| NETMOD | L. Lhotka |
| Internet-Draft | CESNET |
| Intended status: Standards Track | September 23, 2011 |
| Expires: March 26, 2012 |
A YANG Data Model for Routing Configuration
draft-ietf-netmod-routing-cfg-01
This document contains a specification of three YANG modules that together provide a data model for essential configuration of a routing subsystem. It is expected that this module will serve as a basis for further development of data models for individual routing protocols and other related functions. The present data model defines the common building blocks for such configurations - router instances, routes, routing tables, routing protocols and route filters.
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 March 26, 2012.
Copyright (c) 2011 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 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.
This document contains an initial specification of three YANG modules:
ED. QUESTION: Would it be possible/useful to publish the "iana-afn-safi" module as a separate I-D, perhaps together with "iana-if-type"?
The first two modules together define the so-called core routing data model. This data model will serve as a basis for the development of data models for more sophisticated routing configurations. While these two modules can be directly used for simple IPv4-only devices with static routing, their main purpose is to provide essential building blocks for more complicated setups involving other address families such as IPv6, multicast routing, multiple routing protocols, and advanced functions such as route filtering or policy routing. To this end, it is expected that this module 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 [RFC2119].
The following terms are defined in [RFC6241]:
The following terms are defined in [RFC6020]:
In this document, names of data nodes 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 with their standard prefix associated with the corresponding YANG module, as shown in Table 1.
| Prefix | YANG module | Reference |
|---|---|---|
| eth | ex-ethernet | [YANG-IF] |
| if | ietf-interfaces | [YANG-IF] |
| inet | ietf-inet-types | [RFC6021] |
| ip | ietf-ip | [YANG-IP] |
| rip | example-rip | Appendix Appendix A |
| rt | ietf-routing | Section 6 |
| v4ur | ietf-ipv4-unicast-routing | Section 7 |
| yang | ietf-yang-types | [RFC6021] |
The initial design of the core routing data model was driven by the following objectives:
The core routing data model consists of two YANG modules. The first module, "ietf-routing", defines the generic components of a routing system. The second module, "ietf-ipv4-unicast-routing", augments the "ietf-routing" module with new data nodes that are needed for IPv4 unicast routing.
The combined data hierarchy defined by both YANG modules is shown in Figure 1.
+--rw routing
+--rw router [name]
+--rw name
+--rw description?
+--rw enabled?
+--rw routing-protocols
| +--rw routing-protocol [name]
| +--rw name
| +--rw description?
| +--rw type
| +--rw connected-routing-tables
| | +--rw connected-routing-table [name]
| | +--rw name
| | +--rw import-filter?
| | +--rw export-filter?
| +--rw v4ur:ipv4-unicast-static-routes
| +--rw v4ur:static-route [id]
| +--rw v4ur:id
| +--rw v4ur:description?
| +--rw v4ur:destination-prefix?
| +--rw v4ur:next-hop?
| +--rw v4ur:outgoing-interface?
+--rw route-filters
| +--rw route-filter [name]
| +--rw name
| +--rw description?
| +--rw type?
+--rw routing-tables
+--rw routing-table [name]
+--rw name
+--rw address-family?
+--rw safi?
+--rw description?
+--ro routes
| +--ro route
| +--ro source-protocol?
| +--ro last-modified?
| +--ro v4ur:destination-prefix?
| +--ro v4ur:next-hop?
| +--ro v4ur:outgoing-interface?
+--rw recipient-routing-tables [recipient-name]
+--rw recipient-name
+--rw filter?
As can be see from Figure 1, the core routing data model introduces several generic components of a routing framework: routers, routing tables containing routes, routing protocols, route filters and RPC operations. The following subsections provide further details about these components.
By combining the components in various ways, and possibly augmenting them with appropriate contents defined in other modules, various routing setups can be realized.
