Network Working Group X. Liu
Internet-Draft Ericsson
Intended status: Standards Track I. Bryskin
Expires: January 7, 2017 Huawei Technologies
V. Beeram
Juniper Networks
T. Saad
Cisco Systems Inc
H. Shah
Ciena
S. Litkowski
Orange Business Service
July 7, 2016
YANG Data Model for SR and SR TE Topologies
draft-liu-teas-yang-sr-te-topo-00
Abstract
This document defines a YANG data model for Segment Routing (SR)
topology and Segment Routing (SR) traffic engineering (TE) topology.
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Copyright Notice
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Table of Contents
1. Introduction...................................................2
1.1. Terminology...............................................2
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.........................5
2.4. Open Items................................................5
3. Model Structure................................................5
4. YANG Module....................................................8
5. Security Considerations.......................................16
6. References....................................................16
6.1. Normative References.....................................16
6.2. Informative References...................................17
1. Introduction
This document defines a YANG [RFC6020] data model for describing the
presentations of Segment Routing (SR) topology and Segment Routing
(SR) traffic engineering (TE) topology.
1.1. Terminology
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14, [RFC2119].
The following terms are defined in [RFC6020] and are not redefined
here:
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o augment
o data model
o data node
2. Modeling Considerations
2.1. Segment Routing (SR) topology
The Layer 3 network topology model is discussed in [YANG-L3-TOPO].
The Segment Routing (SR) topology model proposed in this document
augments and uses the ietf-l3-unicast-igp-topology module defined in
[YANG-L3-TOPO]. SR related attributes are covered in the ietf-sr-
topology model.
+------------------------------+
| Layer 3 Network Topology |
| ietf-l3-unicast-igp-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
[YANG-NET-TOPO]. For the three types of topologies above, the data
representations are:
L3 Topology:
/nw:networks/nw:network/nw:network-types/l3-unicast-igp-topology
L3 TE Topology:
/nw:networks/nw:network/nw:network-types/l3-unicast-igp-topology/l3-
te
SR Topology:
/nw:networks/nw:network/nw:network-types/l3-unicast-igp-topology/sr
SR TE Topology: (multiple inheritance)
/nw:networks/nw:network/nw:network-types/l3-unicast-igp-topology/l3-
te
/nw:networks/nw:network/nw:network-types/l3-unicast-igp-topology/sr
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2.3. Relations to ietf-segment-routing
[YANG-SR] 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.
2.4. Open Items
a) Coordinating changes to [YANG-SR]: Currently some of the SR
constructs defined in [YANG-SR] cannot be shared as is.
Coordination with the authors of [YANG-SR] is in progress to
define the sharable groupings and types, which will also need to
be not depending on other device models.
b) Protection on link: The feature of link protection will be modeled
in the next revision.
c) Link bundle: The feature of link bundle will be modeled in the
next revision.
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-igp-
topology:
+--rw sr!
augment /nw:networks/nw:network/l3t:igp-topology-attributes:
+--rw sr
+--rw config
+--rw srgb* [lower-bound upper-bound]
+--rw lower-bound uint32
+--rw upper-bound uint32
augment /nw:networks/nw:network/nw:node/l3t:igp-node-attributes:
+--rw sr
+--rw config
| +--rw srgb* [lower-bound upper-bound]
| | +--rw lower-bound uint32
| | +--rw upper-bound uint32
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| +--rw capabilities
| +--rw transport-planes* [transport-plane]
| | +--rw transport-plane identityref
| +--rw segment-stack-push-limit? uint8
| +--rw readable-label-stack-depth? uint8
+--ro state
+--ro information-source? enumeration
+--ro information-source-state
| +--ro credibility-preference? uint16
+--ro capabilities
+--ro transport-planes* [transport-plane]
| +--ro transport-plane identityref
+--ro segment-stack-push-limit? uint8
+--ro readable-label-stack-depth? uint8
augment /nw:networks/nw:network/nw:node/l3t:igp-node-
attributes/l3t:prefix:
+--rw sr!
+--rw value-type? enumeration
+--rw start-sid uint32
+--rw range? uint32
+--rw last-hop-behavior? enumeration {sid-last-hop-behavior}?
