| RFC 8676 | YANG Modules for A+P Softwires | November 2019 |
| Farrer & Boucadair | Standards Track | [Page] |
This document defines YANG modules for the configuration and operation of IPv4-in-IPv6 softwire Border Relays and Customer Premises Equipment for the Lightweight 4over6, Mapping of Address and Port with Encapsulation (MAP-E), and Mapping of Address and Port using Translation (MAP-T) softwire mechanisms.¶
This is an Internet Standards Track document.¶
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8676.¶
Copyright (c) 2019 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 Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.¶
The IETF Softwire Working Group has developed several IPv4-in-IPv6 softwire mechanisms to address various deployment contexts and constraints. As a companion to the architectural specification documents, this document focuses on the provisioning of Address plus Port (A+P) softwire functional elements: Border Routers (BRs) and Customer Edge (CE) (called "Customer Premises Equipment (CPE)" in [RFC7596]). The softwire mechanisms covered in this document are Lightweight 4over6 (lw4o6) [RFC7596], Mapping of Address and Port with Encapsulation (MAP-E) [RFC7597], and Mapping of Address and Port using Translation (MAP-T) [RFC7599].¶
This document focuses on A+P mechanisms [RFC6346]; the reader can refer to [RFC8513] for a YANG module for Dual-Stack Lite (DS-Lite) [RFC6333].¶
This document defines YANG modules [RFC7950] that can be used to configure and manage A+P softwire elements using the NETCONF [RFC6241] or RESTCONF [RFC8040] protocols for:¶
The reader should be familiar with the concepts and terms defined in [RFC7596], [RFC7597], [RFC7599], and the YANG data modeling language defined in [RFC7950].¶
The YANG modules in this document adopt the Network Management Datastore Architecture (NMDA) [RFC8342]. The meanings of the symbols used in tree diagrams are defined in [RFC8340].¶
The document uses the abbreviation 'BR' as a general term for softwire tunnel concentrators, including both MAP Border Routers [RFC7597] and Lightweight 4over6 lwAFTRs [RFC7596].¶
For brevity, "algorithm" is used to refer to the "mapping algorithm" defined in [RFC7597].¶
A network element may support one or multiple instances of a softwire mechanism; each of these instances (i.e., binding instances, MAP-E instances, or MAP-T instances) may have its own configuration and parameters. The term 'algo-instance' is used to denote both MAP-E and MAP-T instances.¶
The document defines the following two YANG modules for the configuration and monitoring of softwire functional elements:¶
In addition, the following module is defined:¶
This approach has been taken so that the various modules can be easily extended to support additional softwire mechanisms, if required.¶
Within the BR and CE modules, the YANG "feature" statement is used to distinguish which of the different softwire mechanism(s) is relevant for a specific element's configuration. For each module, a choice statement 'ce-type' is included for either 'binding' or 'algorithm'. 'Binding' is used for configuring Lightweight 4over6, whereas 'algorithm' is used for configuring MAP-T or MAP-E.¶
In the 'algo-instances' container, a choice statement 'data-plane' is included to specify MAP-E (encapsulation) or MAP-T (translation). Table 1 shows how these choices are used to indicate the desired softwire mechanism:¶
| S46 Mechanism | ce-type? | data-plane? |
|---|---|---|
| Lightweight 4over6 | binding | n/a |
| MAP-E | algorithm | encapsulation |
| MAP-T | algorithm | translation |
NETCONF notifications are also included.¶
The softwire modules only aim to provide configuration relevant for softwires. In order to fully provision a CE element, the following may also be necessary:¶
As YANG modules for the above functions are already defined in other documents, their functionality is not duplicated here and they should be referred to, as needed. Appendix A.3 provides XML examples of how these modules can be used together.¶
The CE must already have minimal IPv6 configuration in place so it is reachable by the NETCONF client to obtain softwire configuration. If additional IPv6-specific configuration is necessary, the YANG modules defined in [RFC8344] and [RFC8349] may be used.¶
The CE module provides configuration and monitoring for all of the softwire mechanisms covered in this document (i.e., Lightweight 4over6, MAP-E, and MAP-T).¶
This module augments "ietf-interfaces", defined in [RFC8343] with an entry for the softwire. This entry can be referenced to configure IPv4 forwarding features for the element. This entry is added only if tunnel type (Section 10) is set to 'aplusp'.¶
Figure 1 shows the tree structure of the softwire CE YANG module:¶
module: ietf-softwire-ce
augment /if:interfaces/if:interface:
+--rw softwire-payload-mtu? uint16
+--rw softwire-path-mru? uint16
+--rw (ce-type)?
+--:(binding) {binding-mode}?
| +--rw binding-ipv6info? union
| +--rw br-ipv6-addr inet:ipv6-address
+--:(algo) {map-e or map-t}?
+--rw algo-instances
+--rw algo-instance* [name]
+--rw name string
+--rw enable? boolean
+--rw algo-versioning
| +--rw version? uint64
| +--rw date? yang:date-and-time
+--rw (data-plane)?
| +--:(encapsulation) {map-e}?
| | +--rw br-ipv6-addr inet:ipv6-address
| +--:(translation) {map-t}?
| +--rw dmr-ipv6-prefix? inet:ipv6-prefix
+--rw ea-len uint8
+--rw rule-ipv6-prefix inet:ipv6-prefix
+--rw rule-ipv4-prefix inet:ipv4-prefix
+--rw forwarding boolean
augment /if:interfaces/if:interface/if:statistics:
+--ro sent-ipv4-packets?
| yang:zero-based-counter64
+--ro sent-ipv4-bytes?
| yang:zero-based-counter64
+--ro sent-ipv6-packets?
| yang:zero-based-counter64
+--ro sent-ipv6-bytes?
| yang:zero-based-counter64
+--ro rcvd-ipv4-packets?
| yang:zero-based-counter64
+--ro rcvd-ipv4-bytes?
| yang:zero-based-counter64
+--ro rcvd-ipv6-packets?
| yang:zero-based-counter64
+--ro rcvd-ipv6-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv4-packets?
| yang:zero-based-counter64
+--ro dropped-ipv4-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv6-packets?
| yang:zero-based-counter64
+--ro dropped-ipv6-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv4-fragments?
| yang:zero-based-counter64
+--ro dropped-ipv4-fragment-bytes?
| yang:zero-based-counter64
+--ro ipv6-fragments-reassembled?
| yang:zero-based-counter64
+--ro ipv6-fragments-bytes-reassembled?
| yang:zero-based-counter64
+--ro out-icmpv4-error-packets?
| yang:zero-based-counter64
+--ro out-icmpv4-error-bytes?
| yang:zero-based-counter64
+--ro out-icmpv6-error-packets?
| yang:zero-based-counter64
+--ro out-icmpv6-error-bytes?
yang:zero-based-counter64
notifications:
+---n softwire-ce-event {binding-mode}?
