Internet DRAFT - draft-zheng-bfd-yang
draft-zheng-bfd-yang
Network Working Group L. Zheng, Ed.
Internet-Draft Huawei Technologies
Intended status: Standards Track R. Rahman, Ed.
Expires: January 6, 2016 Cisco Systems
S. Pallagatti
Juniper Networks
M. Jethanandani
Cisco Systems
G. Mirsky
Ericsson
July 05, 2015
Yang Data Model for Bidirectional Forwarding Detection (BFD)
draft-zheng-bfd-yang-04.txt
Abstract
This document defines a YANG data model that can be used to configure
and manage Bidirectional Forwarding Detection (BFD).
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 6, 2016.
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Copyright Notice
Copyright (c) 2015 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
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to this document. Code Components extracted from this document must
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Contributors . . . . . . . . . . . . . . . . . . . . . . 3
2. Design of the Data Model . . . . . . . . . . . . . . . . . . 3
2.1. Design of Configuration Model . . . . . . . . . . . . . . 4
2.1.1. Single-hop IP . . . . . . . . . . . . . . . . . . . . 4
2.1.2. Multi-hop IP . . . . . . . . . . . . . . . . . . . . 5
2.1.3. Traffic Engineering Tunnels . . . . . . . . . . . . . 6
2.1.4. LDP Label Switched Paths . . . . . . . . . . . . . . 6
2.1.5. Link Aggregation Groups . . . . . . . . . . . . . . . 6
2.1.6. Per-interface Configuration . . . . . . . . . . . . . 7
2.2. Design of Operational Model . . . . . . . . . . . . . . . 7
2.3. Notifications . . . . . . . . . . . . . . . . . . . . . . 8
2.4. RPC Operations . . . . . . . . . . . . . . . . . . . . . 8
2.5. BFD Configuration Data Hierarchy . . . . . . . . . . . . 8
2.5.1. Centralized BFD Configuration . . . . . . . . . . . . 8
2.5.2. Configuration in BFD clients . . . . . . . . . . . . 9
2.6. Operational Data Hierarchy . . . . . . . . . . . . . . . 11
2.7. Notifications . . . . . . . . . . . . . . . . . . . . . . 14
2.8. Examples . . . . . . . . . . . . . . . . . . . . . . . . 16
2.9. Interaction with other YANG modules . . . . . . . . . . . 16
2.10. BFD Yang Module . . . . . . . . . . . . . . . . . . . . . 16
2.11. BFD Client Example Configuration Yang Module . . . . . . 33
2.12. Security Considerations . . . . . . . . . . . . . . . . . 34
2.13. IANA Considerations . . . . . . . . . . . . . . . . . . . 34
2.14. Acknowledgements . . . . . . . . . . . . . . . . . . . . 35
3. References . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.1. Normative References . . . . . . . . . . . . . . . . . . 35
3.2. Informative References . . . . . . . . . . . . . . . . . 35
Appendix A. Change log . . . . . . . . . . . . . . . . . . . . . 36
A.1. Changes between versions -03 and -04 . . . . . . . . . . 36
A.2. Changes between versions -02 and -03 . . . . . . . . . . 36
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A.3. Changes between versions -01 and -02 . . . . . . . . . . 36
A.4. Changes between versions -00 and -01 . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction
YANG [RFC6020] is a data definition language that was introduced to
define the contents of a conceptual data store that allows networked
devices to be managed using NETCONF [RFC6241]. YANG is proving
relevant beyond its initial confines, as bindings to other interfaces
(e.g RESTCONF [I-D.ietf-netconf-restconf]) and encodings other than
XML (e.g JSON) are being defined. Furthermore, YANG data models can
be used as the basis of implementation for other interfaces, such as
CLI and programmatic APIs.
This document defines a YANG data model that can be used to configure
and manage Bidirectional Forwarding Detection (BFD)[RFC5880]. BFD is
a network protocol which is used for liveness detection of arbitrary
paths between systems. Some examples of different types of paths
over which we have BFD:
1) Two systems directly connected via IP. This is known as BFD over
single-hop IP [RFC5881]
2) Two systems connected via multiple hops [RFC5883]
3) Two systems connected via MPLS Label Switched Paths (LSPs)
[RFC5884]
4) Two systems connected via a Link Aggregation Group (LAG) interface
[RFC7130]
BFD typically does not operate on its own. Various control
protocols, also known as BFD clients, use the services provided by
BFD for their own operation [RFC5882]. The obvious candidates which
use BFD are those which do not have Hellos to detect failures, e.g.
static routes, and routing protocols whose Hellos do not suport sub-
second failure detection, e.g. OSPF and IS-IS.
1.1. Contributors
2. Design of the Data Model
The BFD YANG data model follows a VRF-centric model by augmenting the
"routing-protocol" data node in [I-D.ietf-netmod-routing-cfg].
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2.1. Design of Configuration Model
The configuration model consists mainly of the parameters specified
in [RFC5880]. Some examples are desired minimum transmit interval,
required minimum receive interval, detection multiplier, etc
Some implementations have BFD session configuration under the BFD
clients. For example, BFD session configuration is under routing
applications such as OSPF, IS-IS, BGP etc. Other implementations
have BFD session configuration centralized under BFD, i.e. outside
the multiple BFD clients.
The BFD parameters of interest to a BFD client are mainly the
multiplier and interval(s) since those parameters impact the
convergence time of the BFD clients when a failure occurs. So the
configuration model has groupings, containing multiplier and
interval(s), which are to be used by BFD clients. Other parameters
which remain under BFD control, e.g. demand mode and authentication,
are configured under BFD.
We provide groupings, which contain the basic BFD session parameters,
for applications to use. This ensures consistency of BFD parameters
across applications.
Although [RFC5880] allows for different values for transmit and
receive intervals, many implementations allow users to specify just
one interval which is used for both transmit and receive intervals or
separate values for transmit and receive intervals. Our YANG model
supports this: there is a choice between "min-interval", used for
both transmit and receive intervals, and "desired-min-tx-interval"
and "required-min-rx-interval".
2.1.1. Single-hop IP
For single-hop IP, the BFD multiplier and interval(s) are configured
in BFD clients. It is highly desirable to have the BFD configuration
consistent between those clients. Therefore, we have a grouping for
BFD configuration that applications can import in their YANG module:
- This provides consistency since the same grouping is being used in
all applications making use of BFD.
- Not all implementations of those BFD clients have support for BFD,
we must use if-feature in the respective YANG modules.
An application importing the BFD configuration grouping could do so
in a hierarchical manner if it has multiple levels at which BFD
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configuration can be applied. In a subsequent section, we provide an
example of how a BFD client would use the grouping in such a way.
The configuration items are:
enabled
Set to true to enable BFD.
local-multiplier
This is the detection time multiplier as defined in
[RFC5880].
min-interval
This is the Desired Min TX Interval and Required Min RX
Interval as defined in [RFC5880].
OR
desired-min-tx-interval
This is the Desired Min TX Interval as defined in [RFC5880].
required-min-rx-interval
This is the Required Min RX Interval as defined in [RFC5880].
2.1.2. Multi-hop IP
We have a list for BFD sessions over multi-hop IP. The key consists
of:
source address
Address belonging to the local system as per [RFC5883]
destination address
Address belonging to the remote system as per [RFC5883]
Since we are following a VRF-centric model we do not need a VRF field
in the key.
Here is the list of parameters:
local-multiplier
This is the detection time multiplier as defined in
[RFC5880].
desired-min-tx-interval
This is the Desired Min TX Interval as defined in [RFC5880].
required-min-rx-interval
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This is the Required Min RX Interval as defined in [RFC5880].
demand-enabled
Set to true to enable demand mode as defined in [RFC5880].
enable-authentication
Set to true to enable BFD authentication.
authentication-algorithm
Authentication algorithm to use, if enabled.
key-chain-name
Key-chain to be used for authentication, if enabled.
tx-ttl
TTL of outgoing BFD control packets.
rx-ttl
Minimum TTL of incoming BFD control packets.
2.1.3. Traffic Engineering Tunnels
For Traffic Engineering (TE) tunnels, BFD is configured under the TE
tunnel since it is the Traffic Enginnering application which knows
the desired failure detection parameters. The grouping for BFD
clients in Section 2.1.1 can be used by the TE application for the
basic BFD parameters. For BFD parameters which are specific to the
TE application, e.g. whether to tear down the tunnel in the event of
a BFD session failure, these parameters will be defined in the YANG
model of the TE application.
2.1.4. LDP Label Switched Paths
For LDP LSPs, BFD is configured under the LDP FEC. The grouping for
BFD clients in Section 2.1.1 can be used by the LDP application for
the basic BFD parameters. For BFD parameters which are specific to
the LDP application, if any, these parameters will be defined in the
YANG model of the LDP application.
2.1.5. Link Aggregation Groups
Per [RFC7130], configuring BFD on LAG consists of having micro-BFD
sessions on each LAG member link. The grouping for BFD clients in
Section 2.1.1 can be used by the LAG application for the basic BFD
parameters. This grouping can be used per-LAG or per member-link.
For BFD parameters which are specific to the LAG application, e.g.
the IP address of the peer system which can be reached by the LAG,
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the parameters will be defined in the YANG model of the LAG
application.
2.1.6. Per-interface Configuration
With multiplier and intervals configured under the BFD clients, we
still need a central location to configure authentication, demand
mode, etc. This can be done by configuring the following parameters
per interface:
demand-enabled
Set to true to enable demand mode as defined in [RFC5880].
enable-authentication
Set to true to enable BFD authentication.
authentication-algorithm
Authentication algorithm to use, if enabled.
key-chain-name
Key-chain to be used for authentication, if enabled.
desired-min-echo-tx-interval
This is the minimum interval that the local system would like
to use when transmitting BFD echo packets. If 0, the echo
function as defined in [RFC5880] is disabled.
required-min-echo-rx-interval
This is the Required Min Echo RX Interval as defined in
[RFC5880].
2.2. Design of Operational Model
The operational model contains both the overall statistics of BFD
sessions running on the device and the per session operational
statistics. Since BFD is used for liveness detection of arbitrary
paths, there is no uniform key to identify a BFD session. E.g. a BFD
single-hop IP session is uniquely identified by the combination of
destination IP address and interface whereas a multihop IP session is
uniquely identified by the combination of source IP address and
destination IP address (in the context of a VRF). For this reason,
for per-session operational statistics, we do not have a single list
with different type BFD sessions. Instead, we have a container where
we have multiple lists, where each list corresponds to one specific
path type for BFD. For example, we have one operational list for BFD
single-hop IP, another list for BFD multi-hop IP, etc. In each list,
mainly three categories of operational items are shown. The
fundamental information of a BFD session such as the local
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discriminator, remote discriminator and the capability of supporting
demand detect mode are shown in the first category. The second
category includes a BFD session running information, e.g. the FSM the
device in and diagnostic code received. Another example is the
actual transmit interval between the control packets, which may be
different from the desired minimum transmit interval configured, is
shown in this category. Similar examples are actual received
interval between the control packets and the actual transmit interval
between the echo packets. The third category contains the detailed
statistics of the session, e.g. when the session transitioned up/down
and how long it has been in that state.
For some session types, there may be more than 1 session on the
virtual path to the destination. For example, with IP multi-hop
there could be multiple BFD sessions from the source to the same
destination to test the various paths (ECMP) to the destination.
Each of the BFD sessions on the same virtual path is uniquely
identified by the source UDP port
2.3. Notifications
This YANG model defines a list of notifications to inform clients of
BFD of important events detected during the protocol operation. Pair
of local and remote discriminator identifies a BFD session on local
system. Notifications also give more important details about BFD
sessions; e.g. new state, time in previous state, routing-instance
and the reason that the BFD session state changed.
2.4. RPC Operations
TBD
2.5. BFD Configuration Data Hierarchy
2.5.1. Centralized BFD Configuration
The following is the centralized configuration data hierarchy:
We have a container which contains a list for each session type.
This contains session configuration for only IP multi-hop sessions.
We have per-interface configuration for authentication, demand-mode,
etc. This is used e.g. for IP single-hop sessions whose base BFD
configuration belongs to the BFD clients.
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module: ietf-bfd
augment /rt:routing/rt:routing-instance/rt:routing-protocols/
rt:routing-protocol:
+--rw bfd
+--rw bfd-cfg
| +--rw bfd-session-cfg
| | +--rw session-ip-mh* [source-addr dest-addr]
| | +--rw source-addr inet:ip-address
| | +--rw dest-addr inet:ip-address
| | +--rw admin-down? boolean
| | +--rw local-multiplier? multiplier
| | +--rw (interval-config-type)?
| | | +--:(tx-rx-intervals)
| | | | +--rw desired-min-tx-interval uint32
| | | | +--rw required-min-rx-interval uint32
| | | +--:(single-interval)
| | | +--rw min-interval uint32
| | +--rw demand-enabled? boolean
| | +--rw enable-authentication? boolean
| | +--rw authentication-parms {bfd-authentication}?
| | | +--rw key-chain-name? string
| | | +--rw algorithm? bfd-auth-algorithm
| | +--rw tx-ttl? ttl
| | +--rw rx-ttl ttl
| +--rw bfd-interface-cfg* [interface] {bfd-interface-config}?
| +--rw interface if:interface-ref
| +--rw local-multiplier? multiplier
| +--rw (interval-config-type)?
| | +--:(tx-rx-intervals)
| | | +--rw desired-min-tx-interval uint32
| | | +--rw required-min-rx-interval uint32
| | +--:(single-interval)
| | +--rw min-interval uint32
| +--rw demand-enabled? boolean
| +--rw enable-authentication? boolean
| +--rw authentication-parms {bfd-authentication}?
| | +--rw key-chain-name? string
| | +--rw algorithm? bfd-auth-algorithm
| +--rw desired-min-echo-tx-interval? uint32
| +--rw required-min-echo-rx-interval? uint32
2.5.2. Configuration in BFD clients
The following is the configuration data hierarchy for a hypothetical
BFD client called example-bfd-routing-app. The BFD configuration is
supported conditionally via use of if-feature.
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We have a list of areas and in each area we have a list of
interfaces. The BFD configuration grouping is used in a hierarchical
fashion, it can be applied in "area" and "interface":
- If BFD configuration is applied under an interface, that
configuration takes precedence over any BFD configuration, if any, at
the area level
- If BFD configuration is applied under an "area" and none of the
interfaces in that area has BFD configuration, then all interfaces
belong to the "area" in question inherit the BFD configuration for
the area in question.
- If the BFD client implementation supports "interface all", then all
the interfaces belonging to that area will inherit the BFD
configuration under "interface all". Additionally, if there is
specific interface configuration, then the specific interface will
override the "interface all" parameters.
- The tx and rx intervals can be configured separately or a single
interval can be configured.
module: example-bfd-routing-app
+--rw area* [area-id]
+--rw area-id uint32
+--rw bfd-cfg
| +--rw enabled? boolean
| +--rw local-multiplier? multiplier
| +--rw (interval-config-type)?
| +--:(tx-rx-intervals)
| | +--rw desired-min-tx-interval uint32
| | +--rw required-min-rx-interval uint32
| +--:(single-interval)
| +--rw min-interval uint32
+--rw interface* [interface]
+--rw interface if:interface-ref
+--rw bfd-cfg
+--rw enabled? boolean
+--rw local-multiplier? multiplier
+--rw (interval-config-type)?
+--:(tx-rx-intervals)
| +--rw desired-min-tx-interval uint32
| +--rw required-min-rx-interval uint32
+--:(single-interval)
+--rw min-interval uint32
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2.6. Operational Data Hierarchy
The complete data hierarchy of BFD YANG operational model is
presented below.
module: ietf-bfd
augment /rt:routing/rt:routing-instance/rt:routing-protocols/
rt:routing-protocol:
+--rw bfd
+--ro bfd-oper
+--ro bfd-session-statistics
| +--ro ip-sh-session-num? uint32
| +--ro ip-mh-session-num? uint32
| +--ro total-session-num? uint32
| +--ro session-up-num? uint32
| +--ro sess-down-num? uint32
| +--ro sess-admin-down-num? uint32
+--ro bfd-session-lists
+--ro session-ip-sh* [interface dest-addr]
| +--ro interface if:interface-ref
| +--ro dest-addr inet:ip-address
| +--ro source-addr? inet:ip-address
| +--ro session-type? bfd-session-type
| +--ro local-discriminator? discriminator
| +--ro remote-discriminator? discriminator
| +--ro remote-multiplier? multiplier
| +--ro out-interface? if:interface-ref
| +--ro demand-capability? boolean
| +--ro source-port? inet:port-number
| +--ro dest-port? inet:port-number
| +--ro session-running*
| | +--ro session-index? uint32
| | +--ro local-state? state
| | +--ro remote-state? state
| | +--ro local-diagnostic? diagnostic
| | +--ro remote-diagnostic? diagnostic
| | +--ro detection-mode? enumeration
| | +--ro negotiated-tx-interval? uint32
| | +--ro negotiated-rx-interval? uint32
| | +--ro negotiated-echo-tx-interval? uint32
| | +--ro detection-time? uint32
| +--ro sesssion-statistics*
| +--ro create-time? yang:date-and-time
| +--ro last-down-time? yang:date-and-time
| +--ro last-up-time? yang:date-and-time
| +--ro down-count? uint32
| +--ro admin-down-count? uint32
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| +--ro receive-packet-count? uint64
| +--ro send-packet-count? uint64
| +--ro receive-bad-packet? uint64
| +--ro send-failed-packet? uint64
+--ro session-ip-mh-group* [source-addr dest-addr]
| +--ro source-addr inet:ip-address
| +--ro dest-addr inet:ip-address
| +--ro session-ip-mh* [source-port]
| +--ro ttl? ttl
| +--ro session-type? bfd-session-type
| +--ro local-discriminator? discriminator
| +--ro remote-discriminator? discriminator
| +--ro remote-multiplier? multiplier
| +--ro out-interface? if:interface-ref
| +--ro demand-capability? boolean
| +--ro source-port inet:port-number
| +--ro dest-port? inet:port-number
| +--ro session-running*
| | +--ro session-index? uint32
| | +--ro local-state? state
| | +--ro remote-state? state
| | +--ro local-diagnostic? diagnostic
| | +--ro remote-diagnostic? diagnostic
| | +--ro detection-mode? enumeration
| | +--ro negotiated-tx-interval? uint32
| | +--ro negotiated-rx-interval? uint32
| | +--ro negotiated-echo-tx-interval? uint32
| | +--ro detection-time? uint32
| +--ro sesssion-statistics*
| +--ro create-time? yang:date-and-time
| +--ro last-down-time? yang:date-and-time
| +--ro last-up-time? yang:date-and-time
| +--ro down-count? uint32
| +--ro admin-down-count? uint32
| +--ro receive-packet-count? uint64
| +--ro send-packet-count? uint64
| +--ro receive-bad-packet? uint64
| +--ro send-failed-packet? uint64
+--ro session-te-tunnel* [tunnel-name]
| +--ro tunnel-name string
| +--ro session-type? bfd-session-type
| +--ro local-discriminator? discriminator
| +--ro remote-discriminator? discriminator
| +--ro remote-multiplier? multiplier
| +--ro out-interface? if:interface-ref
| +--ro demand-capability? boolean
| +--ro source-port? inet:port-number
| +--ro dest-port? inet:port-number
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| +--ro session-running*
| | +--ro session-index? uint32
| | +--ro local-state? state
| | +--ro remote-state? state
| | +--ro local-diagnostic? diagnostic
| | +--ro remote-diagnostic? diagnostic
| | +--ro detection-mode? enumeration
| | +--ro negotiated-tx-interval? uint32
| | +--ro negotiated-rx-interval? uint32
| | +--ro negotiated-echo-tx-interval? uint32
| | +--ro detection-time? uint32
| +--ro sesssion-statistics*
| +--ro create-time? yang:date-and-time
| +--ro last-down-time? yang:date-and-time
| +--ro last-up-time? yang:date-and-time
| +--ro down-count? uint32
| +--ro admin-down-count? uint32
| +--ro receive-packet-count? uint64
| +--ro send-packet-count? uint64
| +--ro receive-bad-packet? uint64
| +--ro send-failed-packet? uint64
+--ro session-ldp-lsp-group* [ldp-fec]
| +--ro ldp-fec inet:ip-prefix
| +--ro session-ldp-lsp* [source-port]
| +--ro ttl? ttl
| +--ro session-type? bfd-session-type
| +--ro local-discriminator? discriminator
| +--ro remote-discriminator? discriminator
| +--ro remote-multiplier? multiplier
| +--ro out-interface? if:interface-ref
| +--ro demand-capability? boolean
| +--ro source-port inet:port-number
| +--ro dest-port? inet:port-number
| +--ro session-running*
| | +--ro session-index? uint32
| | +--ro local-state? state
| | +--ro remote-state? state
| | +--ro local-diagnostic? diagnostic
| | +--ro remote-diagnostic? diagnostic
| | +--ro detection-mode? enumeration
| | +--ro negotiated-tx-interval? uint32
| | +--ro negotiated-rx-interval? uint32
| | +--ro negotiated-echo-tx-interval? uint32
| | +--ro detection-time? uint32
| +--ro sesssion-statistics*
| +--ro create-time? yang:date-and-time
| +--ro last-down-time? yang:date-and-time
| +--ro last-up-time? yang:date-and-time
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| +--ro down-count? uint32
| +--ro admin-down-count? uint32
| +--ro receive-packet-count? uint64
| +--ro send-packet-count? uint64
| +--ro receive-bad-packet? uint64
| +--ro send-failed-packet? uint64
+--ro session-lag* [lag-name]
+--ro lag-name if:interface-ref
+--ro session-lag-micro* [member-link]
+--ro member-link if:interface-ref
+--ro session-type? bfd-session-type
+--ro local-discriminator? discriminator
+--ro remote-discriminator? discriminator
+--ro remote-multiplier? multiplier
+--ro out-interface? if:interface-ref
+--ro demand-capability? boolean
+--ro source-port? inet:port-number
+--ro dest-port? inet:port-number
+--ro session-running*
| +--ro session-index? uint32
| +--ro local-state? state
| +--ro remote-state? state
| +--ro local-diagnostic? diagnostic
| +--ro remote-diagnostic? diagnostic
| +--ro detection-mode? enumeration
| +--ro negotiated-tx-interval? uint32
| +--ro negotiated-rx-interval? uint32
| +--ro negotiated-echo-tx-interval? uint32
| +--ro detection-time? uint32
+--ro sesssion-statistics*
+--ro create-time? yang:date-and-time
+--ro last-down-time? yang:date-and-time
+--ro last-up-time? yang:date-and-time
+--ro down-count? uint32
+--ro admin-down-count? uint32
+--ro receive-packet-count? uint64
+--ro send-packet-count? uint64
+--ro receive-bad-packet? uint64
+--ro send-failed-packet? uint64
2.7. Notifications
The BFD YANG data model defines notifications for BFD session state
changes.
module: ietf-bfd
augment /rt:routing/rt:routing-instance/rt:routing-protocols/
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rt:routing-protocol:
notifications:
+---n bfd-singlehop-notification
| +--ro local-discr? discriminator
| +--ro remote-discr? discriminator
| +--ro new-state? state
| +--ro state-change-reason? string
| +--ro time-in-previous-state? string
| +--ro dest-addr? inet:ip-address
| +--ro source-addr? inet:ip-address
| +--ro session-index? uint32
| +--ro session-type? bfd-session-type
| +--ro interface? if:interface-ref
| +--ro echo-enabled? boolean
+---n bfd-multihop-notification
| +--ro local-discr? discriminator
| +--ro remote-discr? discriminator
| +--ro new-state? state
| +--ro state-change-reason? string
| +--ro time-in-previous-state? string
| +--ro dest-addr? inet:ip-address
| +--ro source-addr? inet:ip-address
| +--ro session-index? uint32
| +--ro session-type? bfd-session-type
+---n bfd-te-tunnel-notification
| +--ro local-discr? discriminator
| +--ro remote-discr? discriminator
| +--ro new-state? state
| +--ro state-change-reason? string
| +--ro time-in-previous-state? string
| +--ro dest-addr? inet:ip-address
| +--ro source-addr? inet:ip-address
| +--ro session-index? uint32
| +--ro session-type? bfd-session-type
| +--ro tunnel-name? string
+---n bfd-ldp-lsp-notification
| +--ro local-discr? discriminator
| +--ro remote-discr? discriminator
| +--ro new-state? state
| +--ro state-change-reason? string
| +--ro time-in-previous-state? string
| +--ro dest-addr? inet:ip-address
| +--ro source-addr? inet:ip-address
| +--ro session-index? uint32
| +--ro session-type? bfd-session-type
| +--ro ldp-fec? inet:ip-prefix
| +--ro source-port? inet:port-number
+---n bfd-lag-notification
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+--ro local-discr? discriminator
+--ro remote-discr? discriminator
+--ro new-state? state
+--ro state-change-reason? string
+--ro time-in-previous-state? string
+--ro dest-addr? inet:ip-address
+--ro source-addr? inet:ip-address
2.8. Examples
2.9. Interaction with other YANG modules
TBD.
2.10. BFD Yang Module
<CODE BEGINS> file "ietf-bfd@2015-07-01.yang"
module ietf-bfd {
namespace "urn:ietf:params:xml:ns:yang:ietf-bfd";
// replace with IANA namespace when assigned
prefix "bfd";
import ietf-interfaces {
prefix "if";
}
import ietf-inet-types {
prefix "inet";
}
import ietf-yang-types {
prefix "yang";
}
import ietf-routing {
prefix "rt";
}
organization "IETF BFD Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/bfd>
WG List: <rtg-bfd@ietf.org>
WG Chair: Jeff Haas
WG Chair: Nobo Akiya
Editor: Lianshu Zheng and Reshad Rahman";
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description
"This module contains the YANG definition for BFD parameters as
per RFC5880, RFC5881 and RFC5883";
revision 2015-07-01 {
description "Initial revision.";
reference "RFC XXXX: A YANG data model for BFD";
}
identity bfd {
base "rt:routing-protocol";
description "BFD protocol";
}
typedef discriminator {
type uint32 {
range 1..4294967295;
}
description "BFD discriminator";
}
typedef diagnostic {
type enumeration {
enum none {
value 0;
description "None";
}
enum controlExpiry {
value 1;
description "Control timer expiry";
}
enum echoFailed {
value 2;
description "Echo failure";
}
enum nborDown {
value 3;
description "Neighbor down";
}
enum fwdingReset {
value 4;
description "Forwarding reset";
}
enum pathDown {
value 5;
description "Path down";
}
enum concPathDown {
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value 6;
description "Concatenated path down";
}
enum adminDown {
value 7;
description "Admin down";
}
enum reverseConcPathDown {
value 8;
description "Reverse concatenated path down";
}
}
description "BFD diagnostic";
}
typedef state {
type enumeration {
enum adminDown {
value 0;
description "admindown";
}
enum down {
value 1;
description "down";
}
enum init {
value 2;
description "init";
}
enum up {
value 3;
description "up";
}
}
description "BFD state";
}
typedef multiplier {
type uint8 {
range 1..255;
}
description "Multiplier";
}
typedef ttl {
type uint8 {
range 1..255;
}
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description "Time To Live";
}
typedef bfd-session-type {
type enumeration {
enum ip-single-hop {
description "IP single hop";
}
enum ip-multi-hop {
description "IP multi hop";
}
enum te-tunnel {
description "Traffic Engineering tunnes";
}
enum ldp-lsp {
description "LDP Label Switched Path";
}
enum lag {
description "Micro-BFD on LAG member links";
}
}
description
"BFD session type, this indicates the path type that BFD is
running on";
}
typedef bfd-auth-algorithm {
type enumeration {
enum simple-password {
description
"Simple password";
}
enum keyed-md5 {
description
"Keyed message Digest 5";
}
enum meticulous-keyed-md5 {
description
"Meticulous keyed message Digest 5";
}
enum keyed-sha-1 {
description
"Keyed secure hash algorithm (SHA1) ";
}
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enum meticulous-keyed-sha-1 {
description
"Meticulous keyed secure hash algorithm (SHA1) ";
}
}
description "Authentication algorithm";
}
feature bfd-interface-config {
description "BFD per-interface config supported";
}
feature bfd-authentication {
description "BFD authentication supported";
}
grouping bfd-grouping-base-cfg-parms {
description "BFD grouping for base config parameters";
leaf local-multiplier {
type multiplier;
default 3;
description "Multiplier transmitted by local system";
}
choice interval-config-type {
description
"Two interval values or 1 value used for both tx and rx";
case tx-rx-intervals {
leaf desired-min-tx-interval {
type uint32;
units microseconds;
mandatory true;
description
"Desired minimum transmit interval of control packets";
}
leaf required-min-rx-interval {
type uint32;
units microseconds;
mandatory true;
description
"Required minimum receive interval of control packets";
}
}
case single-interval {
leaf min-interval {
type uint32;
units microseconds;
mandatory true;
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description
"Desired minimum transmit interval and required " +
"minimum receive interval of control packets";
}
}
}
}
grouping bfd-grouping-common-cfg-parms {
description "BFD grouping for common config parameters";
uses bfd-grouping-base-cfg-parms;
leaf demand-enabled {
type boolean;
default false;
description "To enbale demand mode";
}
leaf enable-authentication {
type boolean;
default false;
description
"If set, the Authentication Section is present and the
session is to be authenticated (see RFC5880 section 6.7
for details).";
}
container authentication-parms {
if-feature bfd-authentication;
description "Parameters for authentication";
leaf key-chain-name {
type string;
must "../algorithm" {
error-message
"May not be configured without algorithm";
description "Requires algorithm";
}
description
"Key chain name";
}
leaf algorithm {
type bfd-auth-algorithm;
must "../key-chain" {
error-message
"May not be configured without key-chain";
description "Requires key-chain";
}
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description "Authentication algorithm to be used";
}
}
}
grouping bfd-grouping-echo-cfg-parms {
description "BFD grouping for echo config parameters";
leaf desired-min-echo-tx-interval {
type uint32;
units microseconds;
default 0;
description "Desired minumum transmit interval for echo";
}
leaf required-min-echo-rx-interval {
type uint32;
units microseconds;
default 0;
description "Required minimum receive interval for echo";
}
}
grouping bfd-client-base-cfg-parms {
description
"BFD grouping for base config parameters which could be used
by a protocol which is a client of BFD";
container bfd-cfg {
description "BFD configuration";
leaf enabled {
type boolean;
default false;
description "True if BFD is enabled";
}
uses bfd-grouping-base-cfg-parms;
}
}
grouping bfd-all-session {
description "BFD session operational information";
leaf session-type {
type bfd-session-type;
description
"BFD session type, this indicates the path type that BFD is
running on";
}
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leaf local-discriminator {
type discriminator;
description "Local discriminator";
}
leaf remote-discriminator {
type discriminator;
description "Remote discriminator";
}
leaf remote-multiplier {
type multiplier;
description "Remote multiplier";
}
leaf out-interface {
type if:interface-ref;
description "Outgoing physical interface name";
}
leaf demand-capability {
type boolean;
description "Local demand mode capability";
}
leaf source-port {
type inet:port-number;
description "Source UDP port";
}
leaf dest-port {
type inet:port-number;
description "Destination UDP port";
}
list session-running {
description "BFD session running information";
leaf session-index {
type uint32;
description
"An index used to uniquely identify BFD sessions";
}
leaf local-state {
type state;
description "Local state";
}
leaf remote-state {
type state;
description "Remote state";
}
leaf local-diagnostic {
type diagnostic;
description "Local diagnostic";
}
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leaf remote-diagnostic {
type diagnostic;
description "Remote diagnostic";
}
leaf detection-mode {
type enumeration {
enum async-with-echo {
value "1";
description "Async with echo";
}
enum async-without-echo {
value "2";
description "Async without echo";
}
enum demand-with-echo {
value "3";
description "Demand with echo";
}
enum demand-without-echo {
value "4";
description "Demand without echo";
}
}
description "Detection mode";
}
leaf negotiated-tx-interval {
type uint32;
units microseconds;
description "Negotiated transmit interval";
}
leaf negotiated-rx-interval {
type uint32;
units microseconds;
description "Negotiated receive interval";
}
leaf negotiated-echo-tx-interval {
type uint32;
units microseconds;
description "Negotiated echo transmit interval";
}
leaf detection-time {
type uint32;
units microseconds;
description "Detection time";
}
}
list sesssion-statistics {
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description "BFD session statistics";
leaf create-time {
type yang:date-and-time;
description
"Time and date when session was created";
}
leaf last-down-time {
type yang:date-and-time;
description
"Time and date of last time the session went down";
}
leaf last-up-time {
type yang:date-and-time;
description
"Time and date of last time the session went up";
}
leaf down-count {
type uint32;
description "Session Down Count";
}
leaf admin-down-count {
type uint32;
description "Session Admin-Down Count";
}
leaf receive-packet-count {
type uint64;
description "Received Packet Count";
}
leaf send-packet-count {
type uint64;
description "Sent Packet Count";
}
leaf receive-bad-packet {
type uint64;
description "Received bad packet count";
}
leaf send-failed-packet {
type uint64;
description "Packet Failed to Send Count";
}
}
}
augment "/rt:routing/rt:routing-instance/rt:routing-protocols/"
+ "rt:routing-protocol" {
when "rt:type = 'bfd:bfd'" {
description
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"This augment is only valid for a protocol instance
of BFD.";
}
description "BFD augmentation.";
container bfd {
description "BFD top-level container";
container bfd-cfg {
description "BFD configuration";
container bfd-session-cfg {
description "BFD session configuration";
list session-ip-mh {
key "source-addr dest-addr";
description "List of IP multi-hop sessions";
leaf source-addr {
type inet:ip-address;
description
"Local IP address";
}
leaf dest-addr {
type inet:ip-address;
description
"IP address of the peer";
}
leaf admin-down {
type boolean;
default false;
description
"Is the BFD session administratively down";
}
uses bfd-grouping-common-cfg-parms;
leaf tx-ttl {
type ttl;
default 255;
description "TTL of outgoing BFD control packets";
}
leaf rx-ttl {
type ttl;
mandatory true;
description
"Minimum allowed TTL value for incoming BFD control
packets";
}
}
}
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list bfd-interface-cfg {
if-feature bfd-interface-config;
key interface;
description "Per-interface BFD configuration";
leaf interface {
type if:interface-ref;
description "Interface";
}
uses bfd-grouping-common-cfg-parms;
uses bfd-grouping-echo-cfg-parms;
}
}
container bfd-oper {
config "false";
description "BFD operational container";
container bfd-session-statistics {
description "BFD session counters";
leaf ip-sh-session-num {
type uint32;
description "IP single hop session number";
}
leaf ip-mh-session-num {
type uint32;
description "IP multi hop session Number";
}
leaf total-session-num {
type uint32;
description "Total session number";
}
leaf session-up-num {
type uint32;
description "Session up number";
}
leaf sess-down-num {
type uint32;
description "Session down number";
}
leaf sess-admin-down-num {
type uint32;
description "Session admin-down number";
}
}
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container bfd-session-lists {
description
"Contains multiple session lists, one per type";
list session-ip-sh {
key "interface dest-addr";
description "BFD IP single-hop sessions";
leaf interface {
type if:interface-ref;
description
"Interface on which the BFD session is running.";
}
leaf dest-addr {
type inet:ip-address;
description "BFD peer address";
}
leaf source-addr {
type inet:ip-address;
description "BFD source address";
}
uses bfd-all-session;
}
list session-ip-mh-group {
key "source-addr dest-addr";
description
"BFD IP multi-hop group of sessions. A group of " +
"sessions is between 1 source and 1 destination, " +
"each session uses a different source UDP port for " +
"ECMP.";
leaf source-addr {
type inet:ip-address;
description "BFD source address";
}
leaf dest-addr {
type inet:ip-address;
description "BFD peer address";
}
list session-ip-mh {
key "source-port";
description
"The BFD sessions between a source and a. " +
"destination. Source UDP port is unique for " +
"each session in the group.";
leaf ttl {
type ttl;
description "TTL of outgoing packets";
}
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uses bfd-all-session;
}
}
list session-te-tunnel {
key "tunnel-name";
description "BFD over TE tunnel";
leaf tunnel-name {
type string;
description "Name of TE tunnel";
}
uses bfd-all-session;
}
list session-ldp-lsp-group {
key "ldp-fec";
description
"BFD over LDP LSP group of sessions. A group of " +
"sessions is to one LDP FEC, each session uses a " +
"different source UDP port for ECMP.";
leaf ldp-fec {
type inet:ip-prefix;
description "LDP FEC";
}
list session-ldp-lsp {
key "source-port";
description
"The BFD sessions on an LDP FEC. Source UDP " +
"port is unique for each session in the group.";
leaf ttl {
type ttl;
description "TTL of outgoing packets";
}
uses bfd-all-session;
}
}
list session-lag {
key "lag-name";
description "A LAG interface on which BFD is running";
leaf lag-name {
type if:interface-ref ;
description "Name of the LAG";
}
list session-lag-micro {
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key "member-link";
description
"Micro-BFD over LAG. This represents BFD " +
"over one member link";
leaf member-link {
type if:interface-ref;
description
"Member link on which micro-BFD is running";
}
uses bfd-all-session;
}
}
}
}
}
}
grouping bfd-notification-parms {
description
"This group describes common parameters that will be sent " +
"as part of BFD notification";
leaf local-discr {
type discriminator;
description "BFD local discriminator";
}
leaf remote-discr {
type discriminator;
description "BFD remote discriminator";
}
leaf new-state {
type state;
description "Current BFD state";
}
leaf state-change-reason {
type string;
description "BFD state change reason";
}
leaf time-in-previous-state {
type string;
description
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"How long the BFD session was in the previous state";
}
leaf dest-addr {
type inet:ip-address;
description "BFD peer address";
}
leaf source-addr {
type inet:ip-address;
description "BFD local address";
}
leaf session-index {
type uint32;
description "An index used to uniquely identify BFD sessions";
}
leaf session-type {
type bfd-session-type;
description "BFD session type";
}
}
notification bfd-singlehop-notification {
description
"Notification for BFD single-hop session state change. An " +
"implementation may rate-limit notifications, e.g. when a" +
"session is continuously changing state.";
uses bfd-notification-parms;
leaf interface {
type if:interface-ref;
description "Interface to which this BFD session belongs to";
}
leaf echo-enabled {
type boolean;
description "Was echo enabled for BFD";
}
}
notification bfd-multihop-notification {
description
"Notification for BFD multi-hop session state change. An " +
"implementation may rate-limit notifications, e.g. when a" +
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"session is continuously changing state.";
uses bfd-notification-parms;
}
notification bfd-te-tunnel-notification {
description
"Notification for BFD over TE tunnel session state change. " +
"An implementation may rate-limit notifications, e.g. when a" +
"session is continuously changing state.";
uses bfd-notification-parms;
leaf tunnel-name {
type string;
description "TE tunnel to which this BFD session belongs to";
}
}
notification bfd-ldp-lsp-notification {
description
"Notification for BFD over LDP LSP session state change. " +
"An implementation may rate-limit notifications, e.g. when a" +
"session is continuously changing state.";
uses bfd-notification-parms;
leaf ldp-fec {
type inet:ip-prefix;
description "LDP FEC";
}
leaf source-port {
type inet:port-number;
description "Source UDP port";
}
}
notification bfd-lag-notification {
description
"Notification for BFD over LAG session state change. " +
"An implementation may rate-limit notifications, e.g. when a" +
"session is continuously changing state.";
uses bfd-notification-parms;
leaf lag-name {
type if:interface-ref;
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description "LAG interface name";
}
leaf member-link {
type if:interface-ref;
description "Member link on which BFD is running";
}
}
}
<CODE ENDS>
2.11. BFD Client Example Configuration Yang Module
module example-bfd-routing-app {
namespace "urn:ietf:params:xml:ns:yang:example-bfd-routing-app";
prefix bfd-routing-app;
import ietf-bfd {
prefix "bfd";
}
import ietf-interfaces {
prefix "if";
}
organization
"ACME";
contact
"acme@acme.com";
description
"Testing BFD grouping (simulating a routing application)";
revision 2015-07-01 {
description "Initial revision.";
reference "RFC XXXX: An example BFD routing application";
}
feature routing-app-bfd {
description "BFD configuration under routing-app";
}
list area {
key "area-id";
description "Specify a routing area.";
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leaf area-id {
type uint32;
description "Area";
}
uses bfd:bfd-client-base-cfg-parms {
if-feature routing-app-bfd;
}
list interface {
key "interface";
description "List of interfaces";
leaf interface {
type if:interface-ref;
description "Interface";
}
uses bfd:bfd-client-base-cfg-parms {
if-feature routing-app-bfd;
}
}
}
}
2.12. Security Considerations
The YANG module defined in this memo is 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]. The NETCONF access control model
[RFC6536] provides the means to restrict access for particular
NETCONF users to a pre-configured subset of all available NETCONF
protocol operations and content.
The YANG module has writeable data nodes which can be used for
creation of BFD sessions and modification of BFD session parameters.
The system should "police" creation of BFD sessions to prevent new
sessions from causing existing BFD sessions to fail. For BFD session
modification, the BFD protocol has mechanisms in place which allow
for in service modification.
2.13. IANA Considerations
The IANA is requested to as assign a new new namespace URI from the
IETF XML registry.
URI:TBD
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2.14. Acknowledgements
We would also like to thank Nobo Akiya and Jeff Haas for their
encouragement on this work.
3. References
3.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
[RFC5881] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for IPv4 and IPv6 (Single Hop)", RFC 5881, June
2010.
[RFC5882] Katz, D. and D. Ward, "Generic Application of
Bidirectional Forwarding Detection (BFD)", RFC 5882, June
2010.
[RFC5883] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD) for Multihop Paths", RFC 5883, June 2010.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, June 2010.
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", RFC
6241, June 2011.
[RFC7130] Bhatia, M., Chen, M., Boutros, S., Binderberger, M., and
J. Haas, "Bidirectional Forwarding Detection (BFD) on Link
Aggregation Group (LAG) Interfaces", RFC 7130, February
2014.
3.2. Informative References
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[I-D.ietf-netconf-restconf]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", draft-ietf-netconf-restconf-06 (work in
progress), June 2015.
[I-D.ietf-netmod-routing-cfg]
Lhotka, L. and A. Lindem, "A YANG Data Model for Routing
Management", draft-ietf-netmod-routing-cfg-19 (work in
progress), May 2015.
Appendix A. Change log
RFC Editor: Remove this section upon publication as an RFC.
A.1. Changes between versions -03 and -04
o Follow VRF-centric model
o IP single-hop session configuration in BFD clients
A.2. Changes between versions -02 and -03
o Fixed date mismatch
o Updated authors
A.3. Changes between versions -01 and -02
o Fixed errors and warnings from "pyang --ietf"
o Added appendix for "Change log"
A.4. Changes between versions -00 and -01
In the YANG module section:
o Added missing filename
o Added missing CODE ENDS
Authors' Addresses
Lianshu Zheng (editor)
Huawei Technologies
China
Email: vero.zheng@huawei.com
Zheng, et al. Expires January 6, 2016 [Page 36]
Internet-Draft BFD Yang July 2015
Reshad Rahman (editor)
Cisco Systems
Canada
Email: rrahman@cisco.com
Santosh Pallagatti
Juniper Networks
India
Email: santoshpk@juniper.net
Mahesh Jethanandani
Cisco Systems
Email: mjethanandani@gmail.com
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
Zheng, et al. Expires January 6, 2016 [Page 37]
