RFC 8045
RADIUS Extensions for IP Port Configuration and Reporting
Internet Engineering Task Force (IETF) D. Cheng Request for Comments: 8045 Huawei Category: Standards Track J. Korhonen ISSN: 2070-1721 Broadcom Corporation M. Boucadair Orange S. Sivakumar Cisco Systems January 2017 RADIUS Extensions for IP Port Configuration and ReportingAbstract
This document defines three new RADIUS attributes. For devices that implement IP port ranges, these attributes are used to communicate with a RADIUS server in order to configure and report IP transport ports as well as mapping behavior for specific hosts. This mechanism can be used in various deployment scenarios such as Carrier-Grade NAT, IPv4/IPv6 translators, Provider WLAN gateway, etc. This document defines a mapping between some RADIUS attributes and IP Flow Information Export (IPFIX) Information Element identifiers. Status of This Memo 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 http://www.rfc-editor.org/info/rfc8045.
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Table of Contents
1. Introduction ....................................................4 2. Terminology .....................................................5 2.1. Requirements Language ......................................6 3. Extensions of RADIUS Attributes and TLVs ........................7 3.1. Extended Attributes for IP Ports ...........................7 3.1.1. IP-Port-Limit-Info Attribute ........................7 3.1.2. IP-Port-Range Attribute .............................9 3.1.3. IP-Port-Forwarding-Map Attribute ...................12 3.2. RADIUS TLVs for IP Ports ..................................15 3.2.1. IP-Port-Type TLV ...................................16 3.2.2. IP-Port-Limit TLV ..................................17 3.2.3. IP-Port-Ext-IPv4-Addr TLV ..........................18 3.2.4. IP-Port-Int-IPv4-Addr TLV ..........................19 3.2.5. IP-Port-Int-IPv6-Addr TLV ..........................20 3.2.6. IP-Port-Int-Port TLV ...............................21 3.2.7. IP-Port-Ext-Port TLV ...............................22 3.2.8. IP-Port-Alloc TLV ..................................23 3.2.9. IP-Port-Range-Start TLV ............................24 3.2.10. IP-Port-Range-End TLV .............................25 3.2.11. IP-Port-Local-Id TLV ..............................25 4. Applications, Use Cases, and Examples ..........................27 4.1. Managing CGN Port Behavior Using RADIUS ...................27 4.1.1. Configure IP Port Limit for a User .................27 4.1.2. Report IP Port Allocation/Deallocation .............29 4.1.3. Configure Port Forwarding Mapping ..................31 4.1.4. An Example .........................................33 4.2. Report Assigned Port Set for a Visiting UE ................35 5. Table of Attributes ............................................36 6. Security Considerations ........................................36 7. IANA Considerations ............................................37 7.1. New IPFIX Information Elements ............................37 7.2. New RADIUS Attributes .....................................38 7.3. New RADIUS TLVs ...........................................38 8. References .....................................................39 8.1. Normative References ......................................39 8.2. Informative References ....................................40 Acknowledgments ...................................................43 Authors' Addresses ................................................43
1. Introduction
