Network Working Group X. Liu
Internet-Draft Volta Networks
Intended status: Standards Track I. Bryskin
Expires: May 5, 2021 Individual
V. Beeram
T. Saad
Juniper Networks
H. Shah
Ciena
S. Litkowski
Cisco
November 1, 2020
YANG Data Model for SR and SR TE Topologies on MPLS Data Plane
draft-ietf-teas-yang-sr-te-topo-08
Abstract
This document defines a YANG data model for Segment Routing (SR)
topology and Segment Routing (SR) traffic engineering (TE) topology,
using MPLS data plane.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Task Force (IETF). Note that other groups may also distribute
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 5, 2021.
Copyright Notice
Copyright (c) 2020 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
(https://trustee.ietf.org/license-info) in effect on the date of
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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
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3
1.3. Prefixes in Data Node Names . . . . . . . . . . . . . . . 3
2. Modeling Considerations . . . . . . . . . . . . . . . . . . . 3
2.1. Segment Routing (SR) MPLS Topology . . . . . . . . . . . 3
2.2. Segment Routing (SR) MPLS TE Topology . . . . . . . . . . 4
2.3. Relations to ietf-segment-routing . . . . . . . . . . . . 5
2.4. Topology Type Modeling . . . . . . . . . . . . . . . . . 5
2.5. Topology Attributes . . . . . . . . . . . . . . . . . . . 5
2.6. Node Attributes . . . . . . . . . . . . . . . . . . . . . 5
2.7. Link Attributes . . . . . . . . . . . . . . . . . . . . . 6
3. Model Structure . . . . . . . . . . . . . . . . . . . . . . . 7
4. YANG Module . . . . . . . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.1. Normative References . . . . . . . . . . . . . . . . . . 19
7.2. Informative References . . . . . . . . . . . . . . . . . 21
Appendix A. Companion YANG Model for Non-NMDA Compliant
Implementations . . . . . . . . . . . . . . . . . . 22
A.1. SR MPLS Topology State Module . . . . . . . . . . . . . . 22
Appendix B. Data Tree Example . . . . . . . . . . . . . . . . . 25
Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction
This document defines a YANG [RFC7950] data model for describing the
presentations of Segment Routing (SR) topology and Segment Routing
(SR) traffic engineering (TE) topology. The version of the model
limits the transport type to an MPLS dataplane.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
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14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are defined in [RFC7950] and are not redefined
here:
o augment
o data model
o data node
1.2. Tree Diagrams
Tree diagrams used in this document follow the notation defined in
[RFC8340].
1.3. Prefixes in Data Node Names
In this document, names of data nodes, actions, and other data model
objects are often used without a prefix, as long as it is clear from
the context in which YANG module each name is defined. Otherwise,
names are prefixed using the standard prefix associated with the
corresponding YANG module, as shown in Table 1.
+--------+-----------------------------+---------------------------+
| Prefix | YANG module | Reference |
+--------+-----------------------------+---------------------------+
| nw | ietf-network | [RFC8345] |
| nt | ietf-network-topology | [RFC8345] |
| l3t | ietf-l3-unicast-topology | [RFC8346] |
| sr-cmn | ietf-segment-routing-common | [I-D.ietf-spring-sr-yang] |
+--------+-----------------------------+---------------------------+
Table 1: Prefixes and Corresponding YANG Modules
2. Modeling Considerations
2.1. Segment Routing (SR) MPLS Topology
The Layer 3 network topology model is discussed in [RFC8346]. The
Segment Routing (SR) MPLS topology model proposed in this document
augments and uses the ietf-l3-unicast-topology module defined in
[RFC8346]. SR MPLS related attributes are covered in the ietf-sr-
mpls-topology model.
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+------------------------------+
| Layer 3 Network Topology |
| ietf-l3-unicast-topology |
+------------------------------+
|
|
|
V
+------------------------+
| SR MPLS Topology |
| ietf-sr-mpls-topology |
+------------------------+
2.2. Segment Routing (SR) MPLS TE Topology
When traffic engineering is enabled on an SR MPLS topology, there
will be associations between objects in SR MPLS topologies and
objects in TE topologies. An SR MPLS TE topology is both an SR MPLS
topology and a layer 3 TE topology. Multiple inheritance is used to
achieve such relations.
