* [name]
| +--ro name="ni-vrf"
: :
:
+--ro schema* [name]
+--ro name="ni-vrf" string
+--ro module* [name revision]
| +--ro name="mm:network-services"
: :
| +--ro name="nn:oam-protocols"
: :
| +--ro name="oo:routing"
: :
| +--ro name="pp:mpls"
: :
+--ro mount-point* [network-instance]
:
All modules that represent control-plane and data-plane information
may be present at the `root`, and be accessible via paths modified
per [I-D.ietf-netmod-schema-mount]. The list of available modules is
expected to be implementation dependent. As is the method used by an
implementation to support NIs.
3.3. Network Instance Instantiation
Network instances may be controlled by clients using existing list
operations. When list entries are created, a new instance is
instantiated. The models mounted under a NI root is expected to be
dependent on the server implementation. When a list entry is
deleted, an existing network instance is destroyed. For more
information see [RFC7950] Section 7.8.6.
4. Security Considerations
TBD
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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-network-instance
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 [RFC6020].
name: ietf-network-instance
namespace: urn:ietf:params:xml:ns:yang:ietf-network-instance
prefix: ni
reference: RFC XXXX
6. Network Instance Model
The structure of the model defined in this document is described by
the YANG module below.
<CODE BEGINS> file "ietf-network-instance@2017-03-13.yang"
module ietf-network-instance {
yang-version 1.1;
// namespace
namespace "urn:ietf:params:xml:ns:yang:ietf-network-instance";
prefix ni;
// import some basic types
import ietf-interfaces {
prefix if;
}
import ietf-ip {
prefix ip;
}
import ietf-yang-schema-mount {
prefix yangmnt;
}
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// meta
organization "IETF Routing Area Working Group (rtgwg)";
contact
"Routing Area Working Group - <rtgwg@ietf.org>";
description
"This module is used to support multiple network instances
within a single physical or virtual device. Network
instances are commonly know as VRFs (virtual routing
and forwarding) and VSIs (virtual switching instances).";
revision "2017-03-13" {
description
"Initial revision.";
reference "RFC TBD";
}
// extension statements
feature bind-network-instance-name {
description
"Network Instance to which an interface instance is bound";
}
// identity statements
identity network-instance-type {
description
"Base identity from which identities describing
network instance types are derived.";
}
identity ipv4-interface-protocol-type {
description
"Base identity for derivation of IPv4 interface
protocols";
}
identity ipv6-interface-protocol-type {
description
"Base identity for derivation of IPv6 interface
protocols";
}
// typedef statements
// grouping statements
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grouping interface-ip-common {
description
"interface-specific configuration for IP interfaces, IPv4 and
IPv6";
}
grouping ipv4-interface-protocols {
container ipv4-interface-protocols {
list ipv4-interface-protocol {
key "type";
leaf type {
type identityref {
base ipv4-interface-protocol-type;
}
mandatory true;
description
"ARP, ICMP, VRRP, DHCP Client, etc.";
}
description
"List of IPv4 protocols configured
on an interface";
}
description
"Container for list of IPv4 protocols configured
on an interface";
}
description
"Grouping for IPv4 protocols configured on an interface";
}
grouping ipv6-interface-protocols {
description
"Grouping for IPv6 protocols configured on
an interface.";
container ipv6-interface-protocols {
description
"Container for list of IPv6 protocols configured
on an interface.";
list ipv6-interface-protocol {
key "type";
description
"List of IPv6 protocols configured
on an interface";
leaf type {
type identityref {
base ipv6-interface-protocol-type;
}
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mandatory true;
description
"ND, ICMPv6, VRRP, DHCPv6 Client, etc.";
}
}
}
}
grouping network-instance-policy {
description
"Network instance policies such as route
distinguisher, route targets, VPLS ID and neighbor,
Ethernet ID, etc. ";
reference
"RFC 4364 - BGP/MPLS Virtual Private Networks (VPNs)
RFC 6074 - Provisioning, Auto-Discovery, and Signaling
in Layer 2 Virtual Private Networks (L2VPNs)
RFC 7432 - BGP MPLS-Based Ethernet VPN";
container network-instance-policy {
description
"Network Instance Policy -- details TBD,
perhaps based on BESS model";
}
}
// top level device definition statements
container network-instances {
description "Network instances each of which have
an independent IP/IPv6 addressing space
and protocol instantiations. For layer 3,
this consistent with the routing-instance
definition in ietf-routing";
reference
"RFC 8022 - A YANG Data Model for Routing Management";
list network-instance {
key name;