+--ro ce-binding-ipv6-addr-change inet:ipv6-address
¶
Additional information related to the operation of a CE element is provided below:¶
Further details relevant to binding softwire elements are as follows:¶
Additional details relevant to some of the important algorithmic elements are provided below:¶
Additional information on the notification node is listed below:¶
The BR YANG module provides configuration and monitoring for all of the softwire mechanisms covered in this document (i.e., Lightweight 4over6, MAP-E, and MAP-T).¶
Figure 2 provides the tree structure of this module:¶
module: ietf-softwire-br
+--rw br-instances
+--rw (br-type)?
+--:(binding) {binding-mode}?
| +--rw binding
| +--rw bind-instance* [name]
| +--rw name string
| +--rw binding-table-versioning
| | +--rw version? uint64
| | +--rw date? yang:date-and-time
| +--rw softwire-num-max uint32
| +--rw softwire-payload-mtu uint16
| +--rw softwire-path-mru uint16
| +--rw enable-hairpinning? boolean
| +--rw binding-table
| | +--rw binding-entry* [binding-ipv6info]
| | +--rw binding-ipv6info union
| | +--rw binding-ipv4-addr?
| | | inet:ipv4-address
| | +--rw port-set
| | | +--rw psid-offset? uint8
| | | +--rw psid-len uint8
| | | +--rw psid uint16
| | +--rw br-ipv6-addr?
| | inet:ipv6-address
| +--rw icmp-policy
| | +--rw icmpv4-errors
| | | +--rw allow-incoming-icmpv4? boolean
| | | +--rw icmpv4-rate? uint32
| | | +--rw generate-icmpv4-errors? boolean
| | +--rw icmpv6-errors
| | +--rw generate-icmpv6-errors? boolean
| | +--rw icmpv6-rate? uint32
| +--ro traffic-stat
| +--ro discontinuity-time yang:date-and-time
| +--ro sent-ipv4-packets?
| | yang:zero-based-counter64
| +--ro sent-ipv4-bytes?
| | yang:zero-based-counter64
| +--ro sent-ipv6-packets?
| | yang:zero-based-counter64
| +--ro sent-ipv6-bytes?
| | yang:zero-based-counter64
| +--ro rcvd-ipv4-packets?
| | yang:zero-based-counter64
| +--ro rcvd-ipv4-bytes?
| | yang:zero-based-counter64
| +--ro rcvd-ipv6-packets?
| | yang:zero-based-counter64
| +--ro rcvd-ipv6-bytes?
| | yang:zero-based-counter64
| +--ro dropped-ipv4-packets?
| | yang:zero-based-counter64
| +--ro dropped-ipv4-bytes?
| | yang:zero-based-counter64
| +--ro dropped-ipv6-packets?
| | yang:zero-based-counter64
| +--ro dropped-ipv6-bytes?
| | yang:zero-based-counter64
| +--ro dropped-ipv4-fragments?
| | yang:zero-based-counter64
| +--ro dropped-ipv4-fragment-bytes?
| | yang:zero-based-counter64
| +--ro ipv6-fragments-reassembled?
| | yang:zero-based-counter64
| +--ro ipv6-fragments-bytes-reassembled?
| | yang:zero-based-counter64
| +--ro out-icmpv4-error-packets?
| | yang:zero-based-counter64
| +--ro out-icmpv4-error-bytes?
| | yang:zero-based-counter64
| +--ro out-icmpv6-error-packets?
| | yang:zero-based-counter64
| +--ro out-icmpv6-error-bytes?
| | yang:zero-based-counter64
| +--ro dropped-icmpv4-packets?
| | yang:zero-based-counter64
| +--ro dropped-icmpv4-bytes?
| | yang:zero-based-counter64
| +--ro hairpin-ipv4-packets?
| | yang:zero-based-counter64
| +--ro hairpin-ipv4-bytes?
| | yang:zero-based-counter64
| +--ro active-softwire-num?
| uint32
+--:(algo) {map-e or map-t}?
+--rw algorithm
+--rw algo-instance* [name]
+--rw name string
+--rw enable? boolean
+--rw algo-versioning
| +--rw version? uint64
| +--rw date? yang:date-and-time
+--rw (data-plane)?
| +--:(encapsulation) {map-e}?
| | +--rw br-ipv6-addr inet:ipv6-address
| +--:(translation) {map-t}?
| +--rw dmr-ipv6-prefix? inet:ipv6-prefix
+--rw ea-len uint8
+--rw rule-ipv6-prefix inet:ipv6-prefix
+--rw rule-ipv4-prefix inet:ipv4-prefix
+--rw forwarding boolean
+--rw port-set
| +--rw psid-offset? uint8
| +--rw psid-len uint8
| +--rw psid uint16
+--ro traffic-stat
+--ro discontinuity-time yang:date-and-time
+--ro sent-ipv4-packets?
| yang:zero-based-counter64
+--ro sent-ipv4-bytes?
| yang:zero-based-counter64
+--ro sent-ipv6-packets?
| yang:zero-based-counter64
+--ro sent-ipv6-bytes?
| yang:zero-based-counter64
+--ro rcvd-ipv4-packets?
| yang:zero-based-counter64
+--ro rcvd-ipv4-bytes?
| yang:zero-based-counter64
+--ro rcvd-ipv6-packets?
| yang:zero-based-counter64
+--ro rcvd-ipv6-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv4-packets?
| yang:zero-based-counter64
+--ro dropped-ipv4-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv6-packets?
| yang:zero-based-counter64
+--ro dropped-ipv6-bytes?