+-----------------------+ +---------------------+
| SR MPLS Topology | | L3 TE Topology |
| ietf-sr-mpls-topology | | ietf-l3-te-topology |
+-----------------------+ +---------------------+
\ /
\ /
\ /
v v
+------------------------+
| SR MPLS TE Topology |
| |
+------------------------+
Each type of topologies is indicated by "network-types" defined in
[RFC8345]. For the three types of topologies above, the data
representations are:
L3 Topology:
/nd:networks/nd:network/nd:network-types/l3-unicast-topology
L3 TE Topology:
/nd:networks/nd:network/nd:network-types/l3-unicast-topology/l3-te
SR MPLS Topology:
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/nd:networks/nd:network/nd:network-types/l3-unicast-topology/sr-mpls
SR MPLS TE Topology: (multiple inheritance)
/nd:networks/nd:network/nd:network-types/l3-unicast-topology/l3-te
/nd:networks/nd:network/nd:network-types/l3-unicast-topology/sr-mpls
2.3. Relations to ietf-segment-routing
[I-D.ietf-spring-sr-yang] defines ietf-segment-routing that is a
model intended to be used on network elements to configure or operate
segment routing; ietf-sr-mpls-topology defined in this document is
intended to be used on a controller for the network-wide operations
such as path computation.
SR MPLS topology model shares many modeling constructs defined in
ietf-segment-routing. The module ietf-sr-mpls-topology uses the
types and groupings defined in ietf-segment-routing.
2.4. Topology Type Modeling
A new topology type is defined in this document, to indicate a
topology that is a Segment Routing (SR) topology on an MPLS
dataplane.
augment /nw:networks/nw:network/nw:network-types
/l3t:l3-unicast-topology:
+--rw sr-mpls!
2.5. Topology Attributes
The Segment Routing attributes with topology-wide impacts are modeled
by augmenting the container "l3-topology-attributes" in the L3
topology model. SRGB (Segment Routing Global Block) is covered in
this augmentation. A SR domain is mapped to a topology in this
model.
augment /nw:networks/nw:network/l3t:l3-topology-attributes:
+--rw sr-mpls
+--rw srgb* [lower-bound upper-bound]
+--rw lower-bound uint32
+--rw upper-bound uint32
2.6. Node Attributes
The Segment Routing attributes within the node scope are modeled by
augmenting the sub tree /nw:networks/nw:network/nw:node/ in the L3
topology model.
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The SR attributes that have node-scope impact are modeled by
augmenting the container "l3-node-attributes" in the L3 topology
model, including the SR capabilities, SRGB (Segment Routing Global
Block), and SRLB (Segment Routing Local Block) specified on this
mode. This model also provides the information about how these SR
attributes are learned:
augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes:
+--rw sr-mpls!
+--rw srgb* [lower-bound upper-bound]
| +--rw lower-bound uint32
| +--rw upper-bound uint32
+--rw srlb* [lower-bound upper-bound]
| +--rw lower-bound uint32
| +--rw upper-bound uint32
+--ro node-capabilities
| +--ro entropy-readable-label-depth? uint8
+--rw msd? uint8 {msd}?
+--ro information-source? enumeration
+--ro information-source-state
+--ro credibility-preference? uint16
The SR attributes that are related to a IGP-Prefix segment are
modeled by augmenting the list entry "prefix" in the L3 topology
model:
augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes
/l3t:prefix:
+--rw sr-mpls!
+--rw value-type? enumeration
+--rw start-sid uint32
+--rw range? uint32
+--rw algorithm? identityref
+--rw last-hop-behavior? enumeration
| {sid-last-hop-behavior}?
+--rw is-local? boolean
+--rw is-node? boolean
+--ro is-readvertisment? boolean
2.7. Link Attributes
A link in the topology model connects the termination point on the
source node to the termination point on the destination node. When
such a link is instantiated, the bindings between the nodes and the
corresponding Adj-SIDs are formed, and the resulting FIB entries are
installed.
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A link in the topology model is mapped to an SR Adjacency Segment,
formed by a pair of interfaces on two respective adjacent nodes. The
SR Adjacency Segment attributes are modeled by augmenting the link
attributes of the L3 topology model. The modeling structure is as
follows:
augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes:
+--rw sr-mpls!
+--rw value-type? enumeration
+--rw sid uint32
+--rw advertise-protection? enumeration
+--rw is-local? boolean
+--rw msd? uint8 {msd}?
+--rw address-family? enumeration
+--rw is-backup? boolean
+--rw is-part-of-set? boolean
+--rw is-persistent? boolean
+--rw is-on-lan? boolean
+--ro information-source? enumeration
+--ro information-source-state
+--ro credibility-preference? uint16
The usage of the leaf "advertise-protection" is described in
[I-D.ietf-spring-sr-yang].
