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Versions: (draft-liu-teas-yang-sr-te-topo) 00
01 02 03 04 05
Network Working Group X. Liu
Internet-Draft Volta Networks
Intended status: Standards Track I. Bryskin
Expires: September 12, 2019 Huawei Technologies
V. Beeram
Juniper Networks
T. Saad
Cisco Systems Inc
H. Shah
Ciena
S. Litkowski
Orange Business Service
March 11, 2019
YANG Data Model for SR and SR TE Topologies
draft-ietf-teas-yang-sr-te-topo-04
Abstract
This document defines a YANG data model for Segment Routing (SR)
topology and Segment Routing (SR) traffic engineering (TE) topology.
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 https://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 12, 2019.
Copyright Notice
Copyright (c) 2019 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
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3
2. Modeling Considerations . . . . . . . . . . . . . . . . . . . 3
2.1. Segment Routing (SR) Topology . . . . . . . . . . . . . . 3
2.2. Segment Routing (SR) TE Topology . . . . . . . . . . . . 3
2.3. Relations to ietf-segment-routing . . . . . . . . . . . . 4
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 . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.1. Normative References . . . . . . . . . . . . . . . . . . 18
7.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. Companion YANG Model for Non-NMDA Compliant
Implementations . . . . . . . . . . . . . . . . . . 21
A.1. SR Topology State Module . . . . . . . . . . . . . . . . 21
Appendix B. Data Tree Example . . . . . . . . . . . . . . . . . 24
Appendix C. Contributors . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
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
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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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].
2. Modeling Considerations
2.1. Segment Routing (SR) Topology
The Layer 3 network topology model is discussed in [RFC8346]. The
Segment Routing (SR) topology model proposed in this document
augments and uses the ietf-l3-unicast-igp-topology module defined in
[RFC8346]. SR related attributes are covered in the ietf-sr-topology
model.
+------------------------------+
| Layer 3 Network Topology |
| ietf-l3-unicast-topology |
+------------------------------+
|
|
|
V
+------------------------+
| SR Topology |
| ietf-sr-topology |
+------------------------+
2.2. Segment Routing (SR) TE Topology
When traffic engineering is enabled on an SR topology, there will be
associations between objects in SR topologies and objects in TE
topologies. An SR TE topology is both an SR topology and a layer 3
TE topology. Multiple inheritance is used to achieve such relations.
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+------------------+ +---------------------+
| SR Topology | | L3 TE Topology |
| ietf-sr-topology | | ietf-l3-te-topology |
+------------------+ +---------------------+
\ /
\ /
\ /
v v
+------------------------+
| SR 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 Topology:
/nd:networks/nd:network/nd:network-types/l3-unicast-topology/sr-mpls
SR 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-topology defined in this document is
intended to be used on a controller for the network-wide operations
such as path computation.
SR topology model shares many modeling constructs defined in ietf-
segment-routing. The module ietf-sr-topology uses the types and
groupings defined in ietf-segment-routing.
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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
+--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.
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:
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augment /nw:networks/nw:network/nw:node/l3t:l3-node-attributes:
+--rw sr
+--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 transport-planes* [transport-plane]
| | +--ro transport-plane identityref
| +--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!
+--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.
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:
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augment /nw:networks/nw:network/nt:link/l3t:l3-link-attributes:
+--rw sr!
+--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].
Both IGP and BGP 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-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
+--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
+--rw srgb* [lower-bound upper-bound]
| +--rw lower-bound uint32
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| +--rw upper-bound uint32
+--rw srlb* [lower-bound upper-bound]
| +--rw lower-bound uint32
| +--rw upper-bound uint32
+--ro node-capabilities
| +--ro transport-planes* [transport-plane]
| | +--ro transport-plane identityref
| +--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!
+--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!
+--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
<CODE BEGINS> file "ietf-sr-topology@2019-03-09.yang"
module ietf-sr-topology {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-sr-topology";
prefix "srt";
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>
Editor: Tarek Saad
<mailto:tsaad@cisco.com>
Editor: Himanshu Shah
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<mailto:hshah@ciena.com>
Editor: Stephane Litkowski
<mailto:stephane.litkowski@orange.com>";
description
"YANG data model for representing and manipulating Segment
Routing Topologies.
Copyright (c) 2018 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 2019-03-09 {
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.";
}
grouping sr-topology-type {
description
"Identifies the SR-MPLS topology type. This type of network
toplogies use Segment Routing (SR) technology over the MPLS
data plane";
container sr-mpls {
presence "Indiates SR-MPLS topology";
description
"Its presence identifies the SR topology type.";
}
}
augment "/nw:networks/nw:network/nw:network-types/"
+ "l3t:l3-unicast-topology" {
description
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"Defines the SR topology type.";
uses sr-topology-type;
}
augment "/nw:networks/nw:network/l3t:l3-topology-attributes" {
when "../nw:network-types/l3t:l3-unicast-topology/srt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment topology configuration";
uses sr-topology-attributes;
}
augment "/nw:networks/nw:network/nw:node/l3t:l3-node-attributes" {
when "../../nw:network-types/l3t:l3-unicast-topology/"
+ "srt: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/"
+ "srt: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/"
+ "srt:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment link configuration";
uses sr-link-attributes;
}
grouping sr-topology-attributes {
description "SR topology scope attributes.";
container sr {
description
"Containing SR attributes.";
uses sr-cmn:srgb;
} // sr
} // sr-topology-attributes
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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.";
}
enum "ospfv3" {
description "OSPFv3.";
}
enum "isis" {
description "ISIS.";
}
enum "bgp-ls" {
description "BGP-LS.";
reference
"RFC 7752: North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP";
}
enum "system-processed" {
description "System processed entity.";
}
enum "other" {
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
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"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 {
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;
} // sr
} // sr-node-attributes
grouping sr-node-prefix-attributes {
description "Containing SR attributes for a prefix.";
container sr {
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 {
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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 {
presence "Presence indicates SR is enabled.";
description
"Containing SR attributes.";
uses sr-cmn:sid-value-type;
leaf sid {
type uint32;
mandatory true;
description
"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
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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.";
}
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 {
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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).
