]> Orange

Rennes 35000 France mohamed.boucadair@orange.com

Orange

Rennes 35000 France christian.jacquenet@orange.com

Cisco Systems

7100-8 Kit Creek Road Research Triangle Park North Carolina 27709 USA +1 919 392 5158 ssenthil@cisco.com

Internet IPv4 service continuity IPv4 address exhaustion Service Availability Address sharing IPv6 Reliability IPv4 over IPv6 This document defines a YANG data model for the DS-Lite Address Family Transition Router (AFTR).

This document defines a data model for DS-Lite , using the YANG data modeling language . Only the Address Family Transition Router (AFTR) element is covered by this specification. As a reminder, can be used to configure the name of the AFTR to a Basic Bridging BroadBand (B4) element. DS-Lite deployment considerations are discussed in . This document follows the guidelines of . This document uses the common YANG types defined in .

This document makes use of the terms defined in . The terminology for describing YANG data models is defined in .

The meaning of the symbols in these diagrams is as follows: Brackets "[" and "]" enclose list keys. Curly braces "{" and "}" contain names of optional features that make the corresponding node conditional. Abbreviations before data node names: "rw" means configuration (read-write), "ro" state data (read-only). Symbols after data node names: "?" means an optional node, "!" a container with presence, and "*" denotes a "list" or "leaf-list". Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). Ellipsis ("...") stands for contents of subtrees that are not shown.

depicts the YANG data model for the AFTR element. A device can enable multiple AFTR instances; each responsible to service a group of B4s. The data model assumes that each AFTR instance can: be enable/disabled, be provisioned with a dedicated configuration data, and maintain its own mapping table. The data model assumes that pools of IPv4 addresses can be provisioned to the AFTR. These pools may be contiguous or non-contiguous. Also, it assumes that an AFTR can either assign individual port numbers or port sets. This document assumes are enabled by default. Also, the data model relies on the recommendations in and . In addition, the data model supports state migration as per . PCP-related considerations are out of scope of the document. A YANG data model for PCP is documented in .

The following notifications are supported. These notifications are triggered by configurable parameters.

/dslite-aftr-state/dslite-aftr-instances/ | dslite-aftr-instance/id +--ro notify-pool-threshold percent]]>

