A YANG Data Model for
Routing ManagementCZ.NIClhotka@nic.czCisco Systemsacee@cisco.com
Operations and Management
NETMOD Working GroupThis document contains a specification of three YANG modules.
Together they form the core routing data model which serves as a
framework for configuring and managing a routing subsystem. It
is expected that these modules will be augmented by additional
YANG modules defining data models for routing protocols, route
filters and other functions. The core routing data model
provides common building blocks for such extensions - routing
instances, routes, routing information bases (RIB), and routing
protocols.This document contains a specification of the following YANG
modules:
Module "ietf-routing" provides generic components of a
routing data model.Module "ietf-ipv4-unicast-routing" augments the
"ietf-routing" module with additional data specific to IPv4
unicast.Module "ietf-ipv6-unicast-routing" augments the
"ietf-routing" module with additional data specific to IPv6
unicast, including the router configuration variables required
by .These modules together define the so-called core routing data
model, which is intended as a basis for future data model
development covering more sophisticated routing systems. While
these three modules can be directly used for simple IP devices
with static routing (see ), their
main purpose is to provide essential building blocks for more
complicated data models 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.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 .The following terms are defined in :
client,message,protocol operation,server.The following terms are defined in :
augment,configuration data,data model,data node,feature,mandatory node,module,schema tree,state data,RPC operation. YANG data model
comprising "ietf-routing", "ietf-ipv4-unicast-routing" and
"ietf-ipv6-unicast-routing" modules.a route to a directly connected
network.An object
containing a list of routes together with other
information. See for details.An entry of a list in
state data ("config false") that is created by the system
independently of what has been explicitly configured. See
for details.An entry of a list in
state data ("config false") that is created and deleted as a
direct consequence of certain configuration changes. See
for details.A simplified graphical representation of the complete data
tree is presented in , and similar
diagrams of its various subtrees appear in the main text.The meaning of the symbols in these diagrams is as follows:
Brackets "[" and "]" enclose list keys.Curly braces "{" and "}" contain names of optional features that
make the corresponding node conditional.Abbreviations before data node names: "rw" means configuration
(read-write), "ro" state data (read-only), "-x" RPC operations, and
"-n" notifications.Symbols after data node names: "?" means an optional node, "!" a
container with presence, and "*" denotes a "list" or "leaf-list".Parentheses enclose choice and case nodes, and case nodes are
also marked with a colon (":").Ellipsis ("...") stands for contents of subtrees that are not
shown.In this document, names of data nodes, RPC operations and other
data model objects are often used without a prefix, as long as
it is clear from the context in which YANG module each name is
defined. Otherwise, names are prefixed using the standard prefix
associated with the corresponding YANG module, as shown in .PrefixYANG moduleReferenceifietf-interfacesipietf-iprtietf-routingv4urietf-ipv4-unicast-routingv6urietf-ipv6-unicast-routingyangietf-yang-typesinetietf-inet-typesThe initial design of the core routing data model was driven by
the following objectives:
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).A simple IP routing system, such as one that uses only
static routing, should be configurable in a simple way,
ideally without any need to develop additional YANG
modules.On the other hand, the core routing framework must allow
for complicated implementations involving multiple routing
information bases (RIB) and multiple routing protocols, as
well as controlled redistributions of routing information.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.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. Figures and show abridged views of the configuration and
state data hierarchies. See for
the complete data trees.As can be seen from Figures and , the core routing data model introduces
several generic components of a routing framework: routing
instances, RIBs containing lists of routes, and routing
protocols. describes these
components in more detail.The core routing data model defines several lists in the
schema tree, for example "routing-instance" or "rib", that
have to be populated with at least one entry in any properly
functioning device, and additional entries may be configured
by a client.In such a list, the server creates the required item as a
so-called system-controlled entry in state data, i.e., inside
the "routing-state" container.Additional entries may be created in the configuration by
a client, e.g., via the NETCONF protocol. These are so-called
user-controlled entries. If the server accepts a configured