In a broadband network, customer information is usually stored on a RADIUS server [RFC2865]. At the time when a user initiates an IP connection request, if this request is authorized, the RADIUS server will populate the user's configuration information to the Network Access Server (NAS), which is often referred to as a Broadband Network Gateway (BNG) in broadband access networks. The Carrier- Grade NAT (CGN) function may also be implemented on the BNG. Within this document, the CGN may perform Network Address Translation from IPv4 Clients to IPv4 Servers (NAT44) [RFC3022], NAT from IPv6 Clients to IPv4 Servers (NAT64) [RFC6146], or Dual-Stack Lite Address Family Transition Router (AFTR) [RFC6333] function. In such case, the CGN IP transport port (e.g., TCP/UDP port) mapping behaviors can be part of the configuration information sent from the RADIUS server to the NAS/BNG. As part of the accounting information sent from the NAS/BNG to a RADIUS server, the NAS/BNG may also report the IP port mapping behavior applied by the CGN to a user session. When IP packets traverse the CGN, it performs mapping on the IP transport (e.g., TCP/UDP) source port as required. An IP transport source port, along with a source IP address, destination IP address, destination port, and protocol identifier, if applicable, uniquely identify a mapping. Since the number space of IP transport ports in the CGN's external realm is shared among multiple users assigned with the same IPv4 address, the total number of a user's simultaneous IP mappings is likely to be subject to a port quota (see Section 5 of [RFC6269]). The attributes defined in this document may also be used to report the assigned port range in some deployments, such as Provider WLAN [WIFI-SERVICES]. For example, a visiting host can be managed by Customer Premises Equipment (CPE), which will need to report the assigned port range to the service platform. This is required for identification purposes (see TR-146 [TR-146] for more details). This document proposes three new attributes as RADIUS protocol extensions; they are used for separate purposes, as follows: 1. IP-Port-Limit-Info: This attribute may be carried in a RADIUS Access-Accept, Access-Request, Accounting-Request, or CoA-Request packet. The purpose of this attribute is to limit the total number of IP source transport ports allocated to a user and associated with one or more IPv4 or IPv6 addresses. 2. IP-Port-Range: This attribute may be carried in a RADIUS Accounting-Request packet. The purpose of this attribute is for an address-sharing device (e.g., a CGN) to report to the RADIUS
server the range of IP source transport ports that have been
allocated or deallocated for a user. The port range is bound to
an external IPv4 address.
3. IP-Port-Forwarding-Map: This attribute may be carried in RADIUS
Access-Accept, Access-Request, Accounting-Request, or CoA-Request
packet. The purpose of this attribute is to specify how an IP
internal source transport port, together with its internal IPv4
or IPv6 address, are mapped to an external source transport port
along with the external IPv4 address.
IPFIX Information Elements [RFC7012] can be used for IP flow
identification and representation over RADIUS. This document
provides a mapping between some RADIUS TLVs and IPFIX Information
Element identifiers. A new IPFIX Information Element is defined by
this document (see Section 3.2.2).
IP protocol numbers (refer to [ProtocolNumbers]) can be used for
identification of IP transport protocols (e.g., TCP [RFC793], UDP
[RFC768], Datagram Congestion Control Protocol (DCCP) [RFC4340], and
Stream Control Transmission Protocol (SCTP) [RFC4960]) that are
associated with some RADIUS attributes.
This document focuses on IPv4 address sharing. Mechanisms for IPv6
prefix sharing (e.g., IPv6-to-IPv6 Network Prefix Translation
(NPTv6)) are out of scope.
2. Terminology
This document makes use of the following terms:
o IP Port: This refers to an IP transport port (e.g., a TCP port
number or UDP port number).
o IP Port Type: This refers to the IP transport protocol as
indicated by the IP transport protocol number. Refer to
[ProtocolNumbers].
o IP Port Limit: This denotes the maximum number of IP ports for a
specific (or all) IP transport protocol(s) that a device
supporting port ranges can use when performing port number
mappings for a specific user/host. Note that this limit is
usually associated with one or more IPv4/IPv6 addresses.
o IP Port Range: This specifies a set of contiguous IP ports
indicated by the lowest numerical number and the highest numerical
number, inclusively.
o Internal IP Address: This refers to the IP address that is used by
a host as a source IP address in an outbound IP packet sent
towards a device supporting port ranges in the internal realm.