+------------+
| FIB |
+------------+
^
|
+---+
| F |
+---+
^
+--------+ |
| 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 shows an example of a more complicated setup. Several of its features are worth mentioning:
Each router instance in the core routing data model represents a (virtual) router whose configuration and operation is independent of other router instances. Although it it not enforced by the data model, different router instances normally do not internally share any data. They may, however, communicate with each other via routing protocols.
Routes are basic units of information in a routing system. The core routing data model defines only the following minimal set of route attributes:
The above list of route attributes is sufficient 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 in both configuration data, for example as manually configured static routes, and in operational state data, for example as entries in routing tables.
Routing tables are lists of routes complemented with administrative data, namely:
In the core routing data model, the contents of routing tables (list of routes) are defined as operational state data. Routing protocol operations result in route additions, removals and modifications. This also includes manipulations via the "static" pseudo-protocol.
At least the following two routing tables MUST be configured for each router instance:
The main routing table SHOULD serve as the source of active routes for the FIB.
One or more additional routing tables MAY be configured by creating new entries in the "routing-table" list, either being a part of factory-default configuration or configured by the client.
The naming scheme for routing tables, as well as restrictions on the number and configurability of routing tables are implementation-specific.
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.
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, and MUST be assigned a type from a selection which includes all routing protocol types supported by the server, such as static, RIP, OSPF or BGP.
Each routing protocol instance is connected to exactly one routing table. By default, every routing protocol instance is connected to the main routing table, but any routing protocol instance can be configured to use a different routing table, provided such an extra table exists.
Routes learned from the network by a routing protocol are passed to the connected routing table 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 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 routing table:
Note that, for historical reasons, the terms import and export are used from the viewpoint of a routing table.
The "ietf-routing" module defines two special routing protocols - "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. It is the source of routes to directly connected networks (so-called direct routes). Such routes are supplied by the operating system kernel, based on the detected and configured network interfaces, and they usually appear in the main routing table. However, using the framework defined in this document, the target routing table for direct routes can be changed by connecting the "direct" protocol instance to a non-default routing table, and the direct routes can also be filtered before they appear in the routing table.
The "static" routing pseudo-protocol allows for specifying routes manually. It MAY be configured in zero or multiple instances, although a typical implementation will have exactly one instance.
It is expected that future YANG modules will create data models for additional routing protocol types. In order to do so, the new module has to define the protocol-specific information and fit it to the core routing framework in the following way:
The above steps are implemented by the example YANG module for the RIP routing protocol in Appendix 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.";
}
Second, new route attributes specific for the RIP protocol ("metric" and "tag") are defined in a grouping and then added to route definitions appearing in "routing-table" and in the output part of "get-route" RPC method:
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:get-route/rt:output/rt:route" {
description
"Add RIP-specific route content.";
uses route-content;
}
The "when" substatement in the first "augment" guarantees that the new route attributes are only valid when the source protocol is RIP.
Finally, RIP-specific configuration data are integrated into the "rt:routing-protocol" node by using the following "augment" statement, which applies only to 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-configuration {
container rip-interfaces {
list rip-interface {
key "name";
leaf name {
type if:interface-ref;
}
leaf enabled {
type boolean;
default "true";
}
leaf metric {
type rip-metric;
default "1";
}
}
}
leaf update-interval {
type uint8 {
range "10..60";
}
units "seconds";
default "30";
description
"Time interval between periodic updates.";
}
}
}
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 routing table, or between a source and a recipient routing table. Route filters may also manipulate routes, i.e., add, delete, or modify their properties.
By itself, the route filtering framework defined in this document allows to establish only the two extreme routing policies in which either all routes are allowed or all routes are rejected. It is expected that real route filtering framework(s) will be developed separately.
Each route filter is identified by a name which MUST be unique within a router instance. Its type MUST be specified by the "type" identity reference - this opens the space for multiple route filtering framework implementations. The default value for route filter type is the identity "deny-all-route-filter" defined in the "ietf-routing" module, which represents a route filtering policy in which all routes are rejected.