IGPs [RFC8665] [RFC8666] [RFC8667] and BGP-LS [RFC7752]
[I-D.ietf-idr-bgp-ls-segment-routing-ext] can be supported by the
model, the leaf "information-source" is used to indicate where the
information is from.
The bundling capability of the Adjacency Segemnt is achieved by re-
using the existing modeling construct (i.e. "bundle-stack-level")
under /nw:networks/nw:network/nt:link/tet:te
[I-D.ietf-teas-yang-te-topo]
3. Model Structure
The model tree structure of the Segment Routing (SR) topology module
is as shown below:
module: ietf-sr-mpls-topology
augment /nw:networks/nw:network/nw:network-types
/l3t:l3-unicast-topology:
+--rw sr-mpls!
augment /nw:networks/nw:network/l3t:l3-topology-attributes:
+--rw sr-mpls
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+--rw srgb* [lower-bound upper-bound]
+--rw lower-bound uint32
+--rw upper-bound uint32
augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes:
+--rw sr-mpls!
+--rw srgb* [lower-bound upper-bound]
| +--rw lower-bound uint32
| +--rw upper-bound uint32
+--rw srlb* [lower-bound upper-bound]
| +--rw lower-bound uint32
| +--rw upper-bound uint32
+--ro node-capabilities
| +--ro entropy-readable-label-depth? uint8
+--rw msd? uint8 {msd}?
+--ro information-source? enumeration
+--ro information-source-instance? string
+--ro information-source-state
+--ro credibility-preference? uint16
augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes
/l3t:prefix:
+--rw sr-mpls!
+--rw value-type? enumeration
+--rw start-sid uint32
+--rw range? uint32
+--rw algorithm? identityref
+--rw last-hop-behavior? enumeration
| {sid-last-hop-behavior}?
+--rw is-local? boolean
+--rw is-node? boolean
+--ro is-readvertisment? boolean
augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes:
+--rw sr-mpls!
+--rw value-type? enumeration
+--rw sid uint32
+--rw advertise-protection? enumeration
+--rw is-local? boolean
+--rw msd? uint8 {msd}?
+--rw address-family? enumeration
+--rw is-backup? boolean
+--rw is-part-of-set? boolean
+--rw is-persistent? boolean
+--rw is-on-lan? boolean
+--ro information-source? enumeration
+--ro information-source-instance? string
+--ro information-source-state
+--ro credibility-preference? uint16
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4. YANG Module
This module references [RFC7752], [RFC8345], [RFC8346], [RFC8476],
[RFC8491], [RFC8665], [RFC8666], [RFC8667], [RFC8814],
[I-D.ietf-spring-sr-yang], and
[I-D.ietf-idr-bgp-ls-segment-routing-ext].
<CODE BEGINS> file "ietf-sr-mpls-topology@2020-11-01.yang"
module ietf-sr-mpls-topology {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology";
prefix "srmt";
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-l3-unicast-topology {
prefix "l3t";
reference "RFC 8346: A YANG Data Model for Layer 3 Topologies";
}
import ietf-segment-routing-common {
prefix "sr-cmn";
reference
"I-D.ietf-spring-sr-yang: YANG Data Model for Segment Routing";
}
organization
"IETF Traffic Engineering Architecture and Signaling (TEAS)
Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/teas/>
WG List: <mailto:teas@ietf.org>
Editor: Xufeng Liu
<mailto:xufeng.liu.ietf@gmail.com>
Editor: Igor Bryskin
<mailto:Igor.Bryskin@huawei.com>
Editor: Vishnu Pavan Beeram
<mailto:vbeeram@juniper.net>
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Editor: Tarek Saad
<mailto:tsaad@cisco.com>
Editor: Himanshu Shah
<mailto:hshah@ciena.com>
Editor: Stephane Litkowski
<mailto:stephane.litkowski@orange.com>";
description
"YANG data model for representing and manipulating Segment
Routing Topologies on MPLS Data Plane.
Copyright (c) 2020 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.";
revision 2020-11-01 {
description "Initial revision";
reference
"RFC XXXX: YANG Data Model for SR and SR TE Topologies";
}
feature msd {
description
"Support of signaling MSD (Maximum SID Depth) in IGP.";
reference
"RFC 8476: Signaling Maximum SID Depth (MSD) Using OSPF.
