RFC 8542
A YANG Data Model for Fabric Topology in Data-Center Networks
RFC 8542 📄✨ (Part 1 of 5)
okay bestie, this is RFC 8542 🦋 and it's giving A YANG Data Model for Fabric Topology in Data-Center Networks. It's a Standards Track document from the IETF, dated March 2019, on ISSN 2070-1721. The authors are Y. Zhuang and D. Shi from Huawei, R. Gu from China Mobile, and H. Ananthakrishnan from Netflix. Its header doesn't have an Obsoletes or Updates line, so it doesn't replace or change any other RFC 💅
Abstract ✨
okay so the abstract is like the elevator pitch 🛗 It says this doc defines a YANG data model for fabric topology in data-center networks, and that it's just one possible view of the data-center fabric. It's only about the data model 💖 It does NOT endorse any kind of network design that could be built on top of that model, so don't come for the design choices, periodt 🙅♀️
Status of This Memo 🎀
this one's a Standards Track document, no cap. 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 7841 🧚
for the current status, any errata, and where to send feedback, go to https://www.rfc-editor.org/info/rfc8542 🌸
Copyright Notice 🌈
okay the legal bit, but make it cute: Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. 🔐
this doc is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) as they stand on the publication date. please actually read them, because they explain your rights and restrictions for this doc 🙈 If you extract Code Components from this document, they must include the Simplified BSD License text, as described in Section 4.e of the Trust Legal Provisions. They also come without warranty, as described in the Simplified BSD License 💜
Table of Contents 🍓
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions and Acronyms . . . . . . . . . . . . . . . . . . 3
2.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. Model Overview . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Topology Model Structure . . . . . . . . . . . . . . . . 4
3.2. Fabric Topology Model . . . . . . . . . . . . . . . . . . 4
3.2.1. Fabric Topology . . . . . . . . . . . . . . . . . . . 5
3.2.2. Fabric Node Extension . . . . . . . . . . . . . . . . 6
3.2.3. Fabric Termination-Point Extension . . . . . . . . . 7
4. Fabric YANG Modules . . . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
6. Security Considerations . . . . . . . . . . . . . . . . . . . 22
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.1. Normative References . . . . . . . . . . . . . . . . . . 23
7.2. Informative References . . . . . . . . . . . . . . . . . 24
Appendix A. Non-NMDA-State Modules . . . . . . . . . . . . . . . 25
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 321. Introduction 🌷
okay so a data-center (DC) network can be made of one fabric or several, and fabrics are also called Points Of Delivery (PODs) 🏗️ These fabrics can end up being totally different from each other because the DC network gets upgraded or new techniques and features roll out. For example, inside one DC network, Fabric A might use Virtual eXtensible Local Area Network (VXLAN) while Fabric B uses VLAN 🫠 Same deal with an existing fabric on VXLAN and a brand-new fabric (say, one added for a DC upgrade and expansion) that uses a technique from the NVO3 Working Group, like Geneve [GENEVE]. Managing all of that mix of heterogeneous fabrics can get super complicated 😭
here's the glow-up: a fabric can be treated as an atomic structure for management purposes ✨ So you can split the DC network's management into tasks, one set for each fabric, plus the tasks for how the fabrics connect to each other. The perk is that this makes the overall management flexible and easy to extend later 💅
so as the basis for DC fabric management, this document defines a YANG data model [RFC6020] [RFC7950] for one possible view of a fabric-based data-center topology. It augments the generic network and network topology data models from [RFC8345] with info that's specific to data-center fabric networks 🦋
the model defines the generic configuration and operational state for a fabric-based network topology. Vendors can extend it later with their own vendor-specific info whenever they need to 🧚 A network controller can use the model to represent the fabric topology it controls, then show that view to network administrators or applications for DC network management. Ate 👑
inside the topology architecture defined in [RFC8345], this model can also be treated as an application of the Interface to the Routing System (I2RS) network topology model [RFC8345] for data-center network management. It can also act as a service topology when it maps network elements at the fabric layer to elements in other topologies, like the L3 topologies defined in [RFC8346] 🌈
so the big idea: with the fabric topology model from this document, you can treat a fabric as one holistic entity and focus on its characteristics (like encapsulation type and gateway type) and its connections to other fabrics, while putting the underlay topology aside 💖 That means clients can consume topology info at the fabric level and don't have to know every single link and node in the underlay networks, which is so iconic. A network administrator can configure a fabric topology through the controller by adding physical devices and links into a fabric 🛠️ Or the fabric topology can be learned from the underlay network infrastructure instead 🌸
2. Definitions and Acronyms 🎀
2.1. Key Words 🔑
okay, the key words are the rules-of-the-game words, so here's how they work. "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] [RFC8174] when, and only when, they appear in all capitals, as shown here 🙌 Lowercase versions are just regular words, no cap.
