Internet Engineering Task Force (IETF) M. Jethanandani
Request for Comments: 9647 Kloud Services
Category: Standards Track B. Stark
ISSN: 2070-1721 AT&T
October 2024
A YANG Data Model for Babel
Abstract
This document defines a data model for the Babel routing protocol.
The data model is defined using the YANG data modeling language.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9647.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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 Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Introduction
1.1. Requirements Language
1.2. Tree Diagram Annotations
2. Babel Module
2.1. Information Model
2.2. Tree Diagram
2.3. YANG Module
3. IANA Considerations
3.1. URI Registration
3.2. YANG Module Name Registration
4. Security Considerations
5. References
5.1. Normative References
5.2. Informative References
Appendix A. Tree Diagram and Example Configurations
A.1. Complete Tree Diagram
A.2. Statistics Gathering Enabled
A.3. Automatic Detection of Properties
A.4. Override Default Properties
A.5. Configuring Other Properties
Acknowledgements
Authors' Addresses
1. Introduction
This document defines a data model for the Babel routing protocol
[RFC8966]. The data model is defined using YANG 1.1 [RFC7950] and is
compatible with Network Management Datastore Architecture (NMDA)
[RFC8342]. It is based on the Babel information model [RFC9046].
The data model only includes data nodes that are useful for managing
Babel over IPv6.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Tree Diagram Annotations
For a reference to the annotations used in tree diagrams included in
this document, please see "YANG Tree Diagrams" [RFC8340].
2. Babel Module
This document defines a YANG 1.1 [RFC7950] data model for the
configuration and management of Babel. The YANG module is based on
the Babel information model [RFC9046].
2.1. Information Model
It's worth noting a few differences between the Babel information
model and this data module. The information model mandates the
definition of some of the attributes, e.g., "babel-implementation-
version" or the "babel-self-router-id". These attributes are marked
as read-only objects in the information module as well as in this
data module. However, there is no way in the data module to mandate
that a read-only attribute be present. It is up to the
implementation of this data module to make sure that the attributes
that are marked "read only" and are mandatory are indeed present.
2.2. Tree Diagram
The following diagram illustrates a top-level hierarchy of the model.
In addition to the version implemented by this device, the model
contains subtrees on "constants", "interfaces", "mac-key-set",
"dtls", and "routes".
module: ietf-babel
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol:
+--rw babel!
+--ro version? string
+--rw enable boolean
+--ro router-id? binary
+--ro seqno? uint16
+--rw statistics-enabled? boolean
+--rw constants
| ...
+--rw interfaces* [reference]
| ...
+--rw mac-key-set* [name]
| ...
+--rw dtls* [name]
| ...
+--ro routes* [prefix]
...
The "interfaces" subtree describes attributes such as the "interface"
object that is being referenced; the type of link, e.g., wired,
wireless, or tunnel, as enumerated by "metric-algorithm" and "split-
horizon"; and whether the interface is enabled or not.
The "constants" subtree describes the UDP port used for sending and
receiving Babel messages and the multicast group used to send and
receive announcements on IPv6.
The "routes" subtree describes objects such as the prefix for which
the route is advertised, a reference to the neighboring route, and
the "next-hop" address.
Finally, for security, two subtrees are defined to contain Message
Authentication Code (MAC) keys and DTLS certificates. The "mac-key-
set" subtree contains keys used with the MAC security mechanism. The
boolean flag "default-apply" indicates whether the set of MAC keys is
automatically applied to new interfaces. The "dtls" subtree contains
certificates used with the DTLS security mechanism. Similar to the
MAC mechanism, the boolean flag "default-apply" indicates whether the
set of DTLS certificates is automatically applied to new interfaces.
2.3. YANG Module
This YANG module augments the YANG routing management module
[RFC8349] to provide a common framework for all routing subsystems.
By augmenting the module, it provides a common building block for
routes and Routing Information Bases (RIBs). It also has a reference
to an interface defined by "A YANG Data Model for Interface
Management" [RFC8343].
A router running the Babel routing protocol can sometimes determine
the parameters it needs to use for an interface based on the
interface name. For example, it can detect that eth0 is a wired
interface and that wlan0 is a wireless interface. This is not true
for a tunnel interface, where the link parameters need to be
configured explicitly.
For a wired interface, it will assume "two-out-of-three" is set for
"metric-algorithm" and "split-horizon" is set to true. On the other
hand, for a wireless interface, it will assume "etx" is set for
"metric-algorithm" and "split-horizon" is set to false. However, if
the wired link is connected to a wireless radio, the values can be
overridden by setting "metric-algorithm" to "etx" and "split-horizon"
to false. Similarly, an interface that is a metered 3G link and is
used for fallback connectivity needs much higher default time
constants, e.g., "mcast-hello-interval" and "update-interval", in
order to avoid carrying control traffic as much as possible.
In addition to the modules used above, this module imports
definitions from "Common YANG Data Types" [RFC6991] and references
"HMAC: Keyed-Hashing for Message Authentication" [RFC2104], "Using
HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec" [RFC4868],
"Textual Encodings of PKIX, PKCS, and CMS Structures" [RFC7468], "The
BLAKE2 Cryptographic Hash and Message Authentication Code (MAC)"
[RFC7693], "Network Configuration Access Control Model" [RFC8341],
"The Babel Routing Protocol" [RFC8966], "MAC Authentication for the
Babel Routing Protocol" [RFC8967], "Babel Information Model"
[RFC9046], "The Datagram Transport Layer Security (DTLS) Protocol
Version 1.3" [RFC9147], and "YANG Data Types and Groupings for
Cryptography" [RFC9640].
