| Internet-Draft | BFD Authentication Optimization | February 2024 |
| Jethanandani, et al. | Expires 8 August 2024 | [Page] |
This document describes an optimization to BFD Authentication as described in Section 6.7 of BFD RFC 5880. This document updates RFC 5880.¶
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 https://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 8 August 2024.¶
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.¶
Authenticating every BFD [RFC5880] control packet with MD5 Message-Digest Algorithm [RFC1321], or Secure Hash Algorithm (SHA-1) is a computationally intensive process. This makes it difficult, if not impossible to authenticate every packet - particularly at faster rates. Also, the recent escalating series of attacks on MD5 and SHA-1 described in Finding Collisions in the Full SHA-1 [SHA-1-attack1] and New Collision Search for SHA-1 [SHA-1-attack2] raise concerns about their remaining useful lifetime as outlined in Updated Security Considerations for the MD5 Message-Digest and the HMAC-MD5 Algorithm [RFC6151] and Security Considerations for the SHA-0 and SHA-1 Message-Digest Algorithm [RFC6194]. If replaced by stronger algorithms, the computational overhead, will make the task of authenticating every packet even more difficult to achieve.¶
This document proposes that BFD control packets that signal a state change, a demand mode change (to D bit), a poll sequence change (P or F bit change) be categorized as a significant change. Control packets that do not require a poll sequence, such as bfd.RequiredMinRxInterval or bfd.RequiredMinTxInterval, are also considered as a significant change. In other words, the contents of an Up packet MUST NOT change aside from the authentication section without stronger authentication to take advantage of the method described in this document.¶
In the Up state, most packets that are transmitted and received have no state change associated with them. Limiting authentication to packets that affect a BFD session's state allows more sessions to be supported with this optimized method of authentication.¶
Once the session has reached the Up state, the session can choose the Auth Type to be one of:¶
To detect a Person In the Middle (PITM) attack when the session is in Up state, implementations have two options. They can choose to use:¶
Most packets transmitted on a BFD session are BFD Up packets. Authenticating a small subset of these packets with a Poll sequence as described above, for example every one minute, significantly reduces the computational demand for the system while maintaining security of the session across the configured interval.¶
The rest of this document is structured as follows: Section 2 talks about the changes to authentication mode as described in BFD [RFC5880]. Section 3 goes into the details of the new Authentication Type.¶
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 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
This document uses several placeholder values throughout the document. Please replace them as follows and remove this note before publication.¶
RFC XXXX, where XXXX is the number assigned to this document at the time of publication.¶
2024-02-05 with the actual date of the publication of this document.¶
The following terms used in this document have been defined in BFD [RFC5880].¶
The following terms are introduced in this document.¶
| Term | Meaning |
|---|---|
| significant change | State change, a demand mode change (to D bit) or a poll sequence change (P or F bit). Control packets that do not require a poll sequence, such as bfd.RequiredMinRxInterval bfd.RequiredMinTxInterval, or bfd.DetectMult are also considered as a significant change. |
| configured interval | Interval at which BFD control packets are retried with a stronger authentication. |
The cryptographic authentication mechanisms specified in BFD [RFC5880] describes enabling and disabling of authentication as a one time operation. As a security precaution, it mentions that authentication state be allowed to change at most once. Once enabled, every packet must have Authentication Bit set and the associated Authentication Type appended. In addition, it states that an implementation SHOULD NOT allow the authentication state to be changed based on the receipt of a BFD control packet.¶
This document proposes that the authentication mode be modified to be enabled on demand. Instead of authenticating every packet, BFD peers are configured for which packets need to be authenticated, and authenticate only those packets. The remaining packets MAY be transmitted and received without authentication, or use a less expensive authentication. For example, the two ends can be configured such that BFD control packets that indicate a significant change should be authenticated and enable authentication on those packets only. If the two ends have previously been configured as such, but at least one side decides not to authenticate a significant change packet, then the BFD session will fail to come up.¶
The proposal outlines which BFD control packets are required to be authenticated. A BFD control packet that fails authentication is discarded, or a BFD control packet that was supposed to be authenticated, but was not; e.g. a significant change packet, is discarded. However, there is no change to the state machine for BFD, as the decision of a significant change is still decided by how many valid consecutive packets were received, authenticated or otherwise.¶
The following table summarizes when the Auth Type should be set with a Auth or a OPT authentication type. The table should be read with the column indicating the BFD state the receiver is currently in, and the row indicating the BFD state the receiver might transition to based on the BFD control packet received. The intersection of the two indicates whether the received BFD control packet should have the Auth Type set to either Auth, or OPT. The BFD state refers to the states in BFD state machine described in Section 6.2 of BFD [RFC5880].¶
Read : On state change from <column> to <row>
Auth : Strongly authenticated BFD control packet
OPT : Any or no authentication, as configured.