user-controlled entry, then this entry also appears in the
state data version of the list.Corresponding entries in both versions of the list (in
state data and configuration) have the same value of the list
key.The user may also provide supplemental configuration of
system-controlled entries. To do so, the user creates a new
entry in the configuration with the desired contents. In order
to bind this entry with the corresponding entry in the
state data list, the key of the configuration entry has
to be set to the same value as the key of the state entry.An example can be seen in : the
"/routing-state/routing-instance" list has a single
system-controlled entry whose "name" key has the value
"rtr0". This entry is configured by the
"/routing/routing-instance" entry whose "name" key is
also "rtr0".Deleting a user-controlled entry from the configuration list
results in the removal of the corresponding entry in the
state data list. In contrast, if a system-controlled
entry is deleted from the configuration list, only the extra
configuration specified in that entry is removed but the
corresponding state data entry remains in the list.This section describes the essential components of the core
routing data model.The core routing data model supports one or more routing
instances appearing as entries of the "routing-instance"
list. Each routing instance has separate configuration and
state data under "/rt:routing/rt:routing-instance" and
"/rt:routing-state/rt:routing-instance", respectively.The semantics of the term "routing instance" is
deliberately left undefined. It is expected that future YANG
modules will define data models for specific types of routing
instances, such as VRF (virtual routing and forwarding)
instances that are used for BGP/MPLS virtual private
networks . For each type of routing
instance, an identity derived from "rt:routing-instance" SHALL
be defined. This identity is then referred to by the value of
the "type" leaf (a child node of "routing-instance" list).Each network layer interface has to be assigned to one or
more routing instances in order to be able to participate in
packet forwarding, routing protocols and other operations of
those routing instances. The assignment is accomplished by
placing a corresponding (system- or user-controlled) entry in
the leaf-list of routing instance interfaces
("rt:interface"). Each entry is the name of a configured
network layer interface, see the "ietf-interfaces"
module .YANG module "ietf-ipv6-unicast-routing" () augments the configuration and
state data of interfaces with definitions of the following
variables as required by ,
sec. 6.2.1:
send-advertisements,max-rtr-adv-interval,min-rtr-adv-interval,managed-flag,other-config-flag,link-mtu,reachable-time,retrans-timer,cur-hop-limit,default-lifetime,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.NOTES:The "IsRouter" flag, which is also required by , is implemented in the "ietf-ip" module
(leaf "ip:forwarding").The original specification
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.Routes are basic elements of information in a routing
system. The core routing data model defines only the following
minimal set of route attributes:
"destination-prefix": IP prefix specifying the set of
destination addresses for which the route may be used. This
attribute is mandatory."route-preference": an integer value (also known as
administrative distance) that is used for selecting a
preferred route among routes with the same destination
prefix. A lower value means a more preferred route."next-hop": determines the action to be performed with a
packet.Routes are primarily state data that appear as entries of
RIBs () but they may also be found in
configuration data, for example as manually configured static
routes. In the latter case, configurable route attributes are
generally a subset of route attributes described above.Every routing instance manages one or more routing
information bases (RIB). A RIB is a list of routes
complemented with administrative data. Each RIB contains only
routes of one address family. An address family is represented
by an identity derived from the "rt:address-family" base
identity.In the core routing data model, RIBs are state data
represented as entries of the list
"/routing-state/routing-instance/ribs/rib". The contents of
RIBs 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 .Each routing instance has, for every supported address
family, one RIB marked as the so-called default RIB. Its role
is explained in .Simple router implementations that do not advertise the
feature "multiple-ribs" will typically create one
system-controlled RIB per routing instance and supported
address family, and mark it as the default RIB.More complex router implementations advertising the
"multiple-ribs" feature support multiple RIBs per address
family that can be used for policy routing and other
purposes.The core routing data model provides an open-ended framework
for defining multiple routing protocol instances within a routing
instance. Each routing protocol instance MUST be assigned a
type, which is 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 ().Multiple routing protocol instances of the same type MAY be