file "ietf-dslite-aftr@2016-07-27.yang" module ietf-dslite-aftr { namespace "urn:ietf:params:xml:ns:yang:ietf-dslite-aftr"; prefix dslite-aftr; import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; } organization "Softwire Working Group"; contact "Mohamed Boucadair Christian Jacquenet Senthil Sivakumar (ssenthil) "; description "This module is a YANG module for DS-Lite AFTR implementations. Copyright (c) 2016 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 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 treshhold notifications."; reference "-02"; } revision 2015-08-31 { description "Fix a timeout issue."; reference "-01"; } revision 2015-08-17 { description "First spec."; reference "-00"; } // Typedef typedef percent { type uint8 { range "0 .. 100"; } description "Percentage"; } /* * Grouping */ // port numbers: single or port range grouping port-number { description "Individual port or a range of ports."; choice port-type { default single-port-number; description "Port type: single or port-range."; case single-port-number { leaf single-port-number { type inet:port-number; description "Used for single port numbers."; } } case port-range { leaf start-port-number { type inet:port-number; description "Begining of the port range."; } leaf end-port-number { type inet:port-number; description "End of the port range."; } } } } // Timeout variables grouping lifetime { description "Configure values of various timeouts."; leaf udp-lifetime { type uint32; default 120; description "UDP inactivity timeout [RFC4787]."; } leaf tcp-idle-timeout { type uint32; default 7440; description "TCP Idle timeout as per RFC 5382 should be no more than 2 hours and 4 minutes."; } leaf tcp-trans-open-timeout { type uint32; default 240; description "The value of the transitory open connection idle-timeout. Section 2.1 of [RFC7857] clarifies that a NAT should provide different configurable parameters for configuring the open and closing idle timeouts. To accommodate deployments that consider a partially open timeout of 4 minutes as being excessive from a security standpoint, a NAT may allow the configured timeout to be less than 4 minutes. However, a minimum default transitory connection idle-timeout of 4 minutes is recommended."; } leaf tcp-trans-close-timeout { type uint32; default 240; description "The value of the transitory close connection idle-timeout. Section 2.1 of [RFC7857] clarifies that a NAT should provide different configurable parameters for configuring the open and closing idle timeouts."; } leaf tcp-in-syn-timeout { type uint32; default 6; description "6 seconds, as defined in [RFC5382]."; } leaf fragment-min-timeout { type uint32; default 2; description "As long as the AFTR has available resources, the AFTR allows the fragments to arrive over fragment-min-timeout interval. The default value is inspired from RFC6146."; } leaf icmp-timeout { type uint32; default 60; description "60 seconds, as defined in [RFC5508]."; } leaf hold-down-timeout { type uint32; default 120; description "Hold down timer. Ports in the hold down pool are not reassigned till this timer expires. The length of time and the maximum number of ports in this state must be configurable by the administrator [RFC6888]. This is necessary in order to prevent collisions between old and new mappings and sessions. It ensures that all established sessions are broken instead of redirected to a different peer. The default value is defined in REQ#8 from [RFC6888]."; } } // AFTR Parameters grouping aftr-parameters { description "A set of AFTR parameters"; list dslite-aftr-ipv6-address { key address-id; description "set one or multiple IP addresses for the dslite-aftr"; leaf address-id { type uint32; description "The identifier of the address"; } leaf ipv6-address { type inet:ipv6-address; description "IPv6 address of the dslite-aftr."; } } leaf ipv4-address { type inet:ipv4-address; description "IPv4 address of the DS-Lite AFTR. 192.0.0.1 is reserved for the AFTR element [RFC6333]. This address can be used to report ICMP problems and will appear in traceroute outputs."; } 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)."; } list external-ip-address-pool { key address-id; description "Pool of external IP addresses used to service internal hosts. Both contiguous and non-contiguous pools can be configured to an AFTR. Refer to REQ-3 of [RFC6888]."; leaf address-id { type uint32; description "An identifier of the address."; } leaf external-ip-pool { type inet:ipv4-prefix; description "An IPv4 prefix used by the AFTR for NAT purposes."; } } leaf subscriber-mask { type uint8 { range "0 .. 