n/a : Invalid state transition.
Select : Most packets OPT AUTH. Selective (periodic)
packets authenticated.
+--------+--------+--------+--------+
| | DOWN | INIT | UP |
+--------+--------+--------+--------+
| DOWN | OPT | Auth | Auth |
+--------+--------+--------+--------+
| INIT | Auth | OPT | n/a |
+--------+--------+--------+--------+
| UP | Auth | Auth | Select |
+--------+--------+--------+--------+
In other words, the contents of an Up packet MUST NOT change aside from the authentication section without stronger authentication.¶
Implementations supporting this feature can send BFD packets with or without authentication that carries a meticulously increasing sequence number. This meticulously increasing sequence number prevents replay attacks, and it supports BFD Stability [I-D.ietf-bfd-stability].¶
The NULL Authentication type is defined in NULL Authentication Type (Section 3). This authentication type does not provide any authentication of the BFD Control Up packets, but does carry a meticulously increasing sequence number compatible with this specification.¶
Secure BFD Sequence Numbers [I-D.ietf-bfd-secure-sequence-numbers] defines an authentication mechanism that does not provide any authentication of the BFD Control packets, carries a meticulously increasing sequence number, but provides for a stronger mechanism to prevent active attacks against these procedures for Up packets without requiring strong authentication.¶
This section describes a new Authentication Type as:¶
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Auth Len | Auth Key ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:¶
Auth Type: The Authentication Type, which in this case is TBD (NULL, to be assigned by IANA, with a suggested value of 6).¶
Auth Len: The length of the NULL Auth Type, in bytes; i.e. 8 bytes¶
Auth Key ID: The authentication key ID in use for this packet. Must be set to zero.¶
Reserved: This byte MUST be set to zero on transmit and ignored on receive.¶
Sequence Number: The sequence number for this packet. Implementations will use sequence numbers (bfd.XmitAuthSeq) as defined in BFD [RFC5880].¶
The YANG 1.1 [RFC7950] model defined in this document augments the "ietf-bfd" module to add configuration relevant to the management of the feature defined in this document. In particular, it adds crypto algorithms that are described in this model, and in Secure BFD Sequence Numbers [I-D.ietf-bfd-secure-sequence-numbers]. It adds a feature statement to enable optimized authentication. Finally, it adds a flag to enable optimized authentication, an interval value that specifies how often the BFD session should be re-authenticated once it is in the Up state, and the key chain that should be used in the Up state.¶
The tree diagram for the YANG modules defined in this document use annotations defined in YANG Tree Diagrams. [RFC8340].¶
module: ietf-bfd-opt-auth
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh
/bfd-ip-sh:sessions/bfd-ip-sh:session
/bfd-ip-sh:authentication:
+--rw optimized-auth? boolean {optimized-auth}?
+--rw reauth-interval? uint32
+--rw up-auth-type? key-chain:key-chain-ref
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/bfd:bfd/bfd-ip-mh:ip-mh
/bfd-ip-mh:session-groups/bfd-ip-mh:session-group
/bfd-ip-mh:authentication:
+--rw optimized-auth? boolean {optimized-auth}?
+--rw reauth-interval? uint32
+--rw up-auth-type? key-chain:key-chain-ref
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/bfd:bfd/bfd-lag:lag
/bfd-lag:sessions/bfd-lag:session/bfd-lag:authentication:
+--rw optimized-auth? boolean {optimized-auth}?
