One document matched: draft-ietf-radext-ip-port-radius-ext-08.xml
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<rfc category="std" docName="draft-ietf-radext-ip-port-radius-ext-08"
ipr="trust200902">
<front>
<title abbrev="RADIUS Extensions for IP Port ">RADIUS Extensions for IP
Port Configuration and Reporting</title>
<author fullname="Dean Cheng" initials="D." surname="Cheng">
<organization>Huawei</organization>
<address>
<postal>
<street>2330 Central Expressway</street>
<city>Santa Clara</city>
<region>California</region>
<code>95050</code>
<country>USA</country>
</postal>
<email>dean.cheng@huawei.com</email>
</address>
</author>
<author fullname="Jouni Korhonen" initials="J." surname="Korhonen">
<organization>Broadcom Corporation</organization>
<address>
<postal>
<street>3151 Zanker Road</street>
<city>San Jose</city>
<code>95134</code>
<country>USA</country>
</postal>
<email>jouni.nospam@gmail.com</email>
</address>
</author>
<author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
<organization>Orange</organization>
<address>
<postal>
<street></street>
<city>Rennes</city>
<country>France</country>
</postal>
<email>mohamed.boucadair@orange.com</email>
</address>
</author>
<author fullname="Senthil Sivakumar" initials="S." surname="Sivakumar">
<organization>Cisco Systems</organization>
<address>
<postal>
<street>7100-8 Kit Creek Road</street>
<city>Research Triangle Park</city>
<region>North Carolina</region>
<country>USA</country>
</postal>
<email>ssenthil@cisco.com</email>
</address>
</author>
<date year="" />
<abstract>
<t>This document defines three new RADIUS attributes. For devices that
implementing IP port ranges, these attributes are used to communicate
with a RADIUS server in order to configure and report TCP/UDP ports and
ICMP identifiers, 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.</t>
</abstract>
<note title="Requirements Language">
<t>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 <xref
target="RFC2119">RFC 2119</xref>.</t>
</note>
</front>
<middle>
<section title="Introduction">
<t>In a broadband network, customer information is usually stored on a
RADIUS server <xref target="RFC2865"></xref>. 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 NAT44 <xref target="RFC3022"></xref>,
NAT64 <xref target="RFC6146"></xref>, or Dual-Stack Lite AFTR <xref
target="RFC6333"> </xref> function. In such case, the CGN TCP/UDP port
(or ICMP identifier) mapping(s) behavior(s) can be part of the
configuration information sent from the RADIUS server to the NAS/BNG.
The NAS/BNG may also report to the RADIUS Server the port/identifier
mapping behavior applied by the CGN to a user session to the RADIUS
server, as part of the accounting information sent from the NAS/BNG to a
RADIUS server.</t>
<t>When IP packets traverse the CGN, it performs TCP/UDP source port
mapping or ICMP identifier mapping as required. A TCP/ UDP source port
or ICMP identifier, along with source IP address, destination IP
address, destination port and protocol identifier if applicable,
uniquely identify a session. Since the number space of TCP/UDP ports and
ICMP identifiers in CGN's external realm is shared among multiple users
assigned with the same IPv4 address, the total number of a user's
simultaneous IP sessions is likely to be subject to port quota (see
Section 5 of <xref target="RFC6269"></xref>).</t>
<t>The attributes defined in this document may also be used to report
the assigned port range in some deployments such as Provider WLAN <xref
target="I-D.gundavelli-v6ops-community-wifi-svcs"></xref>. For example,
a visiting host can be managed by a CPE (Customer Premises Equipment )
which will need to report the assigned port range to the service
platform. This is required for identification purposes (see TR-146 <xref
target="TR-146"></xref> for more details).</t>
<t>This document proposes three new attributes as RADIUS protocol's
extensions, and they are used for separate purposes as follows:</t>
<t><list style="numbers">
<t>IP-Port-Limit-Info: This attribute may be carried in RADIUS
Access-Accept, Access-Request, Accounting-Request or CoA-Request
packet. The purpose of this attribute is to limit the total number
of TCP/UDP ports and/or ICMP identifiers allocated to a user,
associated with one or more IPv4 addresses.</t>
<t>IP-Port-Range: This attribute may be carried in RADIUS
Accounting-Request packet. The purpose of this attribute is to
report by an address sharing device (e.g., a CGN) to the RADIUS
server the range of TCP/UDP ports and/or ICMP identifiers that have
been allocated or deallocated associated with a given IPv4 address
for a user.</t>
<t>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 IPv4
address and a TCP/ UDP port (or an ICMP identifier) is mapped to
another IPv4 address and a TCP/UDP port (or an ICMP identifier).</t>
</list></t>
<t>IPFIX Information Elements <xref target="RFC7012"></xref> can be used
for IP flow identification and representation over RADIUS. This document
provides a mapping between RADIUS TLV and IPFIX Information Element
Identifiers. As a consequence, new IPFIX Information Elements are
defined by this document (see <xref target="attrs"></xref>).</t>
</section>
<section title="Terminology">
<t>This document makes use of the following terms:<list style="symbols">
<t>IP Port: refers to the port numbers of IP transport protocols,
including TCP port, UDP port and ICMP identifier.</t>
<t>IP Port Type: refers to one of the following: (1) TCP/UDP port
and ICMP identifier, (2) TCP port and UDP port, (3) TCP port, (4)
UDP port, or (5) ICMP identifier.</t>
<t>IP Port Limit: denotes the maximum number of IP ports for a
specific IP port type, that a device supporting port ranges can use
when performing port number mapping for a specific user. Note, this
limit is usually associated with one or more IPv4 addresses.</t>
<t>IP Port Range: specifies a set of contiguous IP ports, indicated
by the lowest numerical number and the highest numerical number,
inclusively.</t>
<t>Internal IP Address: refers to the IP address that is used as a
source IP address in an outbound IP packet sent towards a device
supporting port ranges in the internal realm.</t>
<t>External IP Address: 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.</t>
<t>Internal Port: is a UDP or TCP port, or an ICMP identifier, which
is allocated by a host or application behind a device supporting
port ranges for an outbound IP packet in the internal realm.</t>
<t>External Port: is a UDP or TCP port, or an ICMP identifier, which
is allocated by a device supporting port ranges 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.</t>
<t>External realm: refers to the networking segment where external
IP addresses are used in respective of the device supporting port
ranges.</t>
<t>Internal realm: refers to the networking segment that is behind a
device supporting port ranges and where internal IP addresses are