<CODE BEGINS> file "ietf-babel@2024-10-10.yang"
module ietf-babel {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-babel";
prefix babel;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-interfaces {
prefix if;
reference
"RFC 8343: A YANG Data Model for Interface Management";
}
import ietf-routing {
prefix rt;
reference
"RFC 8349: A YANG Data Model for Routing Management (NMDA
Version)";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC 9640: YANG Data Types and Groupings
for Cryptography";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
organization
"IETF Babel routing protocol Working Group";
contact
"WG Web: https://datatracker.ietf.org/wg/babel/
WG List: babel@ietf.org
Editor: Mahesh Jethanandani
mjethanandani@gmail.com
Editor: Barbara Stark
bs7652@att.com";
description
"This YANG module defines a model for the Babel routing
protocol.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.
Copyright (c) 2024 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 Revised BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9647
(https://www.rfc-editor.org/info/rfc9647); see the RFC itself
for full legal notices.";
revision 2024-10-10 {
description
"Initial version.";
reference
"RFC 9647: A YANG Data Model for Babel";
}
/*
* Features
*/
feature two-out-of-three-supported {
description
"This implementation supports the '2-out-of-3'
computation algorithm.";
}
feature etx-supported {
description
"This implementation supports the Expected Transmission Count
(ETX) metric computation algorithm.";
}
feature mac-supported {
description
"This implementation supports MAC-based security.";
reference
"RFC 8967: MAC Authentication for the Babel Routing
Protocol";
}
feature dtls-supported {
description
"This implementation supports DTLS-based security.";
reference
"RFC 8968: Babel Routing Protocol over Datagram
Transport Layer Security";
}
feature hmac-sha256-supported {
description
"This implementation supports the HMAC-SHA256 MAC algorithm.";
reference
"RFC 8967: MAC Authentication for the Babel Routing
Protocol";
}
feature blake2s-supported {
description
"This implementation supports BLAKE2s MAC algorithms.";
reference
"RFC 8967: MAC Authentication for the Babel Routing
Protocol";
}
feature x-509-supported {
description
"This implementation supports the X.509 certificate type.";
reference
"RFC 8968: Babel Routing Protocol over Datagram
Transport Layer Security";
}
feature raw-public-key-supported {
description
"This implementation supports the raw public key certificate
type.";
reference
"RFC 8968: Babel Routing Protocol over Datagram
Transport Layer Security";
}
/*
* Identities
*/
identity metric-comp-algorithms {
description
"Base identity from which all Babel metric computation
algorithms MUST be derived.";
}
identity two-out-of-three {
if-feature "two-out-of-three-supported";
base metric-comp-algorithms;
description
"2-out-of-3 algorithm.";
reference
"RFC 8966: The Babel Routing Protocol, Section A.2.1";
}
identity etx {
if-feature "etx-supported";
base metric-comp-algorithms;
description
"Expected Transmission Count (ETX) metric computation
algorithm.";
reference
"RFC 8966: The Babel Routing Protocol, Section A.2.2";
}
/*
* Babel MAC algorithms identities.
*/
identity mac-algorithms {
description
"Base identity for all Babel MAC algorithms.";
}
identity hmac-sha256 {
if-feature "mac-supported";
if-feature "hmac-sha256-supported";
base mac-algorithms;
description
"HMAC-SHA256 algorithm supported.";
reference
"RFC 4868: Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512
with IPsec";
}
identity blake2s {
if-feature "mac-supported";
if-feature "blake2s-supported";
base mac-algorithms;
description
"BLAKE2s algorithms supported. Specifically, BLAKE2-128 is
supported.";
reference
"RFC 7693: The BLAKE2 Cryptographic Hash and Message
Authentication Code (MAC)";
}
/*
* Babel Cert Types
*/
identity dtls-cert-types {
description
"Base identity for Babel DTLS certificate types.";
}
identity x-509 {
if-feature "dtls-supported";
if-feature "x-509-supported";
base dtls-cert-types;
description
"X.509 certificate type.";
}
identity raw-public-key {
if-feature "dtls-supported";
if-feature "raw-public-key-supported";
base dtls-cert-types;
description
"Raw public key certificate type.";
}
/*
* Babel routing protocol identity.
*/
identity babel {
base rt:routing-protocol;
description
"Babel routing protocol";
}
/*
* Groupings
*/
grouping routes {
list routes {
key "prefix";
config false;
leaf prefix {
type inet:ip-prefix;
description
"Prefix (expressed in ip-address/prefix-length format) for
which this route is advertised.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
leaf router-id {
type binary {
length "8";
}
description
"router-id of the source router for which this route is
advertised.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
leaf neighbor {
type leafref {
path "/rt:routing/rt:control-plane-protocols/"
+ "rt:control-plane-protocol/babel/interfaces/"
+ "neighbor-objects/neighbor-address";
}
description
"Reference to the neighbor-objects entry for the neighbor
that advertised this route.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
leaf received-metric {
type union {
type enumeration {
enum null {
description
"Route was not received from a neighbor.";
}
}
type uint16;
}
description
"The metric with which this route was advertised by the
neighbor, or maximum value (infinity) to indicate the
route was recently retracted and is temporarily
unreachable. This metric will be NULL if the
route was not received from a neighbor but instead was
injected through means external to the Babel routing
protocol. At least one of calculated-metric or
received-metric MUST be non-NULL.";
reference
"RFC 9046: Babel Information Model, Section 3.6
RFC 8966: The Babel Routing Protocol, Section 2.1";
}
leaf calculated-metric {
type union {
type enumeration {
enum null {
description
"Route has not been calculated.";
}
}
type uint16;
}
description
"A calculated metric for this route. How the metric is
calculated is implementation specific. Maximum value
(infinity) indicates the route was recently retracted
and is temporarily unreachable. At least one of
calculated-metric or received-metric MUST be non-NULL.";
reference
"RFC 9046: Babel Information Model, Section 3.6
RFC 8966: The Babel Routing Protocol, Section 2.1";
}
leaf seqno {
type uint16;
description
"The sequence number with which this route was
advertised.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
leaf next-hop {
type union {
type enumeration {
enum null {
description
"Route has no next-hop address.";
}
}
type inet:ip-address;
}