| yang:zero-based-counter64
+--ro dropped-ipv4-fragments?
| yang:zero-based-counter64
+--ro dropped-ipv4-fragment-bytes?
| yang:zero-based-counter64
+--ro ipv6-fragments-reassembled?
| yang:zero-based-counter64
+--ro ipv6-fragments-bytes-reassembled?
| yang:zero-based-counter64
+--ro out-icmpv4-error-packets?
| yang:zero-based-counter64
+--ro out-icmpv4-error-bytes?
| yang:zero-based-counter64
+--ro out-icmpv6-error-packets?
| yang:zero-based-counter64
+--ro out-icmpv6-error-bytes?
yang:zero-based-counter64
notifications:
+---n softwire-binding-instance-event {binding-mode}?
| +--ro bind-name?
| | -> /br-instances/binding/bind-instance/name
| +--ro invalid-entry* leafref
| +--ro added-entry* inet:ipv6-address
| +--ro modified-entry* leafref
+---n softwire-algorithm-instance-event {map-e, map-t}?
+--ro algo-name
| -> /br-instances/algorithm/algo-instance/name
+--ro invalid-entry-id*
| -> /br-instances/algorithm/algo-instance/name
+--ro added-entry*
| -> /br-instances/algorithm/algo-instance/name
+--ro modified-entry*
-> /br-instances/algorithm/algo-instance/name
¶
The descriptions for leaves that are common with the CE module are provided in Section 4.2. Descriptions for additional elements are provided below:¶
Additional information on some of the important notification nodes is listed below:¶
This module imports the modules defined in [RFC6991], [RFC8343], and [RFC7224]. It also imports the 'ietf-softwire-common' and 'iana-tunnel-type' modules [RFC8675].¶
<CODE BEGINS> file "ietf-softwire-ce@2019-11-16.yang"
module ietf-softwire-ce {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-ce";
prefix softwire-ce;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types, Section 4";
}
import ietf-interfaces {
prefix if;
reference
"RFC 8343: A YANG Data Model for Interface Management";
}
import ietf-softwire-common {
prefix softwire-common;
reference
"RFC 8676: YANG Modules for IPv4-in-IPv6 Address plus Port
Softwires";
}
import iana-tunnel-type {
prefix iana-tunnel-type;
reference
"RFC 8675: A YANG Data Model for Tunnel Interface Types";
}
organization
"IETF Softwire Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/softwire/>
WG List: <mailto:softwire@ietf.org>
Author: Qi Sun
<mailto:sunqi.ietf@gmail.com>
Author: Linhui Sun
<mailto:lh.sunlinh@gmail.com>
Author: Yong Cui
<mailto:yong@csnet1.cs.tsinghua.edu.cn>
Editor: Ian Farrer
<mailto:ian.farrer@telekom.de>
Author: Sladjana Zoric
<mailto:sladjana.zoric@telekom.de>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Rajiv Asati
<mailto:rajiva@cisco.com>";
description
"This document defines a YANG module for the configuration and
management of A+P Softwire Customer Premises Equipment (CEs).
It covers Lightweight 4over6, MAP-E, and MAP-T mechanisms.
Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8676; see
the RFC itself for full legal notices.";
revision 2019-11-16 {
description
"Initial revision.";
reference
"RFC 8676: YANG Modules for IPv4-in-IPv6 Address plus Port
(A+P) Softwires";
}
/*
* Features
*/
feature binding-mode {
description
"Binding is used for configuring the Lightweight 4over6
mechanism.
Binding-based softwire mechanisms are IPv4-over-IPv6 tunneling
transition mechanisms specifically intended for complete
independence between the IPv6 subnet prefix (and IPv6 address)
and IPv4 address, with or without IPv4 address sharing.
This is accomplished by maintaining state for each softwire
(per-subscriber state) in the central Border Relay (BR) and
using a hub-and-spoke forwarding architecture. In order to
delegate the NAPT function and achieve IPv4 address sharing,
port-restricted IPv4 addresses needs to be allocated to CEs.
This feature indicates that the network element can function
as one or more binding-based softwire instances.";
reference
"RFC 7596: Lightweight 4over6: An Extension to the Dual-Stack
Lite Architecture
RFC 7597: Mapping of Address and Port with Encapsulation
(MAP-E)
RFC 7599: Mapping of Address and Port using Translation
(MAP-T)";
}
feature map-e {
description
"MAP-E is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP encapsulation. MAP-E
allows for a reduction of the amount of centralized state
using rules to express IPv4/IPv6 address mappings. This
introduces an algorithmic relationship between the IPv6
subnet and IPv4 address.
This feature indicates that the network element can function
as one or more MAP-E softwire instances.";
reference
"RFC 7597: Mapping of Address and Port with
Encapsulation (MAP-E)";
}
feature map-t {
description
"MAP-T is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP translation. It
leverages a double stateless NAT64-based solution as well as
the stateless algorithmic address and transport layer port
mapping algorithm defined for MAP-E.
This feature indicates that the network element can function
as one or more MAP-T softwire instances.";
reference
"RFC 7599: Mapping of Address and Port using Translation
(MAP-T)";
}
// Binding Entry
grouping binding-entry {
description
"The binding BR (Border Relay) maintains an address
binding table that contains the binding between the CE's
IPv6 address, the allocated IPv4 address, and the
restricted port-set.";
leaf binding-ipv6info {
type union {
type inet:ipv6-address;
type inet:ipv6-prefix;
}
description
"The IPv6 information for a binding entry.
When the IPv6 prefix type is used,
the IPv6 source address of the CE is constructed
according to the description in RFC 7596.