used.</t>
<t>Mapping: associates with a device supporting port ranges for a
relationship between an internal IP address, internal port and the
protocol, and an external IP address, external port, and the
protocol.</t>
<t>Port-based device: a device that is capable of providing IP
address and IP port mapping services and in particular, with the
granularity of one or more subsets within the 16-bit IP port number
range. A typical example of this device is a CGN, CPE, Provider WLAN
Gateway, etc.</t>
</list></t>
<t>Note that the definitions of "internal IP address", "internal port",
"internal realm", "external IP address", "external port", "external
realm", and "mapping" are the same as defined in Port Control Protocol
(PCP) <xref target="RFC6887"></xref>, and the Common Requirements for
Carrier-Grade NATs (CGNs) <xref target="RFC6888"></xref>.</t>
</section>
<section anchor="attrs" title="Extensions of RADIUS Attributes and TLVs">
<t>These three new attributes are defined in the following
sub-sections:</t>
<t><list style="numbers">
<t>IP-Port-Limit-Info Attribute</t>
<t>IP-Port-Range Attribute</t>
<t>IP-Port-Forwarding-Map Attribute</t>
</list></t>
<t>All these attributes are allocated from the RADIUS "Extended Type"
code space per <xref target="RFC6929"></xref>.</t>
<t>These attributes and their embedded TLVs (refer to <xref target="DEFTLVs"></xref>) are defined with globally unique names
and follow the guideline in Section 2.7.1 of <xref target="RFC6929"></xref>. </t>
<t>In all the figures describing the RADIUS attributes and TLV formats
in the following sub-sections, the fields are transmitted from left to
right.</t>
<section anchor="DEFATT" title="Extended Attributes for IP Ports">
<section anchor="sessionlimit" title="IP-Port-Limit-Info Attribute">
<t>This attribute is of type "TLV" as defined in the RADIUS Protocol
Extensions <xref target="RFC6929"></xref>. It contains the following
sub-attributes: <list style="symbols">
<t>an IP-Port-Type TLV (see <xref target="TLV0"></xref>),</t>
<t>an IP-Port-Limit TLV (see <xref target="TLV2"></xref>),</t>
<t>an optional IP-Port-Ext-IPv4-Addr TLV (see <xref
target="TLV3"></xref>).</t>
</list></t>
<t>It specifies the maximum number of IP ports as indicated in
IP-Port-Limit TLV, of a specific port type 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.</t>
<t>Note 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 port device, e.g., a CGN or NAT64
device.</t>
<t>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. However, the RADIUS server is not required to honor such a
preference.</t>
<t>The IP-Port-Limit-Info Attribute MAY appear in a CoA-Request
packet.</t>
<t>The IP-Port-Limit-Info Attribute MAY appear in an
Accounting-Request packet.</t>
<t>The IP-Port-Limit-Info Attribute MUST NOT appear in any other
RADIUS packet.</t>
<t>The format of the IP-Port-Limit-Info Attribute is shown in <xref
target="limit"></xref>.</t>
<figure anchor="limit">
<preamble></preamble>
<artwork><![CDATA[
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 ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>Type</t>
<t><list counter="1" hangIndent="5">
<t>241 (To be confirmed by IANA).</t>
</list>Length <list counter="1" hangIndent="5">
<t>This field indicates the total length in bytes of all fields
of this attribute, including the Type, Length, Extended-Type,
and the entire length of the embedded TLVs.</t>
</list></t>
<t>Extended-Type<list counter="1" hangIndent="5">
<t>TBD1.</t>
</list></t>
<t>Value<list counter="1" hangIndent="5">
<t>This field contains a set of TLVs as follows:</t>
<t>IP-Port-Type TLV<list counter="1" hangIndent="5">
<t>This TLV contains a value that indicates the IP port
type. Refer to <xref target="TLV0"></xref>.</t>
</list></t>
<t>IP-Port-Limit TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV2"></xref>.</t>
</list></t>
<t>IP-Port-Ext-IPv4-Addr TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV3"></xref>.</t>
</list></t>
</list></t>
<t>IP-Port-Limit-Info Attribute is associated with the following
identifier: 241.Extended-Type(TBD1).</t>
</section>
<section anchor="sessionrange" title="IP-Port-Range Attribute">
<t>This attribute is of type "TLV" as defined in the RADIUS Protocol
Extensions <xref target="RFC6929"></xref>. It contains the following
sub-attributes: <list style="symbols">
<t>an IP-Port-Type TLV (see <xref target="TLV0"></xref>),</t>
<t>an IP-Port-Range-Start TLV (see <xref
target="TLV8"></xref>),</t>
<t>an IP-Port-Range-End TLV (see <xref
target="TLV9"></xref>),</t>
<t>an IP-Port-Alloc TLV (see <xref target="TLV7"></xref>),</t>
<t>an optional IP-Port-Ext-IPv4-Addr TLV (see <xref
target="TLV3"></xref>),</t>
<t>an optional IP-Port-Local-Id TLV (see <xref
target="TLV10"></xref>).</t>
</list></t>
<t>This attribute contains a range of contiguous IP ports of a
specific port type and associated with an IPv4 address that are
either allocated or deallocated by a device for a given user, and
the information is intended to be sent to RADIUS server.</t>
<t>This attribute can be used to convey a single IP port number; in
such case IP-Port-Range-Start and IP-Port-Range-End conveys the same
value.</t>
<t>Within an IP-Port-Range Attribute, the IP-Port-Alloc TLV is
always included. For port allocation, both IP-Port-Range-Start TLV
and IP-Port-Range-End TLV must be included; for port deallocation,
the inclusion of these two TLVs is optional and if not included, it
implies that all ports that are previously allocated are now
deallocated. Both IP-Port-Ext-IPv4-Addr TLV and IP-Port-Local-Id TLV
are optional and if included, they are used by a port device (e.g.,
a CGN device) to identify the end user.</t>
<t>The IP-Port-Range Attribute MAY appear in an Accounting-Request
packet.</t>
<t>The IP-Port-Range Attribute MUST NOT appear in any other RADIUS
packet.</t>
<t>The format of the IP-Port-Range Attribute is shown in
<xref target="range"></xref>. </t>
<figure anchor="range">
<preamble></preamble>
<artwork><![CDATA[
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 ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>Type</t>
<t><list counter="1" hangIndent="5">
<t>241 (To be confirmed by IANA).</t>
</list>Length <list counter="1" hangIndent="5">
<t>This field indicates the total length in bytes of all fields
of this attribute, including the Type, Length, Extended-Type,
and the entire length of the embedded TLVs.</t>
</list></t>
<t>Extended-Type<list counter="1" hangIndent="5">
<t>TBD2.</t>
</list></t>
<t>Value<list counter="1" hangIndent="5">
<t>This field contains a set of TLVs as follows:</t>
<t>IP-Port-Type TLV<list counter="1" hangIndent="5">
<t>This TLV contains a value that indicates the IP port
type. Refer to <xref target="TLV0"></xref>.</t>
</list></t>
<t>IP-Port-Alloc TLV<list counter="1" hangIndent="5">
<t>This TLV contains a flag to indicate that 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 <xref
target="TLV7"></xref>.</t>