description
"The next-hop address of this route. This will be NULL
if this route has no next-hop address.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
leaf feasible {
type boolean;
description
"A boolean flag indicating whether this route is
feasible.";
reference
"RFC 9046: Babel Information Model, Section 3.6
RFC 8966, The Babel Routing Protocol, Section 3.5.1";
}
leaf selected {
type boolean;
description
"A boolean flag indicating whether this route is selected,
i.e., whether it is currently being used for forwarding
and is being advertised.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
description
"A set of babel-route-obj objects. Contains routes known to
this node.";
reference
"RFC 9046: Babel Information Model, Section 3.6";
}
description
"Common grouping for routing used in RIB.";
}
/*
* Data model
*/
augment "/rt:routing/rt:control-plane-protocols/"
+ "rt:control-plane-protocol" {
when "derived-from-or-self(rt:type, 'babel')" {
description
"Augmentation is valid only when the instance of the routing
type is of type 'babel'.";
}
description
"Augments the routing module to support a common structure
between routing protocols.";
reference
"RFC 8349: A YANG Data Model for Routing Management (NMDA
Version)";
container babel {
presence "A Babel container.";
description
"Babel information objects.";
reference
"RFC 9046: Babel Information Model, Section 3";
leaf version {
type string;
config false;
description
"The name and version of this implementation of the Babel
protocol.";
reference
"RFC 9046: Babel Information Model, Section 3.1";
}
leaf enable {
type boolean;
mandatory true;
description
"When written, it configures whether the protocol should be
enabled. A read from the <running> or <intended> datastore
therefore indicates the configured administrative value of
whether the protocol is enabled or not.
A read from the <operational> datastore indicates whether
the protocol is actually running or not, i.e., it
indicates the operational state of the protocol.";
reference
"RFC 9046: Babel Information Model, Section 3.1";
}
leaf router-id {
type binary;
must '../enable = "true"';
config false;
description
"Every Babel speaker is assigned a router-id, which is an
arbitrary string of 8 octets that is assumed to be unique
across the routing domain.
The router-id is valid only if the protocol is enabled,
at which time a non-zero value is assigned.";
reference
"RFC 9046: Babel Information Model, Section 3.1
RFC 8966: The Babel Routing Protocol, Section 3";
}
leaf seqno {
type uint16;
config false;
description
"Sequence number included in route updates for routes
originated by this node.";
reference
"RFC 9046: Babel Information Model, Section 3.1";
}
leaf statistics-enabled {
type boolean;
description
"Indicates whether statistics collection is enabled
('true') or disabled ('false') on all interfaces.
On transition to enabled, existing statistics
values are not cleared and will be incremented as
new packets are counted.";
}
container constants {
description
"Babel constants object.";
reference
"RFC 9046: Babel Information Model, Section 3.1";
leaf udp-port {
type inet:port-number;
default "6696";
description
"UDP port for sending and receiving Babel messages. The
default port is 6696.";
reference
"RFC 9046: Babel Information Model, Section 3.2";
}
leaf mcast-group {
type inet:ip-address;
default "ff02::1:6";
description
"Multicast group for sending and receiving multicast
announcements on IPv6.";
reference
"RFC 9046: Babel Information Model, Section 3.2";
}
}
list interfaces {
key "reference";
description
"A set of Babel interface objects.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
leaf reference {
type if:interface-ref;
description
"References the name of the interface over which Babel
packets are sent and received.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf enable {
type boolean;
default "true";
description
"If 'true', Babel sends and receives messages on this
interface. If 'false', Babel messages received on
this interface are ignored and none are sent.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf metric-algorithm {
type identityref {
base metric-comp-algorithms;
}
mandatory true;
description
"Indicates the metric computation algorithm used on this
interface. The value MUST be one of those identities
based on 'metric-comp-algorithms'.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf split-horizon {
type boolean;
description
"Indicates whether or not the split-horizon optimization
is used when calculating metrics on this interface.
A value of 'true' indicates the split-horizon
optimization is used.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf mcast-hello-seqno {
type uint16;
config false;
description
"The current sequence number in use for multicast Hellos
sent on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf mcast-hello-interval {
type uint16;
units "centiseconds";
description
"The current multicast Hello interval in use for Hellos
sent on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf update-interval {
type uint16;
units "centiseconds";
description
"The current update interval in use for this interface.
Units are centiseconds.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf mac-enable {
type boolean;
description
"Indicates whether the MAC security mechanism is enabled
('true') or disabled ('false').";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf-list mac-key-sets {
type leafref {
path "../../mac-key-set/name";
}
description
"List of references to the MAC entries that apply
to this interface. When an interface instance is
created, all MAC instances with default-apply 'true'
will be included in this list.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf mac-verify {
type boolean;
description
"A boolean flag indicating whether MACs in
incoming Babel packets are required to be present and
are verified. If this parameter is 'true', incoming
packets are required to have a valid MAC.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf dtls-enable {
type boolean;
description
"Indicates whether the DTLS security mechanism is enabled
('true') or disabled ('false').";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf-list dtls-certs {
type leafref {
path "../../dtls/name";
}
description
"List of references to the dtls entries that apply to
this interface. When an interface instance
is created, all dtls instances with default-apply
'true' will be included in this list.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf dtls-cached-info {
type boolean;
description
"Indicates whether the cached_info extension is enabled.