128"; } default "56"; description "The subscriber-mask is an integer that indicates the length of significant bits to be applied on the source IPv6 address (internal side) to unambiguously identify a CPE. Subscriber-mask is a system-wide configuration parameter that is used to enforce generic per-subscriberpolicies (e.g., port-quota). The enforcement of these generic policies does not require the configuration of every subscriber's prefix. Example: suppose the 2001:db8:100:100::/56 prefix is assigned to a DS-Lite enabled CPE. Suppose also that the 2001:db8:100:100::1 is the IPv6 address used by the B4 that resides in that CPE. When the AFTR receives a packet from this client, it applies the subscriber-mask (e.g., 56) on the source IPv6 address to compute the associated prefix for this client (that is 2001:db8:100:100::/56). Then, the AFTR enforces policies based on that prefix (2001:db8:100:100::/56), not on the exact source IPv6 address [RFC7785]."; } leaf nat-mapping-type { type enumeration { enum "eim" { description "Endpoint-Independent-Mapping. Refer to Section 4 of [RFC4787]."; } enum "adm" { description "Address-Dependent-Mapping. Refer to Section 4 of [RFC4787]."; } enum "edm" { description "address-and-port-Dependent-Mapping. Refer to Section 4 of [RFC4787]."; } } description "Indicates the type of the NAT mapping."; } leaf nat-filtering-type { type enumeration { enum "eif" { description "Endpoint-Independent-Filtering. Refer to Section 5 of [RFC4787]."; } enum "adf" { description "Address-Dependent-Filtering. Refer to Section 5 of [RFC4787]."; } enum "edf" { description "address-and-port-Dependent-Filtering. Refer to Section 5 of [RFC4787]."; } } description "Indicates the type of the NAT filtering."; } leaf port-quota { type uint16; mandatory true; description "Configures a port quota to be assigned per subscriber. According to [RFC6888], per-subscriber limits must be configurable by the administrator."; } list exclude-ports { key "id"; description "The set of ports not to be assigned by the AFTR."; leaf id { type uint16; description "An identifier"; } uses port-number; } container port-set { description "Manages port-set assignments."; leaf port-set-enable { type boolean; description "Enable/Disable port set assignment."; } leaf port-set-size { type uint16; description "Indicates the size of assigned port sets."; } leaf port-set-timeout { type uint32; description "Inactivty timeout for port sets."; } } leaf enable-app { type boolean; default true; description "Enable/disable the IP address pooling behavior of Paired (APP). APP is recommended in REQ-2 from [RFC4787]."; } leaf max-softwire-per-subscriber { type uint8; default 1; description "Configures the maximum softwire per subscriber feature as per Section 4 of [RFC7785]. 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)."; } list transport-protocol { key "transport-protocol-id"; description "Set of (transport) protocols supported by the AFTR. Default must be set to TCP and UDP."; leaf transport-protocol-id { type uint8; description "Identifier of the transport protocol. IANA Protocol Numbers maintianed in http://www.iana.org/assignments/ protocol-numbers are used."; } } leaf new-mappings-rate-limit { type uint32; description "Rate-limit sessions per subscriber. The goal is to prevent a single subscriber from consuming excessive CPU resources from the AFTR."; } leaf mss-clamping-enable { type boolean; description "Enable/disable MSS rewritting feature."; } leaf port-randomization-enable { type boolean; description "Enable/disable port randomization feature. Section 9 of [RFC7857] specifies that a NAT should follow the recommendations in Section 4 of RFC6056."; } leaf port-preservation-enable { type boolean; description "Indicates whether the AFTR should preserve the internal port number."; } leaf port-parity-preservation-enable { type boolean; description "Indicates whether the AFTR should preserve the port parity of the internal port number. Section 8 of [RFC7857] indicates that a NAT may disable port parity preservation for all dynamic mappings. It also specifies that a NAT should support means to explicitly request to preserve port parity (e.g., [RFC7753])."; } leaf address-roundrobin-enable { type boolean; description "Enable/disable address allocation round robin."; } uses lifetime; leaf v6-v4-dscp-preservation { type boolean; mandatory true; 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."; } container logging-info { description "Information about AFTR logging events."; leaf logging-enable { type boolean; description "Enable logging features as per Section 2.3 of [RFC6908]."; } leaf destination-address { type inet:ip-prefix; description "Address of the collector that receives the logs."; } leaf destination-port { type inet:port-number; description "Destination port of the collector."; } } container notify-address-pool-usage { description "Notification of Pool usage when certain criteria is met."; leaf pool-id { type uint32; description "Pool-ID for which the notification criteria is defined."; } leaf notify-pool-hi-threshold { type percent; mandatory true; description "Notification must