The internal IP address may be IPv4 or IPv6.
o External IP Address: This refers to the IP address that is used as
a source IP address in an outbound IP packet after traversing a
device supporting port ranges in the external realm. This
document assumes that the external IP address is an IPv4 address.
o Internal Port: This is an IP transport port that is allocated by a
host or application behind an address-sharing device for an
outbound IP packet in the internal realm.
o External Port: This is an IP transport port that is allocated by
an address-sharing device upon receiving an outbound IP packet in
the internal realm and is used to replace the internal port that
is allocated by a user or application.
o External Realm: This refers to the networking segment where
external IP addresses are used as source addresses of outbound
packets forwarded by an address-sharing device.
o Internal Realm: This refers to the networking segment that is
behind an address-sharing device and where internal IP addresses
are used.
o Mapping: This denotes a relationship between an internal IP
address, internal port, and protocol, as well as an external IP
address, external port, and protocol.
o Address-Sharing Device: This is a device that is capable of
sharing an IPv4 address among multiple users. A typical example
of this device is a CGN, CPE, Provider WLAN gateway, etc.
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Extensions of RADIUS Attributes and TLVs
These three new attributes are defined in the following subsections: 1. IP-Port-Limit-Info Attribute 2. IP-Port-Range Attribute 3. IP-Port-Forwarding-Map Attribute All these attributes are allocated from the RADIUS "Extended Type" code space per [RFC6929]. These attributes and their embedded TLVs (refer to Section 3.2) are defined with globally unique names and follow the guidelines in Section 2.7.1 of [RFC6929]. In all the figures describing the RADIUS attributes and TLV formats in the following subsections, the fields are transmitted from left to right.3.1. Extended Attributes for IP Ports
3.1.1. IP-Port-Limit-Info Attribute
This attribute is of type "tlv" as defined in the RADIUS Protocol Extensions [RFC6929]. It contains some sub-attributes, and the requirements are as follows: o The IP-Port-Limit-Info Attribute MAY contain the IP-Port-Type TLV (see Section 3.2.1). o The IP-Port-Limit-Info Attribute MUST contain the IP-Port-Limit TLV (see Section 3.2.2). o The IP-Port-Limit-Info Attribute MAY contain the IP-Port-Ext-IPv4-Addr TLV (see Section 3.2.3). The IP-Port-Limit-Info Attribute specifies the maximum number of IP ports, as indicated in IP-Port-Limit TLV, of a specific IP transport protocol, as indicated in IP-Port-Type TLV, and associated with a given IPv4 address, as indicated in IP-Port-Ext-IPv4-Addr TLV, for an end user. Note that when IP-Port-Type TLV is not included as part of the IP-Port-Limit-Info Attribute, the port limit applies to all IP transport protocols.
Note also that when IP-Port-Ext-IPv4-Addr TLV is not included as part of the IP-Port-Limit-Info Attribute, the port limit applies to all the IPv4 addresses managed by the address-sharing device, e.g., a CGN or NAT64 device. The IP-Port-Limit-Info Attribute MAY appear in an Access-Accept packet. It MAY also appear in an Access-Request packet as a preferred maximum number of IP ports indicated by the device supporting port ranges co-located with the NAS, e.g., a CGN or NAT64. The IP-Port-Limit-Info Attribute MAY appear in a CoA-Request packet. The IP-Port-Limit-Info Attribute MAY appear in an Accounting-Request packet. The IP-Port-Limit-Info Attribute MUST NOT appear in any other RADIUS packet. The format of the IP-Port-Limit-Info Attribute is shown in Figure 1. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Extended-Type | Value ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Type 241 Length This field indicates the total length in octets of all fields of this attribute, including the Type, Length, Extended-Type, and the entire length of the embedded TLVs. Extended-Type 5
Value
This field contains a set of TLVs as follows:
IP-Port-Type TLV
This TLV contains a value that indicates the IP port type.
Refer to Section 3.2.1.
IP-Port-Limit TLV
This TLV contains the maximum number of IP ports of a specific
IP port type and associated with a given IPv4 address for an
end user. This TLV MUST be included in the IP-Port-Limit-Info
Attribute. Refer to Section 3.2.2. This limit applies to all
mappings that can be instantiated by an underlying address-
sharing device without soliciting any external entity. In
particular, this limit does not include the ports that are
instructed by an Authentication, Authorization, and Accounting
(AAA) server.