The extension is enabled for inclusion in ClientHello
and ServerHello messages if the value is 'true'.";
reference
"RFC 9046: Babel Information Model, Section 3.3
RFC 8968: Babel Routing Protocol over
Datagram Transport Layer Security, Appendix A";
}
leaf-list dtls-cert-prefer {
type leafref {
path "../../dtls/certs/type";
}
ordered-by user;
description
"List of supported certificate types, in order of
preference. The values MUST be the 'type' attribute
in the list 'certs' of the list 'dtls'
(../../dtls/certs/type). This list is used to populate
the server_certificate_type extension in a ClientHello.
Values that are present in at least one instance in the
certs object under dtls of a referenced dtls instance
and that have a non-empty private key will be used to
populate the client_certificate_type extension in a
ClientHello.";
reference
"RFC 9046: Babel Information Model, Section 3.3
RFC 8968: Babel Routing Protocol over
Datagram Transport Layer Security, Appendix A";
}
leaf packet-log-enable {
type boolean;
description
"If 'true', logging of babel packets received on this
interface is enabled; if 'false', babel packets are
not logged.";
reference
"RFC 9046: Babel Information Model, Section 3.3";
}
leaf packet-log {
type inet:uri;
config false;
description
"A reference or url link to a file that contains a
timestamped log of packets received and sent on
udp-port on this interface. The [libpcap] file
format with .pcap file extension SHOULD be supported for
packet log files. Logging is enabled / disabled by
packet-log-enable.";
reference
"RFC 9046: Babel Information Model, Section 3.3
libpcap: Libpcap File Format, Wireshark Foundation";
}
container statistics {
config false;
description
"Statistics collection object for this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
leaf discontinuity-time {
type yang:date-and-time;
mandatory true;
description
"The time on the most recent occasion at which any one
or more of counters suffered a discontinuity. If no
such discontinuities have occurred since the last
re-initialization of the local management subsystem,
then this node contains the time the local management
subsystem re-initialized itself.";
}
leaf sent-mcast-hello {
type yang:counter32;
description
"A count of the number of multicast Hello packets sent
on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
leaf sent-mcast-update {
type yang:counter32;
description
"A count of the number of multicast update packets sent
on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
leaf sent-ucast-hello {
type yang:counter32;
description
"A count of the number of unicast Hello packets sent
on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
leaf sent-ucast-update {
type yang:counter32;
description
"A count of the number of unicast update packets sent
on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
leaf sent-ihu {
type yang:counter32;
description
"A count of the number of 'I Heard You' (IHU) packets
sent on this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
leaf received-packets {
type yang:counter32;
description
"A count of the number of Babel packets received on
this interface.";
reference
"RFC 9046: Babel Information Model, Section 3.4";
}
action reset {
description
"The information model (RFC 9046) defines reset
action as a system-wide reset of Babel statistics.
In YANG, the reset action is associated with the
container where the action is defined. In this case,
the action is associated with the statistics container
inside an interface. The action will therefore
reset statistics at an interface level.
Implementations that want to support a system-wide
reset of Babel statistics need to call this action
for every instance of the interface.";
reference
"RFC 9046: Babel Information Model";
input {
leaf reset-at {
type yang:date-and-time;
description
"The time when the reset was issued.";
}
}
output {
leaf reset-finished-at {
type yang:date-and-time;
description
"The time when the reset finished.";
}
}
}
}
list neighbor-objects {
key "neighbor-address";
config false;
description
"A set of babel neighbor objects.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
leaf neighbor-address {
type inet:ip-address;
description
"The IPv4 or IPv6 address from which the neighbor sends
packets.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf hello-mcast-history {
type string;
description
"The multicast Hello history of whether or not the
multicast Hello packets prior to exp-mcast-
hello-seqno were received, with a '1' for the most
recent Hello placed in the most significant bit and
prior Hellos shifted right (with '0' bits placed
between prior Hellos and the most recent Hello for any
Hellos not received); represented as a string of
hex digits encoded in utf-8. A bit that is set
indicates that the corresponding Hello was received,
and a bit that is cleared indicates that the
corresponding Hello was not received.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf hello-ucast-history {
type string;
description
"The unicast Hello history of whether or not the
unicast Hello packets prior to exp-ucast-hello-seqno
were received, with a '1' for the most
recent Hello placed in the most significant bit and
prior Hellos shifted right (with '0' bits placed
between prior Hellos and the most recent Hello for any
Hellos not received); represented as a string using
hex digits encoded in utf-8 where a '1' bit = Hello
received and a '0' bit = Hello not received.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf txcost {
type int32;
default "0";
description
"Transmission cost value from the last IHU packet
received from this neighbor, or maximum value
(infinity) to indicate the IHU hold timer for this
neighbor has an expired description.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf exp-mcast-hello-seqno {
type union {
type enumeration {
enum null {
description
"Multicast Hello packets are not expected, or
processing of multicast packets is not
enabled.";
}
}
type uint16;
}
description
"Expected multicast Hello sequence number of next Hello
to be received from this neighbor; if multicast Hello
packets are not expected, or processing of multicast
packets is not enabled, this MUST be NULL.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf exp-ucast-hello-seqno {
type union {
type enumeration {
enum null {
description
"Unicast Hello packets are not expected, or
processing of unicast packets is not enabled.";
}
}
type uint16;
}
default "null";
description
"Expected unicast Hello sequence number of next Hello
to be received from this neighbor; if unicast Hello
packets are not expected, or processing of unicast
packets is not enabled, this MUST be NULL.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf ucast-hello-seqno {
type union {
type enumeration {
enum null {
description
"Unicast Hello packets are not being sent.";
}
}
type uint16;
}
default "null";
description
"The current sequence number in use for unicast Hellos
sent to this neighbor. If unicast Hellos are not being
sent, this MUST be NULL.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf ucast-hello-interval {
type uint16;
units "centiseconds";
description
"The current interval in use for unicast Hellos sent to
this neighbor. Units are centiseconds.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf rxcost {
type uint16;
description
"Reception cost calculated for this neighbor. This
value is usually derived from the Hello history, which
may be combined with other data, such as statistics
maintained by the link layer. The rxcost is sent to a
neighbor in each IHU.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
leaf cost {
type int32;
description
"Link cost is computed from the values maintained in
the neighbor table. The statistics are kept in the
neighbor table about the reception of Hellos, and the
txcost is computed from received IHU packets.";
reference
"RFC 9046: Babel Information Model, Section 3.5";
}
}
}
list mac-key-set {
key "name";
description
"A MAC key set object. If this object is implemented, it
provides access to parameters related to the MAC security
mechanism.";
reference
"RFC 9046: Babel Information Model, Section 3.7";
leaf name {
type string;
description
"A string that uniquely identifies the MAC object.";
}
leaf default-apply {
type boolean;
description
"A boolean flag indicating whether this object
instance is applied to all new interfaces, by default.