be generated when the defined high threshold is reached. For example, if a notification is required when the pool utilization reaches 90%, this configuration parameter must be set to 90%."; } leaf notify-pool-low-threshold { type percent; description "Notification must be generated when the defined low threshold is reached. For example, if a notificationis required when the pool utilization reaches below 10%, this configuration parameter must be set to 10%."; } } leaf ftp-alg-enable { type boolean; description "Enable/Disable FTP ALG."; } leaf tftp-alg-enable { type boolean; description "Enable/Disable TFTP ALG."; } leaf sip-alg-enable { type boolean; description "Enable/Disable SIP ALG."; } leaf rtsp-alg-enable { type boolean; description "Enable/Disable RTSP ALG."; } leaf h323-alg-enable { type boolean; description "Enable/Disable H323 ALG."; } leaf all-algs-enable { type boolean; description "Enable/Disable all the ALGs."; } } // Mapping Entry (Extended NAT44 mapping Entry) grouping mapping-entry { description "A DS-Lite AFTR mapping entry."; leaf index { type uint32; description "A unique identifier of a mapping entry."; } leaf status { type enumeration { enum "disabled" { description "The mapping entry is not in use (Disabled)."; } enum "assigned" { description "This mapping has been granted by the server."; } enum "stale" { description "This is a stale mapping (case of reboot)."; } } description "Indicates the status of a mapping entry."; } leaf type { type enumeration { enum "static" { description "The mapping entry is manually configured."; } enum "implicit" { description "This mapping is created by an outgoing packet."; } enum "explicit" { description "This is a dynamic explicit mapping created as a result of a PCP operation."; } } description "Indicates the type of a mapping entry. E.g., a mapping can be: static, dynamic implicit, or dynamic explicit."; } leaf b4-ip-address { type inet:ipv6-address; mandatory true; description "Corresponds to the IPv6 address used by the B4 element."; } leaf internal-ip-address { type inet:ipv4-prefix; mandatory true; description "Corresponds to the source IPv4 address of the IPv4 packet conveyed over the softwire."; } container internal-port { description "Corresponds to the source port of the IPv4 packet conveyed over the softwire."; uses port-number; } leaf external-ip-address { type inet:ipv4-address; mandatory true; description "External IPv4 address assigned by the AFTR."; } container external-port { description "External port number assigned by the AFTR."; uses port-number; } leaf transport-protocol { type uint8; mandatory true; description "Upper-layer protocol associated with this mapping. Values are taken from the IANA protocol registry. For example, this field contains 6 (TCP) for a TCP mapping or 17 (UDP) for a UDP mapping."; } leaf lifetime { type uint32; mandatory true; description "Lifetime of the mapping."; } 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 enacapsulated IPv4 packet."; } leaf external-v4-dscp { type uint8; description "DSCP value of the translated IPv4 packet as marked by the AFTR."; } leaf description { type string; description "A description string associated with the mapping."; } } /* * DS-Lite AFTR Configuration */ container dslite-aftr-config { description "dslite-aftr"; leaf enable { type boolean; description "Enable/Disable dslite-aftr function."; } container dslite-aftr-instances { description "dslite-aftr instances"; list dslite-aftr-instance { key "id"; description "a dslite-aftr instance."; leaf id { type uint32; description "dslite-aftr instance identifier."; } leaf name { type string; description "A name associated with the dslite-aftr instance."; } uses aftr-parameters; container mapping-table { description "dslite-aftr mapping table maintained by the dslite-aftr server."; list mapping-entry { key "index"; description "dslite-aftr mapping entry."; uses mapping-entry; } } } } } /* * DS-Lite AFTR State */ container dslite-aftr-state { config false; description "dslite-aftr"; container dslite-aftr-instances { description "dslite-aftr instances"; list dslite-aftr-instance { key "id"; description "dslite-aftr instance"; leaf id { type int32; description "The identifier of the dslite-aftr instance."; } leaf name { type string; description "The name of the dslite-aftr instance."; } container aftr-capabilities { description "AFTR capabilities"; leaf eim-support { type boolean; description "Indicates whether EIM is enabled."; } leaf eif-support { type boolean; description "Indicates whether EIF is enabled."; } leaf edm-support { type boolean; description "Indicates whether EDM is enabled."; } leaf edf-support { type boolean; description "Indicates whether EDF is enabled."; } leaf adm-support { type boolean; description "Indicates whether ADM is enabled."; } leaf adf-support { type boolean; description "Indicates whether