IP-Port-Ext-IPv4-Addr TLV
This TLV contains the IPv4 address that is associated with the
IP port limit contained in the IP-Port-Limit TLV. This TLV is
optionally included as part of the IP-Port-Limit-Info
Attribute. Refer to Section 3.2.3.
IP-Port-Limit-Info Attribute is associated with the following
identifier: 241.5.
3.1.2. IP-Port-Range Attribute
This attribute is of type "tlv" as defined in the RADIUS Protocol
Extensions [RFC6929]. It contains some sub-attributes and the
requirement is as follows:
o The IP-Port-Range Attribute MAY contain the IP-Port-Type TLV (see
Section 3.2.1).
o The IP-Port-Range Attribute MUST contain the IP-Port-Alloc TLV
(see Section 3.2.8).
o For port allocation, the IP-Port-Range Attribute MUST contain both
the IP-Port-Range-Start TLV (see Section 3.2.9) and the
IP-Port-Range-End TLV (see Section 3.2.10). For port
deallocation, the IP-Port-Range Attribute MAY contain both of
these two TLVs; if the two TLVs are not included, it implies that
all ports that were previously allocated are now all deallocated.
o The IP-Port-Range Attribute MAY contain the
IP-Port-Ext-IPv4-Addr TLV (see Section 3.2.3).
o The IP-Port-Range Attribute MAY contain the IP-Port-Local-Id TLV
(see Section 3.2.11).
The IP-Port-Range Attribute contains a range of contiguous IP ports.
These ports are either to be allocated or deallocated depending on
the Value carried by the IP-Port-Alloc TLV.
If the IP-Port-Type TLV is included as part of the IP-Port-Range
Attribute, then the port range is associated with the specific IP
transport protocol as specified in the IP-Port-Type TLV, but
otherwise it is for all IP transport protocols.
If the IP-Port-Ext-IPv4-Addr TLV is included as part of the
IP-Port-Range Attribute, then the port range as specified is
associated with the IPv4 address as indicated, but otherwise it is
for all IPv4 addresses by the address-sharing device (e.g., a CGN
device) for the end user.
This attribute can be used to convey a single IP transport port
number: in such case, the Value of the IP-Port-Range-Start TLV and
the IP-Port-Range-End TLV, respectively, contain the same port
number.
The information contained in the IP-Port-Range Attribute is sent to
RADIUS server.
The IP-Port-Range Attribute MAY appear in an Accounting-Request
packet.
The IP-Port-Range Attribute MUST NOT appear in any other RADIUS
packet.
The format of the IP-Port-Range Attribute is shown in Figure 2. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Extended-Type | Value ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Type 241 Length This field indicates the total length in octets of all fields of this attribute, including the Type, Length, Extended-Type, and the entire length of the embedded TLVs. Extended-Type 6 Value This field contains a set of TLVs as follows: IP-Port-Type TLV This TLV contains a value that indicates the IP port type. Refer to Section 3.2.1. IP-Port-Alloc TLV This TLV contains a flag to indicate the range of the specified IP ports for either allocation or deallocation. This TLV MUST be included as part of the IP-Port-Range Attribute. Refer to Section 3.2.8. IP-Port-Range-Start TLV This TLV contains the smallest port number of a range of contiguous IP ports. To report the port allocation, this TLV MUST be included together with IP-Port-Range-End TLV as part of the IP-Port-Range Attribute. Refer to Section 3.2.9.
IP-Port-Range-End TLV
This TLV contains the largest port number of a range of
contiguous IP ports. To report the port allocation, this TLV
MUST be included together with IP-Port-Range-Start TLV as part
of the IP-Port-Range Attribute. Refer to Section 3.2.10.