The "ietf-routing" module defines the "get-route" RPC operation. It is used for querying the forwarding information base of a router instance. The first input parameter is the name of the router instance whose FIB is to be queried, and the second parameter is a destination address. Modules for particular address families are expected to augment the "destination-address" container with the "address" leaf, as it is done in the "ietf-ipv4-unicast-routing" module.
The server replies with an active route which is used for forwarding datagrams to the destination address within the selected router instance. Again, modules for particular address families are expected to augment the definition of output parameters with AFN/SAFI-specific contents.
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 "iana-afn-safi@2011-09-23.yang"
module iana-afn-safi {
namespace "urn:ietf:params:xml:ns:yang:iana-afn-safi";
prefix "ianaaf";
organization
"IANA";
contact
"Internet Assigned Numbers Authority
Postal:
ICANN
4676 Admiralty Way, Suite 330
Marina del Rey, CA 90292
U. S. A.
Tel: +1 310 823 9358
E-Mail: iana&iana.org
";
description
"This YANG module provides two typedefs containing YANG
definitions for the following IANA-registered enumerations:
- Address Family Numbers (AFN)
- Subsequent Address Family Identifiers (SAFI)
The latest revision of this YANG module can be obtained from the
IANA web site.
Copyright (c) 2011 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 2011-09-23 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Routing Configuration";
}
typedef address-family {
type enumeration {
enum other {
value "0";
description
"none of the following";
}
enum ipV4 {
value "1";
description
"IP Version 4";
}
enum ipV6 {
value "2";
description
"IP Version 6";
}
enum nsap {
value "3";
description
"NSAP";
}
enum hdlc {
value "4";
description
"(8-bit multidrop)";
}
enum bbn1822 {
value "5";
description
"BBN Report 1822";
}
enum all802 {
value "6";
description
"(includes all 802 media plus Ethernet 'canonical
format')";
}
enum e163 {
value "7";
description
"E.163";
}
enum e164 {
value "8";
description
"(SMDS, FrameRelay, ATM)";
}
enum f69 {
value "9";
description
"(Telex)";
}
enum x121 {
value "10";
description
"(X.25, Frame Relay)";
}
enum ipx {
value "11";
description
"IPX (Internet Protocol Exchange)";
}
enum appleTalk {
value "12";
description
"Apple Talk";
}
enum decnetIV {
value "13";
description
"DEC Net Phase IV";
}
enum banyanVines {
value "14";
description
"Banyan Vines";
}
enum e164withNsap {
value "15";
description
"(E.164 with NSAP format subaddress)";
}
enum dns {
value "16";
description
"(Domain Name System)";
}
enum distinguishedName {
value "17";
description
"(Distinguished Name, per X.500)";
}
enum asNumber {
value "18";
description
"(16-bit quantity, per the AS number space)";
}
enum xtpOverIPv4 {
value "19";
description
"XTP over IP version 4";
}
enum xtpOverIpv6 {
value "20";
description
"XTP over IP version 6";
}
enum xtpNativeModeXTP {
value "21";
description
"XTP native mode XTP";
}
enum fibreChannelWWPN {
value "22";
description
"Fibre Channel World-Wide Port Name";
}
enum fibreChannelWWNN {
value "23";
description
"Fibre Channel World-Wide Node Name";
}
enum gwid {
value "24";
description
"Gateway Identifier";
}
enum afi {
value "25";
description
"AFI for L2VPN";
}
}
description
"This typedef is a YANG enumeration of IANA-registered address
family numbers (AFN).";
reference
"Address Family Numbers. IANA, 2011-01-20.