RFC 8491: Signaling Maximum SID Depth (MSD) Using IS-IS.
RFC 8814: Signaling Maximum SID Depth (MSD) Using the Border
Gateway Protocol - Link State.";
}
grouping sr-mpls-topology-type {
description
"Identifies the SR-MPLS topology type. This type of network
topologies use Segment Routing (SR) technology over the MPLS
data plane";
container sr-mpls {
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presence "Indicates SR-MPLS topology";
description
"Its presence identifies the SR topology type.";
}
}
augment "/nw:networks/nw:network/nw:network-types/"
+ "l3t:l3-unicast-topology" {
description
"Defines the SR topology type.";
uses sr-mpls-topology-type;
}
augment "/nw:networks/nw:network/l3t:l3-topology-attributes" {
when "../nw:network-types/l3t:l3-unicast-topology/srmt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment topology configuration";
uses sr-mpls-topology-attributes;
}
augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" {
when "../../nw:network-types/l3t:l3-unicast-topology/"
+ "srmt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node configuration.";
uses sr-node-attributes;
}
augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes"
+ "/l3t:prefix" {
when "../../../nw:network-types/l3t:l3-unicast-topology/"
+ "srmt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node prefix.";
uses sr-node-prefix-attributes;
}
augment "/nw:networks/nw:network/nt:link/l3t:l3-link-attributes" {
when "../../nw:network-types/l3t:l3-unicast-topology/"
+ "srmt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment link configuration";
uses sr-link-attributes;
}
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grouping sr-mpls-topology-attributes {
description "SR topology scope attributes.";
container sr-mpls {
description
"Containing SR attributes.";
uses sr-cmn:srgb;
} // sr
} // sr-mpls-topology-attributes
grouping information-source-attributes {
description
"The attributes identifying source that has provided the
related information, and the source credibility.";
leaf information-source {
type enumeration {
enum "unknown" {
description "The source is unknown.";
}
enum "locally-configured" {
description "Configured entity.";
}
enum "ospfv2" {
description "OSPFv2.";
reference
"RFC 8665: OSPF Extensions for Segment Routing.";
}
enum "ospfv3" {
description "OSPFv3.";
reference
"RFC 8666: OSPFv3 Extensions for Segment Routing.";
}
enum "isis" {
description "ISIS.";
reference
"RFC 8667: IS-IS Extensions for Segment Routing.";
}
enum "bgp-ls" {
description "BGP-LS.";
reference
"RFC 7752: North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP.
I-D.ietf-idr-bgp-ls-segment-routing-ext:
BGP Link-State extensions for Segment Routing.";
}
enum "system-processed" {
description "System processed entity.";
}
enum "other" {
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description "Other source.";
}
}
config false;
description
"Indicates the type of the information source.";
}
leaf information-source-instance {
type string;
config false;
description
"The name indicating the instance of the information
source.";
}
container information-source-state {
config false;
description
"The container contains state attributes related to
the information source.";
leaf credibility-preference {
type uint16;
description
"The preference value to calculate the traffic
engineering database credibility value used for
tie-break selection between different
information-source values.
Higher value is more preferable.";
}
}
} // information-source-attributes
grouping sr-node-attributes {
description "SR node scope attributes.";
container sr-mpls {
presence "Presence indicates SR is enabled.";
description
"Containing SR attributes.";
uses sr-cmn:srgb;
uses sr-cmn:srlb;
uses sr-cmn:node-capabilities;
leaf msd {
if-feature "msd";
type uint8;
description
"Node MSD is the lowest MSD supported by the node.";
}
// Operational state data
uses information-source-attributes;
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} // sr
} // sr-node-attributes
grouping sr-node-prefix-attributes {
description "Containing SR attributes for a prefix.";
container sr-mpls {
presence "Presence indicates SR is enabled.";
description
"Containing SR attributes for a prefix.";
uses sr-cmn:prefix-sid-attributes;
uses sr-cmn:last-hop-behavior;
leaf is-local {
type boolean;
default false;
description
"'true' if the SID is local.";
}
leaf is-node {
type boolean;
default false;
description
"'true' if the Prefix-SID refers to the router identified
by the prefix. Typically, the leaf 'is-node' (N-Flag)
is set on Prefix-SIDs attached to a router loopback
address.";
}
leaf is-readvertisment {
type boolean;
config false;
description
"'true' if the prefix to which this Prefix-SID is attached,
has been propagated by the router from another
topology by redistribution.";
}
} // sr
} // sr-node-prefix-attributes
grouping sr-link-attributes {
description "SR link scope attributes";
container sr-mpls {
presence "Presence indicates SR is enabled.";
description
"Containing SR attributes.";
uses sr-cmn:sid-value-type;
leaf sid {
type uint32;
mandatory true;
description
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"Adjacency SID, which can be either IGP-Adjacency SID
or BGP PeerAdj SID, depending on the context.";
}
leaf advertise-protection {
type enumeration {
enum "single" {
description
"A single Adj-SID is associated
with the adjacency and reflects
the protection configuration.";
}
enum "dual" {
description
"Two Adj-SIDs will be associated
with the adjacency if interface
is protected. In this case
one will be enforced with
backup flag set, the other
will be enforced to backup flag unset.