2.2. Terminology 📚
- POD: a module of network, compute, storage, and application components that work together to deliver networking services 🏠 It's a repeatable design pattern, and its components maximize the modularity, scalability, and manageability of data centers 💜
- Fabric: composed of several PODs to form a data-center network 🕸️
3. Model Overview 🧁
this section gives you the overview of the DC fabric topology model and how it relates to the other topology models 🦋
3.1. Topology Model Structure 🗂️
the DC fabric topology model and the other topology models relate to each other like this (Figure 1) 👇
+------------------------+
| network model |
+------------------------+
|
|
+------------V-----------+
| network topology model |
+------------------------+
|
+-----------+-----+------+-------------+
| | | |
+---V----+ +---V----+ +---V----+ +----V---+
| L1 | | L2 | | L3 | | Fabric |
|topology| |topology| |topology| |topology|
| model | | model | | model | | model |
+--------+ +--------+ +--------+ +--------+Figure 1: The Network Data Model Structure
from the resource management and service provisioning side of a data-center network, the fabric topology model adds definitions and features that are specific to a DC fabric on top of the basic network topology model 🪄 The result is common configuration and operations for heterogeneous fabrics, which is honestly the whole point 🫶
3.2. Fabric Topology Model 🌷
the fabric topology model module is designed to be generic, so it can apply to data-center fabrics built with different technologies, like VLAN and VXLAN 🌈 Its main purpose is to configure and manage fabrics and their connections. It also gives data-center applications a fabric-based topology view 👑
3.2.1. Fabric Topology 🕸️
in the fabric topology module, a fabric is modeled as a node of a network. So the fabric-based data-center network is a set of fabric nodes and their connections 💖 Here's a snippet of the definitions that shows the main structure of the model. The notation syntax follows [RFC8340] 🧚
module: ietf-dc-fabric-topology
augment /nw:networks/nw:network/nw:network-types:
+--rw fabric-network!
augment /nw:networks/nw:network/nw:node:
+--rw fabric-attributes
+--rw fabric-id? fabric-id
+--rw name? string
+--rw type? fabrictype:underlay-network-type
+--rw description? string
+--rw options
+--...
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--ro fport-attributes
+--ro name? string
+--ro role? fabric-port-role
+--ro type? fabric-port-typethe fabric topology module augments the generic ietf-network and ietf-network-topology modules like this 🎀
- there's a new topology type,
ietf-dc-fabric-topology, and it's added under thenetwork-typescontainer of the ietf-network module 🦋 - Fabric is defined as a node under the network/node container. There's also a new container,
fabric-attributes, that holds attributes for a fabric, like gateway mode, fabric types, involved device nodes, and links 🌸 - Termination points (in the network topology module) get augmented with fabric port attributes, defined in a container. The termination point is used to represent a fabric "port" that provides connections to other nodes, like an internal device, another fabric externally, or end hosts 🔌
details on the fabric node and fabric termination point extensions are coming up in the next sections, so stay tuned 💅✨
3.2.2. Fabric Node Extension ✨
okay bestie, so a fabric is basically an atomic network 🧚 (a set of nodes and links that makes up a POD and also runs one single overlay/underlay instance). It's made of network elements, meaning devices and their related links 🔥. All of the fabric's config lives under a fabric-attributes container, and the notation follows [RFC8340] 💅.