<http://www.iana.org/assignments/address-family-numbers/
address-family-numbers.xml>
IANA-ADDRESS-FAMILY-NUMBERS-MIB DEFINITIONS
<http://www.iana.org/assignments/ianaaddressfamilynumbers-mib>
";
}
typedef subsequent-address-family {
type enumeration {
enum nlri-unicast {
value "1";
description
"Network Layer Reachability Information used for unicast
forwarding";
reference
"RFC4760";
}
enum nlri-multicast {
value "2";
description
"Network Layer Reachability Information used for multicast
forwarding";
reference
"RFC4760";
}
enum nlri-mpls {
value "4";
description
"Network Layer Reachability Information (NLRI) with MPLS
Labels";
reference
"RFC3107";
}
enum mcast-vpn {
value "5";
description
"MCAST-VPN";
reference
"draft-ietf-l3vpn-2547bis-mcast-bgp-08";
}
enum nlri-dynamic-ms-pw {
value "6";
status "obsolete";
description
"Network Layer Reachability Information used for Dynamic
Placement of Multi-Segment Pseudowires (TEMPORARY -
Expires 2008-08-23)";
reference
"draft-ietf-pwe3-dynamic-ms-pw-13";
}
enum tunnel-safi {
value "64";
description
"Tunnel SAFI";
reference
"draft-nalawade-kapoor-tunnel-safi-05";
}
enum vpls {
value "65";
description
"Virtual Private LAN Service (VPLS)";
reference
"RFC4761, RFC6074";
}
enum bgp-mdt {
value "66";
description
"BGP MDT SAFI";
reference
"RFC6037";
}
enum bgp-4over6 {
value "67";
description
"BGP 4over6 SAFI";
reference
"RFC5747";
}
enum bgp-6over4 {
value "68";
description
"BGP 6over4 SAFI";
reference
"mailto:cuiyong&tsinghua.edu.cn";
}
enum l1vpn-auto-discovery {
value "69";
description
"Layer-1 VPN auto-discovery information";
reference
"draft-ietf-l1vpn-bgp-auto-discovery-05";
}
enum mpls-vpn {
value "128";
description
"MPLS-labeled VPN address";
reference
"RFC4364";
}
enum multicast-bgp-mpls-vpn {
value "129";
description
"Multicast for BGP/MPLS IP Virtual Private Networks
(VPNs)";
reference
"draft-ietf-l3vpn-2547bis-mcast-10,
draft-ietf-l3vpn-2547bis-mcast-10";
}
enum route-target-constraints {
value "132";
description
"Route Target constraints";
reference
"RFC4684";
}
enum ipv4-diss-flow {
value "133";
description
"IPv4 dissemination of flow specification rules";
reference
"RFC5575";
}
enum vpnv4-diss-flow {
value "134";
description
"IPv4 dissemination of flow specification rules";
reference
"RFC5575";
}
enum vpn-auto-discovery {
value "140";
description
"VPN auto-discovery";
reference
"draft-ietf-l3vpn-bgpvpn-auto-09";
}
}
description
"This typedef is a YANG enumeration of IANA-registered
subsequent address family identifiers (SAFI).";
reference
"Subsequent Address Family Identifiers (SAFI) Parameters. IANA,
2011-03-04. <http://www.iana.org/assignments/safi-namespace/
safi-namespace.xml>
";
}
}
<CODE ENDS>
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@2011-09-23.yang"
module ietf-routing {
namespace "urn:ietf:params:xml:ns:yang:ietf-routing";
prefix "rt";
import ietf-yang-types {
prefix "yang";
}
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@cesnet.cz>
";
description
"This module contains YANG definitions of essential components
that may be used for configuring a routing subsystem.
Copyright (c) 2011 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 2011-09-23 {
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;
description
"Route filter that blocks 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.";
leaf source-protocol {
type string;
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 last-modified {
type yang:date-and-time;
description
"Time stamp of the last modification of the route. If the
route was never modified, it is the time when the route was
inserted to the routing table.";
}
}
/* RPC Methods */
rpc get-route {
description
"Query the forwarding information base of a router instance
whose name is given as the first parameter 'router-name'. The
second parameter 'destination-address' should be augmented in
order to support destination addresses of all supported
address families. The server returns the route which is
currently used for forwarding datagrams to that destination
address, or an error message, if no such route exists.";
input {
leaf router-name {
type router-ref;
mandatory "true";
description
"First parameter: name of the router instance whose
forwarding information base is queried.";
}
container destination-address {
uses afn-safi;
description
"Second parameter: destination address.
AFN/SAFI-specific modules must augment this container with
a leaf named 'address'.
