| Network Working Group | M. Boucadair |
| Internet-Draft | C. Jacquenet |
| Intended status: Standards Track | Orange |
| Expires: April 13, 2018 | S. Sivakumar |
| Cisco Systems | |
| October 10, 2017 |
YANG Data Modules for the DS-Lite
draft-ietf-softwire-dslite-yang-07
This document defines YANG modules for the DS-Lite Address Family Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements .
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 13, 2018.
Copyright (c) 2017 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.
This document defines data models for DS-Lite [RFC6333], using the YANG data modeling language [RFC7950]. Both the Address Family Transition Router (AFTR) and Basic Bridging BroadBand (B4) elements are covered by this specification. As a reminder, Figure 1 illustrates an overview of the DS-Lite architecture that involves AFTR and B4 elements.
+-----------+
| Host |
+-----+-----+
|10.0.0.1
|
|
|10.0.0.2
+---------|---------+
| | |
| Home router |
|+--------+--------+|
|| B4 ||
|+--------+--------+|
+--------|||--------+
|||2001:db8:0:1::1
|||
|||<-IPv4-in-IPv6 softwire
|||
-------|||-------
/ ||| \
| ISP core network |
\ ||| /
-------|||-------
|||
|||2001:db8:0:2::1
+--------|||--------+
| AFTR |
|+--------+--------+|
|| Concentrator ||
|+--------+--------+|
| |NAT| |
| +-+-+ |
+---------|---------+
|192.0.2.1
|
--------|--------
/ | \
| Internet |
\ | /
--------|--------
|
|198.51.100.1
+-----+-----+
| IPv4 Host |
+-----------+
Figure 1: DS-Lite Base Architecture
This document follows the guidelines of [RFC6087], uses the common YANG types defined in [RFC6991], and adopts Network Management Datastore Architecture (NMDA).
This document makes use of the terms defined in Section 3 of [RFC6333].
The terminology for describing YANG data modules is defined in [RFC7950].
The meaning of the symbols in tree diagrams is defined in [I-D.ietf-netmod-yang-tree-diagrams].
As shown in Figure 1:
Therefore, the AFTR YANG module is designed to augment both the Interfaces YANG module [RFC7223] and the NAT YANG module [I-D.ietf-opsawg-nat-yang] with DS-Lite specific features. The B4 YANG module augments the interfaces YANG module.
Concretely, the AFTR YANG module (Figure 2) augments the Interfaces YANG module with the following:
In addition, the AFTR YANG module augments the NAT YANG module (nat-policy, in particular) with the following:
Given that the NAT44 table of the AFTR element is extended to include the source IPv6 address of incoming packets, the AFTR YANG module augments the NAT mapping-entry with the following:
module: ietf-dslite-aftr
augment /if:interfaces/if:interface:
+--rw aftr-ipv6-address? inet:ipv6-address
+--rw aftr-ipv4-address? inet:ipv4-address
+--rw tunnel-mtu? uint16
+--rw max-softwire-per-subscriber? uint8
+--rw v6-v4-dscp-preservation? boolean
augment /nat:nat-module/nat:nat-instances/nat:nat-instance/nat:nat-policy:
+--rw state-migrate? boolean
+--rw mss-clamping
+--rw mss-clamping-enable? boolean
+--rw mss-value? uint16
augment /nat:nat-module/nat:nat-instances/nat:nat-instance/nat:mapping-table/nat:mapping-entry:
+--rw b4-ipv6-address? inet:ipv6-address
+--rw v6-dscp? uint8
+--rw internal-v4-dscp? uint8
+--rw external-v4-dscp? uint8
Figure 2: YANG Module for DS-Lite AFTR
The B4 YANG module (Figure 3) augments the Interfaces YANG module with the following:
module: ietf-dslite-b4
augment /if:interfaces/if:interface:
+--rw b4-ipv6-address? inet:ipv6-address
+--rw aftr-ipv6-addr? inet:ipv6-address
+--rw b4-ipv4-address? inet:ipv4-address
+--rw tunnel-mtu? uint16
+--rw v6-v4-dscp-preservation? boolean
Figure 3: YANG Module for DS-Lite B4
PCP-related considerations are out of scope of the document. A YANG module for PCP is documented in [I-D.boucadair-pcp-yang].