IP-Port-Ext-IPv4-Addr TLV
This TLV contains the IPv4 address that is associated with the
IP port range, as is collectively indicated in the
IP-Port-Range-Start TLV and the IP-Port-Range-End TLV. This
TLV is optionally included as part of the IP-Port-Range
Attribute. Refer to Section 3.2.3.
IP-Port-Local-Id TLV
This TLV contains a local significant identifier at the
customer premise, such as the Media Access Control (MAC)
address, interface ID, VLAN ID, PPP sessions ID, VPN Routing
and Forwarding (VRF) ID, IP address/prefix, etc. This TLV is
optionally included as part of the IP-Port-Range Attribute.
Refer to Section 3.2.11.
The IP-Port-Range Attribute is associated with the following
identifier: 241.6.
3.1.3. IP-Port-Forwarding-Map Attribute
This attribute is of type "tlv" as defined in the RADIUS Protocol
Extensions [RFC6929]. It contains some sub-attributes and the
requirement is as follows:
o The IP-Port-Forwarding-Map Attribute MAY contain the
IP-Port-Type TLV (see Section 3.2.1).
o The IP-Port-Forwarding-Map Attribute MUST contain both
IP-Port-Int-Port TLV (see Section 3.2.6) and the
IP-Port-Ext-Port TLV (see Section 3.2.7).
o If the internal realm is with an IPv4 address family, the
IP-Port-Forwarding-Map Attribute MUST contain the
IP-Port-Int-IPv4-Addr TLV (see Section 3.2.4); if the internal
realm is with an IPv6 address family, the IP-Port-Forwarding-Map
Attribute MUST contain the IP-Port-Int-IPv6-Addr TLV (see
Section 3.2.5).
o The IP-Port-Forwarding-Map Attribute MAY contain the
IP-Port-Ext-IPv4-Addr TLV (see Section 3.2.3).
o The IP-Port-Forwarding-Map Attribute MAY contain the
IP-Port-Local-Id TLV (see Section 3.2.11).
The attribute contains a two-octet IP internal port number and a
two-octet IP external port number. The internal port number is
associated with an internal IPv4 or IPv6 address that MUST always be
included. The external port number is associated with a specific
external IPv4 address if included, but otherwise it is associated
with all external IPv4 addresses for the end user.
If the IP-Port-Type TLV is included as part of the
IP-Port-Forwarding-Map Attribute, then the port mapping is associated
with the specific IP transport protocol as specified in the
IP-Port-Type TLV, but otherwise it is for all IP transport protocols.
The IP-Port-Forwarding-Map Attribute MAY appear in an Access-Accept
packet. It MAY also appear in an Access-Request packet to indicate a
preferred port mapping by the device co-located with NAS. However,
the server is not required to honor such a preference.
The IP-Port-Forwarding-Map Attribute MAY appear in a CoA-Request
packet.
The IP-Port-Forwarding-Map Attribute MAY also appear in an
Accounting-Request packet.
The IP-Port-Forwarding-Map Attribute MUST NOT appear in any other
RADIUS packet.
The format of the IP-Port-Forwarding-Map Attribute is shown in Figure 3. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Extended-Type | Value .... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Type 241 Length This field indicates the total length in octets of all fields of this attribute, including the Type, Length, Extended-Type, and the entire length of the embedded TLVs. Extended-Type 7 Value This field contains a set of TLVs as follows: IP-Port-Type TLV This TLV contains a value that indicates the IP port type. Refer to Section 3.2.1. IP-Port-Int-Port TLV This TLV contains an internal IP port number associated with an internal IPv4 or IPv6 address. This TLV MUST be included together with IP-Port-Ext-Port TLV as part of the IP-Port-Forwarding-Map Attribute. Refer to Section 3.2.6. IP-Port-Ext-Port TLV This TLV contains an external IP port number associated with an external IPv4 address. This TLV MUST be included together with IP-Port-Int-Port TLV as part of the IP-Port-Forwarding-Map Attribute. Refer to Section 3.2.7.