";
}
}
output {
container route {
uses afn-safi;
description
"Contents of the reply specific for each address family
should be defined through augmenting.";
uses route-content;
}
}
}
/* Data Nodes */
container routing {
description
"Routing parameters.";
list router {
key "name";
description
"Each list entry is a container for configuration and
operational state data of a single (logical) router.";
leaf name {
type string;
description
"The unique router name.";
}
leaf description {
type string;
description
"Textual description of the router.";
}
leaf enabled {
type boolean;
default "true";
description
"Enable or disable the router. The default value is 'true',
which means that the router is enabled.";
}
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;
}
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 connected-routing-table {
key "name";
description
"List of routing tables to which the routing protocol
instance is connected. No more than one routing
table may be configured for each AFN/SAFI pair.
Implementation may provide default routing tables
for some AFN/SAFI pairs, which are used if the
corresponding entry is not configured.
";
leaf name {
type leafref {
path "../../../../../routing-tables/routing-table/"
+ "name";
}
description
"This must be the name of an existing routing
table.";
}
leaf import-filter {
type leafref {
path "../../../../../route-filters/route-filter/"
+ "name";
}
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 "../../../../../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 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 {
base route-filter;
}
default "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.";
}
}
}
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 {
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. It is expected that this data
node will be augmented with information specific for
routes of each address family.";
uses route-content;
}
}
list recipient-routing-tables {
key "recipient-name";
description
"A list of routing tables that receive routes from this
routing table.";
leaf recipient-name {
type leafref {
path "../../../routing-table/name";
}
description
"The name of the recipient routing table.";
}
leaf filter {
type leafref {
path "../../../../route-filters/route-filter/name";
}
description
"A route filter which is applied to the routes passed
on to the recipient routing table.";
}
}
}
}
}
}
}
<CODE ENDS>
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@2011-09-23.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";
}
import ietf-interfaces {
prefix "if";
}
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@cesnet.cz>
";
description
"This module augments the 'ietf-routing' module with YANG
definitions for basic configuration of IPv4 unicast routing.
Copyright (c) 2011 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 2011-09-23 {
description
"Initial revision.";
reference
"RFC XXXX: A YANG Data Model for Routing Configuration";
}
/* Groupings */
grouping route-content {
description
"Specific parameters of IPv4 unicast routes.";
leaf destination-prefix {
type inet:ipv4-prefix;
description
"IPv4 destination prefix.";
}
leaf next-hop {
type inet:ipv4-address;
description
"IPv4 address of the next hop.";
}
leaf outgoing-interface {
type if:interface-ref;
description
"Outgoing interface.";
}
}
/* RPC Methods */
augment "/rt:get-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:get-route' operation.";
leaf address {
type inet:ipv4-address;
description
"IPv4 destination address.";
}
}
augment "/rt:get-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:get-route' operation.";
uses route-content;
}
/* Data nodes */
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol" {
when "rt:type='rt:static'" {
description
"The augment is only valid for the 'static'
pseudo-protocol.";
}
description
"This augment defines the configuration of the static
pseudo-protocol with data specific for IPv4 unicast.";
container ipv4-unicast-static-routes {
description
"Configuration of a 'static' pseudo-protocol instance
consists of a list of routes.";
list static-route {
key "id";
ordered-by "user";
description
"A user-ordered list of static routes.";
leaf id {
type string;
description
"An identification string for the route.";
}
leaf description {
type string;
description
"Textual description of the route.";
}
uses route-content;
}
}
}
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>
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:iana-afn-safi
Registrant Contact: IANA.
XML: N/A, the requested URI is an XML namespace.
----------------------------------------------------------
This document registers the following YANG modules in the YANG Module Names registry [RFC6020]:
-------------------------------------------------------------------
name: ietf-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: iana-afn-safi
namespace: urn:ietf:params:xml:ns:yang:iana-afn-safi
prefix: ianaaf
reference: RFC XXXX
-------------------------------------------------------------------
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 operations are not properly protected.