+--rw fabric-attributes
+--rw fabric-id? fabrictypes:fabric-id
+--rw name? string
+--rw type? fabrictype:underlay-network-type
+--rw vni-capacity
| +--rw min? int32
| +--rw max? int32
+--rw description? string
+--rw options
| +--rw gateway-mode? enumeration
| +--rw traffic-behavior? enumeration
| +--rw capability-supported* fabrictype:service-capabilities
+--rw device-nodes* [device-ref]
| +--rw device-ref fabrictype:node-ref
| +--rw role*? fabrictype:device-role
+--rw device-links* [link-ref]
| +--rw link-ref fabrictype:link-ref
+--rw device-ports* [port-ref]
+--rw port-ref fabrictypes:tp-ref
+--rw port-type? fabrictypes:port-type
+--rw bandwidth? fabrictypes:bandwidthso the module adds new fabric data to the "node" list of the network module by augmenting it 🎀 (we're talking fabric name, fabric type, and descriptions, plus a bunch of stuff inside an "options" container 💖). That options container holds the gateway-mode (centralized or distributed 👑) and the traffic behavior (whether an Access Control List (ACL) is needed for the traffic 🙈). It also has a list of device nodes and related links, listed as "supporting-node", which together form the fabric network 🌸. Those device nodes and links are leaf-refs pointing at existing nodes and links in the underlay topology 🦋.
For device nodes there's a "role" object that says what the device does inside the fabric, like "SPINE" or "LEAF" 🍓. The role should work together with the gateway-mode 💜. Not me being picky, it's just how these pieces click ✨.
3.2.3. Fabric Termination-Point Extension 🌈
okay so a fabric can be treated as a node 🫶, which means its "termination-points" can stand in for fabric "ports". Those ports connect to other fabrics, to end hosts, and to devices sitting inside the fabric 🔥.
Basically the set of "termination-points" for a fabric shows all of its connections: internal ones, interconnections with other fabrics, and connections to end hosts 💅. The notation follows [RFC8340] too ✨.
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--ro fport-attributes
+--ro name? string
+--ro role? fabric-port-role
+--ro type? fabric-port-type
+--ro device-port? tp-ref
+--ro (tunnel-option)?This structure augments the termination points in the network topology module with fabric port attributes, all tucked inside a container 🎀.
New nodes get defined for fabric ports: the fabric name, the port's role inside the fabric (internal port, external port to the outside network, or access port to end hosts 🦋), and the port type (L2 interface or L3 interface 💖). By defining the device port as a tp-ref, a fabric port can get mapped to a device node in the underlay network 👑.
On top of that, there's a new container for tunnel-options, used to present the tunnel configuration on a port 🧚.
Also, the termination point info is learned from the underlay networks 🙈. It is not configured by the fabric topology layer. Iconic behavior, honestly 💀.
4. Fabric YANG Modules 💜
This module imports typedefs from [RFC8345] 🌸, and it references [RFC7348] and [RFC8344] 🍓.
Here's the whole module, copy-pasted exactly so your implementation matches 💅:
<CODE BEGINS> file "ietf-dc-fabric-types@2019-02-25.yang"
module ietf-dc-fabric-types {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types";
prefix fabrictypes;
import ietf-network {
prefix nw;
reference
"RFC 8345: A YANG Data Model for Network Topologies";
}
organization
"IETF I2RS (Interface to the Routing System) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/i2rs/>
WG List: <mailto:i2rs@ietf.org>
Editor: Yan Zhuang
<mailto:zhuangyan.zhuang@huawei.com>
Editor: Danian Shi
<mailto:shidanian@huawei.com>";
description
"This module contains a collection of YANG definitions for
fabric.