This document registers the following namespace URIs in the IETF XML
registry [RFC3688]:
--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-sr-topology
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
--------------------------------------------------------------------
--------------------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-sr-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]:
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--------------------------------------------------------------------
name: ietf-sr-topology
namespace: urn:ietf:params:xml:ns:yang:ietf-sr-topology
prefix: srt
reference: RFC XXXX
--------------------------------------------------------------------
--------------------------------------------------------------------
name: ietf-sr-topology-state
namespace: urn:ietf:params:xml:ns:yang:ietf-sr-topology-state
prefix: srt-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
[RFC5246].
The NETCONF access control model [RFC6536] 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.
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 topology type. Modifying the
configurations can make SR 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.
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/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 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 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
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>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
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[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>.
[RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration
Protocol (NETCONF) Access Control Model", RFC 6536,
DOI 10.17487/RFC6536, March 2012,
<https://www.rfc-editor.org/info/rfc6536>.
[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>.
[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>.
7.2. Informative References
[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>.
[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>.
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[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>.
[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-19 (work in
progress), February 2019.
[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-12 (work in progress), February 2019.
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Appendix A. Companion YANG Model for Non-NMDA Compliant Implementations
The YANG module ietf-sr-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-topology-state, is defined as state model, which mirrors the
module ietf-sr-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-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 Topology State Module
<CODE BEGINS> file "ietf-sr-topology-state@2019-03-09.yang"
module ietf-sr-topology-state {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-sr-topology-state";
prefix "srt-s";
import ietf-sr-topology {
prefix "srt";
}
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 {
prefix "sr-cmn";
reference
"I-D.ietf-spring-sr-yang: YANG Data Model for Segment Routing";
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}
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, when NMDA is not supported.
Copyright (c) 2018 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 2019-03-09 {
description "Initial revision";
reference
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"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 srt:sr-topology-type;
}
augment "/nw-s:networks/nw-s:network/"
+ "l3t-s:l3-topology-attributes" {
when "../nw-s:network-types/l3t-s:l3-unicast-topology/"
+ "srt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment topology configuration";
uses srt:sr-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/"
+ "srt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node configuration.";
uses srt: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/"
+ "srt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment node prefix.";
uses srt: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/"
+ "srt-s:sr-mpls" {
description "Augment only for SR topology.";
}
description "Augment link configuration";
uses srt:sr-link-attributes;
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}
grouping sr-topology-attributes {
description "SR topology scope attributes.";
container sr {
description
"Containing SR attributes.";
uses sr-cmn:srgb;
} // sr
} // sr-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-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 | |<---------+
\-/ \-/
| |
+------------+
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.
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{
"ietf-network:networks": {
"network": [
{
"network-types": {
"ietf-l3-unicast-topology:l3-unicast-topology": {
"ietf-sr-topology:sr-mpls": {}
}
},
"network-id": "sr-topo-example",
"ietf-l3-unicast-topology:l3-topology-attributes": {
"ietf-sr-topology:sr": {
"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": {
"router-id": ["203.0.113.1"],
"prefix": [
{
"prefix": "203.0.113.1/32",
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"ietf-sr-topology:sr": {
"start-sid": 101,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-topology:sr": {
"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
}
}
],
"ietf-l3-unicast-topology:l3-node-attributes": {
"router-id": ["203.0.113.2"],
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"prefix": [
{
"prefix": "203.0.113.2/32",
"ietf-sr-topology:sr": {
"start-sid": 102,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-topology:sr": {
"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": {
"router-id": ["203.0.113.3"],
"prefix": [
{
"prefix": "203.0.113.3/32",
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"ietf-sr-topology:sr": {
"start-sid": 101,
"range": 1,
"is-local": false,
"is-node": true
}
}
],
"ietf-sr-topology:sr": {
"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-topology:sr": {
"sid": 121,
"is-local": true
}
}
},
{
"link-id": "D2,2-1-1,D1,1-2-1",
"source": {
"source-node": "D2",
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"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-topology:sr": {
"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-topology:sr": {
"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",
"ietf-sr-topology:sr": {
"sid": 311,
"is-local": true
}
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}
},
{
"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-topology:sr": {
"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-topology:sr": {
"sid": 321,
"is-local": true
}
}
}
]
}
]
}
}
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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
Huawei Technologies
EMail: Igor.Bryskin@huawei.com
Vishnu Pavan Beeram
Juniper Networks
EMail: vbeeram@juniper.net
Tarek Saad
Cisco Systems Inc
EMail: tsaad@cisco.com
Himanshu Shah
Ciena
EMail: hshah@ciena.com
Stephane Litkowski
Orange Business Service
EMail: stephane.litkowski@orange.com
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