If the IPv6 address type is used, the CE can use
any valid /128 address from a prefix assigned to
the CE.";
reference
"RFC 7596: Lightweight 4over6: An Extension
to the Dual-Stack Lite Architecture, Section 5.1";
}
leaf br-ipv6-addr {
type inet:ipv6-address;
mandatory true;
description
"The IPv6 address of the binding BR.";
}
}
// configuration and stateful parameters for softwire CE interface
augment "/if:interfaces/if:interface" {
when "derived-from(if:type, 'iana-tunnel-type:aplusp')";
description
"Softwire CE interface configuration";
leaf softwire-payload-mtu {
type uint16;
units "bytes";
description
"The payload IPv4 MTU for the softwire tunnel.";
}
leaf softwire-path-mru {
type uint16;
units "bytes";
description
"The path MRU for the softwire (payload + encapsulation
overhead).";
reference
"RFC 4213: Basic Transition Mechanisms for IPv6 Hosts and
Routers";
}
choice ce-type {
description
"Sets the softwire CE mechanism";
case binding {
if-feature "binding-mode";
description
"CE binding configuration";
uses binding-entry;
}
case algo {
if-feature "map-e or map-t";
description
"CE algorithm configuration";
container algo-instances {
description
"Collection of MAP-E/MAP-T parameters";
list algo-instance {
key "name";
description
"MAP forwarding rule instance for
MAP-E/MAP-T";
leaf name {
type string;
mandatory true;
description
"The name is used to uniquely identify an algorithm
instance.
This name can be automatically assigned
or explicitly configured.";
}
uses softwire-common:algorithm-instance;
}
}
}
}
}
augment "/if:interfaces/if:interface/if:statistics" {
when "derived-from(../if:type, 'iana-tunnel-type:aplusp')";
description
"Softwire CE interface statistics.";
uses softwire-common:traffic-stat;
}
/*
* Notifications
*/
notification softwire-ce-event {
if-feature "binding-mode";
description
"CE notification";
leaf ce-binding-ipv6-addr-change {
type inet:ipv6-address;
mandatory true;
description
"This notification is generated whenever the CE's binding
IPv6 address changes for any reason.";
}
}
}
<CODE ENDS>¶
This module imports typedefs from [RFC6991]. It also imports the 'ietf-softwire-common' module.¶
<CODE BEGINS> file "ietf-softwire-br@2019-11-16.yang"
module ietf-softwire-br {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-br";
prefix softwire-br;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types, Section 4";
}
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types, Section 3";
}
import ietf-softwire-common {
prefix softwire-common;
reference
"RFC 8676: YANG Modules for IPv4-in-IPv6 Address plus Port
(A+P) Softwires";
}
organization
"IETF Softwire Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/softwire/>
WG List: <mailto:softwire@ietf.org>
Author: Qi Sun
<mailto:sunqi.ietf@gmail.com>
Author: Linhui Sun
<mailto:lh.sunlinh@gmail.com>
Author: Yong Cui
<mailto:yong@csnet1.cs.tsinghua.edu.cn>
Editor: Ian Farrer
<mailto:ian.farrer@telekom.de>
Author: Sladjana Zoric
<mailto:sladjana.zoric@telekom.de>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Rajiv Asati
<mailto:rajiva@cisco.com>";
description
"This document defines a YANG module for the configuration and
management of A+P Softwire Border Routers. It covers
Lightweight 4over6, MAP-E, and MAP-T mechanisms.
Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8676; see
the RFC itself for full legal notices.";
revision 2019-11-16 {
description
"Initial revision.";
reference
"RFC 8676: YANG Modules for IPv4-in-IPv6 Address plus Port
(A+P) Softwires";
}
/*
* Groupings
*/
grouping port-set {
description
"Describes a set of Layer 4 port numbers.
This may be a simple port range, or use the Port Set
Identifier (PSID) algorithm to represent a range of transport
layer ports that will be used by a NAPT.";
leaf psid-offset {
type uint8 {
range "0..16";
}
description
"The number of offset bits. In Lightweight 4over6,
the default value is 0 for assigning one contiguous
port range. In MAP-E/T, the default value is 6,
which means the system ports (0-1023) are excluded by
default and the assigned port ranges are distributed across
the entire port space, depending on either psid-len or the
number of contiguous ports.";
}
leaf psid-len {
type uint8 {
range "0..15";
}
mandatory true;
description
"The length of PSID, representing the sharing
ratio for an IPv4 address. This, along with ea-len, can
be used to calculate the number of contiguous ports per
port range";
}
leaf psid {
type uint16;
mandatory true;
description
"Port Set Identifier (PSID) value, which
identifies a set of ports algorithmically.";
}
}
grouping binding-entry {
description
"The binding BR maintains an address binding table that
contains the binding between the CE's IPv6 address,
the allocated IPv4 address and restricted port-set.";
leaf binding-ipv6info {
type union {
type inet:ipv6-address;
type inet:ipv6-prefix;
}
description
"The IPv6 information for a CE binding entry.
When the IPv6 prefix type is used,
the IPv6 source address of the CE is constructed
according to the description in RFC 7596;
if the IPv6 address type is used, the CE can use
any valid /128 address from a prefix assigned to
the CE.";
reference
"RFC 7596: Lightweight 4over6: An Extension to the Dual-Stack
Lite Architecture";
}
leaf binding-ipv4-addr {
type inet:ipv4-address;
description
"The IPv4 address assigned to the binding CE,
which is used as the IPv4 external address
for binding CE local NAPT44.";
}
container port-set {
description
"For Lightweight 4over6, the default value
for offset should be 0, to configure one contiguous
port range.";
uses port-set {
refine "psid-offset" {
default "0";
}
}
}
leaf br-ipv6-addr {
type inet:ipv6-address;
description
"The IPv6 address for binding BR.";
}
}
/*
* Features
*/
feature binding-mode {
description
"Binding is used for configuring the Lightweight 4over6
mechanism.
Binding-based softwire mechanisms are IPv4-over-IPv6 tunneling
transition mechanisms specifically intended for complete
independence between the IPv6 subnet prefix (and IPv6 address)
and IPv4 address, with or without IPv4 address sharing.
This is accomplished by maintaining state for each softwire
(per-subscriber state) in the central Border Relay (BR) and
using a hub-and-spoke forwarding architecture. In order to
delegate the NAPT function and achieve IPv4 address sharing,
port-restricted IPv4 addresses needs to be allocated to CEs.
This feature indicates that the network element can function
as one or more binding-based softwire instances.";
reference
"RFC 7596: Lightweight 4over6: An Extension to the Dual-Stack
Lite Architecture
RFC 7597: Mapping of Address and Port with Encapsulation
(MAP-E)
RFC 7599: Mapping of Address and Port using Translation
(MAP-T)";
}
feature map-e {
description
"MAP-E is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP encapsulation. MAP-E
allows for a reduction of the amount of centralized state
using rules to express IPv4/IPv6 address mappings. This
introduces an algorithmic relationship between the IPv6 subnet
and IPv4 address.
