Softwire S. Jiang, Ed.
Internet-Draft Huawei Technologies Co., Ltd
Intended status: Standards Track Y. Fu, Ed.
Expires: November 3, 2017 CNNIC
B. Liu
Huawei Technologies Co., Ltd
P. Deacon
IEA Software, Inc.
C. Xie
China Telecom
T. Li
Tsinghua University
May 2, 2017
RADIUS Attribute for Softwire Address plus Port based Mechanisms
draft-ietf-softwire-map-radius-12
Abstract
IPv4-over-IPv6 transition mechanisms provide both IPv4 and IPv6
connectivity services simultaneously during the IPv4/IPv6 co-existing
period. The Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
options have been defined to configure Customer Edge (CE) in MAP-E,
MAP-T, and Lightweight 4over6. However, in many networks, the
configuration information may be stored in an Authentication
Authorization and Accounting (AAA) server, while user configuration
information is mainly provided by the Broadband Network Gateway (BNG)
through the DHCPv6 protocol. This document defines two new Remote
Authentication Dial In User Service (RADIUS) attributes that carry CE
configuration information from an AAA server to BNG.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 3, 2017.
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Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Configuration process with RADIUS . . . . . . . . . . . . . . 3
4. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Softwire46-Configuration Attribute . . . . . . . . . . . 6
4.2. S46 Container Options . . . . . . . . . . . . . . . . . . 7
4.3. Sub Options for S46 Container Option . . . . . . . . . . 8
4.3.1. S46-Rule Sub Option . . . . . . . . . . . . . . . . . 8
4.3.2. S46-BR Sub Option . . . . . . . . . . . . . . . . . . 9
4.3.3. S46-DMR Sub Option . . . . . . . . . . . . . . . . . 10
4.3.4. S46-V4V6Bind Sub Option . . . . . . . . . . . . . . . 10
4.3.5. S46-PORTPARAMS Sub Option . . . . . . . . . . . . . . 11
4.4. Sub Options for S46-Rule Sub Option . . . . . . . . . . . 12
4.4.1. Rule-IPv6-Prefix Sub Option . . . . . . . . . . . . . 12
4.4.2. Rule-IPv4-Prefix Sub Option . . . . . . . . . . . . . 13
4.4.3. EA Length Sub Option . . . . . . . . . . . . . . . . 14
4.5. Softwire46 Sub Options Encapsulation . . . . . . . . . . 14
4.6. Softwire46-Priority Attribute . . . . . . . . . . . . . . 14
4.7. Table of attributes . . . . . . . . . . . . . . . . . . . 15
5. Diameter Considerations . . . . . . . . . . . . . . . . . . . 16
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
6.1. S46 Mechanisms and Their Identifying Option Codes . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 17
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . 18
Additional Authors . . . . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
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1. Introduction
Recently providers have started to deploy IPv6 and consider how to
transit to IPv6. Many transition mechanisms based on the Address
plus Port (A+P) [RFC6346] have been proposed for running IPv4 over
IPv6-only infrastructure, including MAP-E, MAP-T, and Lightweight
4over6. Mapping of Address and Port with Encapsulation(MAP-
E)[RFC7597], Mapping of Address and Port using Translation(MAP-
T)[RFC7599] are stateless mechanisms for running IPv4 over IPv6-only
infrastructure. Lightweight 4over6[RFC7596] is a hub-and-spoke IPv4-
over-IPv6 tunneling mechanism, with complete independence of IPv4 and
IPv6 addressing. They provide both IPv4 and IPv6 connectivity
services simultaneously during the IPv4/IPv6 co-existing period.
MAP-E, MAP-T and Lightweight 4over6 have adopted Dynamic Host
Configuration Protocol for IPv6 (DHCPv6) [RFC3315] as auto-
configuring protocol. The Customer Edge (CE) uses DHCPv6 options to
discover the Border Relay (BR) and get Softwire46 (S46)
configurations.
In many networks, user configuration information may be stored in an
Authentication, Authorization, and Accounting (AAA) server.
Currently the AAA servers communicate using the Remote Authentication
Dial In User Service (RADIUS) [RFC2865] protocol. In a fixed line
broadband network, a Broadband Network Gateway (BNG) acts as the
access gateway of users. The BNG is assumed to embed a DHCPv6 server
function that allows it to locally handle any DHCPv6 requests
initiated by hosts.
Since the S46 configuration information is stored in an AAA servers
and user configuration information is mainly transmitted through
DHCPv6 protocol between the BNGs and hosts/CEs, new RADIUS attributes
are needed to propagate the information from the AAA servers to BNGs.
The RADIUS attributes designed in this document are especially for
the MAP-E[RFC7597], MAP-T[RFC7599] and Lightweight 4over6[RFC7596],
providing enough information to form the correspondent DHCPv6
configuration options[RFC7598].
2. Terminology
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 [RFC2119].
3. Configuration process with RADIUS
The Figure 1 below illustrates how the RADIUS protocol and DHCPv6 co-
operate to provide CE with MAP configuration information. The BNG
acts as a RADIUS client and DHCPv6 server.