If 'true', this instance is applied to new babel-
interfaces instances at the time they are created
by including it in the mac-key-sets list under
the interface. If 'false', this instance is not applied
to new interface instances when they are created.";
reference
"RFC 9046: Babel Information Model, Section 3.7";
}
list keys {
key "name";
min-elements 1;
description
"A set of keys objects.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
leaf name {
type string;
description
"A unique name for this MAC key that can be used to
identify the key in this object instance since the
key value is not allowed to be read. This value can
only be provided when this instance is created and is
not subsequently writable.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
leaf use-send {
type boolean;
mandatory true;
description
"Indicates whether this key value is used to compute a
MAC and include that MAC in the sent Babel packet. A
MAC for sent packets is computed using this key if the
value is 'true'. If the value is 'false', this key is
not used to compute a MAC to include in sent Babel
packets.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
leaf use-verify {
type boolean;
mandatory true;
description
"Indicates whether this key value is used to verify
incoming Babel packets. This key is used to verify
incoming packets if the value is 'true'. If the value
is 'false', no MAC is computed from this key for
comparing an incoming packet.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
leaf value {
nacm:default-deny-all;
type binary;
mandatory true;
description
"The value of the MAC key.
This value is of a length suitable for the associated
babel-mac-key-algorithm. If the algorithm is based on
the Hashed Message Authentication Code (HMAC)
construction (RFC 2104), the length MUST be between 0
and an upper limit that is at least the size of the
output length (where the 'HMAC-SHA256' output length
is 32 octets as described in RFC 4868). Longer lengths
MAY be supported but are not necessary if the
management system has the ability to generate a
suitably random value (e.g., by randomly generating a
value or by using a key derivation technique as
recommended in the security considerations of RFC
8967. If the algorithm is 'BLAKE2s-128', the length
MUST be between 0 and 32 bytes inclusive as specified
by RFC 7693.";
reference
"RFC 9046: Babel Information Model, Section 3.8
RFC 2104: HMAC: Keyed-Hashing for Message
Authentication
RFC 4868: Using HMAC-SHA-256, HMAC-SHA-384, and
HMAC-SHA-512 with IPsec
RFC 7693: The BLAKE2 Cryptographic Hash and Message
Authentication Code (MAC)
RFC 8967: MAC Authentication for Babel";
}
leaf algorithm {
type identityref {
base mac-algorithms;
}
mandatory true;
description
"The MAC algorithm used with this key. The
value MUST be one of the identities
listed with the base of 'mac-algorithms'.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
action test {
description
"An operation that allows the MAC key and MAC
algorithm to be tested to see if they produce an
expected outcome. Input to this operation is a
binary string and a calculated MAC (also in the
format of a binary string) for the binary string.
The implementation is expected to create a MAC over
the binary string using the value and algorithm.
The output of this operation is a binary indication
that the calculated MAC matched the input MAC
('true') or the MACs did not match ('false').";
reference
"RFC 9046: Babel Information Model, Section 3.8";
input {
leaf test-string {
type binary;
mandatory true;
description
"Input to this operation is a binary string.
The implementation is expected to create
a MAC over this string using the value and
the algorithm defined as part of the
mac-key-set.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
leaf mac {
type binary;
mandatory true;
description
"Input to this operation includes a MAC.
The implementation is expected to calculate a MAC
over the string using the value and algorithm of
this key object and compare its calculated MAC to
this input MAC.";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
}
output {
leaf indication {
type boolean;
mandatory true;
description
"The output of this operation is a binary
indication that the calculated MAC matched the
input MAC ('true') or the MACs did not match
('false').";
reference
"RFC 9046: Babel Information Model, Section 3.8";
}
}
}
}
}
list dtls {
key "name";
description
"A dtls object. If this object is implemented,
it provides access to parameters related to the DTLS
security mechanism.";
reference
"RFC 9046: Babel Information Model, Section 3.9";
leaf name {
type string;
description
"A string that uniquely identifies a dtls object.";
}
leaf default-apply {
type boolean;
mandatory true;
description
"A boolean flag indicating whether this object
instance is applied to all new interfaces, by default.
If 'true', this instance is applied to new interface
instances at the time they are created by including it
in the dtls-certs list under the interface. If 'false',
this instance is not applied to new interface
instances when they are created.";
reference
"RFC 9046: Babel Information Model, Section 3.9";
}
list certs {
key "name";
min-elements 1;
description
"A set of cert objects. This contains
both certificates for this implementation to present
for authentication and to accept from others.