+--rw is-local? boolean
+--rw algorithm? sr-algorithm
augment /nw:networks/nw:network/nw:node/nt:termination-point/l3t:igp-
termination-point-attributes:
augment /nw:networks/nw:network/nt:link/l3t:igp-link-attributes:
+--rw sr
+--rw config
| +--rw sid? uint32
| +--rw value-type? enumeration
| +--rw is-local? boolean
| +--ro is-part-of-set? boolean
| +--ro is-on-lan? boolean
+--ro state
+--ro information-source? enumeration
+--ro information-source-state
+--ro credibility-preference? uint16
SR topology module is an augmentation to L3 IGP unicast topology
module. When these two modules are put together, the following trees
provider better high level pictures:
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modules: ietf-l3-unicast-igp-topology, ietf-sr-topology:
augment /nw:networks/nw:network:
+--rw igp-topology-attributes
+--rw name? string
+--rw flag* flag-type
+--rw srt:sr
+--rw srt:config
+--rw srt:srgb* [lower-bound upper-bound]
+--rw srt:lower-bound uint32
+--rw srt:upper-bound uint32
augment /nw:networks/nw:network/nw:node:
+--rw igp-node-attributes
+--rw name? inet:domain-name
+--rw flag* flag-type
+--rw router-id* inet:ip-address
+--rw prefix* [prefix]
| +--rw prefix inet:ip-prefix
| +--rw metric? uint32
| +--rw flag* flag-type
| +--rw srt:sr!
| +--rw srt:value-type? enumeration
| +--rw srt:start-sid uint32
| +--rw srt:range? uint32
| +--rw srt:last-hop-behavior? enumeration {sid-last-hop-
behavior}?
| +--rw srt:is-local? boolean
| +--rw srt:algorithm? sr-algorithm
+--rw srt:sr
+--rw srt:config
| +--rw srt:srgb* [lower-bound upper-bound]
| | +--rw srt:lower-bound uint32
| | +--rw srt:upper-bound uint32
| +--rw srt:capabilities
| +--rw srt:transport-planes* [transport-plane]
| | +--rw srt:transport-plane identityref
| +--rw srt:segment-stack-push-limit? uint8
| +--rw srt:readable-label-stack-depth? uint8
+--ro srt:state
+--ro srt:information-source? enumeration
+--ro srt:information-source-state
| +--ro srt:credibility-preference? uint16
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+--ro srt:capabilities
+--ro srt:transport-planes* [transport-plane]
| +--ro srt:transport-plane identityref
+--ro srt:segment-stack-push-limit? uint8
+--ro srt:readable-label-stack-depth? uint8
augment /nw:networks/nw:network/nt:link:
+--rw igp-link-attributes
+--rw name? string
+--rw flag* flag-type
+--rw metric? uint32
+--rw srt:sr
+--rw srt:config
| +--rw srt:sid? uint32
| +--rw srt:value-type? enumeration
| +--rw srt:is-local? boolean
| +--ro srt:is-part-of-set? boolean
| +--ro srt:is-on-lan? boolean
+--ro srt:state
+--ro srt:information-source? enumeration
+--ro srt:information-source-state
+--ro srt:credibility-preference? uint16
augment /nw:networks/nw:network/nw:node/nt:termination-point:
+--rw igp-termination-point-attributes
+--rw (termination-point-type)?
+--:(ip)
| +--rw ip-address* inet:ip-address
+--:(unnumbered)
+--rw unnumbered-id? uint32
4. YANG Module
<CODE BEGINS> file "ietf-sr-topology@2016-06-24.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";
}
import ietf-network-topology {
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prefix "nt";
}
import ietf-l3-unicast-igp-topology {
prefix "l3t";
}
import ietf-segment-routing {
prefix "sr";
}
organization "TBD";
contact "TBD";
description "L3 TE Topology model";
revision "2016-06-24" {
description "Initial revision";
reference "TBD";
}
typedef sr-algorithm {
type enumeration {
enum "spf" {
description "Shortest Path First.";
}
enum "strict-spf" {
description "Strict Shortest Path First.";
}
}
description
"Algorithm to be used for the prefix SID.";
}
grouping sr-topology-type {
description
"Identifies the SR topology type.";
container sr {
presence "Indiates SR Topology";
description
"Its presence identifies the SR topology type.";
}
}
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augment "/nw:networks/nw:network/nw:network-types/"
+ "l3t:l3-unicast-igp-topology" {
description
"Defines the SR topology type.";
uses sr-topology-type;
}
augment "/nw:networks/nw:network/l3t:igp-topology-attributes" {
when "../nw:network-types/l3t:l3-unicast-igp-topology/sr" {
description "Augment only for SR topology.";
}
description "Augment topology configuration";
uses sr-topology-attributes;
}
augment "/nw:networks/nw:network/nw:node/l3t:igp-node-attributes" {
when "../../nw:network-types/l3t:l3-unicast-igp-topology/sr" {
description "Augment only for SR topology.";
}
description "Augment node configuration.";
uses sr-node-attributes;
}
augment "/nw:networks/nw:network/nw:node/l3t:igp-node-attributes"
+ "/l3t:prefix" {
when "../../../nw:network-types/l3t:l3-unicast-igp-topology/sr" {
description "Augment only for SR topology.";
}
description "Augment node prefix.";
uses sr-node-prefix-attributes;
}
augment "/nw:networks/nw:network/nw:node/nt:termination-point/"
+ "l3t:igp-termination-point-attributes" {
when "../../../nw:network-types/l3t:l3-unicast-igp-topology/"
+ "sr" {
description "Augment only for SR topology.";
}
description "Augment termination point configuration";