</list></t>
<t>IP-Port-Range-Start TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV8"></xref>.</t>
</list></t>
<t>IP-Port-Range-End TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV9"></xref>.</t>
</list></t>
<t>IP-Port-Ext-IPv4-Addr TLV<list counter="1" hangIndent="5">
<t>This TLV contains the IPv4 address that is associated
with the IP port range, as 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 <xref target="TLV3"></xref>.</t>
</list></t>
<t>IP-Port-Local-Id TLV<list counter="1" hangIndent="5">
<t>This TLV contains a local session identifier at the
customer premise, such as MAC address, interface ID, VLAN
ID, PPP sessions ID, VRF ID, IPv6 address/prefix, etc. This
TLV is optionally included as part of the IP-Port-Range
Attribute. Refer to <xref target="TLV10"></xref>.</t>
</list></t>
</list></t>
<t>The IP-Port-Range attribute is associated with the following
identifier: 241.Extended-Type(TBD2).</t>
</section>
<section anchor="portmap" title="IP-Port-Forwarding-Map Attribute">
<t>This attribute is of type "TLV" as defined in the RADIUS Protocol
Extensions <xref target="RFC6929"></xref>. It contains the following
sub-attributes: <list style="symbols">
<t>an IP-Port-Type TLV (see <xref target="TLV0"></xref>),</t>
<t>an IP-Port-Int-Port TLV (see <xref
target="TLV5"></xref>),</t>
<t>an IP-Port-Ext-Port TLV (see <xref
target="TLV6"></xref>),</t>
<t>either an IP-Port-Int-IPv4-Addr TLV (see <xref
target="TLV4"></xref>) or an IP-Port-Local-Id TLV (see <xref
target="TLV10"></xref>),</t>
<t>either an IP-Port-Int-IPv6-Addr TLV (see <xref
target="TLV46"></xref>) or an IP-Port-Local-Id TLV (see <xref
target="TLV10"></xref>),</t>
<t>an IP-Port-Ext-IPv4-Addr TLV (see <xref
target="TLV3"></xref>).</t>
</list></t>
<t>The attribute contains a 2-byte IP internal port number that is
associated with an internal IPv4 or IPv6 address, or a locally
significant identifier at the customer site, and a 2-byte IP
external port number that is associated with an external IPv4
address. The internal IPv4 or IPv6 address, or the local identifier
must be included; the external IPv4 address may also be
included.</t>
<t>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.</t>
<t>The IP-Port-Forwarding-Map Attribute MAY appear in a CoA-Request
packet.</t>
<t>The IP-Port-Forwarding-Map Attribute MAY also appear in an
Accounting-Request packet.</t>
<t>The IP-Port-Forwarding-Map Attribute MUST NOT appear in any other
RADIUS packet.</t>
<t>The format of the IP-Port-Forwarding-Map Attribute is shown in
<xref target="map"></xref>.</t>
<figure anchor="map">
<preamble></preamble>
<artwork><![CDATA[
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 ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>Type</t>
<t><list counter="1" hangIndent="5">
<t>241 (To be confirmed by IANA).</t>
</list>Length <list counter="1" hangIndent="5">
<t>This field indicates the total length in bytes of all fields
of this attribute, including the Type, Length, Extended-Type,
and the entire length of the embedded TLVs.</t>
</list></t>
<t>Extended-Type<list counter="1" hangIndent="5">
<t>TBD3.</t>
</list></t>
<t>Value<list counter="1" hangIndent="5">
<t>This field contains a set of TLVs as follows:</t>
<t>IP-Port-Type TLV<list counter="1" hangIndent="5">
<t>This TLV contains a value that indicates the IP port
type. Refer to <xref target="TLV0"></xref>.</t>
</list></t>
<t>IP-Port-Int-Port TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV5"></xref>.</t>
</list></t>
<t>IP-Port-Ext-Port TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV6"></xref>.</t>
</list></t>
<t>IP-Port-Int-IPv4-Addr TLV<list counter="1" hangIndent="5">
<t>This TLV contains an IPv4 address that is associated with
the internal IP port number contained in the
IP-Port-Int-Port TLV. For IPv4 network, either this TLV or
IP-Port-Local-Id TLV must be included as part of the
IP-Port-Forwarding-Map Attribute. Refer to <xref
target="TLV4"></xref>.</t>
</list></t>
<t>IP-Port-Int-IPv6-Addr TLV<list counter="1" hangIndent="5">
<t>This TLV contains an IPv4 address that is associated with
the internal IP port number contained in the
IP-Port-Int-Port TLV. For IPv6 network, either this TLV or
IP-Port-Local-Id TLV must be included as part of the
IP-Port-Forwarding-Map Attribute. Refer to <xref
target="TLV46"></xref>.</t>
</list></t>
<t>IP-Port-Local-Id TLV<list counter="1" hangIndent="5">
<t>This TLV contains a local session identifier at the
customer premise, such as MAC address, interface ID, VLAN
ID, PPP sessions ID, VRF ID, IPv6 address/prefix, etc.
Either this TLV or IP-Port-Int-IP-Addr TLV must be included
as part of the IP-Port-Forwarding-Map Attribute. Refer to
<xref target="TLV10"></xref>.</t>
</list></t>
<t>IP-Port-Ext-IPv4-Addr TLV<list counter="1" hangIndent="5">
<t>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 <xref
target="TLV3"></xref>.</t>
</list></t>
</list></t>
<t>The IP-Port-Forwarding-Map Attribute is associated with the
following identifier: 241.Extended-Type(TBD3).</t>
</section>
</section>
<section anchor="DEFTLVs" title="RADIUS TLVs for IP Ports">
<t>The TLVs that are included in the three attributes
(see <xref target="DEFATT"></xref>) are defined in the following sub-sections. These TLVs use the format defined in
<xref target="RFC6929"></xref>. </t>
<section anchor="TLV0" title="IP-Port-Type TLV">
<t>The format of IP-Port-Type TLV is shown in <xref target="tlv0"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element "transportType"
(TBAx1), and its "Value" field contains the values defined for the
IPFIX Information Element "transportType", which indicates the type
of IP transport as follows:</t>
<t>1:<list counter="1" hangIndent="5">
<t>Refer to TCP port, UDP port, and ICMP identifier as a
whole.</t>
</list></t>
<t>2:<list counter="1" hangIndent="5">
<t>Refer to TCP port and UDP port as a whole.</t>
</list></t>
<t>3:<list counter="1" hangIndent="5">
<t>Refer to TCP port only.</t>
</list></t>
<t>4:<list counter="1" hangIndent="5">
<t>Refer to UDP port only.</t>
</list></t>
<t>5:<list counter="1" hangIndent="5">
<t>Refer to ICMP identifier only.</t>
</list></t>
<figure anchor="tlv0">
<preamble></preamble>
<artwork><![CDATA[
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 | transportType
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
transportType |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>1. This MUST uniquely refer to the IPFIX Information Element identifier TBAx1.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>6.</t>
</list></t>
<t>transportType<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned8) of
transportType (TBAx1) defined in IPFIX, right justified, and the
unused bits in this field MUST be set to zero.</t>
</list></t>
<t>IP-Port-Type TLV is included in the following Attributes:<list style="symbols">
<t>IP-Port-Limit-Info Attribute, identified as
241.TBD1.1 (see Section 3.1.1).</t>