This feature indicates that the network element can function
as one or more MAP-E softwire instances.";
reference
"RFC 7597: Mapping of Address and Port with Encapsulation
(MAP-E)";
}
feature map-t {
description
"MAP-T is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP translation. It
leverages a double stateless NAT64-based solution as well
as the stateless algorithmic address and transport layer
port mapping algorithm defined for MAP-E.
This feature indicates that the network element can function
as one or more MAP-T softwire instances.";
reference
"RFC 7599: Mapping of Address and Port using Translation
(MAP-T)";
}
container br-instances {
description
"BR instances enabled in a network element.";
choice br-type {
description
"Select binding or algorithmic BR functionality.";
case binding {
if-feature "binding-mode";
container binding {
description
"binding mechanism (binding table) configuration.";
list bind-instance {
key "name";
description
"A set of binding instances to be configured.";
leaf name {
type string;
mandatory true;
description
"The name for the binding BR. It is used to uniquely
distinguish a binding instance by its name.";
}
container binding-table-versioning {
description
"binding table's version";
leaf version {
type uint64;
description
"Version number for this binding table.";
}
leaf date {
type yang:date-and-time;
description
"Timestamp when the binding table was activated.
A binding instance may be provided with binding
entries that may change in time (e.g., increase
the size of the port set). When a party who is
the victim of abuse presents an external IP
address/port, the version of the binding table
is important because, depending on the version,
a distinct customer may be identified.
The timestamp is used as a key to find the
appropriate binding table that was put into effect
when an abuse occurred.";
reference
"RFC 7422: Deterministic Address Mapping to Reduce
Logging in Carrier-Grade NAT Deployments";
}
}
leaf softwire-num-max {
type uint32 {
range "1..max";
}
mandatory true;
description
"The maximum number of softwires that can be created
on the binding BR.";
}
leaf softwire-payload-mtu {
type uint16;
units "bytes";
mandatory true;
description
"The payload IPv4 MTU for binding softwire.";
}
leaf softwire-path-mru {
type uint16;
units "bytes";
mandatory true;
description
"The path MRU for binding softwire";
reference
"RFC 4213: Basic Transition Mechanisms for IPv6 Hosts
and Routers";
}
leaf enable-hairpinning {
type boolean;
default "true";
description
"Enables/disables support for locally forwarding
(hairpinning) traffic between two CEs";
reference
"RFC 7596: Lightweight 4over6: An Extension to
the Dual-Stack Lite Architecture, Section 6.2";
}
container binding-table {
description
"binding table";
list binding-entry {
key "binding-ipv6info";
description
"binding entry";
uses binding-entry;
}
}
container icmp-policy {
description
"The binding BR can be configured to process or drop
incoming ICMP messages and to generate outgoing ICMP
error messages.";
container icmpv4-errors {
description
"ICMPv4 error processing configuration";
leaf allow-incoming-icmpv4 {
type boolean;
default "true";
description
"Enables the processing of incoming ICMPv4
packets.";
reference
"RFC 7596: Lightweight 4over6: An Extension to
the Dual-Stack Lite Architecture";
}
leaf icmpv4-rate {
type uint32;
description
"Rate limit threshold in messages per second
for processing incoming ICMPv4 errors messages";
}
leaf generate-icmpv4-errors {
type boolean;
default "true";
description
"Enables the generation of outgoing ICMPv4 error
messages on receipt of an inbound IPv4 packet
with no matching binding table entry.";
reference
"RFC 7596: Lightweight 4over6:
An Extension to the Dual-Stack Lite
Architecture, Section 5.2";
}
}
container icmpv6-errors {
description
"ICMPv6 error processing configuration";
leaf generate-icmpv6-errors {
type boolean;
default "true";
description
"Enables the generation of ICMPv6 error messages
if no matching binding table entry is found for
a received packet.";
reference
"RFC 7596: Lightweight 4over6:
An Extension to the Dual-Stack Lite
Architecture, Section 6.2";
}
leaf icmpv6-rate {
type uint32;
description
"Rate limit threshold in messages per second
for sending ICMPv6 errors messages";
reference
"RFC 7596: Lightweight 4over6: An Extension
to the Dual-Stack Lite Architecture, Section 9";
}
}
}
container traffic-stat {
config false;
description
"Traffic statistics information for the BR.";
leaf discontinuity-time {
type yang:date-and-time;
mandatory true;
description
"The time of the most recent occasion on which the
BR instance suffered a discontinuity. This must
be initialized when the BR instance is configured
or rebooted.";
}
uses softwire-common:traffic-stat;
leaf dropped-icmpv4-packets {
type yang:zero-based-counter64;
description
"ICMPv4 packets that are dropped as a result
of the ICMP policy. Typically, this can be any
incoming ICMPv4 packets if ICMPv4 processing is
disabled or incoming ICMPv4 packets that exceed
the ICMPv4 rate-limit threshold.
Discontinuities in the value of this counter can
occur at re-initialization of the management
system and at other times as indicated by
the value of 'discontinuity-time'.";
}
leaf dropped-icmpv4-bytes {
type yang:zero-based-counter64;
description
"ICMPv4 messages, in bytes, that are dropped as
a result of the ICMP policy. Typically, it
can be any incoming ICMPv4 packets if ICMPv4
processing is disabled or incoming ICMPv4
packets that exceed the ICMPv4 rate-limit
threshold.
Discontinuities in the value of this counter can
occur at re-initialization of the management
system and at other times as indicated by
the value of 'discontinuity-time'.";
}
leaf hairpin-ipv4-packets {
type yang:zero-based-counter64;
description
"IPv4 packets locally routed between two CEs
(hairpinned).
Discontinuities in the value of this counter can
occur at re-initialization of the management
system and at other times as indicated by
the value of 'discontinuity-time'.";
}
leaf hairpin-ipv4-bytes {
type yang:zero-based-counter64;
description
"IPv4 bytes locally routed between two CEs
(hairpinned).