+--rw reauth-interval? uint32
+--rw up-auth-type? key-chain:key-chain-ref
augment /rt:routing/rt:control-plane-protocols
/rt:control-plane-protocol/bfd:bfd/bfd-mpls:mpls
/bfd-mpls:session-groups/bfd-mpls:session-group
/bfd-mpls:authentication:
+--rw optimized-auth? boolean {optimized-auth}?
+--rw reauth-interval? uint32
+--rw up-auth-type? key-chain:key-chain-ref
¶
This YANG module imports YANG Key Chain [RFC8177], A YANG Data Model for Routing Management (NMDA version) [RFC8349], and YANG Data Model for Bidirectional Forwading Detection (BFD) [RFC9314].¶
<CODE BEGINS> file "ietf-bfd-opt-auth@2024-02-05.yang"
module ietf-bfd-opt-auth {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-bfd-opt-auth";
prefix "bfdoa";
import ietf-routing {
prefix "rt";
reference
"RFC 8349: A YANG Data Model for Routing Management
(NMDA version)";
}
import ietf-bfd {
prefix bfd;
reference
"RFC 9314: YANG Data Model for Bidirectional
Forwarding Detection.";
}
import ietf-bfd-ip-sh {
prefix bfd-ip-sh;
reference
"RFC 9314: YANG Data Model for Bidirectional
Forwarding Detection.";
}
import ietf-bfd-ip-mh {
prefix bfd-ip-mh;
reference
"RFC 9314: YANG Data Model for Bidirectional
Forwarding Detection.";
}
import ietf-bfd-lag {
prefix bfd-lag;
reference
"RFC 9314: YANG Data Model for Bidirectional
Forwarding Detection.";
}
import ietf-bfd-mpls {
prefix bfd-mpls;
reference
"RFC 9314: YANG Data Model for Bidirectional
Forwarding Detection.";
}
import ietf-key-chain {
prefix key-chain;
reference
"RFC 8177: YANG Key Chain.";
}
organization
"IETF BFD Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/bfd>
WG List: <rtg-bfd@ietf.org>
Authors: Mahesh Jethanandani (mjethanandani@gmail.com)
Ashesh Mishra (mishra.ashesh@gmail.com)
Ankur Saxena (ankurpsaxena@gmail.com)
Manav Bhatia (mnvbhatia@google.com).";
description
"This YANG module augments the base BFD YANG model to add
attributes related to BFD Optimized Authentication.
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 XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
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.";
revision "2024-02-05" {
description
"Initial Version.";
reference
"RFC XXXX: Optimizing BFD Authentication.";
}
feature optimized-auth {
description
"When enabled, this implementation supports optimized
authentication as described in this document.";
}
identity no-auth {
base key-chain:crypto-algorithm;
description
"No authentication will be used.";
}
identity null {
base key-chain:crypto-algorithm;
description
"BFD Null type defined in this draft.";
reference
"RFC XXXX: Optimizing BFD Authentication.";
}
identity meticulous-keyed-isaac {
base key-chain:crypto-algorithm;
description
"BFD ISAAC Keyed Meticulous.";
reference
"I-D.ietf-bfd-secure-sequence-numbers: Securing BFD Sequence
Numbers.";
}
augment "/rt:routing/rt:control-plane-protocols" +
"/rt:control-plane-protocol/bfd:bfd/bfd-ip-sh:ip-sh" +
"/bfd-ip-sh:sessions/bfd-ip-sh:session" +
"/bfd-ip-sh:authentication" {
leaf optimized-auth {
if-feature optimized-auth;
type boolean;
default false;
description
"If set to true, BFD Single Hop Sessions will be
enabled for optimized authentication.";
}
leaf reauth-interval {
when "../optimized-auth = 'true'";
type uint32;
units "microseconds";
default "60000000";
description
"Interval of time after which a strong authentication
should be enabled to prevent a Person-In-The-Middle
attack. Default is 1 minute.