<t>IP-Port-Range Attribute, identified as
241.TBD2.1 (see Section 3.1.2).</t>
<t>IP-Port-Forwarding-Mapping Attribute, identified as
241.TBD3.1 (see Section 3.1.3).</t>
</list></t>
</section>
<section anchor="TLV2" title="IP-Port-Limit TLV">
<t>The format of IP-Port-Limit TLV is shown in <xref target="tlv"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element natTransportLimit
(TBAx2), and its "Value" field contains IPFIX Information Element
natTransportLimit, which indicates the maximum number of ports for a
given IPv4 address assigned to a user for a specified
IP-Port-Type.</t>
<figure anchor="tlv">
<preamble></preamble>
<artwork><![CDATA[
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 | natTransportLimit
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
natTransportLimit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>2. It MUST uniquely refer to the IPFIX Information
Element identifier TBAx2.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>6.</t>
</list></t>
<t>natTransportLimit<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned16) of
natTransportLimit (TBAx2) defined in IPFIX, right justified, and
the unused bits in this field MUST be set to zero.</t>
</list></t>
<t>IP-Port-Limit TLV is included as part of the IP-Port-Limit-Info Attribute (refer to Section 3.1.1), identified as
241.TBD1.2.</t>
</section>
<section anchor="TLV3" title="IP-Port-Ext-IPv4-Addr TLV">
<t>The format of IP-Port-Ext-IPv4-Addr TLV is shown in <xref target="tlv3"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element
postNATSourceIPv4Address(225), and its "Value" field contains IPFIX
Information Element postNATSourceIPv4Address, which is the IPv4
source address after NAT operation (refer to <xref
target="IPFIX"></xref>).</t>
<figure anchor="tlv3">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>3. This MUST uniquely refer to the IPFIX Information
Element identifier 225.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>6</t>
</list></t>
<t>postNATSourceIPv4Address<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (ipv4Address) of
postNATSourceIPv4Address (225) defined in IPFIX.</t>
</list></t>
<t>IP-Port-Ext-IPv4-Addr TLV MAY be included in the following Attributes:<list style="symbols">
<t>IP-Port-Limit-Info Attribute, identified as
241.TBD1.3 (see Section 3.1.1).</t>
<t>IP-Port-Range Attribute, identified as
241.TBD2.3 (see Section 3.1.2).</t>
<t>IP-Port-Forwarding-Mapping Attribute, identified as
241.TBD3.3 (see Section 3.1.3).</t>
</list></t>
</section>
<section anchor="TLV4" title="IP-Port-Int-IPv4-Addr TLV">
<t>The format of IP-Port-Int-IPv4 TLV is shown in <xref target="tlv4"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element sourceIPv4Address
(8), and its "Value" field contains IPFIX Information Element
sourceIPv4Address, which is the IPv4 source address before NAT
operation (refer to <xref target="IPFIX"></xref>).</t>
<figure anchor="tlv4">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+--+-+-+-+-+-+-++-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>4. It MUST uniquely refer to the IPFIX Information
Element identifier 8.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>6.</t>
</list></t>
<t>sourceIPv4Address <list counter="1" hangIndent="5">
<t>Integer. This field contains the data (ipv4Address) of
sourceIPv4Address (8) defined in IPFIX.</t>
</list></t>
<t>IP-Port-Int-IPv4-Addr TLV MAY be included as part of the
IP-Port-Forwarding-Map Attribute (refer to <xref
target="portmap"></xref>), identified as
241.TBD3.4.</t>
</section>
<section anchor="TLV46" title="IP-Port-Int-IPv6-Addr TLV">
<t>The format of IP-Port-Int-IPv6-Addr TLV is shown in <xref target="tlv46"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element
sourceIPv6Address(27), and its "Value" field contains IPFIX
Information Element sourceIPv6Address, which is the IPv6 source
address before NAT operation (refer to <xref
target="IPFIX"></xref>).</t>
<figure anchor="tlv46">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>5. It MUST uniquely refer to the IPFIX Information
Element identifier 27.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>18.</t>
</list></t>
<t>sourceIPv6Address<list counter="1" hangIndent="5">
<t>IPv6 address (128 bits). This field contains the data
(ipv6Address) of sourceIPv6Address (27) defined in IPFIX.</t>
</list></t>
<t>IP-Port-Int-IPv6-Addr TLV MAY be included as part of the
IP-Port-Forwarding-Map Attribute (refer to <xref
target="portmap"></xref>), identified
as 241.TBD3.5.</t>
</section>
<section anchor="TLV5" title="IP-Port-Int-Port TLV">
<t>The format of IP-Port-Int-Port TLV is shown in <xref target="tlv5"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element
sourceTransportPort (7), and its "Value" field contains IPFIX
Information Element sourceTransportPort, which is the source
transport number associated with an internal IPv4 or IPv6 address
(refer to <xref target="IPFIX"></xref>).</t>
<figure anchor="tlv5">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>6. It MUST uniquely refer to the IPFIX Information
Element identifier 7.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>4.</t>
</list></t>
<t>sourceTransportPort<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned16) of
sourceTrasnportPort (7) defined in IPFIX, right justified, and
unused bits MUST be set to zero.</t>
</list></t>
<t>IP-Port-Int-Port TLV is included as part of the
IP-Port-Forwarding-Map Attribute (refer to <xref
target="portmap"></xref>), identified as 241.TBD3.6.</t>
</section>
<section anchor="TLV6" title="IP-Port-Ext-Port TLV">
<t>The format of IP-Port-Ext-Port TLV is shown in <xref target="tlv6"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element
postNAPTSourceTransportPort (227), and its "Value" field contains
IPFIX Information Element postNAPTSourceTransportPort, which is the
transport number associated with an external IPv4 address(refer to
<xref target="IPFIX"></xref>).</t>
<figure anchor="tlv6">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>7. It MUST uniquely refer to the IPFIX Information
Element identifier 227 .</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>6.</t>
</list></t>
<t>postNAPTSourceTransportPort<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned16) of
postNAPTSourceTrasnportPort (227) defined in IPFIX, right
justified, and unused bits must be set to zero.</t>
</list></t>
<t>IP-Port-Ext-Port TLV is included as part of the
IP-Port-Forwarding-Map Attribute (refer to <xref
target="portmap"></xref>), identified as
241.TBD3.7.</t>
</section>
<section anchor="TLV7" title="IP-Port-Alloc TLV">
<t>The format of IP-Port-Alloc TLV is shown in <xref target="tlv7"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element natEvent (230),
and its "Value" field contains IPFIX Information Element "natEvent",
which is a flag to indicate an action of NAT operation (refer to
<xref target="IPFIX"></xref>).</t>