configured within the same routing instance.The core routing data model defines two special routing
protocol types - "direct" and "static". Both are in fact
pseudo-protocols, which means they are confined to the local
device and do not exchange any routing information with
adjacent routers.Every routing instance MUST implement exactly one
instance of the "direct" pseudo-protocol type. 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 . Direct routes MUST be installed in
default RIBs of all supported address families.A pseudo-protocol of the type "static" allows for specifying
routes manually. It MAY be configured in zero or multiple
instances, although a typical configuration will have exactly
one instance per routing instance.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
state data, and it has to fit it into the core routing
framework in the following way:
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".Additional route attributes MAY be defined, preferably in
one place by means of defining a YANG grouping. The new
attributes have to be inserted by augmenting the definitions
of the nodes
and
and possibly other places in the configuration, state
data, notifications, and RPC input or output.Configuration parameters and/or state data for the new
protocol can be defined by augmenting the
"routing-protocol" data node under both "/routing" and "/routing-state".Per-interface configuration, including activation of
the routing protocol on individual interfaces, can use
references to entries in the leaf-list of routing
instance's interfaces (rt:interface).By using the "when" statement, the augmented configuration
parameters and state data specific to the new protocol SHOULD
be made conditional and valid only if the value of "rt:type"
or "rt:source-protocol" is equal to the new protocol's
identity. It is also RECOMMENDED that protocol-specific data
nodes be encapsulated in appropriately named containers.The above steps are implemented by the example YANG module
for the RIP routing protocol in .The "ietf-routing" module defines one RPC operation:
fib-route: query a routing instance for the active route
in the Forwarding Information Base (FIB). It is the route
that is currently used for sending datagrams to a
destination host whose address is passed as an input
parameter.The semantics of the core routing data model also depends on
several configuration parameters that are defined in other YANG
modules.The following boolean switch is defined in the
"ietf-interfaces" YANG module :
If this switch is set to "false" for a network layer
interface, the device MUST behave exactly as if that
interface was not assigned to any routing instance at all.
The following boolean switches are defined in the "ietf-ip"
YANG module :
If this switch is set to "false" for a network layer
interface, then all IPv4 routing functions related to that
interface MUST be disabled.
If this switch is set to "false" for a network layer
interface, then the forwarding of IPv4 datagrams to and from
this interface MUST be disabled. However, the interface may
participate in other IPv4 routing functions, such as routing
protocols.
If this switch is set to "false" for a network layer
interface, then all IPv6 routing functions related to that
interface MUST be disabled.
If this switch is set to "false" for a network layer
interface, then the forwarding of IPv6 datagrams to and from
this interface MUST be disabled. However, the interface may
participate in other IPv6 routing functions, such as routing
protocols.
In addition, the "ietf-ip" module allows for configuring IPv4
and IPv6 addresses and network prefixes or masks on network
layer interfaces. Configuration of these parameters on an
enabled interface MUST result in an immediate creation of the
corresponding direct route. The destination prefix of this route
is set according to the configured IP address and network
prefix/mask, and the interface is set as the outgoing interface
for that route.RFC Editor: 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).RFC Editor: 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).RFC Editor: 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).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 :This document registers the following YANG modules in the YANG
Module Names registry :Configuration and state data conforming to the core routing
data model (defined in this document) are designed to be accessed
via the NETCONF protocol . The lowest
NETCONF layer is the secure transport layer and the
mandatory-to-implement secure transport is SSH . The NETCONF access control model provides the means to restrict access for
particular NETCONF users to a pre-configured subset of all
available NETCONF protocol operations and content.A number of data nodes defined in the YANG modules belonging to
the configuration part of the core routing data model 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:
This
list assigns a network layer interface to a routing instance and
may also specify interface parameters related to routing.This
list specifies the routing protocols configured on a device.This list
specifies the RIBs configured for the device.