Discontinuities in the value of this counter can
occur at re-initialization of the management
system and at other times as indicated by
the value of 'discontinuity-time'.";
}
leaf active-softwire-num {
type uint32;
config false;
description
"The number of currently active softwires on the
binding instance.
Discontinuities in the value of this counter can
occur at re-initialization of the management
system and at other times as indicated by
the value of 'discontinuity-time'.";
}
}
}
}
}
case algo {
if-feature "map-e or map-t";
container algorithm {
description
"A set of parameters used for MAP-E/MAP-T";
list algo-instance {
key "name";
description
"Instances of algorithm";
leaf name {
type string;
mandatory true;
description
"The name is used to uniquely identify an algorithm
instance.
This name can be automatically assigned
or explicitly configured.";
}
uses softwire-common:algorithm-instance;
container port-set {
description
"Indicates a set of ports.";
uses port-set;
}
container traffic-stat {
config false;
description
"Traffic statistics information for the BR.";
leaf discontinuity-time {
type yang:date-and-time;
mandatory true;
description
"The time of the most recent occasion on which the
BR instance suffered a discontinuity. This must
be reset to the current date-and-time when the BR
instance is configured or rebooted.";
}
uses softwire-common:traffic-stat;
}
}
}
}
}
}
/*
* Notifications
*/
notification softwire-binding-instance-event {
if-feature "binding-mode";
description
"Notifications for the binding instance when an entry is
added, modified, or is not valid anymore.";
leaf bind-name {
type leafref {
path "/br-instances/binding/bind-instance/name";
}
description
"The name of the binding-instance that
generated the notification.";
}
leaf-list invalid-entry {
type leafref {
path "/br-instances/binding/"
+ "bind-instance[name=current()/../bind-name]/"
+ "binding-table/binding-entry/binding-ipv6info";
}
description
"Notify the client that a specific binding entry has
expired or is invalid. The binding-ipv6info identifies
an entry.";
}
leaf-list added-entry {
type inet:ipv6-address;
description
"Notify the client that a binding entry has been added.
The IPv6 address of that entry is the index. The client
gets other information from the binding BR about the entry
indexed by that ipv6 address.";
}
leaf-list modified-entry {
type leafref {
path "/br-instances/binding/"
+ "bind-instance[name=current()/../bind-name]/"
+ "binding-table/binding-entry/binding-ipv6info";
}
description
"The binding table entry that has been modified.";
}
}
notification softwire-algorithm-instance-event {
if-feature "map-e or map-t";
description
"Notifications for an algorithm instance when an entry is
added, modified, or is not valid anymore.";
leaf algo-name {
type leafref {
path "/br-instances/algorithm/algo-instance/name";
}
mandatory true;
description
"Algorithmic instance event.";
}
leaf-list invalid-entry {
type leafref {
path "/br-instances/algorithm/algo-instance/name";
}
description
"Invalid entry.";
}
leaf-list added-entry {
type leafref {
path "/br-instances/algorithm/algo-instance/name";
}
description
"Added entry.";
}
leaf-list modified-entry {
type leafref {
path "/br-instances/algorithm/algo-instance/name";
}
description
"Modified entry.";
}
}
}
<CODE ENDS>¶
This module imports typedefs from [RFC6991].¶
The following YANG module contains definitions that are used by both the softwire CE and softwire BR YANG modules.¶
<CODE BEGINS> file "ietf-softwire-common@2019-11-16.yang"
module ietf-softwire-common {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-softwire-common";
prefix softwire-common;
import ietf-inet-types {
prefix inet;
reference
"RFC 6991: Common YANG Data Types, Section 4";
}
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types, Section 3";
}
organization
"IETF Softwire Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/softwire/>
WG List: <mailto:softwire@ietf.org>
Author: Qi Sun
<mailto:sunqi.ietf@gmail.com>
Author: Linhui Sun
<mailto:lh.sunlinh@gmail.com>
Author: Yong Cui
<mailto:yong@csnet1.cs.tsinghua.edu.cn>
Editor: Ian Farrer
<mailto:ian.farrer@telekom.de>
Author: Sladjana Zoric
<mailto:sladjana.zoric@telekom.de>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Rajiv Asati
<mailto:rajiva@cisco.com>";
description
"This document defines a YANG module defining types
common to all A+P modules.
Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 8676; see
the RFC itself for full legal notices.";
revision 2019-11-16 {
description
"Initial revision.";
reference
"RFC 8676: YANG Modules for IPv4-in-IPv6 Address plus Port
(A+P) Softwires";
}
feature map-e {
description
"MAP-E is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP encapsulation. MAP-E
allows for a reduction of the amount of centralized state
using rules to express IPv4/IPv6 address mappings. This
introduces an algorithmic relationship between the IPv6
subnet and IPv4 address.
This feature indicates that the network element can function
as one or more MAP-E softwire instances.";
reference
"RFC 7597: Mapping of Address and Port with Encapsulation
(MAP-E)";
}
feature map-t {
description
"MAP-T is an IPv6 transition mechanism for transporting IPv4
packets across an IPv6 network using IP translation. It
leverages a double stateless NAT64-based solution as well as
the stateless algorithmic address and transport layer
port mapping algorithm defined for MAP-E.
This feature indicates that the network element can function
as one or more MAP-T softwire instances.";
reference
"RFC 7599: Mapping of Address and Port using Translation
(MAP-T)";
}
/*
* Groupings
*/
grouping algorithm-instance {
description
"A collection of parameters that is used for MAP-E/MAP-T.";
leaf enable {
type boolean;
description
"Enable/disable an individual MAP-E or MAP-T rule.";
}
container algo-versioning {
description
"Version number for this algorithm instance";
leaf version {
type uint64;
description
"A version number for the mapping algorithm
rules provided to the algorithm instance";
}
leaf date {
type yang:date-and-time;
description
"Timestamp when the algorithm instance was activated.
An algorithm instance may be provided with mapping
rules that may change in time (for example, increase
the size of the port set). When a party who is the victim
of abuse presents an external IP address/port, the version
of the algorithm is important because depending on
the version, a distinct customer may be identified.