<t>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.</t>
<figure anchor="tlv7">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>8. It MUST uniquely refer to the IPFIX Information
Element identifier 230 .</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>3.</t>
</list></t>
<t>natEvent<list counter="1" hangIndent="5">
<t>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:</t>
<t>1:<list counter="1" hangIndent="5">
<t>Allocation</t>
</list></t>
<t>2:<list counter="1" hangIndent="5">
<t>Deallocation</t>
</list></t>
</list></t>
<t>Reserved:<list counter="1" hangIndent="5">
<t>0.</t>
</list></t>
<t>IP-Port-Alloc TLV is included as part of the IP-Port-Range
Attribute (refer to <xref target="sessionrange"></xref>), identified as 241.TBD2.8.</t>
</section>
<section anchor="TLV8" title="IP-Port-Range-Start TLV">
<t>The format of IP-Port-Range-Start TLV is shown in <xref target="tlv8"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element portRangeStart
(361), and its "Value" field contains IPFIX Information Element
portRangeStart, which is the smallest port number of a range of
contiguous transport ports (refer to <xref
target="IPFIX"></xref>).</t>
<figure anchor="tlv8">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>9. It MUST uniquely refer to the IPFIX Information
Element identifier 361.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>4.</t>
</list></t>
<t>portRangeStart<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned16) of (361)
defined in IPFIX, right justified, and unused bits must be set
to zero.</t>
</list></t>
<t>IP-Port-Range-Start TLV is included as part of the IP-Port-Range Attribute (refer to <xref target="sessionrange"></xref>), identified as 241.TBD2.9.</t>
</section>
<section anchor="TLV9" title="IP-Port-Range-End TLV">
<t>The format of IP-Port-Range-End TLV is shown in <xref target="tlv9"></xref>. Its "Type" field contains a value
that uniquely refers to IPFIX Information Element portRangeEnd
(362), and its "Value" field contains IPFIX Information Element
portRangeEnd, which is the largest port number of a range of
contiguous transport ports (refer to <xref
target="IPFIX"></xref>).</t>
<figure anchor="tlv9">
<preamble></preamble>
<artwork><![CDATA[
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>10. It MUST uniquely refer to the IPFIX Information
Element identifier 362.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>4. The Length field for IP-Port-Range-End TLV.</t>
</list></t>
<t>portRangeEnd<list counter="1" hangIndent="5">
<t>Integer. This field contains the data (unsigned16) of (362)
defined in IPFIX, right justified, and unused bits must be set
to zero.</t>
</list></t>
<t>IP-Port-Range-End TLV is included as part of the IP-Port-Range Attribute (refer to <xref target="sessionrange"></xref>),
identified as 241.TBD2.10.</t>
</section>
<section anchor="TLV10" title="IP-Port-Local-Id TLV">
<t>The format of IP-Port-Local-Id TLV is shown in <xref target="tlv10"></xref>. Its "Type" field contains a value
that uniquely refers to the IPFIX Information Element localID
(TBAx3), and its "Value" field contains IPFIX Information Element
localID, which is a local significant identifier as explained
below.</t>
<t>In some CGN deployment scenarios such as <!-- L2NAT <xref
target="I-D.miles-behave-l2nat"></xref>, -->DS-Extra-Lite <xref
target="RFC6619"></xref> and Lightweight 4over6 <xref
target="RFC7596"></xref>, parameters at a customer premise such as
MAC address, interface ID, VLAN ID, PPP session ID, IPv6 prefix, VRF
ID, etc., may also be required to pass to the RADIUS server as part
of the accounting record.</t>
<figure anchor="tlv10">
<preamble></preamble>
<artwork><![CDATA[
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 ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
<postamble></postamble>
</figure>
<t>TLV-Type<list counter="1" hangIndent="5">
<t>11. This MUST uniquely refer to the IPFIX Information
Element identifier TBAx3.</t>
</list></t>
<t>Length<list counter="1" hangIndent="5">
<t>Variable number of bytes.</t>
</list></t>
<t>localID<list counter="1" hangIndent="5">
<t>string. This field contains the data (string) of (TBAx3)
defined in IPFIX. This is a local session identifier at the
customer premise, such as MAC address, interface ID, VLAN ID,
PPP sessions ID, VRF ID, IPv6 address/prefix, etc.</t>
</list></t>
<t>IP-Port-Local-Id TLV MAY be included in the following Attributes:<list style="symbols">
<t>IP-Port-Range Attribute, identified as
241.TBD2.11 (see Section 3.1.2).</t>
<t>IP-Port-Forwarding-Mapping Attribute, identified as
241.TBD3.11 (see Section 3.1.3).</t>
</list></t>
</section>
</section>
</section>
<section title="Applications, Use Cases and Examples">
<t>This section describes some applications and use cases to illustrate
the use of the attributes proposed in this document.</t>
<section title="Managing CGN Port Behavior using RADIUS">
<t>In a broadband network, customer information is usually stored on a
RADIUS server, and the BNG acts as a NAS. The communication between
the NAS and the RADIUS server is triggered by a user when it signs in
to the Internet service, where either PPP or DHCP/DHCPv6 is used. When
a user signs in, the NAS sends a RADIUS Access-Request message to the
RADIUS server. The RADIUS server validates the request, and if the
validation succeeds, it in turn sends back a RADIUS Access-Accept
message. The Access-Accept message carries configuration information
specific to that user, back to the NAS, where some of the information
would pass on to the requesting user via PPP or DHCP/DHCPv6.</t>
<t>A CGN function in a broadband network would most likely co-located
on a BNG. In that case, parameters for CGN port/identifier mapping
behavior for users can be configured on the RADIUS server. When a user
signs in to the Internet service, the associated parameters can be
conveyed to the NAS, and proper configuration is accomplished on the
CGN device for that user.</t>
<t>Also, CGN operation status such as CGN port/identifier allocation
and deallocation for a specific user on the BNG can also be
transmitted back to the RADIUS server for accounting purpose using the
RADIUS protocol.</t>
<t>RADIUS protocol has already been widely deployed in broadband
networks to manage BNG, thus the functionality described in this
specification introduces little overhead to the existing network
operation.</t>
<t>In the following sub-sections, we describe how to manage CGN
behavior using RADIUS protocol, with required RADIUS extensions
proposed in <xref target="attrs"></xref>.</t>
<section title="Configure IP Port Limit for a User">
<t>In the face of IPv4 address shortage, there are currently
proposals to multiplex multiple users' connections over a smaller
number of shared IPv4 addresses, such as Carrier Grade NAT <xref
target="RFC6888"></xref>, Dual-Stack Lite <xref
target="RFC6333"></xref>, NAT64 <xref target="RFC6146"></xref>, etc.