<CODE BEGINS> file "ietf-dslite-aftr@2017-10-09.yang"
module ietf-dslite-aftr {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-aftr";
prefix dslite-aftr;
import ietf-inet-types { prefix inet; }
import ietf-interfaces { prefix if; }
import iana-if-type { prefix ianaift; }
import ietf-nat {prefix nat;}
organization "Softwire Working Group";
contact
"Mohamed Boucadair <mohamed.boucadair@orange.com>
Christian Jacquenet <christian.jacquenet@orange.com>
Senthil Sivakumar <ssenthil@cisco.com>";
description
"This module is a YANG module for DS-Lite AFTR
implementations.
Copyright (c) 2017 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 XXXX; see
the RFC itself for full legal notices.";
revision 2017-10-09 {
description "Early yangdoctors review.";
reference "-ietf-07";
}
revision 2017-08-10 {
description "The module augments also the Interface module.";
reference "-ietf-04";
}
revision 2017-07-27 {
description "Redesign the module as an augment of the NAT YANG module.";
reference "-ietf-04";
}
revision 2017-07-03 {
description "Fix some minor points.";
reference "-ietf-03";
}
revision 2017-01-03 {
description "Fixed a compilation error:
https://github.com/mbj4668/pyang/issues/296.";
reference "-ietf-02";
}
revision 2016-11-14 {
description "Integrates the comments from Ian:
add B4 module, add an MSS leaf, add more details about
logging protocols, and other edits.";
reference "-ietf-01";
}
revision 2016-07-27 {
description "-00 IETF version.";
reference "-ietf-00";
}
revision 2016-06-13 {
description "Update the module.";
reference "-04";
}
revision 2015-12-16 {
description "Fix an error.";
reference "-03";
}
revision 2015-09-01 {
description "Add port threshold notifications.";
reference "-02";
}
revision 2015-08-31 {
description "Fix a timeout issue.";
reference "-01";
}
revision 2015-08-17 {
description "First spec.";
reference "-00";
}
// Augment Interface module with DS-Lite Softwire
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:tunnel'";
description
"Augments Interface module with AFTR parameters.
IANA interface types are maintained at this registery:
https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib.
tunnel (131), -- Encapsulation interface";
leaf aftr-ipv6-address {
type inet:ipv6-address;
description
"IPv6 address of the DS-Lite AFTR.";
reference
"RFC 6333.";
}
leaf aftr-ipv4-address {
type inet:ipv4-address;
default "192.0.0.1";
description
"IPv4 address of the DS-Lite AFTR.
192.0.0.1 is reserved for the AFTR element.
This address can be used to report ICMP
problems and will appear in traceroute
outputs.";
reference
"RFC 6333.";
}
leaf tunnel-mtu {
type uint16;
description
"Configures a tunnel MTU.
[RFC6908] specifies that since
fragmentation and reassembly is not
optimal, the operator should do
everything possible to eliminate
the need for it. If the operator uses
simple IPv4-in-IPv6 softwire, it is
recommended that the MTU size of the IPv6
network between the B4 and the AFTR
accounts for the additional overhead
(40 bytes).";
reference
"RFC 6908.";
}
leaf max-softwire-per-subscriber {
type uint8;
default 1;
description
"Configures the maximum softwires per subscriber
feature.
A subscriber is uniquely identified by means
of subscriber-mask.
This policy aims to prevent a misbehaving
subscriber from mounting several DS-Lite
softwires that would consume additional AFTR
resources (e.g., get more external ports if
the quota were enforced on a per-softwire basis,
consume extra processing due to a large number
of active softwires).";
reference
"Section 4 of RFC 7785.";
}
leaf v6-v4-dscp-preservation {
type boolean;
description
"Copies the DSCP value from the IPv6 header
and vice versa.
According to Section 2.10 of [RFC6908],
operators should use this model
by provisioning the network such that
the AFTR copies the DSCP value in the IPv4
header to the Traffic Class field in
the IPv6 header, after the encapsulation
for the downstream traffic.";
reference
"Section 2.10 of RFC 6908.";
}
}
// Augment NAT module with AFTR parameters
augment "/nat:nat-module/nat:nat-instances/"+
"nat:nat-instance/nat:nat-policy" {
when "../nat:nat-capabilities/nat:nat-flavor = 'nat:nat44'";
description
"Augments the NAT44 module with AFTR parameters.";
leaf state-migrate {
type boolean;
default true;
description
"State migration is enabled by default.