In case, protection is not configured,
a single Adj-SID will be advertised
with backup flag unset.";
}
}
default "single";
description
"If set, the Adj-SID refers to an
adjacency being protected.";
}
leaf is-local {
type boolean;
default false;
description
"'true' if the SID is local.";
}
leaf msd {
if-feature "msd";
type uint8;
description
"SID depth of the interface associated with the link.";
}
leaf address-family {
type enumeration {
enum "ipv4" {
description
"The Adj-SID refers to an adjacency with outgoing IPv4
encapsulation.";
}
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enum "ipv6" {
description
"The Adj-SID refers to an adjacency with outgoing IPv6
encapsulation.";
}
}
default "ipv4";
description
"This leaf defines the F-Flag (Address-Family flag) of the
SID.";
}
leaf is-backup {
type boolean;
default false;
description
"'true' if the SID is a backup.";
}
leaf is-part-of-set {
type boolean;
default false;
description
"'true' if the SID is part of a set.";
}
leaf is-persistent {
type boolean;
default true;
description
"'true' if the SID is persistently allocated.";
}
leaf is-on-lan {
type boolean;
default false;
description
"'true' if on a lan.";
}
uses information-source-attributes;
} // sr
} // sr-tp-attributes
}
<CODE ENDS>
5. IANA Considerations
RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
actual RFC number (and remove this note).
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This document registers the following namespace URIs in the IETF XML
registry [RFC3688]:
--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
--------------------------------------------------------------------
--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
--------------------------------------------------------------------
This document registers the following YANG modules in the YANG Module
Names registry [RFC6020]:
--------------------------------------------------------------------
name: ietf-sr-mpls-topology
namespace: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology
prefix: srmt
reference: RFC XXXX
--------------------------------------------------------------------
--------------------------------------------------------------------
name: ietf-sr-mpls-topology-state
namespace: urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state
prefix: srmt-s
reference: RFC XXXX
--------------------------------------------------------------------
6. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
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There are a number of data nodes defined in this YANG module that 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:
nw:network-types/l3t:l3-unicast-topology/sr-mpls
This subtree specifies the SR MPLS topology type. Modifying the
configurations can make SR MPLS topology type invalid and cause
interruption to all SR networks.
/nw:networks/nw:network/l3t:l3-topology-attributes/sr
This subtree specifies the topology-wide configurations, including
the SRGB (Segment Routing Global Block). Modifying the
configurations here can cause traffic disabled or rerouted in this
topology and the connected topologies.
/nw:networks/nw:network/nw:node/l3t:l3-node-attributes
This subtree specifies the SR configurations for nodes. Modifying
the configurations in this subtree can add, remove, or modify SR
nodes, causing traffic disabled or rerouted in the specified nodes
and the related TE topologies.
/nw:networks/nw:network/nt:link/l3t:l3-link-attributes/sr
This subtree specifies the configurations for SR Adjacency
Segments. Modifying the configurations in this subtree can add,
remove, or modify SR Adjacency Segments causing traffic disabled
or rerouted on the specified SR adjacencies, the related nodes,
and the related SR MPLS topologies.
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. These are the subtrees and data
nodes and their sensitivity/vulnerability:
nw:network-types/l3t:l3-unicast-topology/sr-mpls
Unauthorized access to this subtree can disclose the SR MPLS
topology type.
/nw:networks/nw:network/l3t:l3-topology-attributes/sr
Unauthorized access to this subtree can disclose the topology-wide
configurations, including the SRGB (Segment Routing Global Block).
/nw:networks/nw:network/nw:node/l3t:l3-node-attributes
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Unauthorized access to this subtree can disclose the operational
state information of the SR nodes.