As a result, a single IPv4 public address may be shared by hundreds
or even thousands of users. As indicated in <xref
target="RFC6269"></xref>, it is therefore necessary to impose limits
on the total number of ports available to an individual user to
ensure that the shared resource, i.e., the IPv4 address, remains
available in some capacity to all the users using it. The support of
IP port limit is also documented in <xref target="RFC6888"></xref>
as a requirement for CGN.</t>
<t>The IP port limit imposed to a specific user may be on the total
number of TCP and UDP ports plus the number of ICMP identifiers, or
with other granularities as defined in <xref
target="sessionlimit"></xref>.</t>
<t>The per-user based IP port limit is configured on a RADIUS
server, along with other user information such as credentials. The
value of this IP port limit is based on service agreement and its
specification is out of the scope of this document.</t>
<t>When a user signs in to the Internet service successfully, the IP
port limit for the subscriber is passed by the RADIUS server to the
BNG, acting as a NAS and co-located with the CGN, using a new RADIUS
attribute called IP-Port-Limit-Info (defined in <xref
target="sessionlimit"></xref>), along with other configuration
parameters. While some parameters are passed to the user, the IP
port limit is recorded on the CGN device for imposing the usage of
TCP/UDP ports and ICMP identifiers for that user.</t>
<t><xref target="fig1"></xref> illustrates how RADIUS protocol is
used to configure the maximum number of TCP/UDP ports for a given
user on a NAT44 device.</t>
<t><figure anchor="fig1" height=""
title="RADIUS Message Flow for Configuring NAT44 Port Limit">
<artwork><![CDATA[
User NAT44/NAS AAA
| BNG Server
| | |
| | |
|----Service Request------>| |
| | |
| |-----Access-Request -------->|
| | |
| |<----Access-Accept-----------|
| | (IP-Port-Limit-Info) |
| | (for TCP/UDP ports) |
|<---Service Granted ------| |
| (other parameters) | |
| | |
| (NAT44 external port |
| allocation and |
| IPv4 address assignment) |
| | |
]]></artwork>
</figure></t>
<t>The IP port limit created on a CGN device for a specific user
using RADIUS extension may be changed using RADIUS CoA message <xref
target="RFC5176"></xref> that carries the same RADIUS attribute. The
CoA message may be sent from the RADIUS server directly to the NAS,
which once accepts and sends back a RADIUS CoA ACK message, the new
IP port limit replaces the previous one.</t>
<t><xref target="fig2"></xref> illustrates how RADIUS protocol is
used to increase the TCP/UDP port limit from 1024 to 2048 on a NAT44
device for a specific user.</t>
<t><figure anchor="fig2" height=""
title="RADIUS Message Flow for changing a user's NAT44 port limit">
<artwork><![CDATA[
User NAT44/NAS AAA
| BNG Server
| | |
| TCP/UDP Port Limit (1024) |
| | |
| |<---------CoA Request----------|
| | (IP-Port-Limit-Info) |
| | (for TCP/UDP ports) |
| | |
| TCP/UDP Port Limit (2048) |
| | |
| |---------CoA Response--------->|
| | |
]]></artwork>
</figure></t>
</section>
<section title="Report IP Port Allocation/Deallocation">
<t>Upon obtaining the IP port limit for a user, the CGN device needs
to allocate a TCP/UDP port or an ICMP identifiers for the user when
receiving a new IP flow sent from that user.</t>
<t>As one practice, a CGN may allocate a bulk of TCP/UDP ports or
ICMP identifiers once at a time for a specific user, instead of one
port/identifier at a time, and within each port bulk, the
ports/identifiers may be randomly distributed or in consecutive
fashion. When a CGN device allocates bulk of TCP/UDP ports and ICMP
identifiers, the information can be easily conveyed to the RADIUS
server by a new RADIUS attribute called the IP-Port-Range (defined
in <xref target="sessionrange"></xref>). The CGN device may allocate
one or more TCP/UDP port ranges or ICMP identifier ranges, or
generally called IP port ranges, where each range contains a set of
numbers representing TCP/UDP ports or ICMP identifiers, and the
total number of ports/identifiers must be less or equal to the
associated IP port limit imposed for that user. A CGN device may
choose to allocate a small port range, and allocate more at a later
time as needed; such practice is good because its randomization in
nature.</t>
<t>At the same time, the CGN device also needs to decide the shared
IPv4 address for that user. The shared IPv4 address and the
pre-allocated IP port range are both passed to the RADIUS
server.</t>
<t>When a user initiates an IP flow, the CGN device randomly selects
a TCP/UDP port or ICMP identifier from the associated and
pre-allocated IP port range for that user to replace the original
source TCP/UDP port or ICMP identifier, along with the replacement
of the source IP address by the shared IPv4 address.</t>
<t>A CGN device may decide to "free" a previously assigned set of
TCP/UDP ports or ICMP identifiers that have been allocated for a
specific user but not currently in use, and with that, the CGN
device must send the information of the deallocated IP port range
along with the shared IPv4 address to the RADIUS server.</t>
<t><xref target="fig3"></xref> illustrates how RADIUS protocol is
used to report a set of ports allocated and deallocated,
respectively, by a NAT44 device for a specific user to the RADIUS
server.</t>
<t><figure anchor="fig3" height=""
title="RADIUS Message Flow for reporting NAT44 allocation/deallocation of a port set">
<artwork><![CDATA[
Host NAT44/NAS AAA
| BNG Server
| | |
| | |
|----Service Request------>| |
| | |
| |-----Access-Request -------->|
| | |
| |<----Access-Accept-----------|
|<---Service Granted ------| |
| (other parameters) | |
... ... ...
| | |
| | |
| (NAT44 decides to allocate |
| a TCP/UDP port range for the user) |
| | |
| |-----Accounting-Request----->|
| | (IP-Port-Range |
| | for allocation) |
... ... ...