IP-Port-Int-IPv4-Addr TLV
This TLV contains an IPv4 address that is associated with the
internal IP port number contained in the IP-Port-Int-Port TLV.
For the internal realm with an IPv4 address family, this TLV
MUST be included as part of the IP-Port-Forwarding-Map
Attribute. Refer to Section 3.2.4.
IP-Port-Int-IPv6-Addr TLV
This TLV contains an IPv6 address that is associated with the
internal IP port number contained in the IP-Port-Int-Port TLV.
For the internal realm with an IPv6 address family, this TLV
MUST be included as part of the IP-Port-Forwarding-Map
Attribute. Refer to Section 3.2.5.
IP-Port-Ext-IPv4-Addr TLV
This TLV contains an IPv4 address that is associated with the
external IP port number contained in the IP-Port-Ext-Port TLV.
This TLV MAY be included as part of the IP-Port-Forwarding-Map
Attribute. Refer to Section 3.2.3.
IP-Port-Local-Id TLV
This TLV contains a local significant identifier at the
customer premise, such as MAC address, interface ID, VLAN ID,
PPP sessions ID, VRF ID, IP address/prefix, etc. This TLV is
optionally included as part of the IP-Port-Forwarding-Map
Attribute. Refer to Section 3.2.11.
The IP-Port-Forwarding-Map Attribute is associated with the following
identifier: 241.7.
3.2. RADIUS TLVs for IP Ports
The TLVs that are included in the three attributes (see Section 3.1)
are defined in the following subsections. These TLVs use the format
defined in [RFC6929]. As the three attributes carry similar data, we
have defined a common set of TLVs that are used for all three
attributes. That is, the TLVs have the same name and number when
encapsulated in any one of the three parent attributes. See
Sections 3.1.1, 3.1.2, and 3.1.3 for a list of which TLV is permitted
within which parent attribute.
The encoding of the Value field of these TLVs follows the recommendation of [RFC6158]. In particular, IP-Port-Type, IP-Port-Limit, IP-Port-Int-Port, IP-Port-Ext-Port, IP-Port-Alloc, IP-Port-Range-Start, and IP-Port-Range-End TLVs are encoded in 32 bits as per the recommendation in Appendix A.2.1 of [RFC6158].3.2.1. IP-Port-Type TLV
The format of IP-Port-Type TLV is shown in Figure 4. This attribute carries the IP transport protocol number defined by IANA (refer to [ProtocolNumbers]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | Protocol-Number +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Protocol-Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 TLV-Type 1 Length Six octets Protocol-Number Integer. This field contains the data (unsigned8) of the protocol number defined in [ProtocolNumbers], right justified, and the unused bits in this field MUST be set to zero. Protocols that do not use a port number (e.g., the Resource Reservation Protocol (RSVP) or IP Encapsulating Security Payload (ESP)) MUST NOT be included in the IP-Port-Type TLV. IP-Port-Type TLV MAY be included in the following attributes: o IP-Port-Limit-Info Attribute, identified as 241.5.1 (see Section 3.1.1) o IP-Port-Range Attribute, identified as 241.6.1 (see Section 3.1.2) o IP-Port-Forwarding-Map Attribute, identified as 241.7.1 (see Section 3.1.3)
When the IP-Port-Type TLV is included within a RADIUS attribute, the associated attribute is applied to the IP transport protocol as indicated by the Protocol-Number only, such as TCP, UDP, SCTP, DCCP, etc.3.2.2. IP-Port-Limit TLV
The format of IP-Port-Limit TLV is shown in Figure 5. This attribute carries IPFIX Information Element 458, "sourceTransportPortsLimit", which indicates the maximum number of IP transport ports as a limit for an end user to use that is associated with one or more IPv4 or IPv6 addresses. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | sourceTransportPortsLimit +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceTransportPortsLimit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 TLV-Type 2 Length Six octets sourceTransportPortsLimit Integer. This field contains the data (unsigned16) of sourceTransportPortsLimit (458) defined in IPFIX, right justified, and the unused bits in this field MUST be set to zero. IP-Port-Limit TLV MUST be included as part of the IP-Port-Limit-Info Attribute (refer to Section 3.1.1), identified as 241.5.2.