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8542;
see the RFC itself for full legal notices.";
revision 2019-02-25 {
description
"Initial revision.";
reference
"RFC 8542: A YANG Data Model for Fabric Topology
in Data-Center Networks";
}
identity fabric-type {
description
"Base type for fabric networks";
}
identity vxlan-fabric {
base fabric-type;
description
"VXLAN fabric";
}
identity vlan-fabric {
base fabric-type;
description
"VLAN fabric";
}
identity trill-fabric {
base fabric-type;
description
"TRILL fabric";
}
identity port-type {
description
"Base type for fabric port";
}
identity eth {
base port-type;
description
"Ethernet";
}
identity serial {
base port-type;
description
"Serial";
}
identity bandwidth {
description
"Base for bandwidth";
}
identity bw-1M {
base bandwidth;
description
"1M";
}
identity bw-10M {
base bandwidth;
description
"10Mbps";
}
identity bw-100M {
base bandwidth;
description
"100Mbps";
}
identity bw-1G {
base bandwidth;
description
"1Gbps";
}
identity bw-10G {
base bandwidth;
description
"10Gbps";
}
identity bw-25G {
base bandwidth;
description
"25Gbps";
}
identity bw-40G {
base bandwidth;
description
"40Gbps";
}
identity bw-100G {
base bandwidth;
description
"100Gbps";
}
identity bw-400G {
base bandwidth;
description
"400Gbps";
}
identity device-role {
description
"Base for the device role in a fabric.";
}
identity spine {
base device-role;
description
"This is a spine node in a fabric.";
}
identity leaf {
base device-role;
description
"This is a leaf node in a fabric.";
}
identity border {
base device-role;
description
"This is a border node to connect to other
fabric/network.";
}
identity fabric-port-role {
description
"Base for the port's role in a fabric.";
}
identity internal {
base fabric-port-role;
description
"The port is used for devices to access each
other within a fabric.";
}
identity external {
base fabric-port-role;
description
"The port is used for a fabric to connect to
outside network.";
}
identity access {
base fabric-port-role;
description
"The port is used for an endpoint to connect
to a fabric.";
}
identity service-capability {
description
"Base for the service of the fabric ";
}
identity ip-mapping {
base service-capability;
description
"NAT.";
}
identity acl-redirect {
base service-capability;
description
"ACL redirect, which can provide a Service Function Chain (SFC).";
}
identity dynamic-route-exchange {
base service-capability;
description
"Dynamic route exchange.";
}
/*
* Typedefs
*/
typedef fabric-id {
type nw:node-id;
description
"An identifier for a fabric in a topology.
This identifier can be generated when composing a fabric.
The composition of a fabric can be achieved by defining an
RPC, which is left for vendor specific implementation
and not provided in this model.";
}
typedef service-capabilities {
type identityref {
base service-capability;
}
description
"Service capability of the fabric";
}
typedef port-type {
type identityref {
base port-type;
}
description
"Port type: ethernet or serial or others.";
}
typedef bandwidth {
type identityref {
base bandwidth;
}
description
"Bandwidth of the port.";
}
typedef node-ref {
type instance-identifier;
description
"A reference to a node in topology";
}
typedef tp-ref {
type instance-identifier;
description
"A reference to a termination point in topology";
}
typedef link-ref {
type instance-identifier;
description
"A reference to a link in topology";
}
typedef underlay-network-type {
type identityref {
base fabric-type;
}
description
"The type of physical network that implements
this fabric. Examples are VLAN and TRILL.";
}
typedef device-role {
type identityref {
base device-role;
}
description
"Role of the device node.";
}
typedef fabric-port-role {
type identityref {
base fabric-port-role;
}
description
"Role of the port in a fabric.";
}
typedef fabric-port-type {
type enumeration {
enum layer2interface {
description
"L2 interface";
}
enum layer3interface {
description
"L3 interface";
}
enum layer2Tunnel {
description
"L2 tunnel";
}
enum layer3Tunnel {
description
"L3 tunnel";
}
}
description
"Fabric port type";
}
grouping fabric-port {
description
"Attributes of a fabric port.";
leaf name {
type string;
description
"Name of the port.";
}
leaf role {
type fabric-port-role;
description
"Role of the port in a fabric.";
}
leaf type {
type fabric-port-type;
description
"Type of the port";
}
leaf device-port {
type tp-ref;
description
"The device port it mapped to.";
}
choice tunnel-option {
description
"Tunnel options to connect two fabrics.
It could be L2 Tunnel or L3 Tunnel.";
}
}
}<CODE ENDS>
<CODE BEGINS> file "ietf-dc-fabric-topology@2019-02-25.yang"
module ietf-dc-fabric-topology {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology";
prefix fabric;
import ietf-network {
prefix nw;
reference
"RFC 8345: A YANG Data Model for Network Topologies";
}
import ietf-network-topology {
prefix nt;
reference
"RFC 8345: A YANG Data Model for Network Topologies";
}
import ietf-dc-fabric-types {
prefix fabrictypes;
reference
"RFC 8542: A YANG Data Model for Fabric Topology in
Data-Center Networks";
}
organization
"IETF I2RS (Interface to the Routing System) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/i2rs/>
WG List: <mailto:i2rs@ietf.org>
Editor: Yan Zhuang
<mailto:zhuangyan.zhuang@huawei.com>
Editor: Danian Shi
<mailto:shidanian@huawei.com>";
description
"This module contains a collection of YANG definitions for
fabric.