This value SHOULD have jitter applied to it to avoid
self-synchronization during expensive authentication
operations.";
}
leaf up-auth-type {
type key-chain:key-chain-ref;
must "(../optimized-auth = 'true') and " +
"(../bfd-ip-sh:meticulous = 'true')";
description
"The authentication type that should be used once the
connection transitions to Up state. In case
of optimized auth, the choices are Reserved (or no
authentication), NULL Auth, or Meticulous Keyed ISAAC.";
}
description
"Augment the 'bfd' container to add attributes related to BFD
optimized authentication.";
}
augment "/rt:routing/rt:control-plane-protocols/" +
"rt:control-plane-protocol/bfd:bfd/bfd-ip-mh:ip-mh/" +
"bfd-ip-mh:session-groups/bfd-ip-mh:session-group/" +
"bfd-ip-mh:authentication" {
leaf optimized-auth {
if-feature optimized-auth;
type boolean;
default false;
description
"If set to true, BFD Multi Hop Sessions will be
enabled for optimized authentication.";
}
leaf reauth-interval {
when "../optimized-auth = 'true'";
type uint32;
units "microseconds";
default "60000000";
description
"Interval of time after which a strong authentication
should be enabled to prevent a Person-In-The-Middle
attack. Default is 1 minute.
This value SHOULD have jitter applied to it to avoid
self-synchronization during expensive authentication
operations.";
}
leaf up-auth-type {
type key-chain:key-chain-ref;
must "(../optimized-auth = 'true') and " +
"(../bfd-ip-mh:meticulous = 'true')";
description
"The authentication type that should be used once the
connection transitions to Up state. In case
of optimized auth, the choices are Reserved (or no
authentication), NULL Auth, or Meticulous Keyed ISAAC.";
}
description
"Augment the 'bfd' container to add attributes related to BFD
optimized authentication.";
}
augment "/rt:routing/rt:control-plane-protocols/" +
"rt:control-plane-protocol/bfd:bfd/bfd-lag:lag/" +
"bfd-lag:sessions/bfd-lag:session/" +
"bfd-lag:authentication" {
leaf optimized-auth {
if-feature optimized-auth;
type boolean;
default false;
description
"If set to true, BFD LAG Sessions will be
enabled for optimized authentication.";
}
leaf reauth-interval {
when "../optimized-auth = 'true'";
type uint32;
units "microseconds";
default "60000000";
description
"Interval of time after which a strong authentication
should be enabled to prevent a Person-In-The-Middle
attack. Default is 1 minute.
This value SHOULD have jitter applied to it to avoid
self-synchronization during expensive authentication
operations.";
}
leaf up-auth-type {
type key-chain:key-chain-ref;
must "(../optimized-auth = 'true') and " +
"(../bfd-lag:meticulous = 'true')";
description
"The authentication type that should be used once the
connection transitions to Up state. In case
of optimized auth, the choices are Reserved (or no
authentication), NULL Auth, or Meticulous Keyed ISAAC.";
}
description
"Augment the 'bfd' container to add attributes related to BFD
optimized authentication.";
}
augment "/rt:routing/rt:control-plane-protocols/" +
"rt:control-plane-protocol/bfd:bfd/bfd-mpls:mpls/" +
"bfd-mpls:session-groups/bfd-mpls:session-group/" +
"bfd-mpls:authentication" {
leaf optimized-auth {
if-feature optimized-auth;
type boolean;
default false;
description
"If set to true, BFD MPLS Sessions will be
enabled for optimized authentication.";
}
leaf reauth-interval {
when "../optimized-auth = 'true'";
type uint32;
units "microseconds";
default "60000000";
description
"Interval of time after which a strong authentication
should be enabled to prevent a Person-In-The-Middle
attack. Default is 1 minute.