In the event a new IPv6 address is assigned to the B4 element,
the AFTR should migrate existing state to be bound to the new
IPv6 address. This operation ensures that traffic destined to
the previous B4's IPv6 address will be redirected to the newer
B4's IPv6 address. The destination IPv6 address for tunneling
return traffic from the AFTR should be the last seen as the B4's
IPv6 source address from the CPE.
The AFTR uses the subscriber-mask to determine whether two
IPv6 addresses belong to the same CPE (e.g., if the
subscriber-mask is set to 56, the AFTR concludes that
2001:db8:100:100::1 and 2001:db8:100:100::2 belong to the same
CPE assigned with 2001:db8:100:100::/56).";
reference
"RFC 7785.";
}
container mss-clamping {
description
"MSS rewriting configuration to avoid IPv6
fragmentation.";
leaf mss-clamping-enable {
type boolean;
description
"Enable/disable MSS rewriting feature.";
}
leaf mss-value {
type uint16;
units "octets";
description
"Sets the MSS value to be used for
MSS rewriting.";
}
}
}
// Augment NAT mapping entry: Extended NAT44 mapping Entry
augment "/nat:nat-module/nat:nat-instances/nat:nat-instance/"+
"nat:mapping-table/nat:mapping-entry"{
when "../../nat:nat-capabilities/nat:nat-flavor = 'nat:nat44'";
description
"Augments the NAT44 mapping table with DS-Lite specifics.";
leaf b4-ipv6-address {
type inet:ipv6-address;
description
"Corresponds to the IPv6 address
used by the B4 element.";
reference
"RFC 6333.";
}
leaf v6-dscp {
type uint8;
description
"DSCP value used at the softwire level
(i.e., IPv6 header).";
}
leaf internal-v4-dscp {
type uint8;
description
"DSCP value of the encapsulated IPv4 packet.";
}
leaf external-v4-dscp {
type uint8;
description
"DSCP value of the translated IPv4 packet
as marked by the AFTR.";
}
}
}
<CODE ENDS>
<CODE BEGINS> file "ietf-dslite-b4@2017-10-09.yang"
module ietf-dslite-b4 {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-b4";
prefix dslite-b4;
import ietf-inet-types { prefix inet; }
import ietf-interfaces { prefix if; }
import iana-if-type { prefix ianaift; }
organization "Softwire Working Group";
contact
"Mohamed Boucadair <mohamed.boucadair@orange.com>
Christian Jacquenet <christian.jacquenet@orange.com>
Senthil Sivakumar <ssenthil@cisco.com>";
description
"This module is a YANG module for DS-Lite B4 implementations.
Copyright (c) 2017 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 XXXX; see
the RFC itself for full legal notices.";
revision 2017-10-09 {
description "Early yangdoctors review.";
reference "-ietf-07";
}
revision 2017-08-10 {
description "Augment the interfaces YANG module.";
reference "-ietf-05";
}
revision 2017-07-27 {
description "Separate B4 from AFTR.";
reference "-ietf-04";
}
// Augment Interface module with DS-Lite Softwire
augment "/if:interfaces/if:interface" {
when "if:type = 'ianaift:tunnel'";
description
"Augments Interface module with B4 parameters.
IANA interface types are maintained at this registry:
https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib.
tunnel (131), -- Encapsulation interface";
leaf b4-ipv6-address {
type inet:ipv6-address;
description
"The IPv6 address used by the B4 element.";
reference
"RFC 6333.";
}
leaf aftr-ipv6-addr {
type inet:ipv6-address;
description
"The AFTR's IPv6 address.";
reference
"RFC 6333.";
}
leaf b4-ipv4-address {
type inet:ipv4-address;
default "192.0.0.2";
description
"IPv4 address of the DS-Lite B4.
192.0.0.0/29 is reserved for the B4 element.
This address can be used to report ICMP
problems and will appear in traceroute
outputs.";
reference
"RFC 6333.";
}
leaf tunnel-mtu {
type uint16;
description
"Configures a tunnel MTU.
[RFC6908] specifies that since
fragmentation and reassembly is not
optimal, the operator should do
everything possible to eliminate
the need for it. If the operator uses
simple IPv4-in-IPv6 softwire, it is
recommended that the MTU size of the IPv6
network between the B4 and the AFTR
accounts for the additional overhead
(40 bytes).";
reference
"RFC 6908.";
}
leaf v6-v4-dscp-preservation {
type boolean;
description
"Copies the DSCP value from the IPv6 header
and vice versa.