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8542;
see the RFC itself for full legal notices.";
revision 2019-02-25 {
description
"Initial revision.";
reference
"RFC 8542: A YANG Data Model for Fabric Topology
in Data-Center Networks";
}
//grouping statements
grouping fabric-network-type {
description
"Identify the topology type to be fabric.";
container fabric-network {
presence "indicates fabric Network";
description
"The presence of the container node indicates
fabric topology";
}
}
grouping fabric-options {
description
"Options for a fabric";
leaf gateway-mode {
type enumeration {
enum centralized {
description
"The Fabric uses centralized
gateway, in which gateway is deployed on SPINE
node.";
}
enum distributed {
description
"The Fabric uses distributed
gateway, in which gateway is deployed on LEAF
node.";
}
}
default "distributed";
description
"Gateway mode of the fabric";
}
leaf traffic-behavior {
type enumeration {
enum normal {
description
"Normal means no policy is needed
for all traffic";
}
enum policy-driven {
description
"Policy driven means policy is
needed for the traffic; otherwise, the traffic
will be discarded.";
}
}
default "normal";
description
"Traffic behavior of the fabric";
}
leaf-list capability-supported {
type fabrictypes:service-capabilities;
description
"It provides a list of supported services of the
fabric. The service-capabilities is defined as
identity-ref. Users can define more services
by defining new identities.";
}
}
grouping device-attributes {
description
"device attributes";
leaf device-ref {
type fabrictypes:node-ref;
description
"The device that the fabric includes that refers
to a node in another topology.";
}
leaf-list role {
type fabrictypes:device-role;
default "fabrictypes:leaf";
description
"It is a list of device roles to represent the roles
that a device plays within a POD, such as SPINE,
LEAF, Border, or Border-Leaf.
The device role is defined as identity-ref. If more
than 2 stages are used for a POD, users can
define new identities for the device role.";
}
}
grouping link-attributes {
description
"Link attributes";
leaf link-ref {
type fabrictypes:link-ref;
description
"The link that the fabric includes that refers to
a link in another topology.";
}
}
grouping port-attributes {
description
"Port attributes";
leaf port-ref {
type fabrictypes:tp-ref;
description
"The port that the fabric includes that refers to
a termination-point in another topology.";
}
leaf port-type {
type fabrictypes:port-type;
description
"Port type is defined as identity-ref. The current
types include ethernet or serial. If more types
are needed, developers can define new identities.";
}
leaf bandwidth {
type fabrictypes:bandwidth;
description
"Bandwidth of the port. It is defined as identity-ref.
If more speeds are introduced, developers can define
new identities for them. Current speeds include 1M, 10M,
100M, 1G, 10G, 25G, 40G, 100G, and 400G.";
}
}
grouping fabric-attributes {
description
"Attributes of a fabric";
leaf fabric-id {
type fabrictypes:fabric-id;
description
"An identifier for a fabric in a topology.
This identifier can be generated when composing a fabric.