Certificates with a non-empty private key
can be presented by this implementation for
authentication.";
reference
"RFC 9046: Babel Information Model, Section 3.10";
leaf name {
type string;
description
"A unique name for this certificate that can be
used to identify the certificate in this object
instance, since the value is too long to be useful
for identification. This value MUST NOT be empty
and can only be provided when this instance is created
(i.e., it is not subsequently writable).";
reference
"RFC 9046: Babel Information Model, Section 3.10";
}
leaf value {
nacm:default-deny-write;
type string;
mandatory true;
description
"The certificate in Privacy-Enhanced Mail (PEM) format
(RFC 7468). This value can only be provided when this
instance is created and is not subsequently
writable.";
reference
"RFC 9046: Babel Information Model, Section 3.10
RFC 7468: Textual Encodings of PKIX, PKCS, and CMS
Structures";
}
leaf type {
nacm:default-deny-write;
type identityref {
base dtls-cert-types;
}
mandatory true;
description
"The certificate type of this object instance.
The value MUST be the same as one of the
identities listed with the base 'dtls-cert-types'.
This value can only be provided when this
instance is created and is not subsequently
writable.";
reference
"RFC 9046: Babel Information Model, Section 3.10";
}
leaf private-key {
nacm:default-deny-all;
type binary;
mandatory true;
description
"The value of the private key. If this is non-empty,
this certificate can be used by this implementation to
provide a certificate during DTLS handshaking.";
reference
"RFC 9046: Babel Information Model, Section 3.10";
}
leaf algorithm {
nacm:default-deny-write;
type identityref {
base ct:private-key-format;
}
mandatory true;
description
"Identifies the algorithm identity with which the
private key has been encoded. This value can only be
provided when this instance is created and is not
subsequently writable.";
}
}
}
uses routes;
}
}
}
<CODE ENDS>
3. IANA Considerations
3.1. URI Registration
IANA has registered the following URI in the "ns" registry of the
"IETF XML Registry" [RFC3688].
URI: urn:ietf:params:xml:ns:yang:ietf-babel
Registrant Contact: The IESG
XML: N/A; the requested URI is an XML namespace.
3.2. YANG Module Name Registration
IANA has registered the following in the "YANG Module Names" registry
[RFC6020].
Name: ietf-babel
Namespace: urn:ietf:params:xml:ns:yang:ietf-babel
Prefix: babel
Reference: RFC 9647
4. Security Considerations
This section is modeled after the template defined in Section 3.7.1
of [RFC8407].
The "ietf-babel" YANG module defines a data model that is designed to
be accessed via YANG-based management protocols, such as NETCONF
[RFC6241] and RESTCONF [RFC8040]. These protocols have mandatory-to-
implement secure transport layers (e.g., Secure Shell (SSH)
[RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and mandatory-to-
implement mutual authentication.
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF users to
a preconfigured subset of all available NETCONF protocol operations
and content.
The security considerations outlined here are specific to the YANG
data model and do not cover security considerations of the Babel
protocol or its security mechanisms in "The Babel Routing Protocol"
[RFC8966], "MAC Authentication for the Babel Routing Protocol"
[RFC8967], and "Babel Routing Protocol over Datagram Transport Layer
Security" [RFC8968]. Each of these has its own Security
Considerations section for considerations that are specific to it.
There are a number of data nodes defined in the YANG module that are
writable/created/deleted (i.e., config true, which is the default).
These data nodes may be considered sensitive or vulnerable in some
network environments. Write operations (e.g., <edit-config>) to
these data nodes without proper protection can have a negative effect
on network operations. These are the subtrees and data nodes and
their sensitivity/vulnerability from a config true perspective:
'babel': This container includes an 'enable' parameter that can be
used to enable or disable use of Babel on a router.
'babel/constants': This container includes configuration parameters
that can prevent reachability if misconfigured.
'babel/interfaces': This leaf-list has configuration parameters that
can enable/disable security mechanisms and change performance
characteristics of the Babel protocol. For example, enabling
logging of packets and giving unintended access to the log files
gives an attacker detailed knowledge of the network and allows it
to launch an attack on the traffic traversing the network device.
'babel/hmac' and 'babel/dtls': These contain security credentials
that influence whether incoming packets are trusted and whether
outgoing packets are produced in such a way that the receiver will
treat them as trusted.
Some of the readable data or config false nodes in this YANG module
may be considered sensitive or vulnerable in some network
environments. It is thus important to control read access (e.g., via
get, get-config, or notification) to these data nodes. These are the
subtrees and data nodes and their sensitivity/vulnerability from a
config false perspective:
'babel': Access to the information in the various nodes can disclose
the network topology. Additionally, the routes used by a network
device may be used to mount a subsequent attack on traffic
traversing the network device.
'babel/hmac' and 'babel/dtls': These contain security credentials,
including private credentials of the router; however, it is
required that these values not be readable.
Some of the RPC operations in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control access to these operations. These are the
operations and their sensitivity/vulnerability from an RPC operation
perspective:
This model defines two actions. Resetting the statistics within an
interface container would be visible to any monitoring processes,
which should be designed to account for the possibility of such a
reset. The "test" action allows for validation that a MAC key and
MAC algorithm have been properly configured. The MAC key is a
sensitive piece of information, and it is important to prevent an
attacker that does not know the MAC key from being able to determine
the MAC value by trying different input parameters. The "test"
action has been designed to not reveal such information directly.
Such information might also be revealed indirectly due to side
channels such as the time it takes to produce a response to the
action. Implementations SHOULD use a constant-time comparison
between the input MAC and the locally generated MAC value for
comparison in order to avoid such side channel leakage.
5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/info/rfc4252>.
[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
384, and HMAC-SHA-512 with IPsec", RFC 4868,
DOI 10.17487/RFC4868, May 2007,
<https://www.rfc-editor.org/info/rfc4868>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7693] Saarinen, M., Ed. and J. Aumasson, "The BLAKE2
Cryptographic Hash and Message Authentication Code (MAC)",
RFC 7693, DOI 10.17487/RFC7693, November 2015,
<https://www.rfc-editor.org/info/rfc7693>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.