/nw:networks/nw:network/nt:link/l3t:l3-link-attributes/sr
Unauthorized access to this subtree can disclose the operational
state information of SR Adjacency Segments.
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>.
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[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>.
[RFC8476] Tantsura, J., Chunduri, U., Aldrin, S., and P. Psenak,
"Signaling Maximum SID Depth (MSD) Using OSPF", RFC 8476,
DOI 10.17487/RFC8476, December 2018,
<https://www.rfc-editor.org/info/rfc8476>.
[RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
"Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491,
DOI 10.17487/RFC8491, November 2018,
<https://www.rfc-editor.org/info/rfc8491>.
[RFC8814] Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G.,
and N. Triantafillis, "Signaling Maximum SID Depth (MSD)
Using the Border Gateway Protocol - Link State", RFC 8814,
DOI 10.17487/RFC8814, August 2020,
<https://www.rfc-editor.org/info/rfc8814>.
[I-D.ietf-spring-sr-yang]
Litkowski, S., Qu, Y., Lindem, A., Sarkar, P., and J.
Tantsura, "YANG Data Model for Segment Routing", draft-
ietf-spring-sr-yang-22 (work in progress), August 2020.
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7.2. Informative References
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[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>.
[RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler,
H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", RFC 8665,
DOI 10.17487/RFC8665, December 2019,
<https://www.rfc-editor.org/info/rfc8665>.
[RFC8666] Psenak, P., Ed. and S. Previdi, Ed., "OSPFv3 Extensions
for Segment Routing", RFC 8666, DOI 10.17487/RFC8666,
December 2019, <https://www.rfc-editor.org/info/rfc8666>.
[RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C.,
Bashandy, A., Gredler, H., and B. Decraene, "IS-IS
Extensions for Segment Routing", RFC 8667,
DOI 10.17487/RFC8667, December 2019,
<https://www.rfc-editor.org/info/rfc8667>.
[I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16
(work in progress), June 2019.
[I-D.ietf-teas-yang-te-topo]
Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
O. Dios, "YANG Data Model for Traffic Engineering (TE)
Topologies", draft-ietf-teas-yang-te-topo-22 (work in
progress), June 2019.
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Appendix A. Companion YANG Model for Non-NMDA Compliant Implementations
The YANG module ietf-sr-mpls-topology defined in this document is
designed to be used in conjunction with implementations that support
the Network Management Datastore Architecture (NMDA) defined in
[RFC8342]. In order to allow implementations to use the model even
in cases when NMDA is not supported, the following companion module,
ietf-sr-mpls-topology-state, is defined as state model, which mirrors
the module ietf-sr-mpls-topology defined earlier in this document.
However, all data nodes in the companion module are non-configurable,
to represent the applied configuration or the derived operational
states.
The companion module, ietf-sr-mpls-topology-state, is redundant and
SHOULD NOT be supported by implementations that support NMDA.
As the structure of the companion module mirrors that of the
coorespinding NMDA model, the YANG tree of the companion module is
not depicted separately.
A.1. SR MPLS Topology State Module
This module references [RFC8345] and [RFC8346].
<CODE BEGINS> file "ietf-sr-mpls-topology-state@2020-11-01.yang"
module ietf-sr-mpls-topology-state {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-sr-mpls-topology-state";
prefix "srmt-s";
import ietf-sr-mpls-topology {
prefix "srmt";
}
import ietf-network-state {
prefix "nw-s";
reference "RFC 8345: A YANG Data Model for Network Topologies";
}
import ietf-network-topology-state {
prefix "nt-s";
reference "RFC 8345: A YANG Data Model for Network Topologies";
}
import ietf-l3-unicast-topology-state {
prefix "l3t-s";
reference "RFC 8346: A YANG Data Model for Layer 3 Topologies";
}
import ietf-segment-routing-common {
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prefix "sr-cmn";
reference
"I-D.ietf-spring-sr-yang: YANG Data Model for Segment Routing";
}
organization
"IETF Traffic Engineering Architecture and Signaling (TEAS)
Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/teas/>
WG List: <mailto:teas@ietf.org>
Editor: Xufeng Liu
<mailto:xufeng.liu.ietf@gmail.com>
Editor: Igor Bryskin
<mailto:Igor.Bryskin@huawei.com>
Editor: Vishnu Pavan Beeram
<mailto:vbeeram@juniper.net>
Editor: Tarek Saad
<mailto:tsaad@cisco.com>
Editor: Himanshu Shah
<mailto:hshah@ciena.com>
Editor: Stephane Litkowski
<mailto:stephane.litkowski@orange.com>";
description
"YANG data model for representing operational state information
of Segment Routing Topologies on MPLS data plane, when NMDA is
not supported.