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.The authors wish to thank Nitin Bahadur, Martin Bjorklund,
Dean Bogdanovic, Jeff Haas, Joel Halpern, Wes Hardaker,
Sriganesh Kini, David Lamparter, Andrew McGregor, Jan Medved,
Xiang Li, Stephane Litkowski, Thomas Morin, Tom Petch,
Bruno Rijsman, Juergen Schoenwaelder, Phil Shafer, Dave Thaler,
Yi Yang, Derek Man-Kit Yeung and Jeffrey Zhang for their helpful
comments and suggestions.Key words for use in RFCs to Indicate Requirement LevelsHarvard University1350 Mass. Ave.CambridgeMA 02138- +1 617 495 3864sob@harvard.edu
General
keyword
In many standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized. This document defines these words as they should be
interpreted in IETF documents. Authors who follow these guidelines
should incorporate this phrase near the beginning of their document:
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
RFC 2119.
Note that the force of these words is modified by the requirement
level of the document in which they are used.
The IETF XML RegistryThis document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.Neighbor Discovery for IP version 6 (IPv6)This document specifies the Neighbor Discovery protocol for IP Version 6. IPv6 nodes on the same link use Neighbor Discovery to discover each other's presence, to determine each other's link-layer addresses, to find routers, and to maintain reachability information about the paths to active neighbors. [STANDARDS-TRACK]YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]Common YANG Data TypesThis document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021.Network Configuration Protocol (NETCONF)The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]A YANG Data Model for Interface ManagementThis document defines a YANG data model for the management of network interfaces. It is expected that interface-type-specific data models augment the generic interfaces data model defined in this document. The data model includes configuration data and state data (status information and counters for the collection of statistics).A YANG Data Model for IP ManagementThis document defines a YANG data model for management of IP implementations. The data model includes configuration data and state data.Guidelines for Authors and Reviewers of YANG Data Model DocumentsThis memo provides guidelines for authors and reviewers of Standards Track specifications containing YANG data model modules. Applicable portions may be used as a basis for reviews of other YANG data model documents. Recommendations and procedures are defined, which are intended to increase interoperability and usability of Network Configuration Protocol (NETCONF) implementations that utilize YANG data model modules. This document is not an Internet Standards Track specification; it is published for informational purposes.Using the NETCONF Protocol over Secure Shell (SSH)This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK]Network Configuration Protocol (NETCONF) Access Control ModelThe standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF protocol access for particular users to a pre-configured subset of all available NETCONF protocol operations and content. This document defines such an access control model. [STANDARDS-TRACK]BGP/MPLS IP Virtual Private Networks (VPNs)This document describes a method by which a Service Provider may use an IP backbone to provide IP Virtual Private Networks (VPNs) for its customers. This method uses a "peer model", in which the customers' edge routers (CE routers) send their routes to the Service Provider's edge routers (PE routers); there is no "overlay" visible to the customer's routing algorithm, and CE routers at different sites do not peer with each other. Data packets are tunneled through the backbone, so that the core routers do not need to know the VPN routes. [STANDARDS-TRACK]This appendix presents the complete configuration and
state data trees of the core routing data model.
See for an explanation of the
symbols used. Data type of every leaf node is shown near the right
end of the corresponding line.Some parts and options of the core routing model, such as
user-defined routing tables, are intended only for advanced
routers. This appendix gives basic non-normative guidelines for
implementing a bare minimum of available functions. Such an
implementation may be used for hosts or very simple routers.A minimum implementation will provide a single
system-controlled routing instance, and will not allow clients to
create any user-controlled instances.Typically, the feature "multiple-ribs" will not be
supported. This means that a single system-controlled RIB is
available for each supported address family - IPv4, IPv6 or
both. These RIBs must be the default RIBs. No user-controlled
RIBs are allowed.In addition to the mandatory instance of the "direct"
pseudo-protocol, a minimum implementation should support