ADF is enabled."; } leaf pcp-support { type boolean; description "Indicates whether a PCP server is enabled."; } leaf subscriber-mask-support{ type boolean; description "Indicates whether the subscriber-mask feature is supported."; } leaf port-set-support { type boolean; description "Indicates whether port set assignment is supported."; } leaf self-state-migration-support { type boolean; description "Indicates whether mappings migration to the new IPv6 address used by the B4 is supported [RFC7785]."; } leaf mss-clamping-support { type boolean; description "Indicates whether the MSS clamping feature is supported."; } leaf port-randomization-support { type boolean; description "Indicates whether port randomization is supported."; } leaf port-preservation-support { type boolean; description "Indicates whether port preservation is supported."; } leaf port-parity-preservation-support { type boolean; description "Indicates whether port parity preservation is supported."; } list transport-proto-capabilities { key "transport-protocol-id"; description "A set of supported transport protocols."; leaf transport-protocol-id { type uint8; description "ID of the transport protocol."; } } leaf v6-v4-dscp-preservation-support { type boolean; description "Copy the DSCP value from the IPv6 header and vice versa."; } leaf logging-support { type boolean; description "Indicates whether a logging feature is supported."; } leaf ftp-alg-support { type boolean; description "Indicates whether FTP ALG is supported."; } leaf tftp-support { type boolean; description "Indicates whether TFTP ALG is supported."; } leaf sip-alg-support { type boolean; description "Indicates whether SIP ALG is supported."; } leaf rtsp-alg-support { type boolean; description "Indicates whether RTSP ALG is supported."; } leaf h323-alg-support { type boolean; description "Indicates whether H323 ALG is supported."; } } container aftr-current-config { description "current config"; uses aftr-parameters; } container mapping-table { description "Mapping table"; list mapping-entry { key "index"; description "mapping entry"; uses mapping-entry; } } container statistics { description "traffic statistics"; container traffic-statistics { description "Generic traffic statistics."; leaf sent-packet { type yang:zero-based-counter64; description "Number of packets sent."; } leaf sent-byte { type yang:zero-based-counter64; description "Counter for sent traffic in bytes."; } leaf rcvd-packet { type yang:zero-based-counter64; description "Number of received packets."; } leaf rcvd-byte { type yang:zero-based-counter64; description "Counter for received traffic in bytes."; } leaf dropped-packet { type yang:zero-based-counter64; description "Number of dropped packets."; } leaf dropped-byte { type yang:zero-based-counter64; description "Counter for dropped traffic in bytes."; } } container mapping-table-stats { description "Mapping table statistics."; leaf current-mt-size { type yang:zero-based-counter64; description "Size of the mapping table."; } leaf max-mt-size { type uint32; description "Maximum configured size of the mapping table."; } leaf total-tcp-mappings { type uint32; description "Total number of TCP Mappings present at the time."; } leaf total-udp-mappings { type uint32; description "Total number of UDP Mappings present at the time."; } leaf total-icmp-mappings { type uint32; description "Total number of ICMP Mappings present at the time."; } } } leaf available-capacity-client { type percent; description "Ratio of available capacity in the customer-facing interfaces."; } leaf available-capacity-ext { type percent; description "Ratio of available capacity in the Internet-facing interfaces."; } leaf address-pool-in-use { type percent; description "Ratio of the shared address pool."; } leaf port-in-use { type percent; description "Ratio of the port usage."; } } } } /* * Notifications */ notification dslite-aftr-event { description "Notifications must be generated when the defined high/low threshold is reached. Related configuration parameters must be provided to trigger the notifications."; leaf id { type leafref { path "/dslite-aftr-state/dslite-aftr-instances/" + "dslite-aftr-instance/id"; } description "AFTR instance ID."; } leaf notify-pool-threshold { type percent; mandatory true; description "A treshhold has been fired."; } } } ]]>

The YANG module defined in this memo is designed to be accessed via the NETCONF protocol . The lowest NETCONF layer is the secure transport layer and the support of SSH is mandatory to implement secure transport . The NETCONF access control model 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.

This document requests IANA to register the following URI in the "IETF XML Registry" :

This document requests IANA to register the following YANG module in the "YANG Module Names" registry .

Thanks to Q. Wu for identifying a compiling error.