Operators should use this model
by provisioning the network such that
the AFTR copies the DSCP value in the IPv4
header to the Traffic Class field in
the IPv6 header, after the encapsulation
for the downstream traffic.";
reference
"Section 2.10 of RFC 6908.";
}
}
}
<CODE ENDS>
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 support of SSH is mandatory to implement secure transport [RFC6242]. The NETCONF access control model [RFC6536] provides means to restrict access for particular NETCONF users to a pre-configured subset of all available NETCONF protocol operations and contents.
All data nodes defined in the YANG module which can be created, modified and deleted (i.e., config true, which is the default). These data nodes are considered sensitive. Write operations (e.g., edit-config) applied to these data nodes without proper protection can negatively affect network operations.
URI: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-dslite-b4
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
name: ietf-dslite-aftr
namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-aftr
prefix: dslite-aftr
reference: RFC XXXX
name: ietf-dslite-b4
namespace: urn:ietf:params:xml:ns:yang:ietf-dslite-b4
prefix: dslite-b4
reference: RFC XXXX
This document requests IANA to register the following URIs in the "IETF XML Registry" [RFC3688]: [RFC7950].
Thanks to Q. Wu for identifying a compiling error. Mahesh Jethanandani provided an eraly ynagdoctors review; many thanks to him.
Many thanks to Ian Farrer for the review and comments
| [I-D.boucadair-pcp-yang] | Boucadair, M., Jacquenet, C., Sivakumar, S. and S. Vinapamula, "YANG Data Models for the Port Control Protocol (PCP)", Internet-Draft draft-boucadair-pcp-yang-04, May 2017. |
| [I-D.ietf-netmod-yang-tree-diagrams] | Bjorklund, M. and L. Berger, "YANG Tree Diagrams", Internet-Draft draft-ietf-netmod-yang-tree-diagrams-01, June 2017. |
| [RFC6087] | Bierman, A., "Guidelines for Authors and Reviewers of YANG Data Model Documents", RFC 6087, DOI 10.17487/RFC6087, January 2011. |
| [RFC6908] | Lee, Y., Maglione, R., Williams, C., Jacquenet, C. and M. Boucadair, "Deployment Considerations for Dual-Stack Lite", RFC 6908, DOI 10.17487/RFC6908, March 2013. |
| [RFC7785] | Vinapamula, S. and M. Boucadair, "Recommendations for Prefix Binding in the Context of Softwire Dual-Stack Lite", RFC 7785, DOI 10.17487/RFC7785, February 2016. |
The following example shows an AFTR that is reachable at 2001:db8::2. Also, this XML snippet indicates that the AFTR is provided with an IPv4 address (192.0.0.1) to be used for troubleshooting purposes such as reporting problems to B4s. Moreover, the AFTR is instructed to limit the number of softwires per subscriber to '1'.
<interface> <name>myAFTR</name> <type>ianaift:tunnel</type> <enabled>true</enabled> <aftr-ipv6-address>2001:db8::2</aftr-ipv6-address> <aftr-ipv4-address>192.0.0.1</aftr-ipv4-address> <max-softwire-per-subscriber>1</max-softwire-per-subscriber> </interface>
The following shows an XML excerpt depicting a dynamic UDP mapping entry maintained by a DS-Lite AFTR. In reference to this example, the UDP packet received with a source IPv6 address (2001:db8::1), a source IPv4 address (192.0.2.1) and source port number (1568) is translated into a UDP packet having a source IPv4 address (198.51.100.1) and source port (15000). The lifetime of this mapping is 300 seconds.
<mapping-entry>
<index>15</index>
<type>
dynamic-explicit
</type>
<transport-protocol>
17
</transport-protocol>
<b4-ipv6-address>
2001:db8::1
</b4-ipv6-address>
<internal-src-address>
192.0.2.1
</internal-dst-address>
<internal-src-port>
<single-port-number>
1568
</single-port-number>
</internal-dst-port>
<external-dst-address>
198.51.100.1
</external-dst-address>
<external-dst-port>
<single-port-number>
15000
</single-port-number>
</external-dst-port>
<lifetime>
300
</lifetime>
</mapping-entry>