The vulnerable "config true" subtrees and data nodes are the following:
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 author wishes to thank Martin Bjorklund, Joel Halpern, Tom Petch and Juergen Schoenwaelder for their helpful comments and suggestions.
| [IANA-AFN] | IANA, "Address Family Numbers.", January 2011. |
| [IANA-SAFI] | IANA, "Subsequent Address Family Identifiers (SAFI) Parameters.", March 2011. |
| [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. |
| [RFC6020] | Bjorklund, M, "YANG - A Data Modeling Language for Network Configuration Protocol (NETCONF)", RFC 6020, September 2010. |
| [RFC6021] | Schoenwaelder, J., "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", Internet-Draft draft-ietf-netmod-interfaces-cfg-02, September 2011. |
| [YANG-IP] | Bjorklund, M., "A YANG Data Model for IP Configuration", Internet-Draft draft-ietf-netmod-ip-cfg-00, September 2011. |
| [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. |
This appendix demonstrates how the core routing data model can be extended to support a new routing protocol. Appendix Appendix A.1 contains the YANG module which is used for this purpose. It is intended only as an illustration and not as a real definition of a data model for the RIP routing protocol. Also, for the sake of brevity, we do not follow all the guidelines specified in [RFC6087].
Appendix Appendix A.2 then contains a complete instance XML document - a reply to the NETCONF <get> message from a server that uses the RIP protocol as well as static routing.
<CODE BEGINS> file "example-rip@2011-09-23.yang"
module example-rip {
namespace "http://example.com/rip";
prefix "rip";
import ietf-routing {
prefix "rt";
}
import ietf-interfaces {
prefix "if";
}
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.";
}
}
augment "/rt:get-route/rt:output/rt:route" {
description
"Add RIP-specific route content.";
uses route-content;
}
augment "/rt:routing/rt:router/rt:routing-protocols/"
+ "rt:routing-protocol" {
when "rt:type = 'rip:rip'";
container rip-configuration {
container rip-interfaces {
list rip-interface {
key "name";
leaf name {
type if:interface-ref;
}
leaf enabled {
type boolean;
default "true";
}
leaf metric {
type rip-metric;
default "1";
}
}
}
leaf update-interval {
type uint8 {
range "10..60";
}
units "seconds";
default "30";
description
"Time interval between periodic updates.";
}
}
}
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;
}
}
<CODE ENDS>
This section contains a sample reply to the NETCONF <get> message, which could be sent by a server supporting (and advertising in the NETCONF <hello> message) the following YANG modules:
We assume a simple network setup as shown in Figure 12: routers "ISP" and "A" use RIP for exchanging routing information whereas static routing is used in the private network. In order to avoid the redistribution of the routes to the private subnetworks 192.168.1.0/24 and 192.168.2.0/24 in RIP, an export filter is used in the RIP protocol configuration preventing the routes from the main routing table from appearing in RIP updates.
+-----------------+
| |
| Router ISP |
| |
+--------+--------+
|192.0.2.2
|
|
eth0|192.0.2.1
+--------+--------+
| |
| Router A |
| |
+--------+--------+
eth1|192.168.1.1
|
|
|192.168.1.254
+--------+--------+
| |
| Router B |
| |
+--------+--------+
|192.168.2.1
|
Router "A" then could send the following XML document as its reply to the NETCONF <get> message:
<?xml version="1.0"?>
<nc:rpc-reply
message-id="101"
xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv4-unicast-routing"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0"
xmlns:if="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:eth="http://example.com/ethernet"
xmlns:ip="urn:ietf:params:xml:ns:yang:ietf-ip"
xmlns:rt="urn:ietf:params:xml:ns:yang:ietf-routing"
xmlns:rip="http://example.com/rip">
<nc: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>
</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>192.168.1.1</ip:ip>
<ip:prefix-length>24</ip:prefix-length>
</ip:address>
</ip:ipv4>
</if:interface>
</if:interfaces>
<rt:routing>
<rt:router>
<rt:name>inet-0</rt:name>
<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>
<ipv4-unicast-static-routes>
<static-route>
<id>id-6378</id>
<destination-prefix>192.168.2.0/24</destination-prefix>
<next-hop>192.168.1.254</next-hop>
</static-route>
</ipv4-unicast-static-routes>
</rt:routing-protocol>
<rt:routing-protocol>
<rt:name>rip0</rt:name>
<rt:description>
RIP is used on the uplink. Static routes to the
internal networks are not advertized in RIP.