3.2.3. IP-Port-Ext-IPv4-Addr TLV
The format of IP-Port-Ext-IPv4-Addr TLV is shown in Figure 6. This attribute carries IPFIX Information Element 225, "postNATSourceIPv4Address", which is the IPv4 source address after NAT operation (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | postNATSourceIPv4Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ postNATSourceIPv4Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 TLV-Type 3 Length Six octets postNATSourceIPv4Address Integer. This field contains the data (ipv4Address) of postNATSourceIPv4Address (225) defined in IPFIX. IP-Port-Ext-IPv4-Addr TLV MAY be included in the following attributes: o IP-Port-Limit-Info Attribute, identified as 241.5.3 (see Section 3.1.1) o IP-Port-Range Attribute, identified as 241.6.3 (see Section 3.1.2) o IP-Port-Forwarding-Mapping Attribute, identified as 241.7.3 (see Section 3.1.3)
3.2.4. IP-Port-Int-IPv4-Addr TLV
The format of IP-Port-Int-IPv4 TLV is shown in Figure 7. This attribute carries IPFIX Information Element 8, "sourceIPv4Address", which is the IPv4 source address before NAT operation (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | sourceIPv4Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceIPv4Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7 TLV-Type 4 Length Six octets sourceIPv4Address Integer. This field contains the data (ipv4Address) of sourceIPv4Address (8) defined in IPFIX. If the internal realm is with an IPv4 address family, the IP-Port-Int-IPv4-Addr TLV MUST be included as part of the IP-Port-Forwarding-Map Attribute (refer to Section 3.1.3), identified as 241.7.4.
3.2.5. IP-Port-Int-IPv6-Addr TLV
The format of IP-Port-Int-IPv6-Addr TLV is shown in Figure 8. This attribute carries IPFIX Information Element 27, "sourceIPv6Address", which is the IPv6 source address before NAT operation (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | sourceIPv6Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceIPv6Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceIPv6Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceIPv6Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceIPv6Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 8 TLV-Type 5 Length Eighteen octets sourceIPv6Address IPv6 address (128 bits). This field contains the data (ipv6Address) of sourceIPv6Address (27) defined in IPFIX. If the internal realm is with an IPv6 address family, the IP-Port-Int-IPv6-Addr TLV MUST be included as part of the IP-Port-Forwarding-Map Attribute (refer to Section 3.1.3), identified as 241.7.5.
3.2.6. IP-Port-Int-Port TLV
The format of IP-Port-Int-Port TLV is shown in Figure 9. This attribute carries IPFIX Information Element 7, "sourceTransportPort", which is the source transport number associated with an internal IPv4 or IPv6 address (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | sourceTransportPort +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ sourceTransportPort | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 9 TLV-Type 6 Length Six octets sourceTransportPort Integer. This field contains the data (unsigned16) of sourceTransportPort (7) defined in IPFIX, right justified, and unused bits MUST be set to zero. IP-Port-Int-Port TLV MUST be included as part of the IP-Port-Forwarding-Map Attribute (refer to Section 3.1.3), identified as 241.7.6.
3.2.7. IP-Port-Ext-Port TLV
The format of IP-Port-Ext-Port TLV is shown in Figure 10. This attribute carries IPFIX Information Element 227, "postNAPTSourceTransportPort", which is the transport number associated with an external IPv4 address (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | postNAPTSourceTransportPort +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ postNAPTSourceTransportPort | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 10 TLV-Type 7 Length Six octets postNAPTSourceTransportPort Integer. This field contains the data (unsigned16) of postNAPTSourceTransportPort (227) defined in IPFIX, right justified, and unused bits MUST be set to zero. IP-Port-Ext-Port TLV MUST be included as part of the IP-Port-Forwarding-Map Attribute (refer to Section 3.1.3), identified as 241.7.7.