This value SHOULD have jitter applied to it to avoid
self-synchronization during expensive authentication
operations.";
}
leaf up-auth-type {
type key-chain:key-chain-ref;
must "(../optimized-auth = 'true') and " +
"(../bfd-mpls:meticulous = 'true')";
description
"The authentication type that should be used once the
connection transitions to Up state. In case
of optimized auth, the choices are Reserved (or no
authentication), NULL Auth, or Meticulous Keyed ISAAC.";
}
description
"Augment the 'bfd' container to add attributes related to BFD
optimized authentication.";
}
}
<CODE ENDS>¶
This documents requests two new authentication types, one URI, one YANG model, and an update to an existing IANA YANG model.¶
This document requests an update to the registry titled "BFD Authentication Types". IANA is requested to assign two new BFD AuthType:¶
This document registers one URIs in the "ns" subregistry of the "IETF XML" registry [RFC3688]. Following the format in [RFC3688], the following registration is requested:¶
URI: urn:ietf:params:xml:ns:yang:ietf-bfd-opt-auth Registrant Contact: The IESG XML: N/A, the requested URI is an XML namespace.¶
This document registers one YANG modules in the "YANG Module Names" registry [RFC6020]. Following the format in [RFC6020], the following registrations are requested:¶
name: ietf-bfd-opt-auth namespace: urn:ietf:params:xml:ns:yang:ietf-bfd-opt-auth prefix: bfdoa reference: RFC XXXX¶
This document also requests an update to an existing IANA YANG module described in Updated BFD IANA Module (Appendix A)¶
The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446]. The NETCONF Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶
There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (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. Some of the subtrees and data nodes and their sensitivity/vulnerability are described here.¶
Some of the readable data 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.¶
There are no read-only data nodes defined in this model.¶
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.¶
There are no RPC operations defined in this model.¶
The approach described in this document enhances the ability to authenticate a BFD session by taking away the onerous requirement that every BFD control packet be authenticated. By authenticating packets that affect the state of the session, the security of the BFD session is maintained. In this mode, packets that are a significant change but are not authenticated, are dropped by the system. Therefore, a malicious user that tries to inject a non-authenticated packet; e.g. with a Down state to take a session down will fail. That combined with the proposal of using sequence number defined in Secure BFD Sequence Numbers [I-D.ietf-bfd-secure-sequence-numbers] further enhances the security of BFD sessions.¶
This section carries the updated IANA BFD Module, iana-bfd-types.yang module, first defined in YANG Data Model for Bidirectional Forward Detection (BFD) [RFC9127]. The updated module carries two new authentication type enum definitions, 'null' with a suggested value of 6, and 'meticulous-keyed-isaac' with a suggested value of 7. This module should replace the version that currently exists in the IANA registry.¶
<CODE BEGINS> file "iana-bfd-types@2024-02-05.yang"
=============== NOTE: '\' line wrapping per RFC 8792 ===============
module iana-bfd-types {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:iana-bfd-types";
prefix iana-bfd-types;
organization
"IANA";
contact
"Internet Assigned Numbers Authority
Postal: ICANN
12025 Waterfront Drive, Suite 300
Los Angeles, CA 90094-2536
United States of America
Tel: +1 310 301 5800
<mailto:iana@iana.org>";
description
"This module defines YANG data types for IANA-registered
BFD parameters.
This YANG module is maintained by IANA and reflects the
'BFD Diagnostic Codes' and 'BFD Authentication Types'
registries.
Copyright (c) 2021 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 9127; see the
RFC itself for full legal notices.";
reference
"RFC 9127: YANG Data Model for Bidirectional Forwarding
Detection (BFD)";
revision 2024-02-05 {
description
"Add NULL and Meticulous ISAAC authentication type.";
reference
"I-D.ietf-bfd-optimized-auth: Optimizing BFD Authentication.";
}
revision 2021-10-21 {
description
"Initial revision.";
reference
"RFC 9127: YANG Data Model for Bidirectional Forwarding
Detection (BFD)";
}
/*
* Type definitions
*/
typedef diagnostic {
type enumeration {
enum none {
value 0;
description
"No Diagnostic.";
}
enum control-expiry {
value 1;
description
"Control Detection Time Expired.";
}
enum echo-failed {
value 2;
description
"Echo Function Failed.";
}
enum neighbor-down {
value 3;
description
"Neighbor Signaled Session Down.";
}
enum forwarding-reset {
value 4;
description
"Forwarding Plane Reset.";
}
enum path-down {
value 5;
description
"Path Down.";
}
enum concatenated-path-down {
value 6;
description
"Concatenated Path Down.";
}
enum admin-down {
value 7;
description
"Administratively Down.";
}
enum reverse-concatenated-path-down {
value 8;
description
"Reverse Concatenated Path Down.";
}
enum mis-connectivity-defect {
value 9;
description
"Mis-connectivity defect.";
reference
"RFC 5880: Bidirectional Forwarding Detection (BFD)
RFC 6428: Proactive Connectivity Verification, Continuity
Check, and Remote Defect Indication for the MPLS Transpo\
rt
Profile";
}
}
description
"BFD diagnostic codes as defined in RFC 5880. Values are
maintained in the 'BFD Diagnostic Codes' IANA registry.