</rt:description>
<rt:type>rip:rip</rt:type>
<rt:connected-routing-tables>
<rt:connected-routing-table>
<rt:name>ipv4-unicast-main</rt:name>
<rt:export-filter>deny-all</rt:export-filter>
</rt:connected-routing-table>
</rt:connected-routing-tables>
<rip:rip-configuration>
<rip:rip-interfaces>
<rip:rip-interface>
<rip:name>eth0</rip:name>
</rip:rip-interface>
</rip:rip-interfaces>
</rip:rip-configuration>
</rt:routing-protocol>
</rt:routing-protocols>
<rt:route-filters>
<rt:route-filter>
<rt:name>deny-all</rt:name>
</rt:route-filter>
</rt:route-filters>
<rt:routing-tables>
<rt:routing-table>
<rt:name>ipv4-unicast-fib</rt:name>
<rt:routes>
<rt:route>
<destination-prefix>192.0.2.1/24</destination-prefix>
<rt:source-protocol>direct</rt:source-protocol>
<outgoing-interface>eth0</outgoing-interface>
<rt:last-modified>2011-09-23T17:11:27+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>192.168.1.0/24</destination-prefix>
<rt:source-protocol>direct</rt:source-protocol>
<outgoing-interface>eth1</outgoing-interface>
<rt:last-modified>2011-09-23T17:11:27+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>192.168.2.0/24</destination-prefix>
<rt:source-protocol>st0</rt:source-protocol>
<next-hop>192.168.1.254</next-hop>
<rt:last-modified>2011-09-23T17:11:32+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>0.0.0.0/0</destination-prefix>
<rt:source-protocol>rip0</rt:source-protocol>
<next-hop>192.0.2.2</next-hop>
<rip:metric>2</rip:metric>
<rip:tag>64500</rip:tag>
<rt:last-modified>2011-09-23T18:02:45+01:00</rt:last-modified>
</rt:route>
</rt:routes>
</rt:routing-table>
<rt:routing-table>
<rt:name>ipv4-unicast-main</rt:name>
<rt:recipient-routing-tables>
<rt:recipient-name>ipv4-unicast-fib</rt:recipient-name>
</rt:recipient-routing-tables>
<rt:routes>
<rt:route>
<destination-prefix>192.0.2.1/24</destination-prefix>
<rt:source-protocol>direct</rt:source-protocol>
<outgoing-interface>eth0</outgoing-interface>
<rt:last-modified>2011-09-23T17:11:27+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>192.168.1.0/24</destination-prefix>
<rt:source-protocol>direct</rt:source-protocol>
<outgoing-interface>eth1</outgoing-interface>
<rt:last-modified>2011-09-23T17:11:27+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>192.168.2.0/24</destination-prefix>
<rt:source-protocol>st0</rt:source-protocol>
<next-hop>192.168.1.254</next-hop>
<rt:last-modified>2011-09-23T17:11:32+01:00</rt:last-modified>
</rt:route>
<rt:route>
<destination-prefix>0.0.0.0/0</destination-prefix>
<rt:source-protocol>rip0</rt:source-protocol>
<next-hop>192.0.2.2</next-hop>
<rip:metric>2</rip:metric>
<rip:tag>64500</rip:tag>
<rt:last-modified>2011-09-23T18:02:45+01:00</rt:last-modified>
</rt:route>
</rt:routes>
</rt:routing-table>
</rt:routing-tables>
</rt:router>
</rt:routing>
</nc:data>
</nc:rpc-reply>
RFC Editor: remove this section upon publication as an RFC.