The timestamp is used as a key to find the appropriate
algorithm that was put into effect when an abuse
occurred.";
reference
"RFC 7422: Deterministic Address Mapping to Reduce
Logging in Carrier-Grade NAT Deployments";
}
}
choice data-plane {
description
"Selects MAP-E (encapsulation) or MAP-T
(translation)";
case encapsulation {
if-feature "map-e";
description
"encapsulation for MAP-E";
leaf br-ipv6-addr {
type inet:ipv6-address;
mandatory true;
description
"The IPv6 address of the MAP-E BR.";
}
}
case translation {
if-feature "map-t";
description
"translation for MAP-T";
leaf dmr-ipv6-prefix {
type inet:ipv6-prefix;
description
"The IPv6 prefix of the MAP-T BR.";
}
}
}
leaf ea-len {
type uint8;
mandatory true;
description
"Embedded Address (EA) bits are the IPv4 EA-bits in the IPv6
address identifying an IPv4 prefix/address (or part thereof)
or a shared IPv4 address (or part thereof) and a port-set
identifier. The length of the EA-bits is defined as part of
a MAP rule for a MAP domain.";
}
leaf rule-ipv6-prefix {
type inet:ipv6-prefix;
mandatory true;
description
"The Rule IPv6 prefix defined in the mapping rule.";
}
leaf rule-ipv4-prefix {
type inet:ipv4-prefix;
mandatory true;
description
"The Rule IPv4 prefix defined in the mapping rule.";
}
leaf forwarding {
type boolean;
mandatory true;
description
"This parameter specifies whether the rule may be used for
forwarding; if set, this rule is used as a Forwarding
Mapping Rule (FMR); if not set, this rule is a Basic
Mapping Rule (BMR) only and must not be used for
forwarding.";
}
}
grouping traffic-stat {
description
"Traffic statistics";
leaf sent-ipv4-packets {
type yang:zero-based-counter64;
description
"Number of decapsulated and forwarded IPv4 packets.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf sent-ipv4-bytes {
type yang:zero-based-counter64;
description
"Decapsulated/translated IPv4 traffic sent, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf sent-ipv6-packets {
type yang:zero-based-counter64;
description
"Number of encapsulated IPv6 packets sent.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf sent-ipv6-bytes {
type yang:zero-based-counter64;
description
"Encapsulated IPv6 traffic sent, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf rcvd-ipv4-packets {
type yang:zero-based-counter64;
description
"Number of IPv4 packets received.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf rcvd-ipv4-bytes {
type yang:zero-based-counter64;
description
"IPv4 traffic received, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf rcvd-ipv6-packets {
type yang:zero-based-counter64;
description
"Number of IPv4-in-IPv6 packets received.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf rcvd-ipv6-bytes {
type yang:zero-based-counter64;
description
"IPv4-in-IPv6 traffic received, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv4-packets {
type yang:zero-based-counter64;
description
"Number of IPv4 packets dropped at the
Internet-facing interface.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv4-bytes {
type yang:zero-based-counter64;
description
"IPv4 traffic dropped at the Internet-facing
interface, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv6-packets {
type yang:zero-based-counter64;
description
"Number of IPv4-in-IPv6 packets dropped.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv6-bytes {
type yang:zero-based-counter64;
description
"IPv4-in-IPv6 traffic dropped, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv4-fragments {
type yang:zero-based-counter64;
description
"Number of fragmented IPv4 packets dropped.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf dropped-ipv4-fragment-bytes {
type yang:zero-based-counter64;
description
"Fragmented IPv4 traffic dropped, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf ipv6-fragments-reassembled {
type yang:zero-based-counter64;
description
"Number of IPv6 fragments successfully reassembled.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf ipv6-fragments-bytes-reassembled {
type yang:zero-based-counter64;
description
"IPv6 fragments successfully reassembled, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf out-icmpv4-error-packets {
type yang:zero-based-counter64;
description
"Internally generated ICMPv4 error packets.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf out-icmpv4-error-bytes {
type yang:zero-based-counter64;
description
"Internally generated ICMPv4 error messages, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf out-icmpv6-error-packets {
type yang:zero-based-counter64;
description
"Internally generated ICMPv6 error packets.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
leaf out-icmpv6-error-bytes {
type yang:zero-based-counter64;
description
"Internally generated ICMPv6 error messages, in bytes.
Discontinuities in the value of this counter can occur
at re-initialization of the management system and at
other times as indicated by the value of
'discontinuity-time'.";
}
}
}
<CODE ENDS>¶
The YANG modules defined in this document are 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 Network Configuration 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.¶
All data nodes defined in the YANG modules which can be created, modified, and deleted (i.e., config true, which is the default) are considered sensitive. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. An attacker who is able to access the BR can undertake various attacks, such as:¶
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. These subtrees and data nodes can be misused to track the activity of a host:¶
Security considerations related to lw4o6, MAP-T, and MAP-E are discussed in [RFC7596], [RFC7597], and [RFC7599] respectively.¶
Security considerations given in [RFC7950] are also applicable here.¶
IANA has assigned the following new tunnel type under the tunnelType subregistry of the "ifType Definitions" registry maintained in the SMI Numbers registry [TUNNELTYPE-IANA-REGISTRY]:¶
IANA has registered the following in the "ns" subregistry within the "IETF XML Registry" [RFC3688]:¶