configuring instance(s) of the "static" pseudo-protocol.Platforms with severely constrained resources may use
deviations for restricting the data model, e.g., limiting the
number of "static" routing protocol instances.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 as an illustration
rather than a real definition of a data model for the RIP
routing protocol. For the sake of brevity, this module does not
obey all the guidelines specified in . See also .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:
ietf-interfaces ,ietf-ip ,ietf-routing (),ietf-ipv4-unicast-routing (),ietf-ipv6-unicast-routing ().We assume a simple network set-up as shown in : 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.A reply to the NETCONF <get> message sent by router "A"
would then be as follows:RFC Editor: Remove this section upon publication as an RFC.The container "ribs" was moved under "routing-instance"
(in both "routing" and "routing-state").Typedefs "rib-ref" and "rib-state-ref" were removed.Removed "recipient-ribs" (both state and configuration).Removed "connected-ribs" from "routing-protocol" (both
state and configuration).Configuration and state data for IPv6 RA were moved
under "if:interface" and "if:interface-state".Assignment of interfaces to routing instances now use
leaf-list rather than list (both config and state). The
opposite reference from "if:interface" to
"rt:routing-instance" was changed to a single leaf (an
interface cannot belong to multiple routing instances).Specification of a default RIB is now a simple flag
under "rib" (both config and state).Default RIBs are marked by a flag in state data.Added Acee as a co-author.Removed all traces of route filters.Removed numeric IDs of list entries in state data.Removed all next-hop cases except "simple-next-hop" and
"special-next-hop".Removed feature "multipath-routes".Augmented "ietf-interfaces" module with a leaf-list of
leafrefs pointing form state data of an interface entry to
the routing instance(s) to which the interface is
assigned.Added 'type' as the second key component of
'routing-protocol', both in configuration and state
data.The restriction of no more than one connected RIB per
address family was removed.Removed the 'id' key of routes in RIBs. This list has
no keys anymore.Remove the 'id' key from static routes and make
'destination-prefix' the only key.Added 'route-preference' as a new attribute of routes
in RIB.Added 'active' as a new attribute of routes in
RIBs.Renamed RPC operation 'active-route' to 'fib-route'.Added 'route-preference' as a new parameter of routing
protocol instances, both in configuration and state data.Renamed identity 'rt:standard-routing-instance' to
'rt:default-routing-instance'.Added next-hop lists to state data.Added two cases for specifying next-hops indirectly -
via a new RIB or a recursive list of next-hops.Reorganized next-hop in static routes.Removed all 'if-feature' statements from state data.Removed all defaults from state data.Removed default from 'cur-hop-limit' in config.Removed dependency of 'connected-ribs' on the
'multiple-ribs' feature.Removed default value of 'cur-hop-limit' in state data.Moved parts of descriptions and all references on IPv6 RA
parameters from state data to configuration.Added reference to RFC 6536 in the Security section.Wrote appendix about minimum implementation.Remove "when" statement for IPv6 router interface
state data - it was dependent on a config value that
may not be present.Extra container for the next-hop list.Names rather than numeric ids are used for referring to
list entries in state data.Numeric ids are always declared as mandatory and
unique. Their description states that they are ephemeral.Descriptions of "name" keys in state data lists
are required to be persistent.Removed "if-feature multiple-ribs;" from connected-ribs."rib-name" instead of "name" is used as the name of
leafref nodes."next-hop" instead of "nexthop" or "gateway" used
throughout, both in node names and text.Removed feature "advanced-router" and introduced two
features instead: "multiple-ribs" and "multipath-routes".Unified the keys of config and state versions of
"routing-instance" and "rib" lists.Numerical identifiers of state list entries are not keys
anymore, but they are constrained using the "unique" statement.Updated acknowledgements.Migrated address families from IANA enumerations to
identities.Terminology and node names aligned with
the I2RS RIB model: router -> routing instance, routing
table -> RIB.Introduced uint64 keys for state lists: routing-instance,
rib, route, nexthop.Described the relationship between system-controlled and
user-controlled list entries.Feature "user-defined-routing-tables" changed into "advanced-router".Made nexthop into a choice in order to allow for
nexthop-list (I2RS requirement).Added nexthop-list with entries having priorities