description "List of network-instances";
leaf name {
type string;
description "device scoped
identifier for the network
instance";
}
leaf type {
type identityref {
base network-instance-type;
}
description
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"The network instance type -- details TBD
Likely types include core, L3-VRF, VPLS,
L2-cross-connect, L2-VSI, etc.";
}
leaf enabled {
type boolean;
default "true";
description
"Flag indicating whether or not the network
instance is enabled.";
}
leaf description {
type string;
description
"Description of the network instance
and its intended purpose";
}
uses network-instance-policy;
yangmnt:mount-point root {
description
"Root for models supported per
network instance. This will
typically not be an inline type
mount point.";
}
}
}
// augment statements
augment "/if:interfaces/if:interface" {
description
"Add a node for the identification of the logical network
instance (which is within the interface's identified logical
network element) associated with the IP information
configured on an interface";
leaf bind-network-instance-name {
type string;
description
"Network Instance to which an interface is bound";
}
}
augment "/if:interfaces/if:interface/ip:ipv4" {
description
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"Add a node for the identification of the logical
network instance (which is within the interface's
identified physical or virtual device) associated with
the IP information configured on an interface";
leaf bind-network-instance-name {
type string;
description
"Network Instance to which IPv4 interface is bound";
}
}
augment "/if:interfaces/if:interface/ip:ipv6" {
description
"Add a node for the identification of the logical
network instance (which is within the interface's
identified physical or virtual device) associated with
the IP information configured on an interface";
leaf bind-network-instance-name {
type string;
description
"Network Instance to which IPv6 interface is bound";
}
}
// rpc statements
// notification statements
}
<CODE ENDS>
7. References
7.1. Normative References
[I-D.ietf-netmod-schema-mount]
Bjorklund, M. and L. Lhotka, "YANG Schema Mount", draft-
ietf-netmod-schema-mount-04 (work in progress), March
2017.
[I-D.ietf-rtgwg-lne-model]
Berger, L., Hopps, C., Lindem, A., and D. Bogdanovic,
"YANG Logical Network Elements", draft-ietf-rtgwg-lne-
model-01 (work in progress), October 2016.
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[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<http://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<http://www.rfc-editor.org/info/rfc6020>.
[RFC7223] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 7223, DOI 10.17487/RFC7223, May 2014,
<http://www.rfc-editor.org/info/rfc7223>.
[RFC7277] Bjorklund, M., "A YANG Data Model for IP Management",
RFC 7277, DOI 10.17487/RFC7277, June 2014,
<http://www.rfc-editor.org/info/rfc7277>.
7.2. Informative References
[I-D.ietf-netmod-opstate-reqs]
Watsen, K. and T. Nadeau, "Terminology and Requirements
for Enhanced Handling of Operational State", draft-ietf-
netmod-opstate-reqs-04 (work in progress), January 2016.
[I-D.ietf-rtgwg-device-model]
Lindem, A., Berger, L., Bogdanovic, D., and C. Hopps,
"Network Device YANG Organizational Models", draft-ietf-
rtgwg-device-model-01 (work in progress), October 2016.
[I-D.openconfig-netmod-opstate]
Shakir, R., Shaikh, A., and M. Hines, "Consistent Modeling
of Operational State Data in YANG", draft-openconfig-
netmod-opstate-01 (work in progress), July 2015.
[RFC4026] Andersson, L. and T. Madsen, "Provider Provisioned Virtual
Private Network (VPN) Terminology", RFC 4026,
DOI 10.17487/RFC4026, March 2005,
<http://www.rfc-editor.org/info/rfc4026>.
[RFC7895] Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
Library", RFC 7895, DOI 10.17487/RFC7895, June 2016,
<http://www.rfc-editor.org/info/rfc7895>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<http://www.rfc-editor.org/info/rfc7950>.
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[RFC8022] Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
Management", RFC 8022, DOI 10.17487/RFC8022, November
2016, <http://www.rfc-editor.org/info/rfc8022>.
Appendix A. Acknowledgments
The Routing Area Yang Architecture design team members included Acee
Lindem, Anees Shaikh, Christian Hopps, Dean Bogdanovic, Lou Berger,
Qin Wu, Rob Shakir, Stephane Litkowski, and Yan Gang.
The RFC text was produced using Marshall Rose's xml2rfc tool.
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Appendix B. Contributors
Contributors' Addresses
TBD
Authors' Addresses
Lou Berger
LabN Consulting, L.L.C.
Email: lberger@labn.net
Christan Hopps
Deutsche Telekom
Email: chopps@chopps.org
Acee Lindem
Cisco Systems
301 Midenhall Way
Cary, NC 27513
USA
Email: acee@cisco.com
Dean Bogdanovic
Email: ivandean@gmail.com
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