Range is 0 to 31.";
reference
"RFC 5880: Bidirectional Forwarding Detection (BFD)";
}
typedef auth-type {
type enumeration {
enum reserved {
value 0;
description
"Reserved.";
}
enum simple-password {
value 1;
description
"Simple Password.";
}
enum keyed-md5 {
value 2;
description
"Keyed MD5.";
}
enum meticulous-keyed-md5 {
value 3;
description
"Meticulous Keyed MD5.";
}
enum keyed-sha1 {
value 4;
description
"Keyed SHA1.";
}
enum meticulous-keyed-sha1 {
value 5;
description
"Meticulous Keyed SHA1.";
}
enum null {
value 6;
description
"NULL Auth.";
}
enum meticulous-keyed-isaac {
value 7;
description
"Meticulous Keyed ISAAC.";
}
}
description
"BFD authentication type as defined in RFC 5880. Values are
maintained in the 'BFD Authentication Types' IANA registry.
Range is 0 to 255.";
reference
"RFC 5880: Bidirectional Forwarding Detection (BFD)";
}
}
<CODE ENDS>¶
This section tries to show some examples in how the model can be configured.¶
This example demonstrates how a Single Hop BFD session can be configured for optimized authentication.¶
=============== NOTE: '\' line wrapping per RFC 8792 ===============
<?xml version="1.0" encoding="UTF-8"?>
<key-chains
xmlns="urn:ietf:params:xml:ns:yang:ietf-key-chain">
<key-chain>
<name>bfd-auth-config</name>
<description>"An example for BFD Optimized Auth configuration."\
</description>
<key>
<key-id>55</key-id>
<lifetime>
<send-lifetime>
<start-date-time>2017-01-01T00:00:00Z</start-date-time>
<end-date-time>2017-02-01T00:00:00Z</end-date-time>
</send-lifetime>
<accept-lifetime>
<start-date-time>2016-12-31T23:59:55Z</start-date-time>
<end-date-time>2017-02-01T00:00:05Z</end-date-time>
</accept-lifetime>
</lifetime>
<crypto-algorithm xmlns:opt-auth=
"urn:ietf:params:xml:ns:yang:ietf-bfd-opt-auth">opt-auth:meti\
culous-keyed-isaac</crypto-algorithm>
<key-string>
<keystring>testvector</keystring>
</key-string>
</key>
</key-chain>
</key-chains>
<interfaces
xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces"
xmlns:if-type="urn:ietf:params:xml:ns:yang:iana-if-type">
<interface>
<name>eth0</name>
<type>if-type:ethernetCsmacd</type>
</interface>
</interfaces>
<routing
xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"
xmlns:bfd-types="urn:ietf:params:xml:ns:yang:ietf-bfd-types"
xmlns:iana-bfd-types="urn:ietf:params:xml:ns:yang:iana-bfd-type\
s"
xmlns:opt-auth="urn:ietf:params:xml:ns:yang:ietf-bfd-opt-auth">
<control-plane-protocols>
<control-plane-protocol>
<type>bfd-types:bfdv1</type>
<name>name:BFD</name>
<bfd xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd">
<ip-sh xmlns="urn:ietf:params:xml:ns:yang:ietf-bfd-ip-sh">
<sessions>
<session>
<interface>eth0</interface>
<dest-addr>2001:db8:0:113::101</dest-addr>
<desired-min-tx-interval>10000</desired-min-tx-interv\
al>
<required-min-rx-interval>
10000
</required-min-rx-interval>
<authentication>
<meticulous>true</meticulous>
<opt-auth:optimized-auth>true</opt-auth:optimized-a\
uth>
<opt-auth:reauth-interval>30000</opt-auth:reauth-in\
terval>
<opt-auth:up-auth-type>bfd-auth-config</opt-auth:up\
-auth-type>
</authentication>
</session>
</sessions>
</ip-sh>
</bfd>
</control-plane-protocol>
</control-plane-protocols>
</routing>
¶