[RFC8349] Lhotka, L., Lindem, A., and Y. Qu, "A YANG Data Model for
Routing Management (NMDA Version)", RFC 8349,
DOI 10.17487/RFC8349, March 2018,
<https://www.rfc-editor.org/info/rfc8349>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8966] Chroboczek, J. and D. Schinazi, "The Babel Routing
Protocol", RFC 8966, DOI 10.17487/RFC8966, January 2021,
<https://www.rfc-editor.org/info/rfc8966>.
[RFC8967] Dô, C., Kolodziejak, W., and J. Chroboczek, "MAC
Authentication for the Babel Routing Protocol", RFC 8967,
DOI 10.17487/RFC8967, January 2021,
<https://www.rfc-editor.org/info/rfc8967>.
[RFC8968] Décimo, A., Schinazi, D., and J. Chroboczek, "Babel
Routing Protocol over Datagram Transport Layer Security",
RFC 8968, DOI 10.17487/RFC8968, January 2021,
<https://www.rfc-editor.org/info/rfc8968>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9046] Stark, B. and M. Jethanandani, "Babel Information Model",
RFC 9046, DOI 10.17487/RFC9046, June 2021,
<https://www.rfc-editor.org/info/rfc9046>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
<https://www.rfc-editor.org/info/rfc9147>.
[RFC9640] Watsen, K., "YANG Data Types and Groupings for
Cryptography", RFC 9640, DOI 10.17487/RFC9640, October
2024, <https://www.rfc-editor.org/info/rfc9640>.
5.2. Informative References
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
April 2015, <https://www.rfc-editor.org/info/rfc7468>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8407] Bierman, A., "Guidelines for Authors and Reviewers of
Documents Containing YANG Data Models", BCP 216, RFC 8407,
DOI 10.17487/RFC8407, October 2018,
<https://www.rfc-editor.org/info/rfc8407>.
[W3C.REC-xml-20081126]
Bray, T., Paoli, J., Sperberg-McQueen, C. M., Maler, E.,
and F. Yergeau, "Extensible Markup Language (XML) 1.0
(Fifth Edition)", W3C Recommendation REC-xml-20081126,
November 2008, <https://www.w3.org/TR/xml/>.
Appendix A. Tree Diagram and Example Configurations
This section is devoted to including a complete tree diagram and
examples that demonstrate how Babel can be configured.
Note that various examples are encoded using Extensible Markup
Language (XML) [W3C.REC-xml-20081126].
A.1. Complete Tree Diagram
This section includes the complete tree diagram for the Babel YANG
module.
module: ietf-babel
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol:
+--rw babel!
+--ro version? string
+--rw enable boolean
+--ro router-id? binary
+--ro seqno? uint16
+--rw statistics-enabled? boolean
+--rw constants
| +--rw udp-port? inet:port-number
| +--rw mcast-group? inet:ip-address
+--rw interfaces* [reference]
| +--rw reference if:interface-ref
| +--rw enable? boolean
| +--rw metric-algorithm identityref
| +--rw split-horizon? boolean
| +--ro mcast-hello-seqno? uint16
| +--rw mcast-hello-interval? uint16
| +--rw update-interval? uint16
| +--rw mac-enable? boolean
| +--rw mac-key-sets* -> ../../mac-key-set/name
| +--rw mac-verify? boolean
| +--rw dtls-enable? boolean
| +--rw dtls-certs* -> ../../dtls/name
| +--rw dtls-cached-info? boolean
| +--rw dtls-cert-prefer* -> ../../dtls/certs/type
| +--rw packet-log-enable? boolean
| +--ro packet-log? inet:uri
| +--ro statistics
| | +--ro discontinuity-time yang:date-and-time
| | +--ro sent-mcast-hello? yang:counter32
| | +--ro sent-mcast-update? yang:counter32
| | +--ro sent-ucast-hello? yang:counter32
| | +--ro sent-ucast-update? yang:counter32
| | +--ro sent-ihu? yang:counter32
| | +--ro received-packets? yang:counter32
| | +---x reset
| | +---w input
| | | +---w reset-at? yang:date-and-time
| | +--ro output
| | +--ro reset-finished-at? yang:date-and-time
| +--ro neighbor-objects* [neighbor-address]
| +--ro neighbor-address inet:ip-address
| +--ro hello-mcast-history? string
| +--ro hello-ucast-history? string
| +--ro txcost? int32
| +--ro exp-mcast-hello-seqno? union
| +--ro exp-ucast-hello-seqno? union
| +--ro ucast-hello-seqno? union
| +--ro ucast-hello-interval? uint16
| +--ro rxcost? uint16
| +--ro cost? int32
+--rw mac-key-set* [name]
| +--rw name string
| +--rw default-apply? boolean
| +--rw keys* [name]
| +--rw name string
| +--rw use-send boolean
| +--rw use-verify boolean
| +--rw value binary
| +--rw algorithm identityref
| +---x test
| +---w input
| | +---w test-string binary
| | +---w mac binary
| +--ro output
| +--ro indication boolean
+--rw dtls* [name]
| +--rw name string
| +--rw default-apply boolean
| +--rw certs* [name]
| +--rw name string
| +--rw value string
| +--rw type identityref
| +--rw private-key binary
| +--rw algorithm identityref
+--ro routes* [prefix]
+--ro prefix inet:ip-prefix
+--ro router-id? binary
+--ro neighbor? leafref
+--ro received-metric? union
+--ro calculated-metric? union
+--ro seqno? uint16
+--ro next-hop? union
+--ro feasible? boolean
+--ro selected? boolean
A.2. Statistics Gathering Enabled
In this example, interface eth0 is being configured for routing
protocol Babel, and statistics gathering is enabled. For security,
HMAC-SHA256 is supported. Every sent Babel packet is signed with the
key value provided, and every received Babel packet is verified with
the same key value.