(backup) and weights (load balancing).Updated bibliography references.Added subtree for state data ("/routing-state").Terms "system-controlled entry" and "user-controlled
entry" defined and used.New feature "user-defined-routing-tables". Nodes that are
useful only with user-defined routing tables are now conditional.Added grouping "router-id".In routing tables, "source-protocol" attribute of routes
now reports only protocol type, and its datatype is
"identityref".Renamed "main-routing-table" to "default-routing-table".Fixed "must" expresion for "connected-routing-table".Simplified "must" expression for "main-routing-table".Moved per-interface configuration of a new routing
protocol under 'routing-protocol'. This also affects the
'example-rip' module.Changed reference from RFC6021 to RFC6021bis.The contents of <get-reply> in was updated: "eth[01]" is used as
the value of "location", and "forwarding" is on for both
interfaces and both IPv4 and IPv6.The "must" expression for "main-routing-table" was
modified to avoid redundant error messages reporting address
family mismatch when "name" points to a non-existent routing
table.The default behavior for IPv6 RA prefix advertisements
was clarified.Changed type of "rt:router-id" to "ip:dotted-quad".Type of "rt:router-id" changed to "yang:dotted-quad".Fixed missing prefixes in XPath expressions.Document title changed: "Configuration" was replaced by
"Management".New typedefs "routing-table-ref" and "route-filter-ref".Double slashes "//" were removed from XPath expressions
and replaced with the single "/".Removed uniqueness requirement for "router-id".Complete data tree is now in .Changed type of "source-protocol" from "leafref" to "string".Clarified the relationship between routing protocol
instances and connected routing tables.Added a must constraint saying that a routing table
connected to the direct pseudo-protocol must not be a main
routing table.Routing tables are now global, i.e., "routing-tables" is
a child of "routing" rather than "router"."must" statement for "static-routes" changed to "when".Added "main-routing-tables" containing references to main
routing tables for each address family.Removed the defaults for "address-family" and "safi" and
made them mandatory.Removed the default for route-filter/type and made this
leaf mandatory.If there is no active route for a given destination, the
"active-route" RPC returns no output.Added "enabled" switch under "routing-protocol".Added "router-type" identity and "type" leaf under
"router".Route attribute "age" changed to "last-updated", its type
is "yang:date-and-time".The "direct" pseudo-protocol is always connected to main
routing tables.Entries in the list of connected routing tables renamed
from "routing-table" to "connected-routing-table".Added "must" constraint saying that a routing table must
not be its own recipient.Changed "error-tag" for both RPC operations from "missing
element" to "data-missing".Removed the decrementing behavior for advertised IPv6
prefix parameters "valid-lifetime" and
"preferred-lifetime".Changed the key of the static route lists from "seqno" to
"id" because the routes needn't be sorted.Added 'must' constraint saying that "preferred-lifetime"
must not be greater than "valid-lifetime".Module "iana-afn-safi" moved to I-D "iana-if-type".Removed forwarding table.RPC "get-route" changed to "active-route". Its output is
a list of routes (for multi-path routing).New RPC "route-count".For both RPCs, specification of negative responses was
added.Relaxed separation of router instances.Assignment of interfaces to router instances needn't be
disjoint.Route filters are now global.Added "allow-all-route-filter" for symmetry.Added about
interactions with "ietf-interfaces" and "ietf-ip".Added "router-id" leaf.Specified the names for IPv4/IPv6 unicast main routing
tables.Route parameter "last-modified" changed to "age".Added container "recipient-routing-tables".Added module "ietf-ipv6-unicast-routing".The example in now uses
IP addresses from blocks reserved for documentation.Direct routes appear by default in the forwarding
table.Network layer interfaces must be assigned to a router
instance. Additional interface configuration may be present.The "when" statement is only used with "augment", "must" is
used elsewhere.Additional "must" statements were added.The "route-content" grouping for IPv4 and IPv6 unicast now
includes the material from the "ietf-routing" version via
"uses rt:route-content".Explanation of symbols in the tree representation of data
model hierarchy.AFN/SAFI-independent stuff was moved to the "ietf-routing"
module.Typedefs for AFN and SAFI were placed in a separate
"iana-afn-safi" module.Names of some data nodes were changed, in particular
"routing-process" is now "router".The restriction of a single AFN/SAFI per router was
lifted.RPC operation "delete-route" was removed.Illegal XPath references from "get-route" to the datastore
were fixed.Section "Security Considerations" was written.