| | |
| (NAT44 decides to deallocate |
| a TCP/UDP port range for the user) |
| | |
| |-----Accounting-Request----->|
| | (IP-Port-Range |
| | for deallocation) |
| | |
]]></artwork>
</figure></t>
<t></t>
</section>
<section title="Configure Forwarding Port Mapping">
<t>In most scenarios, the port mapping on a NAT device is
dynamically created when the IP packets of an IP connection
initiated by a user arrives. For some applications, the port mapping
needs to be pre-defined allowing IP packets of applications from
outside a CGN device to pass through and "port forwarded" to the
correct user located behind the CGN device.</t>
<t>Port Control Protocol <xref target="RFC6887"> </xref>, provides a
mechanism to create a mapping from an external IP address and port
to an internal IP address and port on a CGN device just to achieve
the "port forwarding" purpose. PCP is a server-client protocol
capable of creating or deleting a mapping along with a rich set of
features on a CGN device in dynamic fashion. In some deployment, all
users need is a few, typically just one pre-configured port mapping
for applications such as web cam at home, and the lifetime of such a
port mapping remains valid throughout the duration of the customer's
Internet service connection time. In such an environment, it is
possible to statically configure a port mapping on the RADIUS server
for a user and let the RADIUS protocol to propagate the information
to the associated CGN device.</t>
<t><xref target="fig4"></xref> illustrates how RADIUS protocol is
used to configure a forwarding port mapping on a NAT44 device by
using RADIUS protocol.</t>
<t><figure anchor="fig4" height=""
title="RADIUS Message Flow for configuring a forwarding port mapping">
<artwork><![CDATA[
Host NAT/NAS AAA
| BNG Server
| | |
|----Service Request------>| |
| | |
| |---------Access-Request------->|
| | |
| |<--------Access-Accept---------|
| | (IP-Port-Forwarding-Map) |
|<---Service Granted ------| |
| (other parameters) | |
| | |
| (Create a port mapping |
| for the user, and |
| associate it with the |
| internal IP address |
| and external IP address) |
| | |
| | |
| |------Accounting-Request------>|
| | (IP-Port-Forwarding-Map) |
]]></artwork>
</figure></t>
<t>A port forwarding mapping that is created on a CGN device using
RADIUS extension as described above may also be changed using RADIUS
CoA message <xref target="RFC5176"></xref> that carries the same
RADIUS associate. The CoA message may be sent from the RADIUS server
directly to the NAS, which once accepts and sends back a RADIUS CoA
ACK message, the new port forwarding mapping then replaces the
previous one.</t>
<t><xref target="fig5"></xref> illustrates how RADIUS protocol is
used to change an existing port mapping from (a:X) to (a:Y), where
"a" is an internal port, and "X" and "Y" are external ports,
respectively, for a specific user with a specific IP address</t>
<t><figure anchor="fig5" height=""
title="RADIUS Message Flow for changing a user's forwarding port mapping">
<artwork><![CDATA[
Host NAT/NAS AAA
| BNG Server
| | |
| Internal IP Address |
| Port Map (a:X) |
| | |
| |<---------CoA Request----------|
| | (IP-Port-Forwarding-Map) |
| | |
| Internal IP Address |
| Port Map (a:Y) |
| | |
| |---------CoA Response--------->|
| | (IP-Port-Forwarding-Map) |
]]></artwork>
</figure></t>
</section>
<section title="An Example">
<t>An Internet Service Provider (ISP) assigns TCP/UDP 500 ports for
the user Joe. This number is the limit that can be used for TCP/UDP
ports on a NAT44 device for Joe, and is configured on a RADIUS
server. Also, Joe asks for a pre-defined port forwarding mapping on
the NAT44 device for his web cam applications (external port 5000
maps to internal port 80).</t>
<t>When Joe successfully connects to the Internet service, the
RADIUS server conveys the TCP/UDP port limit (1000) and the
forwarding port mapping (external port 5000 to internal port 80) to
the NAT44 device, using IP-Port-Limit-Info Attribute and
IP-Port-Forwarding-Map attribute, respectively, carried by an
Access-Accept message to the BNG where NAS and CGN co-located.</t>
<t>Upon receiving the first outbound IP packet sent from Joe's
laptop, the NAT44 device decides to allocate a small port pool that
contains 40 consecutive ports, from 3500 to 3540, inclusively, and
also assign a shared IPv4 address 192.0.2.15, for Joe. The NAT44
device also randomly selects one port from the allocated range (say
3519) and use that port to replace the original source port in
outbound IP packets.</t>
<t>For accounting purpose, the NAT44 device passes this port range
(3500-3540) and the shared IPv4 address 192.0.2.15 together to the
RADIUS server using IP-Port-Range attribute carried by an
Accounting-Request message.</t>
<t>When Joe works on more applications with more outbound IP
sessions and the port pool (3500-3540) is close to exhaust, the
NAT44 device allocates a second port pool (8500-8800) in a similar
fashion, and also passes the new port range (8500-8800) and IPv4
address 192.0.2.15 together to the RADIUS server using IP-Port-Range
attribute carried by an Accounting-Request message. Note when the
CGN allocates more ports, it needs to assure that the total number
of ports allocated for Joe is within the limit.</t>
<t>Joe decides to upgrade his service agreement with more TCP/UDP
ports allowed (up to 1000 ports). The ISP updates the information in
Joe's profile on the RADIUS server, which then sends a CoA-Request
message that carries the IP-Port-Limit-Info Attribute with 1000
ports to the NAT44 device; the NAT44 device in turn sends back a
CoA-ACK message. With that, Joe enjoys more available TCP/UDP ports
for his applications.</t>
<t>When Joe travels, most of the IP sessions are closed with their
associated TCP/UDP ports released on the NAT44 device, which then
sends the relevant information back to the RADIUS server using
IP-Port-Range attribute carried by Accounting-Request message.</t>
<t>Throughout Joe's connection with his ISP Internet service,
applications can communicate with his web cam at home from external
realm directly traversing the pre-configured mapping on the CGN
device.</t>
<t>When Joe disconnects from his Internet service, the CGN device
will deallocate all TCP/UDP ports as well as the port-forwarding
mapping, and send the relevant information to the RADIUS server.</t>
</section>
</section>
<section title="Report Assigned Port Set for a Visiting UE">
<t><xref target="wifi"></xref> illustrates an example of the flow
exchange which occurs when a visiting UE connects to a CPE offering
WLAN service.</t>
<t>For identification purposes (see <xref target="RFC6967"></xref>),
once the CPE assigns a port set, it issues a RADIUS message to report
the assigned port set.</t>
<t><figure anchor="wifi" height=""
title="RADIUS Message Flow for reporting CPE allocation/deallocation of a port set to a visiting UE">
<artwork><![CDATA[
UE CPE NAS AAA
| BNG Server
| | |
| | |
|----Service Request------>| |
| | |
| |-----Access-Request -------->|
| | |
| |<----Access-Accept-----------|
|<---Service Granted ------| |
| (other parameters) | |
... | ... ...
|<---IP@----| | |
| | | |
| (CPE assigns a TCP/UDP port |
| range for this visiting UE) |
| | |
| |--Accounting-Request-...------------------->|
| | (IP-Port-Range |
| | for allocation) |
... | ... ...