The composition of a fabric can be achieved by defining an
RPC, which is left for vendor-specific implementation and
not provided in this model.";
}
leaf name {
type string;
description
"Name of the fabric";
}
leaf type {
type fabrictypes:underlay-network-type;
description
"The type of physical network that implements this
fabric. Examples are VLAN and TRILL.";
}
container vni-capacity {
description
"The range of the VXLAN Network Identifier
(VNI) defined in RFC 7348 that the POD uses.";
leaf min {
type int32;
description
"The lower-limit VNI.";
}
leaf max {
type int32;
description
"The upper-limit VNI.";
}
}
leaf description {
type string;
description
"Description of the fabric";
}
container options {
description
"Options of the fabric";
uses fabric-options;
}
list device-nodes {
key "device-ref";
description
"Device nodes that are included in a fabric.";
uses device-attributes;
}
list device-links {
key "link-ref";
description
"Links that are included within a fabric.";
uses link-attributes;
}
list device-ports {
key "port-ref";
description
"Ports that are included in the fabric.";
uses port-attributes;
}
}
// augment statements
augment "/nw:networks/nw:network/nw:network-types" {
description
"Introduce a new network type for fabric-based topology";
uses fabric-network-type;
}
augment "/nw:networks/nw:network/nw:node" {
when '/nw:networks/nw:network/nw:network-types/'
+ 'fabric:fabric-network' {
description
"Augmentation parameters apply only for networks
with fabric topology";
}
description
"Augmentation for fabric nodes created by
fabric topology.";
container fabric-attributes {
description
"Attributes for a fabric network";
uses fabric-attributes;
}
}
augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
when '/nw:networks/nw:network/nw:network-types/'
+ 'fabric:fabric-network' {
description
"Augmentation parameters apply only for networks
with fabric topology";
}
description
"Augmentation for port on fabric.";
container fport-attributes {
config false;
description
"Attributes for fabric ports";
uses fabrictypes:fabric-port;
}
}
}
<CODE ENDS>5. IANA Considerations 🎀
Okay, so IANA time! 💅 This doc registers three namespace URIs in the "IETF XML Registry" [RFC3688]. Each one is an XML namespace, so there's no XML to register, just the URI itself, and the registrant is The IESG. 🌸
URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
URI:urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.Then it also registers three YANG modules in the "YANG Module Names" registry [RFC6020]. Same vibe, the reference for all of them is RFC 8542. 🦋
Name: ietf-dc-fabric-types
Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-types
Prefix: fabrictypes
Reference: RFC 8542
Name: ietf-dc-fabric-topology
Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology
Prefix: fabric
Reference: RFC 8542
Name: ietf-dc-fabric-topology-state
Namespace: urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state
Prefix: sfabric
Reference: RFC 85426. Security Considerations 🔥
Okay, this section is serious, bestie, so pay attention! 😭 The YANG module in this doc is meant to be reached through network management protocols like NETCONF [RFC6241] or RESTCONF [RFC8040]. For NETCONF, the bottom layer is a secure transport, and the one every implementation has to support is SSH [RFC6242]. For RESTCONF, the bottom layer is HTTPS, and the mandatory transport is TLS [RFC8446]. 🔐
The Network Configuration Access Control Model (NACM) [RFC8341] lets you restrict particular NETCONF or RESTCONF users to a preset subset of protocol operations and content. It's giving access control, literally. 💜
Lots of data nodes in this module are writable, creatable, and deletable (that's config true, which is the default). These can be sensitive or vulnerable in some network environments. Writing to them without proper protection (think edit-config) can seriously mess up network operations. 💀 Here's the breakdown for the ietf-dc-fabric-topology module:
fabric-attributes: A malicious client could try to sabotage the configuration of important fabric attributes, like device nodes or type. 😱
Some of the readable data nodes are also sensitive or vulnerable in some environments, so it's really important to control read access to them (via get, get-config, or notification). Here's the breakdown for the same module:
fport-attributes: A malicious client could try to read fabric connections without permission, likedevice-portandname. 🙈
Lock your data down, bestie. Access control is not optional. 🔒✨
7. References 📚✨
7.1. Normative References
- [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997,
https://www.rfc-editor.org/info/rfc2119. 📖 - [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004,
https://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,
https://www.rfc-editor.org/info/rfc6020. 🧶 - [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
https://www.rfc-editor.org/info/rfc6241. 🔧 - [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
https://www.rfc-editor.org/info/rfc6242. 🔐 - [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016,
https://www.rfc-editor.org/info/rfc7950. 💜 - [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
https://www.rfc-editor.org/info/rfc8040. 🌐 - [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017,
https://www.rfc-editor.org/info/rfc8174. 🔠 - [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018,
https://www.rfc-editor.org/info/rfc8341. 🛡️ - [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