3.2.8. IP-Port-Alloc TLV
The format of IP-Port-Alloc TLV is shown in Figure 11. This attribute carries IPFIX Information Element 230, "natEvent", which is a flag to indicate an action of NAT operation (refer to [IPFIX]). When the value of natEvent is "1" (Create event), it means to allocate a range of transport ports; when the value is "2", it means to deallocate a range of transports ports. For the purpose of this TLV, no other value is used. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | natEvent +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ natEvent | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 11 TLV-Type 8 Length Six octets natEvent Integer. This field contains the data (unsigned8) of natEvent (230) defined in IPFIX, right justified, and unused bits MUST be set to zero. It indicates the allocation or deallocation of a range of IP ports as follows: 0: Reserved 1: Allocation 2: Deallocation IP-Port-Alloc TLV MUST be included as part of the IP-Port-Range Attribute (refer to Section 3.1.2), identified as 241.6.8.
3.2.9. IP-Port-Range-Start TLV
The format of IP-Port-Range-Start TLV is shown in Figure 12. This attribute carries IPFIX Information Element 361, "portRangeStart", which is the smallest port number of a range of contiguous transport ports (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | portRangeStart +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ portRangeStart | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 12 TLV-Type 9 Length Six octets portRangeStart Integer. This field contains the data (unsigned16) of portRangeStart (361) defined in IPFIX, right justified, and unused bits MUST be set to zero. IP-Port-Range-Start TLV is included as part of the IP-Port-Range Attribute (refer to Section 3.1.2), identified as 241.6.9.
3.2.10. IP-Port-Range-End TLV
The format of IP-Port-Range-End TLV is shown in Figure 13. This attribute carries IPFIX Information Element 362, "portRangeEnd", which is the largest port number of a range of contiguous transport ports (refer to [IPFIX]). 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | portRangeEnd +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ portRangeEnd | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 13 TLV-Type 10 Length Six octets portRangeEnd Integer. This field contains the data (unsigned16) of portRangeEnd (362) defined in IPFIX, right justified, and unused bits MUST be set to zero. IP-Port-Range-End TLV is included as part of the IP-Port-Range Attribute (refer to Section 3.1.2), identified as 241.6.10.3.2.11. IP-Port-Local-Id TLV
The format of IP-Port-Local-Id TLV is shown in Figure 14. This attribute carries a string called "localID", which is a local significant identifier as explained below. The primary issue addressed by this TLV is that there are CGN deployments that do not distinguish internal hosts by their internal IP address alone but use further identifiers for unique subscriber identification. For example, this is the case if a CGN supports overlapping private or shared IP address spaces (as described in [RFC1918] and [RFC6598]) for internal hosts of different subscribers. In such cases, different internal hosts are identified and mapped at the CGN by their IP address and/or another identifier, for example,
the identifier of a tunnel between the CGN and the subscriber. In these scenarios (and similar ones), the internal IP address is not sufficient to demultiplex connections from internal hosts. An additional identifier needs to be present in the IP-Port-Range Attribute and IP-Port-Forwarding-Mapping Attribute in order to uniquely identify an internal host. The IP-Port-Local-Id TLV is used to carry this identifier. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV-Type | Length | localID .... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 14 TLV-Type 11 Length Variable number of octets localID String. The data type of this field is string (refer to [RFC8044]). This field contains the data that is a local significant identifier at the customer premise, such as MAC address, interface ID, VLAN ID, PPP sessions ID, VRF ID, IP address/prefix, or another local significant identifier. IP-Port-Local-Id TLV MAY be included in the following Attributes if it is necessary to identify the subscriber: o IP-Port-Range Attribute, identified as 241.6.11 (see Section 3.1.2) o IP-Port-Forwarding-Mapping Attribute, identified as 241.7.11 (see Section 3.1.3)
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