Copyright (c) 2020 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.";
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revision 2020-11-01 {
description "Initial revision";
reference
"RFC XXXX: YANG Data Model for SR and SR TE Topologies";
}
augment "/nw-s:networks/nw-s:network/nw-s:network-types/"
+ "l3t-s:l3-unicast-topology" {
description
"Defines the SR topology type.";
uses srmt:sr-mpls-topology-type;
}
augment "/nw-s:networks/nw-s:network/"
+ "l3t-s:l3-topology-attributes" {
when "../nw-s:network-types/l3t-s:l3-unicast-topology/"
+ "srmt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment topology configuration";
uses srmt:sr-mpls-topology-attributes;
}
augment "/nw-s:networks/nw-s:network/nw-s:node/"
+ "l3t-s:l3-node-attributes" {
when "../../nw-s:network-types/l3t-s:l3-unicast-topology/"
+ "srmt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node configuration.";
uses srmt:sr-node-attributes;
}
augment "/nw-s:networks/nw-s:network/nw-s:node/"
+ "l3t-s:l3-node-attributes/l3t-s:prefix" {
when "../../../nw-s:network-types/l3t-s:l3-unicast-topology/"
+ "srmt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node prefix.";
uses srmt:sr-node-prefix-attributes;
}
augment "/nw-s:networks/nw-s:network/nt-s:link/"
+ "l3t-s:l3-link-attributes" {
when "../../nw-s:network-types/l3t-s:l3-unicast-topology/"
+ "srmt-s:sr-mpls" {
description "Augment only for SR topology.";
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}
description "Augment link configuration";
uses srmt:sr-link-attributes;
}
grouping sr-mpls-topology-attributes {
description "SR topology scope attributes.";
container sr-mpls {
description
"Containing SR attributes.";
uses sr-cmn:srgb;
} // sr
} // sr-mpls-topology-attributes
}
<CODE ENDS>
Appendix B. Data Tree Example
This section contains an example of an instance data tree in the JSON
encoding [RFC7951]. The example instantiates "ietf-sr-mpls-topology"
for the topology that is depicted in the following diagram.
+------------+ +------------+
| D1 | | D2 |
/-\ /-\ /-\ /-\
| | 1-0-1 | |---------------->| | 2-1-1 | |
| | 1-2-1 | |<----------------| | 2-0-1 | |
\-/ 1-3-1 \-/ \-/ 2-3-1 \-/
| /----\ | | /----\ |
+---| |---+ +---| |---+
\----/ \----/
A | A |
| | | |
| | | |
| | +------------+ | |
| | | D3 | | |
| | /-\ /-\ | |
| +----->| | 3-1-1 | |-------+ |
+---------| | 3-2-1 | |<---------+
\-/ \-/
| |
+------------+
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The corresponding instance data tree is depicted below. Note that
some lines have been wrapped to adhere to the 72-character line
limitation of RFCs.
{
"ietf-network:networks": {
"network": [
{
"network-types": {
"ietf-l3-unicast-topology:l3-unicast-topology": {
"ietf-sr-mpls-topology:sr-mpls": {}
}
},
"network-id": "sr-topo-example",
"ietf-l3-unicast-topology:l3-topology-attributes": {
"ietf-sr-mpls-topology:sr-mpls": {
"srgb": [
{
"lower-bound": 16000,
"upper-bound": 23999
}
]
}
},
"node": [
{
"node-id": "D1",
"ietf-network-topology:termination-point": [
{
"tp-id": "1-0-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 101
}
},
{
"tp-id": "1-2-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 121
}
},
{
"tp-id": "1-3-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 131
}
}
],
"ietf-l3-unicast-topology:l3-node-attributes": {
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"router-id": ["203.0.113.1"],
"prefix": [
{
"prefix": "203.0.113.1/32",
"ietf-sr-mpls-topology:sr-mpls": {
"start-sid": 101,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-mpls-topology:sr-mpls": {
"srgb": [
{
"lower-bound": 16000,
"upper-bound": 23999
}
],
"srlb": [
{
"lower-bound": 15000,
"upper-bound": 15999
}
]
}
}
},
{
"node-id": "D2",
"ietf-network-topology:termination-point": [