https://www.rfc-editor.org/info/rfc8342. 🗄️ - [RFC8345] Clemm, A., Medved, J., Varga, R., Bahadur, N., Ananthakrishnan, H., and X. Liu, "A YANG Data Model for Network Topologies", RFC 8345, DOI 10.17487/RFC8345, March 2018,
https://www.rfc-editor.org/info/rfc8345. 🗺️ - [RFC8346] Clemm, A., Medved, J., Varga, R., Liu, X., Ananthakrishnan, H., and N. Bahadur, "A YANG Data Model for Layer 3 Topologies", RFC 8346, DOI 10.17487/RFC8346, March 2018,
https://www.rfc-editor.org/info/rfc8346. 🧭 - [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
https://www.rfc-editor.org/info/rfc8446. 🔒
7.2. Informative References
- [GENEVE] Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic Network Virtualization Encapsulation", Work in Progress, draft-ietf-nvo3-geneve-12, March 2019. 🦋
- [RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger, L., Sridhar, T., Bursell, M., and C. Wright, "Virtual eXtensible Local Area Network (VXLAN): A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
https://www.rfc-editor.org/info/rfc7348. 🌸 - [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
https://www.rfc-editor.org/info/rfc8340. 🌳 - [RFC8344] Bjorklund, M., "A YANG Data Model for IP Management", RFC 8344, DOI 10.17487/RFC8344, March 2018,
https://www.rfc-editor.org/info/rfc8344. 🍓
Appendix A. Non-NMDA-State Modules 🧚
okay so the YANG module, ietf-dc-fabric-topology, from this document augments two modules, ietf-network and ietf-network-topology. they're designed to be used with implementations that support the Network Management Datastore Architecture (NMDA) from [RFC8342]. 💅 but not every implementation supports NMDA, so there's a set of companion modules that model networks and network topologies as state: ietf-network-state and ietf-network-topology-state, respectively. 🫶
so if you want to use the fabric topology model with non-NMDA-compliant implementations, you need a companion module for it too. ✨ that's ietf-dc-fabric-topology-state. it mirrors ietf-dc-fabric-topology, except it augments ietf-network-state (instead of ietf-network and ietf-network-topology), and all of its data nodes are non-configurable. 🔥
bestie, the thing to know: like ietf-network-state and ietf-network-topology-state, ietf-dc-fabric-topology-state SHOULD NOT be supported by implementations that support NMDA. 💀 that's literally why it lives in the Appendix and not up in the main body. 🙈
the module is defined below. since it mirrors its underlying module, the YANG tree isn't drawn out separately. 🌈
<CODE BEGINS> file "ietf-dc-fabric-topology-state@2019-02-25.yang"module ietf-dc-fabric-topology-state {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dc-fabric-topology-state";
prefix sfabric;
import ietf-network-state {
prefix nws;
reference
"RFC 8345: A Data Model for Network Topologies";
}
import ietf-dc-fabric-types {
prefix fabrictypes;
reference
"RFC 8542: A YANG Data Model for Fabric Topology in
Data-Center Networks";
}
organization
"IETF I2RS (Interface to the Routing System) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/i2rs/>
WG List: <mailto:i2rs@ietf.org>
Editor: Yan Zhuang
<mailto:zhuangyan.zhuang@huawei.com>
Editor: Danian Shi
<mailto:shidanian@huawei.com>";
description
"This module contains a collection of YANG definitions for
fabric state, representing topology that either is learned
or results from applying topology that has been
configured per the ietf-dc-fabric-topology model, mirroring
the corresponding data nodes in this model.
This model mirrors the configuration tree of ietf-dc-fabric
-topology but contains only read-only state data. The model
is not needed when the implementation infrastructure supports
the Network Management Datastore Architecture (NMDA).
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8542;
see the RFC itself for full legal notices.";
revision 2019-02-25 {
description
"Initial revision.";
reference
"RFC 8542: A YANG Data Model for Fabric Topology in
Data-Center Networks";
}
//grouping statements
grouping fabric-network-type {
description
"Identify the topology type to be fabric.";
container fabric-network {
presence "indicates fabric Network";
description
"The presence of the container node indicates
fabric topology";
}
}
grouping fabric-options {
description
"Options for a fabric";
leaf gateway-mode {
type enumeration {
enum centralized {
description
"The fabric uses centralized
gateway, in which gateway is deployed on SPINE
node.";
}
enum distributed {
description
"The fabric uses distributed
gateway, in which gateway is deployed on LEAF
node.";
}
}
default "distributed";
description
"Gateway mode of the fabric";
}
leaf traffic-behavior {
type enumeration {
enum normal {
description
"Normal means no policy is needed
for all traffic";
}
enum policy-driven {
description
"Policy driven means policy is
needed for the traffic; otherwise, the traffic
will be discarded.";
}
}
default "normal";
description
"Traffic behavior of the fabric";
}
leaf-list capability-supported {
type fabrictypes:service-capabilities;
description
"It provides a list of supported services of the
fabric. The service-capabilities is defined as
identity-ref. Users can define more services
by defining new identities.";
}
}
grouping device-attributes {
description
"device attributes";
leaf device-ref {
type fabrictypes:node-ref;
description
"The device that the fabric includes that refers
to a node in another topology.";
}
leaf-list role {
type fabrictypes:device-role;
default "fabrictypes:leaf";
description
"It is a list of device roles to represent the roles
that a device plays within a POD, such as SPINE,
LEAF, Border, or Border-Leaf.