IANA has registered the following YANG modules in the "YANG Module Names" subregistry [RFC6020] within the "YANG Parameters" registry.¶
The following sections provide examples of how the softwire YANG modules can be used for configuring softwire elements.¶
The lwAFTR maintains an address binding table that contains the following 3-tuples:¶
The entry has two functions: the IPv6 encapsulation of inbound IPv4 packets destined to the lwB4 and the validation of outbound IPv4-in-IPv6 packets received from the lwB4 for decapsulation.¶
Consider an example for the following lw4o6 binding table entry:¶
<br-instances>
<binding>
<bind-instance>
<name>mybinding-instance</name>
<binding-table>
<binding-entry>
<binding-ipv6info>2001:db8::1</binding-ipv6info>
<binding-ipv4-addr>192.0.2.1</binding-ipv4-addr>
<port-set>
<psid>52</psid>
<psid-len>8</psid-len>
</port-set>
<br-ipv6-addr>2001:db8:1::2</br-ipv6-addr>
</binding-entry>
</binding-table>
<softwire-num-max>1024</softwire-num-max>
<softwire-path-mru>1540</softwire-path-mru>
<softwire-payload-mtu>1500</softwire-payload-mtu>
</bind-instance>
</binding>
</br-instances> ¶
A MAP-E BR is configured with forward mapping rules for the CEs it is serving. In this example (taken from [RFC7597], Appendix A, Example 2), the following parameters are required:¶
The mapping rule has two functions: identifying the destination CE IPv6 address for encapsulating inbound IPv4 packets and the validation of outbound IPv4-in-IPv6 packets received from the CE for de-capsulation.¶
The transport type for the data plane also needs to be configured for encapsulation to enable MAP-E and forwarding needs to be enabled.¶
Consider an example for the following MAP-E Forwarding Mapping Rule:¶
Figure 4 provides the example MAP-E BR configuration xml.¶
<br-instances>
<algorithm>
<algo-instance>
<name>myalgo-instance</name>
<encapsulation>
<br-ipv6-addr>2001:db8:ffff::1</br-ipv6-addr>
</encapsulation>
<ea-len>16</ea-len>
<rule-ipv4-prefix>192.0.2.0/24</rule-ipv4-prefix>
<rule-ipv6-prefix>2001:db8::/40</rule-ipv6-prefix>
<forwarding>true</forwarding>
<port-set>
<psid-offset>6</psid-offset>
<psid-len>8</psid-len>
</port-set>
</algo-instance>
</algorithm>
</br-instances> ¶
This section provides XML examples for configuring a lw4o6 CE. Examples for routing and NAT44 are also provided for convenience.¶
Consider an example for the following lw4o6 CE configuration:¶
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
<interface>
<name>lw4o6-wan</name>
<type>iana-tunnel-type:aplusp</type>
<br-ipv6-addr
xmlns="urn:ietf:params:xml:ns:yang:ietf-softwire-ce">
2001:db8:1::2
</br-ipv6-addr>
<binding-ipv6info
xmlns="urn:ietf:params:xml:ns:yang:ietf-softwire-ce">
2001:db8::1
</binding-ipv6info>
</interface>
</interfaces>
</config>
¶
In the example depicted in Figure 5, the interface name is defined for the softwire tunnel. This name is then referenced by the routing configuration for the IPv4 route. Figure 6 provides an example configuration for the CE's IPv4 routing using the YANG module described in [RFC8349].¶
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<routing xmlns="urn:ietf:params:xml:ns:yang:ietf-routing">
<control-plane-protocols>
<control-plane-protocol>
<type>static</type>
<name>v4</name>
<static-routes>
<ipv4
xmlns="urn:ietf:params:xml:ns:yang:ietf-ipv4-unicas\
t-routing">
<route>
<destination-prefix>0.0.0.0/0</destination-prefix>
<next-hop>
<outgoing-interface>lw4o6-wan</outgoing-interface>
</next-hop>
</route>
</ipv4>
</static-routes>
</control-plane-protocol>
</control-plane-protocols>
</routing>
</config>
¶
Figure 7 provides an example configuration for the CE's NAPT44 function using the YANG module described in [RFC8512].¶
<config xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<nat xmlns="urn:ietf:params:xml:ns:yang:ietf-nat">
<instances>
<instance>
<id>1</id>
<policy>
<policy-id>1</policy-id>
<external-ip-address-pool>
<pool-id>1</pool-id>
<external-ip-pool>192.0.2.1</external-ip-pool>
</external-ip-address-pool>
<port-set-restrict>
<port-set-algo>
<psid-offset>6</psid-offset>
<psid-len>8</psid-len>
<psid>52</psid>
</port-set-algo>
</port-set-restrict>
<notify-pool-usage>
<pool-id>1</pool-id>
<high-threshold>80</high-threshold>
</notify-pool-usage>
</policy>
<mapping-limits>
<limit-per-protocol>
<protocol-id>1</protocol-id>
<limit>8</limit>
</limit-per-protocol>
<limit-per-protocol>
<protocol-id>6</protocol-id>
<limit>32</limit>
</limit-per-protocol>
<limit-per-protocol>
<protocol-id>17</protocol-id>
<limit>16</limit>
</limit-per-protocol>
</mapping-limits>
<mapping-table>
<mapping-entry>
<index>1</index>
<external-src-address>
192.0.2.1/32
</external-src-address>
<internal-src-address>
192.168.1.0/24
</internal-src-address>
<transport-protocol>6</transport-protocol>
</mapping-entry>
<mapping-entry>
<index>2</index>
<external-src-address>
192.0.2.1/32
</external-src-address>
<internal-src-address>
192.168.1.0/24
</internal-src-address>
<transport-protocol>17</transport-protocol>
</mapping-entry>
<mapping-entry>
<index>3</index>
<external-src-address>
192.0.2.1/32
</external-src-address>
<internal-src-address>
192.168.1.0/24
</internal-src-address>
<transport-protocol>1</transport-protocol>
</mapping-entry>
</mapping-table>
</instance>
</instances>
</nat>
</config>
¶
The authors would like to thank Lishan Li, Bert Wijnen, Giles Heron, Ole Troan, Andy Wingo, and Leo Tietz for their contributions to this work.¶
Thanks to Sheng Jiang for the review.¶
Special thanks to Tom Petch and Martin Bjorklund for the detailed review and suggestions.¶
The following individuals are co-authors:¶
Yong Cui Tsinghua University China Phone: +86-10-6260-3059 Email: cuiyong@tsinghua.edu.cn¶
Qi Sun Tsinghua University China Phone: +86-10-6278-5822 Email: sunqi.ietf@gmail.com¶
Linhui Sun Tsinghua University China Phone: +86-10-6278-5822 Email: lh.sunlinh@gmail.com¶
Sladjana Zechlin Deutsche Telekom AG Germany Email: sladjana.zechlin@telekom.de¶
Rajiv Asati Cisco Systems, Inc. United States of America Email: Rajiva@cisco.com¶
Hao Wang Tsinghua University China Phone: +86-10-6278-5822 Email: wangh13@mails.tsinghua.edu.cn¶