NETMOD L. Lhotka
Internet-Draft CZ.NIC
Intended status: Standards Track July 9, 2012
Expires: January 10, 2013
A YANG Data Model for Routing Configuration
draft-ietf-netmod-routing-cfg-04
Abstract
This document contains a specification of three YANG modules.
Together they form the core routing data model which serves as a
framework for configuring a routing subsystem. It is therefore
expected that these modules will be augmented by additional YANG
modules defining data models for individual routing protocols and
other related functions. The core routing data model provides common
building blocks for such configurations - router instances, routes,
routing tables, routing protocols and route filters.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 10, 2013.
Copyright Notice
Copyright (c) 2012 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
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Notation . . . . . . . . . . . . . . . . . . . 4
2.1. Glossary of New Terms . . . . . . . . . . . . . . . . . . 4
2.2. Prefixes in Data Node Names . . . . . . . . . . . . . . . 5
3. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. The Design of the Core Routing Data Model . . . . . . . . . . 7
4.1. Router . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1.1. Configuration of IPv6 Router Interfaces . . . . . . . 10
4.2. Route . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Routing Tables . . . . . . . . . . . . . . . . . . . . . . 12
4.4. Routing Protocols . . . . . . . . . . . . . . . . . . . . 13
4.4.1. Routing Pseudo-Protocols . . . . . . . . . . . . . . . 14
4.4.2. Defining New Routing Protocols . . . . . . . . . . . . 14
4.5. Route Filters . . . . . . . . . . . . . . . . . . . . . . 17
4.6. RPC Operations . . . . . . . . . . . . . . . . . . . . . . 18
4.6.1. Operation "active-route" . . . . . . . . . . . . . . . 18
4.6.2. Operation "route-count" . . . . . . . . . . . . . . . 19
5. Interactions with Other YANG Modules . . . . . . . . . . . . . 20
5.1. Module "ietf-interfaces" . . . . . . . . . . . . . . . . . 20
5.2. Module "ietf-ip" . . . . . . . . . . . . . . . . . . . . . 20
6. Routing YANG Module . . . . . . . . . . . . . . . . . . . . . 22
7. IPv4 Unicast Routing YANG Module . . . . . . . . . . . . . . . 34
8. IPv6 Unicast Routing YANG Module . . . . . . . . . . . . . . . 38
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 47
10. Security Considerations . . . . . . . . . . . . . . . . . . . 49
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 50
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 51
12.1. Normative References . . . . . . . . . . . . . . . . . . . 51
12.2. Informative References . . . . . . . . . . . . . . . . . . 51
Appendix A. Example: Adding a New Routing Protocol . . . . . . . 52
Appendix B. Example: Reply to the NETCONF <get> Message . . . . . 55
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 60
C.1. Changes Between Versions -03 and -04 . . . . . . . . . . . 60
C.2. Changes Between Versions -02 and -03 . . . . . . . . . . . 60
C.3. Changes Between Versions -01 and -02 . . . . . . . . . . . 61
C.4. Changes Between Versions -00 and -01 . . . . . . . . . . . 61
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 62
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1. Introduction
This document contains a specification of the following YANG modules:
o Module "ietf-routing" provides generic components of a routing
data model.
o Module "ietf-ipv4-unicast-routing" augments the "ietf-routing"
module with additional data specific to IPv4 unicast.
o Module "ietf-ipv6-unicast-routing" augments the "ietf-routing"
module with additional data specific to IPv6 unicast, including
the router configuration variables required by [RFC4861].
These modules together define the so-called core routing data model,
which is proposed as a basis for the development of data models for
more sophisticated routing configurations. While these three modules
can be directly used for simple IP devices with static routing, their
main purpose is to provide essential building blocks for more
complicated setups involving multiple routing protocols, multicast
routing, additional address families, and advanced functions such as
route filtering or policy routing. To this end, it is expected that
the core routing data model will be augmented by numerous modules
developed by other IETF working groups.
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2. Terminology and Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The following terms are defined in [RFC6241]:
o client
o message
o protocol operation
o server
The following terms are defined in [RFC6020]:
o augment
o configuration data
o container
o data model
o data node
o data type
o identity
o mandatory node
o module
o operational state data
o prefix
o RPC operation
2.1. Glossary of New Terms
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active route: a route which is actually used for sending packets.
If there are multiple candidate routes with a matching destination
prefix, then it is up to the routing algorithm to select the
active route (or several active routes in the case of multi-path
routing).
core routing data model: YANG data model resulting from the
combination of "ietf-routing", "ietf-ipv4-unicast-routing" and
"ietf-ipv6-unicast-routing" modules.
direct route: a route to a directly connected network.
2.2. Prefixes in Data Node Names
In this document, names of data nodes, RPC methods and other data
model objects are used mostly 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 |
+--------+---------------------------+--------------+
| ianaaf | iana-afn-safi | [IANA-IF-AF] |
| | | |
| if | ietf-interfaces | [YANG-IF] |
| | | |
| ip | ietf-ip | [YANG-IP] |
| | | |
| rip | example-rip | Appendix A |
| | | |
| rt | ietf-routing | Section 6 |
| | | |
| v4ur | ietf-ipv4-unicast-routing | Section 7 |
| | | |
| v6ur | ietf-ipv6-unicast-routing | Section 8 |
| | | |
| yang | ietf-yang-types | [RFC6021] |
| | | |
| inet | ietf-inet-types | [RFC6021] |
+--------+---------------------------+--------------+
Table 1: Prefixes and corresponding YANG modules
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3. Objectives
The initial design of the core routing data model was driven by the
following objectives:
o The data model should be suitable for the common address families,
in particular IPv4 and IPv6, and for unicast and multicast
routing, as well as Multiprotocol Label Switching (MPLS).
o Simple routing setups, such as static routing, should be
configurable in a simple way, ideally without any need to develop
additional YANG modules.
o On the other hand, the core routing framework must allow for
complicated setups involving multiple routing tables and multiple
routing protocols, as well as controlled redistributions of
routing information.
o Device vendors will want to map the data models built on this
generic framework to their proprietary data models and
configuration interfaces. Therefore, the framework should be
flexible enough to facilitate such a mapping and accommodate data
models with different logic.
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4. The Design of the Core Routing Data Model
The core routing data model consists of three YANG modules. The
first module, "ietf-routing", defines the generic components of a
routing system. The other two modules, "ietf-ipv4-unicast-routing"
and "ietf-ipv6-unicast-routing", augment the "ietf-routing" module
with additional data nodes that are needed for IPv4 and IPv6 unicast
routing, respectively. The combined data hierarchy is shown in
Figure 1, where brackets enclose list keys, "rw" means configuration,
"ro" operational state data, and "?" means optional node.
Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
+--rw routing
+--rw router [name]
| +--rw name
| +--rw router-id?
| +--rw description?
| +--rw enabled?
| +--rw interfaces
| | +--rw interface [name]
| | +--rw name
| | +--rw v6ur:ipv6-router-advertisements
| | +--rw v6ur:send-advertisements?
| | +--rw v6ur:max-rtr-adv-interval?
| | +--rw v6ur:min-rtr-adv-interval?
| | +--rw v6ur:managed-flag?
| | +--rw v6ur:other-config-flag?
| | +--rw v6ur:link-mtu?
| | +--rw v6ur:reachable-time?
| | +--rw v6ur:retrans-timer?
| | +--rw v6ur:cur-hop-limit?
| | +--rw v6ur:default-lifetime?
| | +--rw v6ur:prefix-list
| | +--rw v6ur:prefix [prefix-spec]
| | +--rw v6ur:prefix-spec
| | +--rw (control-adv-prefixes)?
| | +--:(no-advertise)
| | | +--rw v6ur:no-advertise?
| | +--:(advertise)
| | +--rw v6ur:valid-lifetime?
| | +--rw v6ur:on-link-flag?
| | +--rw v6ur:preferred-lifetime?
| | +--rw v6ur:autonomous-flag?
| +--rw routing-protocols
| | +--rw routing-protocol [name]
| | +--rw name
| | +--rw description?
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| | +--rw type
| | +--rw connected-routing-tables
| | | +--rw routing-table [name]
| | | +--rw name
| | | +--rw import-filter?
| | | +--rw export-filter?
| | +--rw static-routes
| | +--rw v4ur:ipv4
| | | +--rw v4ur:route [id]
| | | +--rw v4ur:id
| | | +--rw v4ur:description?
| | | +--rw v4ur:outgoing-interface?
| | | +--rw v4ur:dest-prefix
| | | +--rw v4ur:next-hop?
| | +--rw v6ur:ipv6
| | +--rw v6ur:route [id]
| | +--rw v6ur:id
| | +--rw v6ur:description?
| | +--rw v6ur:outgoing-interface?
| | +--rw v6ur:dest-prefix
| | +--rw v6ur:next-hop?
| +--rw routing-tables
| +--rw routing-table [name]
| +--rw name
| +--rw address-family?
| +--rw safi?
| +--rw description?
| +--ro routes
| | +--ro route
| | +--ro outgoing-interface?
| | +--ro source-protocol
| | +--ro age
| | +--ro v4ur:dest-prefix?
| | +--ro v4ur:next-hop?
| | +--ro v6ur:dest-prefix?
| | +--ro v6ur:next-hop?
| +--rw recipient-routing-tables
| +--rw recipient-routing-table [name]
| +--rw name
| +--rw filter?
+--rw route-filters
+--rw route-filter [name]
+--rw name
+--rw description?
+--rw type?
Figure 1: Data hierarchy of the core routing data model.
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As can be seen from Figure 1, the core routing data model introduces
several generic components of a routing framework: routers, routing
tables containing routes, routing protocols and route filters. The
following subsections describe these components in more detail.
By combining the components in various ways, and possibly augmenting
them with appropriate contents defined in other modules, various
routing setups can be realized.
+--------+
| direct | +---+ +--------------+ +---+ +--------------+
| routes |--->| F |--->| |<---| F |<---| |
+--------+ +---+ | main | +---+ | additional |
| routing | | routing |
+--------+ +---+ | table | +---+ | table |
| static |--->| F |--->| |--->| F |--->| |
| routes | +---+ +--------------+ +---+ +--------------+
+--------+ ^ | ^ |
| v | v
+---+ +---+ +---+ +---+
| F | | F | | F | | F |
+---+ +---+ +---+ +---+
^ | ^ |
| v | v
+----------+ +----------+
| routing | | routing |
| protocol | | protocol |
+----------+ +----------+
Figure 2: Example setup of the routing subsystem
The example in Figure 2 shows a typical (though certainly not the
only possible) organization of a more complex routing subsystem for a
single address family. Several of its features are worth mentioning:
o Along with the main routing table, which must always be present,
an additional routing table is configured.
o Each routing protocol instance, including the "static" and
"direct" pseudo-protocols, is connected to one routing table with
which it can exchange routes (in both directions, except for the
"static" and "direct" pseudo-protocols).
o Routing tables may also be connected to each other and exchange
routes in either direction (or both).
o Route exchanges along all connections may be controlled by means
of route filters, denoted by "F" in Figure 2.
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4.1. Router
Each router instance in the core routing data model represents a
logical router. The exact semantics of this term is left to
implementations. For example, router instances may be completely
isolated virtual routers or, alternatively, they may internally share
certain information.
Each network layer interface must be assigned to one or more router
instances in order to be able to participate in packet forwarding,
routing protocols and other operations of those router instances.
The assignment is accomplished by creating a corresponding entry in
the list of router interfaces ("rt:interface"). The key of the list
entry MUST be the name of a configured network layer interface, i.e.,
the value of a node /if:interfaces/if:interface/if:name defined in
the "ietf-interfaces" module [YANG-IF].
Implementations MAY specify additional rules for the assignment of
interfaces to logical routers. For example, it may be required that
the sets of interfaces assigned to different logical routers be
disjoint.
Apart from the key, each entry of the "rt:interface" list MAY contain
other configuration or operational state data related to the
corresponding router interface.
4.1.1. Configuration of IPv6 Router Interfaces
The module "ietf-ipv6-unicast-routing" augments the definition of the
data node "rt:interface" with definitions of the following
configuration variables as required by [RFC4861], sec. 6.2.1:
o send-advertisements,
o max-rtr-adv-interval,
o min-rtr-adv-interval,
o managed-flag,
o other-config-flag,
o link-mtu,
o reachable-time,
o retrans-timer,
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o cur-hop-limit,
o default-lifetime,
o prefix-list: a list of prefixes to be advertised. The following
parameters are associated with each prefix in the list:
* valid-lifetime,
* on-link-flag,
* preferred-lifetime,
* autonomous-flag.
The definitions and descriptions of the above parameters can be found
in the text of the module "ietf-ipv6-unicast-routing" (Section 8).
NOTES:
1. The "IsRouter" flag, which is also required by [RFC4861], is
implemented in the "ietf-ip" module [YANG-IP] (leaf "ip:ip-
forwarding").
2. The original specification [RFC4861] allows the implementations
to decide whether the "valid-lifetime" and "preferred-lifetime"
parameters remain the same in consecutive advertisements, or
decrement in real time. However, the latter behavior seems
problematic because the values might be reset again to the
(higher) configured values after a configuration is reloaded.
Moreover, no implementation is known to use the decrementing
behavior. The "ietf-ipv6-unicast-routing" module therefore
assumes the former behavior with constant values.
4.2. Route
Routes are basic units of information in a routing system. The core
routing data model defines only the following minimal set of route
attributes:
o "destination-prefix": IP prefix specifying the set of destination
addresses for which the route may be used. This attribute is
mandatory.
o "next-hop": IP address of an adjacent router or host to which
packets with destination addresses belonging to "destination-
prefix" should be sent.
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o "outgoing-interface": network interface that should be used for
sending packets with destination addresses belonging to
"destination-prefix".
The above list of route attributes suffices for a simple static
routing configuration. It is expected that future modules defining
routing protocols will add other route attributes such as metrics or
preferences.
Routes and their attributes are used both in configuration data, for
example as manually configured static routes, and in operational
state data, for example as entries in routing tables.
4.3. Routing Tables
Routing tables are lists of routes complemented with administrative
data, namely:
o "source-protocol": name of the routing protocol from which the
route was originally obtained.
o "age": number of seconds since the route was created or last
updated.
Each routing table may contain only routes of the same address
family. Address family information consists of two parameters -
"address-family" and "safi" (Subsequent Address Family Identifier,
SAFI). The permitted values for these two parameters are defined by
IANA and represented using YANG enumeration types "ianaaf:address-
family" and "ianaaf:subsequent-address-family" [IANA-IF-AF].
In the core routing data model, the "routing-table" node represents
configuration while the descendant list of routes is defined as
operational state data. The contents of route lists are controlled
and manipulated by routing protocol operations which may result in
route additions, removals and modifications. This also includes
manipulations via the "static" and/or "direct" pseudo-protocols, see
Section 4.4.1.
One routing table MUST be present for each router instance and each
address family supported by that router instance. It is the so-
called main routing table to which all routing protocol instances
supporting the given address family SHOULD be connected by default.
For the two address families that are part of the core routing data
model, the names of the main routing tables SHOULD be as follows:
o "main-ipv4-unicast" for IPv4 unicast,
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o "main-ipv6-unicast" for IPv6 unicast.
Additional routing tables MAY be configured by creating new entries
in the "routing-table" list, either as a part of factory-default
configuration, or by a client's action.
The naming scheme for additional routing tables, as well as
restrictions on the number and configurability of routing tables are
implementation-specific.
The way how the routing system uses information from routing tables
is outside the scope of this document. Typically, implementations
will either use a forwarding table, or perform a direct look-up in
the main routing table in conjunction with a route cache.
Every routing table can serve as a source of routes for other routing
tables. To achieve this, one or more recipient routing tables may be
specified in the configuration of the source routing table. In
addition, a route filter may be configured for each recipient routing
table, which selects and/or manipulates the routes that are passed on
between the source and recipient routing table.
4.4. Routing Protocols
The core routing data model provides an open-ended framework for
defining multiple routing protocol instances. Each of them is
identified by a name, which MUST be unique within a router instance.
Each protocol MUST be assigned a type, which MUST be an identity
derived from the "rt:routing-protocol" base identity. The core
routing data model defines two identities for the direct and static
pseudo-protocols (Section 4.4.1).
Each routing protocol instance is connected to exactly one routing
table for each address family that the routing protocol instance
supports. By default, every routing protocol instance SHOULD be
connected to the main routing table or tables. An implementation MAY
allow any or all routing protocol instances to be configured to use a
different routing table.
Routes learned from the network by a routing protocol are passed to
the connected routing table(s) and vice versa - routes appearing in a
routing table are passed to all routing protocols connected to the
table (except "direct" and "static" pseudo-protocols) and may be
advertised by that protocol to the network.
Two independent route filters (see Section 4.5) may be defined for a
routing protocol instance to control the exchange of routes in both
directions between the routing protocol instance and the connected
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routing table:
o import filter controls which routes are passed from a routing
protocol instance to the routing table,
o export filter controls which routes the routing protocol instance
may receive from the connected routing table.
Note that, for historical reasons, the terms import and export are
used from the viewpoint of a routing table.
4.4.1. Routing Pseudo-Protocols
The core routing data model defines two special routing protocol
types - "direct" and "static". Both are in fact pseudo-protocols,
which means that they are confined to the local device and do not
exchange any routing information with neighboring routers. Routes
from both "direct" and "static" protocol instances are passed to the
connected routing table (subject to route filters, if any), but an
exchange in the opposite direction is not allowed.
Every router instance MUST contain exactly one instance of the
"direct" pseudo-protocol type. The name of this instance MUST also
be "direct". It is the source of direct routes for all configured
address families. Direct routes are normally supplied by the
operating system kernel, based on the configuration of network
interface addresses, see Section 5.2. Direct routes SHOULD by
default appear in the main routing table for each configured address
family. However, using the framework defined in this document, the
target routing table for direct routes MAY be changed by connecting
the "direct" protocol instance to a non-default routing table.
Direct routes can also be filtered before they appear in the routing
table.
A pseudo-protocol of the type "static" allows for specifying routes
manually. It MAY be configured in zero or multiple instances,
although a typical implementation will have exactly one instance per
logical router.
4.4.2. Defining New Routing Protocols
It is expected that future YANG modules will create data models for
additional routing protocol types. Such a new module has to define
the protocol-specific configuration and operational state data, and
it has to fit it into the core routing framework in the following
way:
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o A new identity MUST be defined for the routing protocol and its
base identity MUST be set to "rt:routing-protocol", or to an
identity derived from "rt:routing-protocol".
o Additional route attributes MAY be defined, preferably in one
place by means of defining a YANG grouping. The new attributes
have to be inserted as operational state data by augmenting the
definition of "rt:route" inside "rt:routing-table", and possibly
to other places in the configuration, operational state data and
RPC input or output.
o Per-interface configuration parameters can be added by augmenting
the data node "rt:interface" (the list of router interfaces).
o Other configuration parameters and operational state data can be
defined by augmenting the "routing-protocol" data node. By using
the "when" statement, this augment SHOULD be made conditional and
valid only if the value of the "rt:type" child leaf equals to the
new protocol's identity.
It is RECOMMENDED that both per-interface and other configuration
data specific to the new protocol be encapsulated in an appropriately
named container.
The above steps are implemented by the example YANG module for the
RIP routing protocol in Appendix A. First, the module defines a new
identity for the RIP protocol:
identity rip {
base rt:routing-protocol;
description "Identity for the RIP routing protocol.";
}
New route attributes specific to the RIP protocol ("metric" and
"tag") are defined in a grouping and then added to the route
definitions appearing in "routing-table" and in the output part of
the "active-route" RPC method:
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grouping route-content {
description
"RIP-specific route content.";
leaf metric {
type rip-metric;
}
leaf tag {
type uint16;
default "0";
description
"This leaf may be used to carry additional info, e.g. AS
number.";
}
}
augment "/rt:routing/rt:router/rt:routing-tables/rt:routing-table/"
+ "rt:routes/rt:route" {
when "../../../../rt:routing-protocols/"
+ "rt:routing-protocol[rt:name=current()/rt:source-protocol]/"
+ "rt:type='rip:rip'" {
description
"This augment is only valid if the source protocol from which
the route originated is RIP.";
}
description
"RIP-specific route components.";
uses route-content;
}
augment "/rt:active-route/rt:output/rt:route" {
description
"Add RIP-specific route content.";
uses route-content;
}
Per-interface configuration data are defined by the following
"augment" statement:
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augment "/rt:routing/rt:router/rt:interfaces/rt:interface" {
when "../../rt:routing-protocols/rt:routing-protocol/rt:type = "
+ "'rip:rip'";
container rip {
description
"Per-interface RIP configuration.";
leaf enabled {
type boolean;
default "true";
}
leaf metric {
type rip-metric;
default "1";
}
}
}
Finally, global RIP configuration data are integrated into the "rt:
routing-protocol" node by using the following "augment" statement,
which is again valid only for routing protocol instances whose type
is "rip:rip":
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol" {
when "rt:type = 'rip:rip'";
container rip {
leaf update-interval {
type uint8 {
range "10..60";
}
units "seconds";
default "30";
description
"Time interval between periodic updates.";
}
}
}
4.5. Route Filters
The core routing data model provides a skeleton for defining route
filters that can be used to restrict the set of routes being
exchanged between a routing protocol instance and a connected routing
table, or between a source and a recipient routing table. Route
filters may also manipulate routes, i.e., add, delete, or modify
their attributes.
Route filters are global, which means that a configured route filter
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may be used by any or all router instances.
By itself, the route filtering framework defined in this document
allows for applying only the extreme routing policies which are
represented by the following pre-defined route filter types:
o "deny-all-route-filter": all routes are blocked,
o "allow-all-route-filter": all routes are permitted.
Note that the latter type is equivalent to no route filter.
It is expected that more comprehensive route filtering frameworks
will be developed separately.
Each route filter is identified by a name which MUST be unique within
the entire configuration. Its type MUST be specified by the "type"
identity reference - this opens the space for multiple route
filtering framework implementations. The default value for the route
filter type is the identity "deny-all-route-filter".
4.6. RPC Operations
The "ietf-routing" module defines two RPC operations:
o active-route,
o route-count.
Their parameters and semantics are described in the following
subsections.
4.6.1. Operation "active-route"
Description: Retrieve one or more active routes from the forwarding
information base (FIB) of a router instance, i.e., the route(s)
that are currently used by that router instance for sending
datagrams to the destination whose address is provided as an input
parameter.
Parameters:
router-name: Name of the router instance whose FIB is to be
queried.
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destination-address: Network layer destination address for which
the active routes are requested.
Positive Response: One or more "route" elements containing the
active route(s).
Negative Response:
If the logical router is not found, the server sends an "rpc-
error" message with "error-tag" set to "data-missing", and "error-
app-tag" set to "router-not-found".
If no route exists for the given destination address, the server
sends an "rpc-error" message with "error-tag" set to "data-
missing" and "error-app-tag" set to "no-route".
4.6.2. Operation "route-count"
Description: Retrieve the total number of routes in a routing table.
Parameters:
router-name: Name of the logical router containing the routing
table.
routing-table: Name of the routing table.
Positive Response: Element "number-of-routes" containing the
requested nonnegative number.
Negative Response: If the logical router or the routing table is not
found, the server sends an "rpc-error" message with "error-tag"
set to "data-missing", and "error-app-tag" set to "router-not-
found" or "routing-table-not-found", respectively.
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5. Interactions with Other YANG Modules
The semantics of the core routing data model also depend on several
configuration parameters that are defined in other YANG modules. The
following subsections describe these interactions.
5.1. Module "ietf-interfaces"
The following boolean switch is defined in the "ietf-interfaces" YANG
module [YANG-IF]:
/if:interfaces/if:interface/if:enabled
If this switch is set to "false" for a given network layer
interface, the device MUST behave exactly as if that interface was
not assigned to any logical router at all.
5.2. Module "ietf-ip"
The following boolean switches are defined in the "ietf-ip" YANG
module [YANG-IP]:
/if:interfaces/if:interface/ip:ipv4/ip:enabled
If this switch is set to "false" for a given interface, then all
IPv4 routing functions related to that interface MUST be disabled.
/if:interfaces/if:interface/ip:ipv4/ip:ip-forwarding
If this switch is set to "false" for a given interface, then the
forwarding of IPv4 datagrams to and from this interface MUST be
disabled. However, the interface may participate in other routing
functions, such as routing protocols.
/if:interfaces/if:interface/ip:ipv6/ip:enabled
If this switch is set to "false" for a given interface, then all
IPv6 routing functions related to that interface MUST be disabled.
/if:interfaces/if:interface/ip:ipv6/ip:ip-forwarding
If this switch is set to "false" for a given interface, then the
forwarding of IPv6 datagrams to and from this interface MUST be
disabled. However, the interface may participate in other routing
functions, such as routing protocols.
In addition, the "ietf-ip" module allows for configuring IPv4 and
IPv6 addresses and subnet masks. Configuration of these parameters
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on an enabled interface MUST result in an immediate creation of the
corresponding direct route (usually in the main routing table). Its
destination prefix is set according to the configured IP address and
subnet mask, and the interface is set as the outgoing interface for
that route.
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6. Routing YANG Module
RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
actual RFC number and all occurrences of the revision date below with
the date of RFC publication (and remove this note).
<CODE BEGINS> file "ietf-routing@2012-07-09.yang"
module ietf-routing {
namespace "urn:ietf:params:xml:ns:yang:ietf-routing";
prefix "rt";
import ietf-inet-types {
prefix "inet";
}
import ietf-interfaces {
prefix "if";
}
import iana-afn-safi {
prefix "ianaaf";
}
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
WG Chair: David Kessens
<mailto:david.kessens@nsn.com>
WG Chair: Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>
Editor: Ladislav Lhotka
<mailto:lhotka@nic.cz>
";
description
"This YANG module defines essential components that may be used
for configuring a routing subsystem.
Copyright (c) 2012 IETF Trust and the persons identified as
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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 2012-07-09 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Routing Configuration";
}
/* Identities */
identity routing-protocol {
description
"Base identity from which routing protocol identities are
derived.";
}
identity direct {
base routing-protocol;
description
"Routing pseudo-protocol which provides routes to directly
connected networks.";
}
identity static {
base routing-protocol;
description
"Static routing pseudo-protocol.";
}
identity route-filter {
description
"Base identity from which all route filters are derived.";
}
identity deny-all-route-filter {
base route-filter;
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description
"Route filter that blocks all routes.";
}
identity allow-all-route-filter {
base route-filter;
description
"Route filter that permits all routes.
";
}
/* Type Definitions */
typedef router-ref {
type leafref {
path "/rt:routing/rt:router/rt:name";
}
description
"This type is used for leafs that reference a router
instance.";
}
/* Groupings */
grouping afn-safi {
leaf address-family {
type ianaaf:address-family;
default "ipv4";
description
"Address family of routes in the routing table.";
}
leaf safi {
type ianaaf:subsequent-address-family;
default "nlri-unicast";
description
"Subsequent address family identifier of routes in the
routing table.";
}
description
"This grouping provides two parameters specifying address
family and subsequent address family.";
}
grouping route-content {
description
"Generic parameters of routes.
A module for an address family should define a specific
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version of this grouping containing 'uses rt:route-content'.
";
leaf outgoing-interface {
type if:interface-ref;
description
"Outgoing interface.";
}
}
/* RPC Methods */
rpc active-route {
description
"Return the active route (or multiple routes, in the case of
multi-path routing) to a destination address.
Parameters
1. 'router-name',
2. 'destination-address'.
If the logical router with 'router-name' doesn't exist, then
this operation will fail with error-tag 'missing-element' and
error-app-tag 'router-not-found'.
If there is no active route for 'destination-address', then
this operation will fail with error-tag 'data-missing' and
error-app-tag 'no-route'.
";
input {
leaf router-name {
type router-ref;
mandatory "true";
description
"Name of the router instance whose forwarding information
base is being queried.";
}
container destination-address {
uses afn-safi;
description
"Network layer destination address.
AFN/SAFI-specific modules must augment this container with
a leaf named 'address'.
";
}
}
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output {
list route {
min-elements "1";
uses afn-safi;
uses route-content;
description
"Route contents specific for each address family should be
defined through augmenting.";
}
}
}
rpc route-count {
description
"Return the current number of routes in a routing table.
Parameters:
1. 'router-name',
2. 'routing-table-name'.
If the logical router with 'router-name' doesn't exist, then
this operation will fail with error-tag 'missing-element' and
error-app-tag 'router-not-found'.
If the routing table with 'routing-table-name' doesn't exist,
then this operation will fail with error-tag 'missing-element'
and error-app-tag 'routing-table-not-found'.
";
input {
leaf router-name {
type router-ref;
mandatory "true";
description
"Name of the router instance containing the routing
table.";
}
leaf routing-table {
type leafref {
path "/routing/router/routing-tables/routing-table/name";
}
mandatory "true";
description
"Name of the routing table.";
}
}
output {
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leaf number-of-routes {
type uint32;
mandatory "true";
description
"Number of routes in the routing table.";
}
}
}
/* Data Nodes */
container routing {
description
"Routing parameters.";
list router {
key "name";
unique "router-id";
description
'Each list entry is a container for configuration and
operational state data of a single (logical) router.
Network layer interfaces assigned to the router must have
their entries in the "interfaces" list.
';
leaf name {
type string;
description
"The unique router name.";
}
leaf router-id {
type inet:ipv4-address;
description
"Global router ID in the form of an IPv4 address.
An implementation may select a value if this parameter is
not configured.
Routing protocols may override this global parameter
inside their configuration.
";
}
leaf description {
type string;
description
"Textual description of the router.";
}
leaf enabled {
type boolean;
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default "true";
description
"Enable the router. The default value is 'true'.
If this parameter is false, the parent router instance is
disabled, despite any other configuration that might be
present.
";
}
container interfaces {
description
"Router interface parameters.";
list interface {
key "name";
description
"List of network layer interfaces assigned to the router
instance.";
leaf name {
type if:interface-ref;
description
"A reference to the name of a configured network layer
interface.";
}
}
}
container routing-protocols {
description
"Container for the list of configured routing protocol
instances.";
list routing-protocol {
key "name";
description
"An instance of a routing protocol.";
leaf name {
type string;
description
"The name of the routing protocol instance.";
}
leaf description {
type string;
description
"Textual description of the routing protocol
instance.";
}
leaf type {
type identityref {
base routing-protocol;
}
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mandatory "true";
description
"Type of the routing protocol - an identity derived
from the 'routing-protocol' base identity.";
}
container connected-routing-tables {
description
"Container for connected routing tables.";
list routing-table {
must "not(../../../../routing-tables/"
+ "routing-table[rt:name=current()/"
+ "preceding-sibling::routing-table/name]/"
+ "address-family=../../../../routing-tables/"
+ "routing-table[rt:name=current()/name]/"
+ "address-family and ../../../../routing-tables/"
+ "routing-table[rt:name=current()/"
+ "preceding-sibling::routing-table/name]/safi=../"
+ "../../../routing-tables/"
+ "routing-table[rt:name=current()/name]/safi)" {
error-message "Each routing protocol may have no "
+ "more than one connected routing "
+ "table for each AFN and SAFI.";
description
"For each AFN/SAFI pair there may be at most one
connected routing table.";
}
key "name";
description
"List of routing tables to which the routing protocol
instance is connected.
If no connected routing table is defined for an
address family, the routing protocol should be
connected by default to the main routing table for
that address family.
";
leaf name {
type leafref {
path "../../../../../routing-tables/routing-table/"
+ "name";
}
description
"Reference to an existing routing table.";
}
leaf import-filter {
type leafref {
path "/routing/route-filters/route-filter/name";
}
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description
"Reference to a route filter that is used for
filtering routes passed from this routing protocol
instance to the routing table specified by the
'name' sibling node. If this leaf is not present,
the behavior is protocol-specific, but typically
it means that all routes are accepted.";
}
leaf export-filter {
type leafref {
path "/routing/route-filters/route-filter/name";
}
description
"Reference to a route filter that is used for
filtering routes passed from the routing table
specified by the 'name' sibling node to this
routing protocol instance. If this leaf is not
present, the behavior is protocol-specific -
typically it means that all routes are accepted,
except for the 'direct' and 'static'
pseudo-protocols which accept no routes from any
routing table.";
}
}
}
container static-routes {
must "../type='rt:static'" {
error-message "Static routes may be configured only "
+ "for 'static' routing protocol.";
description
"This container is only valid for the 'static'
routing protocol.";
}
description
"Configuration of 'static' pseudo-protocol.";
}
}
}
container routing-tables {
description
"Container for configured routing tables.";
list routing-table {
key "name";
description
"Each entry represents a routing table identified by the
'name' key. All routes in a routing table must have the
same AFN and SAFI.";
leaf name {
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type string;
description
"The name of the routing table.";
}
uses afn-safi;
leaf description {
type string;
description
"Textual description of the routing table.";
}
container routes {
config "false";
description
"Current contents of the routing table (operational
state data).";
list route {
description
"A routing table entry. This data node must augmented
with information specific for routes of each address
family.";
uses route-content;
leaf source-protocol {
type leafref {
path "/routing/router/routing-protocols/"
+ "routing-protocol/name";
}
mandatory "true";
description
"The name of the routing protocol instance from
which the route comes. This routing protocol must
be configured (automatically or manually) in the
device.";
}
leaf age {
type uint32;
units "seconds";
mandatory "true";
description
"The number of seconds since the parent route was
created or last updated.";
}
}
}
container recipient-routing-tables {
description
"Container for recipient routing tables.";
list recipient-routing-table {
key "name";
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description
"A list of routing tables that receive routes from
this routing table.";
leaf name {
type leafref {
path "/routing/router/routing-tables/"
+ "routing-table/name";
}
description
"The name of the recipient routing table.";
}
leaf filter {
type leafref {
path "/routing/route-filters/route-filter/name";
}
description
"A route filter which is applied to the routes
passed on to the recipient routing table.";
}
}
}
}
}
}
container route-filters {
description
"Container for configured route filters.";
list route-filter {
key "name";
description
"Route filters are used for filtering and/or manipulating
routes that are passed between a routing protocol and a
routing table or vice versa, or between two routing
tables. It is expected that other modules augment this
list with contents specific for a particular route filter
type.";
leaf name {
type string;
description
"The name of the route filter.";
}
leaf description {
type string;
description
"Textual description of the route filter.";
}
leaf type {
type identityref {
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base route-filter;
}
default "rt:deny-all-route-filter";
description
"Type of the route-filter - an identity derived from the
'route-filter' base identity. The default value
represents an all-blocking filter.";
}
}
}
}
}
<CODE ENDS>
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7. IPv4 Unicast Routing YANG Module
RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
actual RFC number and all occurrences of the revision date below with
the date of RFC publication (and remove this note).
<CODE BEGINS> file "ietf-ipv4-unicast-routing@2012-07-09.yang"
module ietf-ipv4-unicast-routing {
namespace "urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing";
prefix "v4ur";
import ietf-routing {
prefix "rt";
}
import ietf-inet-types {
prefix "inet";
}
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
WG Chair: David Kessens
<mailto:david.kessens@nsn.com>
WG Chair: Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>
Editor: Ladislav Lhotka
<mailto:lhotka@nic.cz>
";
description
"This YANG module augments the 'ietf-routing' module with basic
configuration and operational state data for IPv4 unicast
routing.
Every implementation must preconfigure a routing table with the
name 'main-ipv4-unicast', which is the main routing table for
IPv4 unicast.
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Copyright (c) 2012 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 2012-07-09 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Routing Configuration";
}
/* Groupings */
grouping route-content {
description
"Parameters of IPv4 unicast routes.";
leaf dest-prefix {
type inet:ipv4-prefix;
description
"IPv4 destination prefix.";
}
leaf next-hop {
type inet:ipv4-address;
description
"IPv4 address of the next hop.";
}
}
/* RPC Methods */
augment "/rt:active-route/rt:input/rt:destination-address" {
when "address-family='ipv4' and safi='nlri-unicast'" {
description
"This augment is valid only for IPv4 unicast.";
}
description
"The 'address' leaf augments the 'rt:destination-address'
parameter of the 'rt:active-route' operation.";
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leaf address {
type inet:ipv4-address;
description
"IPv4 destination address.";
}
}
augment "/rt:active-route/rt:output/rt:route" {
when "address-family='ipv4' and safi='nlri-unicast'" {
description
"This augment is valid only for IPv4 unicast.";
}
description
"Contents of the reply to 'rt:active-route' operation.";
uses route-content;
}
/* Data nodes */
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol/rt:static-routes" {
description
"This augment defines the configuration of the 'static'
pseudo-protocol with data specific for IPv4 unicast.";
container ipv4 {
description
"Configuration of a 'static' pseudo-protocol instance
consists of a list of routes.";
list route {
key "id";
ordered-by "user";
description
"A user-ordered list of static routes.";
leaf id {
type uint32 {
range "1..max";
}
description
'Numeric identifier of the route.
It is not required that the routes be sorted according
to their "id".
';
}
leaf description {
type string;
description
"Textual description of the route.";
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}
uses rt:route-content;
uses route-content {
refine "dest-prefix" {
mandatory "true";
}
}
}
}
}
augment "/rt:routing/rt:router/rt:routing-tables/rt:routing-table/"
+ "rt:routes/rt:route" {
when "../../rt:address-family='ipv4' and "
+ "../../rt:safi='nlri-unicast'" {
description
"This augment is valid only for IPv4 unicast.";
}
description
"This augment defines the content of IPv4 unicast routes.";
uses route-content;
}
}
<CODE ENDS>
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8. IPv6 Unicast Routing YANG Module
RFC Ed.: In this section, replace all occurrences of 'XXXX' with the
actual RFC number and all occurrences of the revision date below with
the date of RFC publication (and remove this note).
<CODE BEGINS> file "ietf-ipv6-unicast-routing@2012-07-09.yang"
module ietf-ipv6-unicast-routing {
namespace "urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing";
prefix "v6ur";
import ietf-routing {
prefix "rt";
}
import ietf-inet-types {
prefix "inet";
}
import ietf-interfaces {
prefix "if";
}
import ietf-ip {
prefix "ip";
}
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
WG Chair: David Kessens
<mailto:david.kessens@nsn.com>
WG Chair: Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>
Editor: Ladislav Lhotka
<mailto:lhotka@nic.cz>
";
description
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"This YANG module augments the 'ietf-routing' module with basic
configuration and operational state data for IPv6 unicast
routing.
Every implementation must preconfigure a routing table with the
name 'main-ipv6-unicast', which is the main routing table for
IPv6 unicast.
Copyright (c) 2012 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 2012-07-09 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Routing Configuration";
}
/* Groupings */
grouping route-content {
description
"Specific parameters of IPv6 unicast routes.";
leaf dest-prefix {
type inet:ipv6-prefix;
description
"IPv6 destination prefix.";
}
leaf next-hop {
type inet:ipv6-address;
description
"IPv6 address of the next hop.";
}
}
/* RPC Methods */
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augment "/rt:active-route/rt:input/rt:destination-address" {
when "address-family='ipv6' and safi='nlri-unicast'" {
description
"This augment is valid only for IPv6 unicast.";
}
description
"The 'address' leaf augments the 'rt:destination-address'
parameter of the 'rt:active-route' operation.";
leaf address {
type inet:ipv6-address;
description
"IPv6 destination address.";
}
}
augment "/rt:active-route/rt:output/rt:route" {
when "address-family='ipv6' and safi='nlri-unicast'" {
description
"This augment is valid only for IPv6 unicast.";
}
description
"Contents of the reply to 'rt:active-route' operation.";
uses route-content;
}
/* Data nodes */
augment "/rt:routing/rt:router/rt:interfaces/rt:interface" {
when "/if:interfaces/if:interface[name=current()/name]/ip:ipv6/"
+ "ip:enabled='true'" {
description
"This augment is only valid for router interfaces with
enabled IPv6.
NOTE: Parameter 'is-router' is not included, it is expected
that it will be implemented by the 'ietf-ip' module.
";
}
description
"IPv6-specific parameters of router interfaces.";
container ipv6-router-advertisements {
description
"Parameters of IPv6 Router Advertisements.";
reference
"RFC 4861: Neighbor Discovery for IP version 6 (IPv6).
RFC 4862: IPv6 Stateless Address Autoconfiguration.
";
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leaf send-advertisements {
type boolean;
default "false";
description
"A flag indicating whether or not the router sends periodic
Router Advertisements and responds to Router
Solicitations.";
}
leaf max-rtr-adv-interval {
type uint16 {
range "4..1800";
}
units "seconds";
default "600";
description
"The maximum time allowed between sending unsolicited
multicast Router Advertisements from the interface.";
}
leaf min-rtr-adv-interval {
type uint16 {
range "3..1350";
}
units "seconds";
description
"The minimum time allowed between sending unsolicited
multicast Router Advertisements from the interface.
Must be no greater than 0.75 * max-rtr-adv-interval.
Its default value is dynamic:
- if max-rtr-adv-interval >= 9 seconds, the default value
is 0.33 * max-rtr-adv-interval;
- otherwise it is 0.75 * max-rtr-adv-interval.
";
}
leaf managed-flag {
type boolean;
default "false";
description
"The boolean value to be placed in the 'Managed address
configuration' flag field in the Router Advertisement.";
}
leaf other-config-flag {
type boolean;
default "false";
description
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"The boolean value to be placed in the 'Other
configuration' flag field in the Router Advertisement.";
}
leaf link-mtu {
type uint32;
default "0";
description
"The value to be placed in MTU options sent by the router.
A value of zero indicates that no MTU options are sent.";
}
leaf reachable-time {
type uint32 {
range "0..3600000";
}
units "milliseconds";
default "0";
description
"The value to be placed in the Reachable Time field in the
Router Advertisement messages sent by the router. The
value zero means unspecified (by this router).";
}
leaf retrans-timer {
type uint32;
units "milliseconds";
default "0";
description
"The value to be placed in the Retrans Timer field in the
Router Advertisement messages sent by the router. The
value zero means unspecified (by this router).";
}
leaf cur-hop-limit {
type uint8;
default "64";
description
"The default value to be placed in the Cur Hop Limit field
in the Router Advertisement messages sent by the router.
The value should be set to the current diameter of the
Internet. The value zero means unspecified (by this
router).
The default should be set to the value specified in IANA
Assigned Numbers that was in effect at the time of
implementation.
";
reference
"IANA: IP Parameters,
http://www.iana.org/assignments/ip-parameters";
}
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leaf default-lifetime {
type uint16 {
range "0..9000";
}
units "seconds";
description
"The value to be placed in the Router Lifetime field of
Router Advertisements sent from the interface, in seconds.
MUST be either zero or between max-rtr-adv-interval and
9000 seconds. A value of zero indicates that the router is
not to be used as a default router. These limits may be
overridden by specific documents that describe how IPv6
operates over different link layers.
The default value is dynamic and should be set to 3 *
max-rtr-adv-interval.
";
}
container prefix-list {
description
"A list of prefixes to be placed in Prefix Information
options in Router Advertisement messages sent from the
interface.
By default, all prefixes that the router advertises via
routing protocols as being on-link for the interface from
which the advertisement is sent. The link-local prefix
should not be included in the list of advertised prefixes.
";
list prefix {
key "prefix-spec";
description
"Advertised prefix entry.";
leaf prefix-spec {
type inet:ipv6-prefix;
description
"IPv6 address prefix.";
}
choice control-adv-prefixes {
default "advertise";
description
"The prefix either may be explicitly removed from the
set of advertised prefixes, or parameters with which
it is advertised may be specified (default case).";
leaf no-advertise {
type empty;
description
"The prefix will not be advertised.
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This may be used for removing the prefix from the
default set of advertised prefixes.
";
}
case advertise {
leaf valid-lifetime {
type uint32;
units "seconds";
default "2592000";
description
"The value to be placed in the Valid Lifetime in
the Prefix Information option, in seconds. The
designated value of all 1's (0xffffffff)
represents infinity.
";
}
leaf on-link-flag {
type boolean;
default "true";
description
"The value to be placed in the on-link flag
('L-bit') field in the Prefix Information
option.";
}
leaf preferred-lifetime {
type uint32;
units "seconds";
must ". <= ../valid-lifetime" {
description
"This value must not be larger than
valid-lifetime.";
}
default "604800";
description
"The value to be placed in the Preferred Lifetime
in the Prefix Information option, in seconds. The
designated value of all 1's (0xffffffff)
represents infinity.
";
}
leaf autonomous-flag {
type boolean;
default "true";
description
"The value to be placed in the Autonomous Flag
field in the Prefix Information option.";
}
}
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}
}
}
}
}
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol/rt:static-routes" {
description
"This augment defines the configuration of the 'static'
pseudo-protocol with data specific for IPv6 unicast.";
container ipv6 {
description
"Configuration of a 'static' pseudo-protocol instance
consists of a list of routes.";
list route {
key "id";
ordered-by "user";
description
"A user-ordered list of static routes.";
leaf id {
type uint32 {
range "1..max";
}
description
'Numeric identifier of the route.
It is not required that the routes be sorted according
to their "id".
';
}
leaf description {
type string;
description
"Textual description of the route.";
}
uses rt:route-content;
uses route-content {
refine "dest-prefix" {
mandatory "true";
}
}
}
}
}
augment "/rt:routing/rt:router/rt:routing-tables/rt:routing-table/"
+ "rt:routes/rt:route" {
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when "../../rt:address-family='ipv6' and "
+ "../../rt:safi='nlri-unicast'" {
description
"This augment is valid only for IPv6 unicast.";
}
description
"This augment defines the content of IPv6 unicast routes.";
uses route-content;
}
}
<CODE ENDS>
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9. 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-routing
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
----------------------------------------------------------
----------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
----------------------------------------------------------
----------------------------------------------------------
URI: urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
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-routing
namespace: urn:ietf:params:xml:ns:yang:ietf-routing
prefix: rt
reference: RFC XXXX
-------------------------------------------------------------------
-------------------------------------------------------------------
name: ietf-ipv4-unicast-routing
namespace: urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing
prefix: v4ur
reference: RFC XXXX
-------------------------------------------------------------------
-------------------------------------------------------------------
name: ietf-ipv6-unicast-routing
namespace: urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing
prefix: v6ur
reference: RFC XXXX
-------------------------------------------------------------------
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10. Security Considerations
The YANG modules defined in this document are designed to be accessed
via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the
secure transport layer and the mandatory-to-implement secure
transport is SSH [RFC6242].
A number of data nodes defined in the YANG modules are writable/
creatable/deletable (i.e., "config true" in YANG terms, which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations to these data nodes,
such as "edit-config", can have negative effects on the network if
the protocol operations are not properly protected.
The vulnerable "config true" subtrees and data nodes are the
following:
/rt:routing/rt:router/rt:interfaces/rt:interface This list assigns a
network layer interface to a router instance and may also specify
interface parameters related to routing.
/rt:routing/rt:router/rt:routing-protocols/rt:routing-protocol This
list specifies the routing protocols configured on a device.
/rt:routing/rt:router/rt:route-filters/rt:route-filter This list
specifies the configured route filters which represent the
administrative policies for redistributing and modifying routing
information.
Unauthorized access to any of these lists can adversely affect the
routing subsystem of both the local device and the network. This may
lead to network malfunctions, delivery of packets to inappropriate
destinations and other problems.
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11. Acknowledgments
The author wishes to thank Martin Bjorklund, Joel Halpern, Thomas
Morin, Tom Petch, Juergen Schoenwaelder, Dave Thaler and Yi Yang for
their helpful comments and suggestions.
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12. References
12.1. Normative References
[IANA-IF-AF]
Bjorklund, M., "IANA Interface Type and Address Family
YANG Modules", draft-ietf-netmod-iana-if-type-02 (work in
progress), April 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
Network Configuration Protocol (NETCONF)", RFC 6020,
September 2010.
[RFC6021] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6021, September 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "NETCONF Configuration Protocol", RFC 6241,
June 2011.
[YANG-IF] Bjorklund, M., "A YANG Data Model for Interface
Configuration", draft-ietf-netmod-interfaces-cfg-04 (work
in progress), April 2012.
[YANG-IP] Bjorklund, M., "A YANG Data Model for IP Configuration",
draft-ietf-netmod-ip-cfg-03 (work in progress),
April 2012.
12.2. Informative References
[RFC6087] Bierman, A., "Guidelines for Authors and Reviewers of YANG
Data Model Documents", RFC 6087, January 2011.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, June 2011.
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Appendix A. Example: Adding a New Routing Protocol
This appendix demonstrates how the core routing data model can be
extended to support a new routing protocol. The YANG module
"example-rip" shown below is intended only as an illustration rather
than a real definition of a data model for the RIP routing protocol.
For the sake of brevity, we do not follow all the guidelines
specified in [RFC6087]. See also Section 4.4.2.
<CODE BEGINS> file "example-rip@2012-07-09.yang"
module example-rip {
namespace "http://example.com/rip";
prefix "rip";
import ietf-routing {
prefix "rt";
}
identity rip {
base rt:routing-protocol;
description
"Identity for the RIP routing protocol.";
}
typedef rip-metric {
type uint8 {
range "0..16";
}
}
grouping route-content {
description
"RIP-specific route content.";
leaf metric {
type rip-metric;
}
leaf tag {
type uint16;
default "0";
description
"This leaf may be used to carry additional info, e.g. AS
number.";
}
}
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augment "/rt:routing/rt:router/rt:routing-tables/rt:routing-table/"
+ "rt:routes/rt:route" {
when "../../../../rt:routing-protocols/"
+ "rt:routing-protocol[rt:name=current()/rt:source-protocol]/"
+ "rt:type='rip:rip'" {
description
"This augment is only valid if the source protocol from which
the route originated is RIP.";
}
description
"RIP-specific route components.";
uses route-content;
}
augment "/rt:active-route/rt:output/rt:route" {
description
"Add RIP-specific route content.";
uses route-content;
}
augment "/rt:routing/rt:router/rt:interfaces/rt:interface" {
when "../../rt:routing-protocols/rt:routing-protocol/rt:type = "
+ "'rip:rip'";
container rip {
description
"Per-interface RIP configuration.";
leaf enabled {
type boolean;
default "true";
}
leaf metric {
type rip-metric;
default "1";
}
}
}
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol" {
when "rt:type = 'rip:rip'";
container rip {
leaf update-interval {
type uint8 {
range "10..60";
}
units "seconds";
default "30";
description
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"Time interval between periodic updates.";
}
}
}
}
<CODE ENDS>
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Appendix B. Example: Reply to the NETCONF <get> Message
This section contains a sample reply to the NETCONF <get> message,
which could be sent by a server supporting (i.e., advertising them in
the NETCONF <hello> message) the following YANG modules:
o ietf-interfaces [YANG-IF],
o ietf-ip [YANG-IP],
o ietf-routing (Section 6),
o ietf-ipv4-unicast-routing (Section 7),
o ietf-ipv6-unicast-routing (Section 8).
We assume a simple network setup as shown in Figure 3: router "A"
uses static default routes with the "ISP" router as the next hop.
IPv6 router advertisements are configured only on the "eth1"
interface and disabled on the upstream "eth0" interface.
+-----------------+
| |
| Router ISP |
| |
+--------+--------+
|2001:db8:0:1::2
|192.0.2.2
|
|
|2001:db8:0:1::1
eth0|192.0.2.1
+--------+--------+
| |
| Router A |
| |
+--------+--------+
eth1|198.51.100.1
|2001:db8:0:2::1
|
Figure 3: Example network configuration
A reply to the NETCONF <get> message sent by router "A" would then be
as follows:
<?xml version="1.0"?>
<rpc-reply
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message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:v4ur="urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing"
xmlns:v6ur="urn:ietf:params:xml:ns:yang:ietf-ipv6-unicast-routing"
xmlns:if="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip"
xmlns:rt="urn:ietf:params:xml:ns:yang:ietf-routing">
<data>
<if:interfaces>
<if:interface>
<if:name>eth0</if:name>
<if:type>ethernetCsmacd</if:type>
<if:location>05:00.0</if:location>
<ip:ipv4>
<ip:address>
<ip:ip>192.0.2.1</ip:ip>
<ip:prefix-length>24</ip:prefix-length>
</ip:address>
</ip:ipv4>
<ip:ipv6>
<ip:address>
<ip:ip>2001:0db8:0:1::1</ip:ip>
<ip:prefix-length>64</ip:prefix-length>
</ip:address>
<ip:autoconf>
<ip:create-global-addresses>false</ip:create-global-addresses>
</ip:autoconf>
</ip:ipv6>
</if:interface>
<if:interface>
<if:name>eth1</if:name>
<if:type>ethernetCsmacd</if:type>
<if:location>05:00.1</if:location>
<ip:ipv4>
<ip:address>
<ip:ip>198.51.100.1</ip:ip>
<ip:prefix-length>24</ip:prefix-length>
</ip:address>
</ip:ipv4>
<ip:ipv6>
<ip:address>
<ip:ip>2001:0db8:0:2::1</ip:ip>
<ip:prefix-length>64</ip:prefix-length>
</ip:address>
<ip:autoconf>
<ip:create-global-addresses>false</ip:create-global-addresses>
</ip:autoconf>
</ip:ipv6>
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</if:interface>
</if:interfaces>
<rt:routing>
<rt:router>
<rt:name>rtr0</rt:name>
<rt:interfaces>
<rt:interface>
<rt:name>eth0</rt:name>
</rt:interface>
<rt:interface>
<rt:name>eth1</rt:name>
<v6ur:ipv6-router-advertisements>
<v6ur:send-advertisements>true</v6ur:send-advertisements>
<v6ur:prefix-list>
<v6ur:prefix>
<v6ur:prefix-spec>2001:db8:0:2::/64</v6ur:prefix-spec>
</v6ur:prefix>
</v6ur:prefix-list>
</v6ur:ipv6-router-advertisements>
</rt:interface>
</rt:interfaces>
<rt:routing-protocols>
<rt:routing-protocol>
<rt:name>direct</rt:name>
<rt:type>rt:direct</rt:type>
</rt:routing-protocol>
<rt:routing-protocol>
<rt:name>st0</rt:name>
<rt:description>
Static routing is used for the internal network.
</rt:description>
<rt:type>rt:static</rt:type>
<rt:static-routes>
<v4ur:ipv4>
<v4ur:route>
<v4ur:id>1</v4ur:id>
<v4ur:dest-prefix>0.0.0.0/0</v4ur:dest-prefix>
<v4ur:next-hop>192.0.2.2</v4ur:next-hop>
</v4ur:route>
</v4ur:ipv4>
<v6ur:ipv6>
<v6ur:route>
<v6ur:id>1</v6ur:id>
<v6ur:dest-prefix>::/0</v6ur:dest-prefix>
<v6ur:next-hop>2001:db8:0:1::2</v6ur:next-hop>
</v6ur:route>
</v6ur:ipv6>
</rt:static-routes>
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<rt:connected-routing-tables>
<rt:routing-table>
<rt:name>main-ipv4-unicast</rt:name>
</rt:routing-table>
<rt:routing-table>
<rt:name>main-ipv6-unicast</rt:name>
</rt:routing-table>
</rt:connected-routing-tables>
</rt:routing-protocol>
</rt:routing-protocols>
<rt:routing-tables>
<rt:routing-table>
<rt:name>main-ipv4-unicast</rt:name>
<rt:routes>
<rt:route>
<v4ur:dest-prefix>192.0.2.1/24</v4ur:dest-prefix>
<rt:outgoing-interface>eth0</rt:outgoing-interface>
<rt:source-protocol>direct</rt:source-protocol>
<rt:age>3512</rt:age>
</rt:route>
<rt:route>
<v4ur:dest-prefix>198.51.100.0/24</v4ur:dest-prefix>
<rt:outgoing-interface>eth1</rt:outgoing-interface>
<rt:source-protocol>direct</rt:source-protocol>
<rt:age>3512</rt:age>
</rt:route>
<rt:route>
<v4ur:dest-prefix>0.0.0.0/0</v4ur:dest-prefix>
<rt:source-protocol>st0</rt:source-protocol>
<v4ur:next-hop>192.0.2.2</v4ur:next-hop>
<rt:age>2551</rt:age>
</rt:route>
</rt:routes>
</rt:routing-table>
<rt:routing-table>
<rt:name>main-ipv6-unicast</rt:name>
<rt:address-family>ipv6</rt:address-family>
<rt:safi>nlri-unicast</rt:safi>
<rt:routes>
<rt:route>
<v6ur:dest-prefix>2001:db8:0:1::/64</v6ur:dest-prefix>
<rt:outgoing-interface>eth0</rt:outgoing-interface>
<rt:source-protocol>direct</rt:source-protocol>
<rt:age>3513</rt:age>
</rt:route>
<rt:route>
<v6ur:dest-prefix>2001:db8:0:2::/64</v6ur:dest-prefix>
<rt:outgoing-interface>eth1</rt:outgoing-interface>
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<rt:source-protocol>direct</rt:source-protocol>
<rt:age>3513</rt:age>
</rt:route>
<rt:route>
<v6ur:dest-prefix>::/0</v6ur:dest-prefix>
<v6ur:next-hop>2001:db8:0:1::2</v6ur:next-hop>
<rt:source-protocol>st0</rt:source-protocol>
<rt:age>2550</rt:age>
</rt:route>
</rt:routes>
</rt:routing-table>
</rt:routing-tables>
</rt:router>
</rt:routing>
</data>
</rpc-reply>
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Appendix C. Change Log
RFC Editor: remove this section upon publication as an RFC.
C.1. Changes Between Versions -03 and -04
o Changed "error-tag" for both RPC methods from "missing element" to
"data-missing".
o Removed the decrementing behavior for advertised IPv6 prefix
parameters "valid-lifetime" and "preferred-lifetime".
o Changed the key of the static route lists from "seqno" to "id"
because the routes needn't be sorted.
o Added 'must' constraint saying that "preferred-lifetime" must not
be greater than "valid-lifetime".
C.2. Changes Between Versions -02 and -03
o Module "iana-afn-safi" moved to I-D "iana-if-type".
o Removed forwarding table.
o RPC "get-route" changed to "active-route". Its output is a list
of routes (for multi-path routing).
o New RPC "route-count".
o For both RPCs, specification of negative responses was added.
o Relaxed separation of router instances.
o Assignment of interfaces to router instances needn't be disjoint.
o Route filters are now global.
o Added "allow-all-route-filter" for symmetry.
o Added Section 5 about interactions with "ietf-interfaces" and
"ietf-ip".
o Added "router-id" leaf.
o Specified the names for IPv4/IPv6 unicast main routing tables.
o Route parameter "last-modified" changed to "age".
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o Added container "recipient-routing-tables".
C.3. Changes Between Versions -01 and -02
o Added module "ietf-ipv6-unicast-routing".
o The example in Appendix B now uses IP addresses from blocks
reserved for documentation.
o Direct routes appear by default in the FIB table.
o Network layer interfaces must be assigned to a router instance.
Additional interface configuration may be present.
o The "when" statement is only used with "augment", "must" is used
elsewhere.
o Additional "must" statements were added.
o The "route-content" grouping for IPv4 and IPv6 unicast now
includes the material from the "ietf-routing" version via "uses
rt:route-content".
o Explanation of symbols in the tree representation of data model
hierarchy.
C.4. Changes Between Versions -00 and -01
o AFN/SAFI-independent stuff was moved to the "ietf-routing" module.
o Typedefs for AFN and SAFI were placed in a separate "iana-afn-
safi" module.
o Names of some data nodes were changed, in particular "routing-
process" is now "router".
o The restriction of a single AFN/SAFI per router was lifted.
o RPC operation "delete-route" was removed.
o Illegal XPath references from "get-route" to the datastore were
fixed.
o Section "Security Considerations" was written.
Lhotka Expires January 10, 2013 [Page 61]
Internet-Draft YANG Routing Configuration July 2012
Author's Address
Ladislav Lhotka
CZ.NIC
Email: lhotka@nic.cz
Lhotka Expires January 10, 2013 [Page 62]