The device role is defined as identity-ref. If more
than 2 stages are used for a POD, users can
define new identities for the device role.";
}
}
grouping link-attributes {
description
"Link attributes";
leaf link-ref {
type fabrictypes:link-ref;
description
"The link that the fabric includes that refers to
a link in another topology.";
}
}
grouping port-attributes {
description
"Port attributes";
leaf port-ref {
type fabrictypes:tp-ref;
description
"The port that the fabric includes that refers to
a termination-point in another topology.";
}
leaf port-type {
type fabrictypes:port-type;
description
"Port type is defined as identity-ref. The current
types include ethernet or serial. If more types
are needed, developers can define new identities.";
}
leaf bandwidth {
type fabrictypes:bandwidth;
description
"Bandwidth of the port. It is defined as
identity-ref. If more speeds are introduced,
developers can define new identities for them. Current
speeds include 1M, 10M, 100M, 1G, 10G,
25G, 40G, 100G, and 400G.";
}
}
grouping fabric-attributes {
description
"Attributes of a fabric";
leaf fabric-id {
type fabrictypes:fabric-id;
description
"Fabric ID";
}
leaf name {
type string;
description
"Name of the fabric";
}
leaf type {
type fabrictypes:underlay-network-type;
description
"The type of physical network that implements this
fabric. Examples are VLAN and TRILL.";
}
container vni-capacity {
description
"The range of the VXLAN Network
Identifier (VNI) defined in RFC 7348 that the POD uses.";
leaf min {
type int32;
description
"The lower-limit VNI.";
}
leaf max {
type int32;
description
"The upper-limit VNI.";
}
}
leaf description {
type string;
description
"Description of the fabric";
}
container options {
description
"Options of the fabric";
uses fabric-options;
}
list device-nodes {
key "device-ref";
description
"Device nodes that are included in a fabric.";
uses device-attributes;
}
list device-links {
key "link-ref";
description
"Links that are included within a fabric.";
uses link-attributes;
}
list device-ports {
key "port-ref";
description
"Ports that are included in the fabric.";
uses port-attributes;
}
}
// augment statements
augment "/nws:networks/nws:network/nws:network-types" {
description
"Introduce a new network type for fabric-based logical
topology";
uses fabric-network-type;
}
augment "/nws:networks/nws:network/nws:node" {
when '/nws:networks/nws:network/nws:network-types'
+ '/sfabric:fabric-network' {
description
"Augmentation parameters apply only for
networks with fabric topology.";
}
description
"Augmentation for fabric nodes.";
container fabric-attributes-state {
description
"Attributes for a fabric network";
uses fabric-attributes;
}
}
}<CODE ENDS>
That's the whole state module wrapped up, bestie 🎀 Every node in it mirrors the config tree, and it's read-only, so nothing here is changing anything. Lowkey iconic. ✨
Acknowledgements 🫶
Huge thanks to Alexander Clemm, Donald E. Eastlake 3rd, Xufeng Liu, Susan Hares, Wei Song, Luis M. Contreras, and Benoit Claise 💖 They gave really helpful contributions, comments, and suggestions, and this spec is so much better because of them 🌸
Authors' Addresses 💜
Yan Zhuang
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: zhuangyan.zhuang@huawei.com
Danian Shi
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: shidanian@huawei.com
Rong Gu
China Mobile
32 Xuanwumen West Ave, Xicheng District
Beijing, Beijing 100053
China
Email: gurong_cmcc@outlook.com
Hariharan Ananthakrishnan
Netflix
Email: hari@netflix.com📦 where this page comes from
- ietf: rfc8542 2019-03
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms