Internet DRAFT - draft-ding-rtgwg-arp-yang-model
draft-ding-rtgwg-arp-yang-model
RTGWG X. Ding
Internet-Draft F. Zheng
Intended status: Standards Track Huawei
Expires: December 30, 2018 R. Wilton
Cisco Systems
June 28, 2018
YANG Data Model for ARP
draft-ding-rtgwg-arp-yang-model-02
Abstract
This document defines a YANG data model to describe Address
Resolution Protocol (ARP) configurations. The data model performs as
a guideline for configuring ARP capabilities on a system. It is
intended this model be used by service providers who manipulate
devices from different vendors in a standard way.
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
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This Internet-Draft will expire on December 30, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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include Simplified BSD License text as described in Section 4.e of
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. Design of the Data Model . . . . . . . . . . . . . . . . . . 4
3.1. ARP Caching . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. proxy ARP . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. gratuitous ARP . . . . . . . . . . . . . . . . . . . . . 4
3.4. ietf-arp Module . . . . . . . . . . . . . . . . . . . . . 5
4. ARP YANG Module . . . . . . . . . . . . . . . . . . . . . . . 5
5. Data Model Examples . . . . . . . . . . . . . . . . . . . . . 12
5.1. Static ARP Entries . . . . . . . . . . . . . . . . . . . 12
5.2. ARP Dynamic Learning . . . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
This document defines a YANG [RFC7950] data model for Address
Resolution Protocol [RFC826] implementation and identification of
some common properties within a device. Devices have common
properties that need to be configured and monitored in a standard
way. This document is intended to present universal ARP protocol
configuration and many vendors can implement it.
The data model convers configuration of system parameters of ARP,
such as static ARP entries, timeout for dynamic ARP entries,
interface ARP, proxy ARP, and so on. It also provides information
about running state of ARP implementations.
1.1. Terminology
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].
The following terms are defined in [RFC6241] and are not redefined
here:
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o client
o configuration data
o server
o state data
1.2. Tree Diagrams
A simplified graphical representation of the data model is presented
in Section 3.
o Brackets "[" and "]" enclose list keys.
o Abbreviations before data node names: "rw" means configuration
(read-write) and "ro" state data (read-only).
o Symbols after data node names: "?" means an optional node, "!"
means a presence container, and "*" denotes a list and leaf-list.
o Parentheses enclose choice and case nodes, and case nodes are also
marked with a colon (":").
o Ellipsis ("...") stands for contents of subtrees that are not
shown.
Tree diagrams used in this document use the notation defined in
[RFC8340].
2. Problem Statement
This document defines a YANG [RFC7950] configuration data model that
may be used to configure the ARP feature running on a system. Data
model "ietf-ip" [I-D.ietf-netmod-rfc7277bis] covers the address
mapping functionality. However, this functionality is strictly
dependent on IPv4 networks, and many ARP related functionalities are
missing, e.g. device global ARP entries and control, configuration
related to dynamic ARP learning, proxy ARP, gratuitous ARP, etc.
The data model makes use of the YANG "feature" construct which allows
implementations to support only those ARP features that lie within
their capabilities. It is intended this model be used by service
providers who manipulate devices from different vendors in a standard
way.
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This model can be used to configure the ARP applications for
discovering the link layer address associated with a given Internet
layer address.
3. Design of the Data Model
This data model intends to describe the processing that a protocol
finds the hardware address, also known as Media Access Control (MAC)
address, of a host from its known IP address. These tasks include,
but are not limited to, adding a static entry in the ARP cache,
configuring dynamic ARP learning, proxy ARP, gratuitous ARP. There
are two kind of ARP configurations: global ARP configuration, which
is across all interfaces on the device, and per interface ARP
configuration.
3.1. ARP Caching
ARP caching is the method of storing network addresses and the
associated data-link addresses in memory for a period of time as the
addresses are learned. This minimizes the use of valuable network
resources to broadcast for the same address each time a datagram is
sent.
There are static ARP cache entries and dynamic ARP cache entries.
Static entries are manually configured and kept in the cache table on
a permanent basis. Dynamic entries are added by vendor software,
kept for a period of time, and then removed. We can specify how long
an entry remains in the ARP cache. If we specify a timeout of 0
seconds, entries are never cleared from the ARP cache.
3.2. proxy ARP
Proxy ARP [RFC1027] can be configured to enable the switch to respond
to ARP queries for network addresses by offering its own Ethernet
media access control (MAC) address. With proxy ARP enabled, the
switch captures and routes traffic to the intended destination.
3.3. gratuitous ARP
Gratuitous ARP requests help detect duplicate IP addresses. A
gratuitous ARP is a broadcast request for a router's own IP address.
If a router or switch sends an ARP request for its own IP address and
no ARP replies are received, the router- or switch-assigned IP
address is not being used by other nodes. However, if a router or
switch sends an ARP request for its own IP address and an ARP reply
is received, the router- or switch-assigned IP address is already
being used by another node.
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3.4. ietf-arp Module
This module has one top level container, ARP, which consists of two
second level containers, which are used for static entries
configuration and global parameters control.
module: ietf-arp
+--rw arp
+--rw global-static-entries {global-static-entries}?
| +--rw static-entry* [ip-address]
| +--rw ip-address inet:ipv4-address-no-zone
| +--rw mac-address yang:mac-address
+--rw global-control
+--rw enable-learning? boolean
+--rw enable-proxy? boolean
augment /if:interfaces/if:interface:
+--rw arp-dynamic-learning
+--rw expire-time? yang:timeticks
+--rw learn-disable? boolean
+--rw proxy
| +--rw mode? enumeration
+--rw probe
| +--rw interval? uint8
| +--rw times? uint8
| +--rw unicast? boolean
+--rw gratuitous
| +--rw enable? boolean
| +--rw interval? uint32
| +--rw drop? boolean
+--ro statistics
+--ro in-requests-pkts? uint16
+--ro in-replies-pkts? uint16
+--ro in-gratuitous-pkts? uint16
+--ro out-requests-pkts? uint16
+--ro out-replies-pkts? uint16
+--ro out-gratuitous-pkts? uint16
augment /if:interfaces/if:interface/ip:ipv4/ip:neighbor:
+--ro remaining-expire-time? uint32
4. ARP YANG Module
This section presents the ARP YANG module defined in this document.
This YANG module imports typedefs from [RFC6991].
<CODE BEGINS>file "ietf-arp@2018-01-27.yang"
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module ietf-arp {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-arp";
prefix arp;
import ietf-inet-types {
prefix inet;
reference "RFC 6991: INET Types Model";
}
import ietf-yang-types {
prefix yang;
reference "RFC 6991: yang Types Model";
}
import ietf-interfaces {
prefix if;
description
"A Network Management Datastore Architecture (NMDA)
compatible version of the ietf-interfaces module
is required.";
}
import ietf-ip {
prefix ip;
description
"A Network Management Datastore Architecture (NMDA)
compatible version of the ietf-ip module is
required.";
}
organization
"IETF Routing Area Working Group (rtgwg)";
contact
"WG Web: <http://tools.ietf.org/wg/rtgwg/>
WG List: <mailto: rtgwg@ietf.org>
Editor: Xiaojian Ding
dingxiaojian1@huawei.com
Editor: Feng Zheng
habby.zheng@huawei.com
Editor: Robert Wilton
rwilton@cisco.com";
description
"Address Resolution Protocol (ARP) management, which includes
static ARP configuration, dynamic ARP learning, ARP entry query,
and packet statistics collection.";
revision 2018-01-27 {
description
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"Init revision";
// NOTE TO RFC EDITOR:
// Please replace the following reference
// to draft-ding-rtgwg-arp-yang-model-02 with
// RFC number when published (i.e. RFC xxxx).
reference
"draft-ding-rtgwg-arp-yang-model-02";
}
/*
* Features
*/
feature global-static-entries {
description
"This feature indicates that the device allows static entries
to be configured globally.";
}
container arp {
description
"Address Resolution Protocol (ARP) management, which includes
static ARP configuration, dynamic ARP learning, ARP entry
query, and packet statistics collection.";
container global-static-entries {
if-feature "global-static-entries";
description
"Set a global static ARP entry, which is independent of the interface.";
list static-entry {
key "ip-address";
description
"List of ARP static entries that can be configured globally.";
leaf ip-address {
type inet:ipv4-address-no-zone;
description
"IP address, in dotted decimal notation.";
}
leaf mac-address {
type yang:mac-address;
mandatory true;
description
"MAC address in the format of H-H-H, in which H is
a hexadecimal number of 1 to 4 bits.";
}
}
}
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container global-control {
description
"Set global control parameters, which are independent of interface.";
leaf enable-learning {
type boolean;
default "true";
description
"Enables or disables global dynamic ARP learning.
If 'true', then enforcement is enabled.
If 'false', then enforcement is disabled.";
}
leaf enable-proxy {
type boolean;
default "true";
description
"Proxy ARP is enabled by default; perform this
task to globally disable proxy ARP on all interfaces.";
}
}
}
augment "/if:interfaces/if:interface" {
description
"Augment interface configuration with parameters of ARP.";
container arp-dynamic-learning {
description
"Support for ARP configuration on interfaces.";
leaf expire-time {
type yang:timeticks {
range "60..86400";
}
units "second";
description
"Aging time of a dynamic ARP entry.";
}
leaf learn-disable {
type boolean;
default "false";
description
"Whether dynamic ARP learning is disabled on an interface.
If the value is True, dynamic ARP learning is disabled.
If the value is False, dynamic ARP learning is enabled.";
}
container proxy {
description
"Configuration parameters for proxy ARP";
leaf mode {
type enumeration {
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enum DISABLE {
description
"The system should not respond to ARP requests that
do not specify an IP address configured on the local
subinterface as the target address.";
}
enum REMOTE_ONLY {
description
"The system responds to ARP requests only when the
sender and target IP addresses are in different
subnets.";
}
enum ALL {
description
"The system responds to ARP requests where the sender
and target IP addresses are in different subnets, as well
as those where they are in the same subnet.";
}
}
default "DISABLE";
description
"When set to a value other than DISABLE, the local system should
respond to ARP requests that are for target addresses other than
those that are configured on the local subinterface using its own
MAC address as the target hardware address. If the REMOTE_ONLY
value is specified, replies are only sent when the target address
falls outside the locally configured subnets on the interface,
whereas with the ALL value, all requests, regardless of their
target address are replied to.";
reference "RFC1027: Using ARP to Implement Transparent Subnet Gateways";
}
}
container probe {
description
"Common configuration parameters for all ARP probe.";
leaf interval {
type uint8 {
range "1..5";
}
units "second";
description
"Interval for detecting dynamic ARP entries.";
}
leaf times {
type uint8 {
range "0..10";
}
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description
"Number of aging probe attempts for a dynamic ARP entry.
If a device does not receive an ARP reply message after
the number of aging probe attempts reaches a specified
number,thedynamic ARP entry is deleted.";
}
leaf unicast {
type boolean;
default "false";
description
"Send unicast ARP aging probe messages for a dynamic ARP
entry.";
}
}
container gratuitous {
description
"Configure gratuitous ARP.";
leaf enable {
type boolean;
default "false";
description
"Enable or disable sending gratuitous-arp packet on
interface.";
}
leaf interval {
type uint32 {
range "1..86400";
}
units "second";
description
"The interval of sending gratuitous-arp packet on the
interface.";
}
leaf drop {
type boolean;
default "false";
description
"Drop the receipt of gratuitous ARP packets on the interface.";
}
}
container statistics {
config false;
description
"IP ARP Statistics information on interfaces";
leaf in-requests-pkts {
type uint16;
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description
"Total ARP requests received";
}
leaf in-replies-pkts {
type uint16;
description
"Total ARP replies received";
}
leaf in-gratuitous-pkts {
type uint16;
description
"Total gratuitous ARP received";
}
leaf out-requests-pkts {
type uint16;
description
"Total ARP requests sent";
}
leaf out-replies-pkts {
type uint16;
description
"Total ARP replies sent";
}
leaf out-gratuitous-pkts {
type uint16;
description
"Total gratuitous ARP sent";
}
}
}
}
augment "/if:interfaces/if:interface/ip:ipv4/ip:neighbor" {
description
"Augment neighbor list with parameters of ARP,
eg., support for remaining expire time query on interfaces.";
leaf remaining-expire-time {
type uint32;
config false;
description
"Remaining expire time of a dynamic ARP entry. ";
}
}
}
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5. Data Model Examples
This section presents a simple but complete example of configuring
static ARP entries and dynamic learning, based on the YANG modules
specified in Section 4.
5.1. Static ARP Entries
Requirement:
Enable static ARP entry global configuration (not rely on interface).
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<arp xmlns="urn:ietf:params:xml:ns:yang:ietf-arp">
<static-tables>
<ip-address> 10.2.2.3 </ip-address>
<mac-address> 00e0-fc01-0000 </mac-address>
</static-tables>
</arp>
Requirement:
Enable static ARP entry configuration on interface (defined in
draft [I-D.ietf-netmod-rfc7277bis]).
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<neighbor>
<ip-address> 10.2.2.3 </ip-address>
<mac-address> 00e0-fc01-0000 </mac-address>
<if-name> GE1/0/1 </if-name>
</neighbor>
</ipv4>
5.2. ARP Dynamic Learning
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Requirement:
Enable ARP dynamic learning configuration.
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<arp-dynamic-learning xmlns="urn:ietf:params:xml:ns:yang:ietf-arp-dynamic-learning">
<if-name> GE1/0/1 </if-name>
<expire-time>1200</expire-time>
<learn-disable>false</learn-disable>
<proxy>
<mode>DISABLE</mode>
</proxy>
<probe>
<interval>5</interval>
<times>3</times>
<unicast>false</unicast>
</probe>
<gratuitous>
<gratuitous-enable>false<gratuitous-enable>
<interval>60</interval>
<drop>false</drop>
<gratuitous>
</arp-dynamic-learning>
6. Security Considerations
The YANG module defined in this document is designed to be accessed
via YANG based management protocols, such as NETCONF [RFC6241] and
RESTCONF [RFC8040]. Both of these protocols have mandatory-to-
implement secure transport layers (e.g., SSH, TLS) with mutual
authentication.
The NETCONF access control model (NACM) [RFC6536] provides the means
to restrict access for particular users to a pre-configured subset of
all available protocol operations and content.
These are the subtrees and data nodes and their sensitivity/
vulnerability:
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.
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7. Acknowledgments
The authors wish to thank Alex Campbell and Reshad Rahman, Qin Wu,
many others for their helpful comments.
8. References
8.1. Normative References
[I-D.ietf-netmod-rfc7223bis]
Bjorklund, M., "A YANG Data Model for Interface
Management", draft-ietf-netmod-rfc7223bis-03 (work in
progress), January 2018.
[I-D.ietf-netmod-rfc7277bis]
Bjorklund, M., "A YANG Data Model for IP Management",
draft-ietf-netmod-rfc7277bis-03 (work in progress),
January 2018.
[RFC1027] Carl-Mitchell, S. and J. Quarterman, "Using ARP to
implement transparent subnet gateways", RFC 1027,
DOI 10.17487/RFC1027, October 1987,
<https://www.rfc-editor.org/info/rfc1027>.
[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>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[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>.
8.2. Informative References
[RFC0826] Plummer, D., "An Ethernet Address Resolution Protocol: Or
Converting Network Protocol Addresses to 48.bit Ethernet
Address for Transmission on Ethernet Hardware", STD 37,
RFC 826, DOI 10.17487/RFC0826, November 1982,
<https://www.rfc-editor.org/info/rfc826>.
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[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>.
[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>.
[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>.
Authors' Addresses
Xiaojian Ding
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: dingxiaojian1@huawei.com
Feng Zheng
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: habby.zheng@huawei.com
Robert Wilton
Cisco Systems
Email: rwilton@cisco.com
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