<?xml version="1.0" encoding="UTF-8"?>
<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
</interface>
</interfaces>
<routing
xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
<control-plane-protocols>
<control-plane-protocol>
<type
xmlns:babel=
"urn:ietf:params:xml:ns:yang:ietf-babel">babel:babel</type>
<name>name:babel</name>
<babel
xmlns="urn:ietf:params:xml:ns:yang:ietf-babel">
<enable>true</enable>
<statistics-enabled>true</statistics-enabled>
<interfaces>
<reference>eth0</reference>
<metric-algorithm>two-out-of-three</metric-algorithm>
<split-horizon>true</split-horizon>
</interfaces>
<mac-key-set>
<name>hmac-sha256</name>
<keys>
<name>hmac-sha256-keys</name>
<use-send>true</use-send>
<use-verify>true</use-verify>
<value>base64encodedvalue==</value>
<algorithm>hmac-sha256</algorithm>
</keys>
</mac-key-set>
</babel>
</control-plane-protocol>
</control-plane-protocols>
</routing>
A.3. Automatic Detection of Properties
In this example, babeld is configured on two interfaces:
interface eth0
interface wlan0
This says to run Babel on interfaces eth0 and wlan0. Babeld will
automatically detect that eth0 is wired and wlan0 is wireless and
will configure the right parameters automatically.
<?xml version="1.0" encoding="UTF-8"?>
<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
</interface>
<interface>
<name>wlan0</name>
<type>ianaift:ieee80211</type>
<enabled>true</enabled>
</interface>
</interfaces>
<routing
xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
<control-plane-protocols>
<control-plane-protocol>
<type
xmlns:babel=
"urn:ietf:params:xml:ns:yang:ietf-babel">babel:babel</type>
<name>name:babel</name>
<babel
xmlns="urn:ietf:params:xml:ns:yang:ietf-babel">
<enable>true</enable>
<interfaces>
<reference>eth0</reference>
<enable>true</enable>
<metric-algorithm>two-out-of-three</metric-algorithm>
<split-horizon>true</split-horizon>
</interfaces>
<interfaces>
<reference>wlan0</reference>
<enable>true</enable>
<metric-algorithm>etx</metric-algorithm>
<split-horizon>false</split-horizon>
</interfaces>
</babel>
</control-plane-protocol>
</control-plane-protocols>
</routing>
A.4. Override Default Properties
In this example, babeld is configured on three interfaces:
interface eth0
interface eth1 type wireless
interface tun0 type tunnel
Here, interface eth1 is an Ethernet bridged to a wireless radio, so
babeld's autodetection fails, and the interface type needs to be
configured manually. Tunnels are not detected automatically, so this
needs to be specified.
This is equivalent to the following:
interface eth0 metric-algorithm 2-out-of-3 split-horizon true
interface eth1 metric-algorithm etx split-horizon false
interface tun0 metric-algorithm 2-out-of-3 split-horizon true
<?xml version="1.0" encoding="UTF-8"?>
<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
</interface>
<interface>
<name>eth1</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
</interface>
<interface>
<name>tun0</name>
<type>ianaift:tunnel</type>
<enabled>true</enabled>
</interface>
</interfaces>
<routing
xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
<control-plane-protocols>
<control-plane-protocol>
<type
xmlns:babel=
"urn:ietf:params:xml:ns:yang:ietf-babel">babel:babel</type>
<name>name:babel</name>
<babel
xmlns="urn:ietf:params:xml:ns:yang:ietf-babel">
<enable>true</enable>
<interfaces>
<reference>eth0</reference>
<enable>true</enable>
<metric-algorithm>two-out-of-three</metric-algorithm>
<split-horizon>true</split-horizon>
</interfaces>
<interfaces>
<reference>eth1</reference>
<enable>true</enable>
<metric-algorithm>etx</metric-algorithm>
<split-horizon>false</split-horizon>
</interfaces>
<interfaces>
<reference>tun0</reference>
<enable>true</enable>
<metric-algorithm>two-out-of-three</metric-algorithm>
<split-horizon>true</split-horizon>
</interfaces>
</babel>
</control-plane-protocol>
</control-plane-protocols>
</routing>
A.5. Configuring Other Properties
In this example, two interfaces are configured for babeld:
interface eth0
interface ppp0 hello-interval 30 update-interval 120
Here, ppp0 is a metered 3G link used for fallback connectivity. It
runs with much higher than default time constants in order to avoid
control traffic as much as possible.
<?xml version="1.0" encoding="UTF-8"?>
<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:ianaift="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>ianaift:ethernetCsmacd</type>
<enabled>true</enabled>
</interface>
<interface>
<name>ppp0</name>
<type>ianaift:ppp</type>
<enabled>true</enabled>
</interface>
</interfaces>
<routing
xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
<control-plane-protocols>
<control-plane-protocol>
<type
xmlns:babel=
"urn:ietf:params:xml:ns:yang:ietf-babel">babel:babel</type>
<name>name:babel</name>
<babel
xmlns="urn:ietf:params:xml:ns:yang:ietf-babel">
<enable>true</enable>
<interfaces>
<reference>eth0</reference>
<enable>true</enable>
<metric-algorithm>two-out-of-three</metric-algorithm>
<split-horizon>true</split-horizon>
</interfaces>
<interfaces>
<reference>ppp0</reference>
<enable>true</enable>
<mcast-hello-interval>30</mcast-hello-interval>
<update-interval>120</update-interval>
<metric-algorithm>two-out-of-three</metric-algorithm>
</interfaces>
</babel>
</control-plane-protocol>
</control-plane-protocols>
</routing>
Acknowledgements
Juliusz Chroboczek provided most of the example configurations for
babel that are shown in Appendix A.
Authors' Addresses
Mahesh Jethanandani
Kloud Services
California
United States of America
Email: mjethanandani@gmail.com
Barbara Stark
AT&T
Atlanta, GA
United States of America
Email: barbara.stark@att.com