uses sr-tp-attributes;
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}
augment "/nw:networks/nw:network/nt:link/l3t:igp-link-attributes" {
when "../../nw:network-types/l3t:l3-unicast-igp-topology/sr" {
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.";
container config {
description
"Configuraiton attributes.";
uses sr:srgb-cfg;
}
} // sr
} // sr-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.";
}
enum "ospfv3" {
description "OSPFv3.";
}
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enum "isis" {
description "ISIS.";
}
enum "system-processed" {
description "System processed entity.";
}
enum "other" {
description "Other source.";
}
}
description
"Indicates the source of the information.";
}
container information-source-state {
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 {
description
"Containing SR attributes.";
container config {
description
"Configuraiton attributes.";
uses sr:srgb-cfg;
uses sr-node-capabilities;
} // config
container state {
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config false;
description
"Operational state data.";
uses information-source-attributes;
uses sr-node-capabilities;
}
} // sr
} // sr-node-attributes
grouping sr-node-capabilities {
description "Containing SR node capabilities.";
container capabilities {
list transport-planes {
key transport-plane;
leaf transport-plane {
type identityref {
base sr:segment-routing-transport;
}
description
"Transport plane supported";
}
description
"List of supported transport planes.";
}
leaf segment-stack-push-limit {
type uint8;
description
"Describes the number of segments
that can be pushed by the node.";
}
leaf readable-label-stack-depth {
type uint8;
description
"Number of MPLS labels that
can be read in the stack.";
}
description
"Shows the SR capability of the node.";
} // capabilities
} // sr-node-capabilitie
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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:sid-value-type;
leaf start-sid {
type uint32;
mandatory true;
description
"Value associated with
prefix. The value must
be interpreted in the
context of value-type.";
}
leaf range {
type uint32;
description
"Describes how many SIDs could be
allocated.";
}
uses sr:last-hop-behavior;
leaf is-local {
type boolean;
description
"'true' if the SID is local.";
}
leaf algorithm {
type sr-algorithm;
description
"Algorithm used.";
}
} // sr
} // sr-node-prefix-attributes
grouping sr-tp-attributes {
description "SR termination point scope attributes";
} // sr-tp-attributes
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grouping sr-link-attributes {
description "SR link scope attributes";
container sr {
description
"Containing SR attributes.";
container config {
description
"Configuraiton attributes.";
leaf sid {
type uint32;
description
"SID.";
}
uses sr:sid-value-type;
leaf is-local {
type boolean;
description
"'true' if the SID is local.";
}
leaf is-part-of-set {
type boolean;
config false;
description
"'true' if the SID is part of a set.";
}
leaf is-on-lan {
type boolean;
config false;
description
"'true' if on a lan.";
}
}
container state {
config false;
description
"Operational state data.";
uses information-source-attributes;
}
} // sr
} // sr-link-attributes
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}
<CODE ENDS>
5. Security Considerations
The configuration, state, action and notification data defined in
this document are designed to be accessed via the NETCONF protocol
[RFC6241]. The data-model by itself does not create any security
implications. The security considerations for the NETCONF protocol
are applicable. The NETCONF protocol used for sending the data
supports authentication and encryption.
6. References
6.1. Normative References
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman,
"Network Configuration Protocol (NETCONF)", RFC 6241, June
2011.
[RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
Syntax Specifications: ABNF", RFC 2234, Internet Mail
Consortium and Demon Internet Ltd., November 1997.
[YANG-NET-TOPO]Clemm, A., "A Data Model for Network Topologies",
draft-ietf-i2rs-yang-network-topo (Work in Progress).
[YANG-L3-TOPO] Clemm, A., et al., "A YANG Data Model for Layer 3
Topologies", draft-ietf-i2rs-yang-l3-topology, (Work in
Progress).
[YANG-TE-TOPO] Liu, X., et al., "YANG Data Model for TE Topologies",
draft-ietf-teas-yang-te-topo, Work in Progress).
[YANG-SR] Litkowski, S., et al., "YANG Data Model for Segment
Routing", draft-ietf-spring-sr-yang, Work in Progress).
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6.2. Informative References
[RFC6087] Bierman, A., "Guidelines for Authors and Reviewers of YANG
Data Model Documents", RFC 6087, January 2011.
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Authors' Addresses
Xufeng Liu
Ericsson / Kuatro Technologies Inc.
8281 Greensboro Drive, Suite 200
McLean, VA 22102
USA
Email: xliu@kuatrotech.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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