{
"tp-id": "2-0-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 201
}
},
{
"tp-id": "2-1-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 211
}
},
{
"tp-id": "2-3-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 231
}
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}
],
"ietf-l3-unicast-topology:l3-node-attributes": {
"router-id": ["203.0.113.2"],
"prefix": [
{
"prefix": "203.0.113.2/32",
"ietf-sr-mpls-topology:sr-mpls": {
"start-sid": 102,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-mpls-topology:sr-mpls": {
"srgb": [
{
"lower-bound": 16000,
"upper-bound": 23999
}
],
"srlb": [
{
"lower-bound": 15000,
"upper-bound": 15999
}
]
}
}
},
{
"node-id": "D3",
"ietf-network-topology:termination-point": [
{
"tp-id": "3-1-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 311
}
},
{
"tp-id": "3-2-1",
"ietf-l3-unicast-topology:l3-termination-point-attributes": {
"unnumbered-id": 321
}
}
],
"ietf-l3-unicast-topology:l3-node-attributes": {
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"router-id": ["203.0.113.3"],
"prefix": [
{
"prefix": "203.0.113.1/32",
"ietf-sr-mpls-topology:sr-mpls": {
"start-sid": 101,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-mpls-topology:sr-mpls": {
"srgb": [
{
"lower-bound": 16000,
"upper-bound": 23999
}
],
"srlb": [
{
"lower-bound": 15000,
"upper-bound": 15999
}
]
}
}
}
],
"ietf-network-topology:link": [
{
"link-id": "D1,1-2-1,D2,2-1-1",
"source": {
"source-node": "D1",
"source-tp": "1-2-1"
},
"destination": {
"dest-node": "D2",
"dest-tp": "2-1-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
"ietf-sr-mpls-topology:sr-mpls": {
"sid": 121,
"is-local": true
}
}
},
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{
"link-id": "D2,2-1-1,D1,1-2-1",
"source": {
"source-node": "D2",
"source-tp": "2-1-1"
},
"destination": {
"dest-node": "D1",
"dest-tp": "1-2-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
"ietf-sr-mpls-topology:sr-mpls": {
"sid": 211,
"is-local": true
}
}
},
{
"link-id": "D1,1-3-1,D3,3-1-1",
"source": {
"source-node": "D1",
"source-tp": "1-3-1"
},
"destination": {
"dest-node": "D3",
"dest-tp": "3-1-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
"ietf-sr-mpls-topology:sr-mpls": {
"sid": 131,
"is-local": true
}
}
},
{
"link-id": "D3,3-1-1,D1,1-3-1",
"source": {
"source-node": "D3",
"source-tp": "3-1-1"
},
"destination": {
"dest-node": "D1",
"dest-tp": "1-3-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
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"ietf-sr-mpls-topology:sr-mpls": {
"sid": 311,
"is-local": true
}
}
},
{
"link-id": "D2,2-3-1,D3,3-2-1",
"source": {
"source-node": "D2",
"source-tp": "2-3-1"
},
"destination": {
"dest-node": "D3",
"dest-tp": "3-2-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
"ietf-sr-mpls-topology:sr-mpls": {
"sid": 231,
"is-local": true
}
}
},
{
"link-id": "D3,3-2-1,D2,2-3-1",
"source": {
"source-node": "D3",
"source-tp": "3-2-1"
},
"destination": {
"dest-node": "D2",
"dest-tp": "2-3-1"
},
"ietf-l3-unicast-topology:l3-link-attributes": {
"metric1": "100",
"ietf-sr-mpls-topology:sr-mpls": {
"sid": 321,
"is-local": true
}
}
}
]
}
]
}
}
Liu, et al. Expires May 5, 2021 [Page 31]
Internet-Draft YANG SR MPLS Topology November 2020
Appendix C. Contributors
Jeff Tantsura
Email: jefftant.ietf@gmail.com
Yingzhen Qu
Email: yingzhen.qu@huawei.com
Authors' Addresses
Xufeng Liu
Volta Networks
EMail: xufeng.liu.ietf@gmail.com
Igor Bryskin
Individual
EMail: i_bryskin@yahoo.com
Vishnu Pavan Beeram
Juniper Networks
EMail: vbeeram@juniper.net
Tarek Saad
Juniper Networks
EMail: tsaad@juniper.net
Himanshu Shah
Ciena
EMail: hshah@ciena.com
Stephane Litkowski
Cisco
EMail: slitkows.ietf@gmail.com
Liu, et al. Expires May 5, 2021 [Page 32]