| | | |
| | | |
| (CPE withdraws a TCP/UDP port |
| range for a visiting UE) |
| | |
| |--Accounting-Request-...------------------->|
| | (IP-Port-Range |
| | for deallocation) |
| | |
]]></artwork>
</figure></t>
<t></t>
</section>
</section>
<section anchor="Table" title="Table of Attributes">
<t>This document proposes three new RADIUS attributes and their formats
are as follows:</t>
<t><list style="symbols">
<t>IP-Port-Limit-Info: 241.TBD1.</t>
<t>IP-Port-Range: 241.TBD2.</t>
<t>IP-Port-Forwarding-Map: 241.TBD3.</t>
</list></t>
<t>Note to IANA: it is assumed that Extended-Type-1 "241" will be
used for these attributes.</t>
<t>The following table provides a guide as what type of RADIUS packets
that may contain these attributes, and in what quantity.</t>
<texttable style="none">
<ttcol>Request</ttcol>
<ttcol>Accept</ttcol>
<ttcol>Reject</ttcol>
<ttcol>Challenge</ttcol>
<ttcol>Acct. Request</ttcol>
<ttcol>#</ttcol>
<ttcol>Attribute</ttcol>
<c>0+</c>
<c>0+</c>
<c>0</c>
<c>0</c>
<c>0+</c>
<c>TBA</c>
<c>IP-Port-Limit-Info</c>
<c>0</c>
<c>0</c>
<c>0</c>
<c>0</c>
<c>0+</c>
<c>TBA</c>
<c>IP-Port-Range</c>
<c>0+</c>
<c>0+</c>
<c>0</c>
<c>0</c>
<c>0+</c>
<c>TBA</c>
<c>IP-Port-Forwarding-Map</c>
</texttable>
<t>The following table defines the meaning of the above table
entries.</t>
<t></t>
<texttable style="none" suppress-title="true">
<ttcol></ttcol>
<ttcol></ttcol>
<c>0</c>
<c>This attribute MUST NOT be present in packet.</c>
<c>0+</c>
<c>Zero or more instances of this attribute MAY be present in
packet.</c>
<!--<c>0-1</c>
<c>Zero or one instance of this attribute MAY be present in packet.</c> -->
</texttable>
</section>
<section anchor="Security" title="Security Considerations">
<t>This document does not introduce any security issue other than the
ones already identified in RADIUS <xref target="RFC2865"></xref>.</t>
</section>
<section anchor="IANA" title="IANA Considerations">
<t>This document requires new code point assignments for both IPFIX
Information Elements and RADIUS attributes as explained in the following
sub-sections.</t>
<t>It is assumed that Extended-Type-1 "241" will be used for
RADIUS attributes in <xref target="IPFIX-RADIUS"></xref>.</t>
<section anchor="IPFIX-IANA"
title="IANA Considerations on New IPFIX Information Elements">
<t>The following are code point assignments for new IPFIX Information
Elements as requested by this document:<list style="symbols">
<t>transportType (refer to <xref target="TLV0"></xref>): The
identifier of this IPFIX Information Element is TBAx1. The data
type of this IPFIX Information Element is unsigned8, and the
Element's value indicates TCP/UDP ports and ICMP Identifiers (1),
TCP/UDP ports (2), TCP ports (3), UDP ports (4) or ICMP
identifiers (5).</t>
<t>natTransportLimit (refer to <xref target="TLV2"></xref>): The
identifier of this IPFIX Information Element is TBAx2. The data
type of this IPFIX Information Element is unsigned16, and the
Element's value is the max number of IP transport ports to be
assigned to an end user associated with one or more IPv4
addresses.</t>
<t>localID (refer to <xref target="TLV10"></xref>): The identifier
of this IPFIX Information Element is TBAx3. The data type of this
IPFIX Information Element is string, and the Element's value is an
IPv4 or IPv6 address, a MAC address, a VLAN ID, etc.</t>
</list></t>
</section>
<section anchor="IPFIX-RADIUS"
title="IANA Considerations on New RADIUS Attributes">
<t>The authors request that Attribute Types and Attribute Values
defined in this document be registered by the Internet Assigned
Numbers Authority (IANA) from the RADIUS namespaces as described in
the "IANA Considerations" section of <xref target="RFC3575"></xref>,
in accordance with BCP 26 <xref target="RFC5226"></xref>. For RADIUS
packets, attributes and registries created by this document IANA is
requested to place them at
http://www.iana.org/assignments/radius-types.</t>
<t>In particular, this document defines three new RADIUS attributes,
entitled "IP-Port-Limit-Info" (see <xref
target="sessionlimit"></xref>), "IP-Port-Range" (see <xref
target="sessionrange"></xref>) and "IP-Port-Forwarding-Map" (see <xref
target="portmap"></xref>), with assigned values of 241.TBD1, 241.TBD2
and 241.TBD3 from the Short Extended Space of <xref
target="RFC6929"></xref>: <figure>
<artwork><![CDATA[ Type Name Meaning
---- ---- -------
241.TBD1 IP-Port-Limit-Info see Section 3.1.1
241.TBD2 IP-Port-Range see Section 3.1.2
241.TBD3 IP-Port-Forwarding-Map see Section 3.1.3
]]></artwork>
</figure></t>
<t></t>
</section>
<section title="IANA Considerations on New RADIUS TLVs">
<t>This specification requests allocation of the following TLVs:</t>
<t><figure>
<artwork><![CDATA[
Name Value Meaning
---- ----- -------
IP-Port-Type 1 see Section 3.2.1
IP-Port-Limit 2 see Section 3.2.2
IP-Port-Ext-IPv4-Addr 3 see Section 3.2.3
IP-Port-Int-IPv4-Addr 4 see Section 3.2.4
IP-Port-Int-IPv6-Addr 5 see Section 3.2.5
IP-Port-Int-Port 6 see Section 3.2.6
IP-Port-Ext-Port 7 see Section 3.2.7
IP-Port-Alloc 8 see Section 3.2.8
IP-Port-Range-Start 9 see Section 3.2.9
IP-Port-Range-End 10 see Section 3.2.10
IP-Port-Local-Id 11 see Section 3.2.11
]]></artwork>
</figure></t>
</section>
</section>
<section title="Acknowledgements">
<t>Many thanks to Dan Wing, Roberta Maglione, Daniel Derksen, David
Thaler, Alan Dekok, Lionel Morand, and Peter Deacon for their useful
comments and suggestions.</t>
<t>Special thanks to Lionel Morand for the Shepherd review.</t>
</section>
</middle>
<back>
<references title="Normative References">
&RFC2119;
&RFC2865;
<?rfc include='reference.RFC.6929'?>
<?rfc include='reference.RFC.7012'?>
<?rfc include='reference.RFC.3575'?>
<?rfc include='reference.RFC.5226'?>
<reference anchor="IPFIX"
target="http://www.iana.org/assignments/ipfix/ipfix.xhtml">
<front>
<title>IP Flow Information Export (IPFIX) Entities</title>
<author fullname="" surname="">
<organization>IANA</organization>
</author>
<date day="" month="" year="" />
</front>
</reference>
</references>
<references title="Informative References">
<?rfc include='reference.RFC.3022'?>
<?rfc include='reference.RFC.5176'?>
<?rfc include='reference.RFC.6887'?>
<?rfc include='reference.RFC.6619'?>
<?rfc include='reference.RFC.7596'?>
<?rfc include='reference.I-D.gundavelli-v6ops-community-wifi-svcs'?>
<?rfc include='reference.RFC.6967'?>
<?rfc include='reference.RFC.6888'?>
&RFC6146;
&RFC6269;
&RFC6333;
<reference anchor="TR-146"
target="http://www.broadband-forum.org/technical/download/TR-146.pdf">
<front>
<title>TR-146: Subscriber Sessions</title>
<author fullname="" surname="">
<organization>Broadband Forum</organization>
</author>
<date day="" month="" year="" />
</front>
</reference>
<!-- &I-D.miles-behave-l2nat;-->
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 20:50:18 |