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CE BNG AAA Server
| | |
|-------1.DHCPv6 Solicit------->| |
| (ORO w/container option code) | |
| |-------2.Access-Request------->|
| | (S46-Configuration attribute) |
| | |
| |<------3.Access-Accept---------|
|<---4.DHCPv6 Advertisement-----| (S46-Configuration attribute) |
| (container option) | |
|-------5.DHCPv6 Request------>| |
| (container Option) | |
|<------6.DHCPv6 Reply----------| |
| (container option) | |
| | |
DHCPv6 RADIUS
Figure 1: the cooperation between DHCPv6 and RADIUS combining with
RADIUS authentication
1. First, the CE MAY initiate a DHCPv6 Solicit message that includes
an Option Request option(6) [RFC3315] with the S46 Container option
codes as defined in[RFC7598]. As described in [RFC7598],
OPTION_S46_CONT_MAPE should be included for MAP-E[RFC7597],
OPTION_S46_CONT_MAPT for MAP-T [RFC7599], and OPTION_S46_CONT_LW for
Lightweight 4over6 [RFC7596]. Note however, that the ORO (Option
Request option) with the S46 Container option code could be optional
if the network was planned as being S46-enabled as default.
2. When the BNG receives the Solicit message, it should initiate a
radius Access-Request message, in which an User-Name attribute (1)
should be filled by a CE MAC address or interface-id or both, to the
RADIUS server and a User-password attribute (2) should be filled by
the shared password that has been preconfigured on the DHCPv6 server,
requesting authentication as defined in [RFC2865] with the
corresponding Softwire46-Configuration Attribute, which will be
defined in the next Section.
3. If the authentication request is approved by the AAA server, an
Access-Accept message MUST be acknowledged with the corresponding
Softwire46-Configuration Attribute.
4. After receiving the Access-Accept message with the corresponding
Attribute, the BNG SHOULD respond to the DHCPv6 Client (CE) with an
Advertisement message.
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5. After receiving the Advertise message, the CE MAY request for the
corresponding S46 Container option, by including the S46 Container
option in the Request message.
6. After receiving the client's Request message, containing the
corresponding S46 Container option the BNG SHOULD reply to the CE
with the message containing the S46 Container option. The
recommended format of the MAC address is defined as Calling-Station-
Id (Section 3.20 in [RFC3580] without the SSID (Service Set
Identifier) portion.
For Lightweight 4over6 [RFC7596], the subscriber's binding state
should be synchronized between the AAA server and lwAFTR. If the
bindings are pre-configured statically, in both the AAA server and
lwAFTR, an AAA server does not need to configure the lwAFTR anymore.
Otherwise, if the bindings are locally created on-demand in an AAA
server, it should inform the lwAFTR with the subscriber's binding
state, in order to synchronize the binding information of the lwB4
with the lwAFTR.
The authorization operation could also be done independently after
the authentication process. In such a scenario, after the
authentication operation, the client MAY initiate a DHCPv6 Request
message that includes the corresponding S46 Container options.
Similar to the above scenario, the ORO with the corresponding S46
Container option code in the initial DHCPv6 request could be optional
if the network was planned as being S46-enabled by default. When the
BNG receives the DHCPv6 Request, it SHOULD initiate the radius
Access-Request message, which MUST contain a Service-Type attribute
(6) with the value Authorize Only (17), the corresponding
Softwire46-Configuration Attribute, and a State attribute obtained
from the previous authentication process according to [RFC5080]. If
the authorization request is approved by an AAA server, an Access-
Accept message MUST be acknowledged with the corresponding
Softwire46-Configuration Attribute. The BNG SHOULD then send the
DHCPv6 Reply message containing the S46 Container option.
In both the above-mentioned scenarios, Message-authenticator (type
80) [RFC2869] SHOULD be used to protect both Access-Request and
Access-Accept messages.
If the BNG does not receive the corresponding
Softwire46-Configuration Attribute in the Access-Accept message it
MAY fallback to a pre-configured default S46 configuration, if any.
If the BNG does not have any pre-configured default S46
configuration, or if the BNG receives an Access-Reject, then S46
connection cannot be established.
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As specified in [RFC3315], section 18.1.4, "Creation and Transmission
of Rebind Messages ", if the DHCPv6 server to which the DHCPv6 Renew
message was sent at time T1 has not responded by time T2, the CE
(DHCPv6 client) SHOULD enter the Rebind state and attempt to contact
any available server. In this situation, the secondary BNG receiving
the DHCPv6 message MUST initiate a new Access-Request message towards
the AAA server. The secondary BNG MAY include the
Softwire46-Configuration Attribute in its Access-Request message.
4. Attributes
This section defines the Softwire46-Configuration Attribute and the
Softwire46-Priority Attribute. The attribute design follows
[RFC6158] and refers to [RFC6929]. The Softwire46-Configuration
Attribute carries the configuration information for MAP-E, MAP-T, and
Lightweight 4over6. The configuration information for each S46
mechanism is carried in the corresponding S46 Container option.
Different sub options are required for each type of S46 Container
option. The RADIUS attribute for Dual-Stack Lite [RFC6333] is
defined in [RFC6519].
A client may be capable of supporting several different S46
mechanisms. Depending on the deployment scenario, a client might
request for more than one S46 mechanism at a time. The
Softwire46-Priority Attribute contains information allowing the
client to prioritize which mechanism to use, corresponding to
OPTION_S46_PRIORITY defined in [RFC8026].
4.1. Softwire46-Configuration Attribute
The Softwire46-Configuration Attribute can only encapsulate S46
Container Option(s). The Softwire46-Configuration Attribute is
structured as follows:
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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 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ S46 Container Option(s) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
TBD
Length
2 + the length of the S46 Container option(s) specified in octets
S46 Container Option (s)
A variable field that may contains one or more S46 Container
option(s), defined in Section 4.2.
4.2. S46 Container Options
The S46 Container Option can only be encapsulated in the
Softwire46-Configuration Attribute. Depending on the deployment
scenario, a client might request for more than one transition
mechanism at a time, there MUST be at least one S46 Container option
encapsulated in one Softwire46-Configuration Attribute. There MUST
be at most one instance of each type of S46 Container Option
encapsulated in one Softwire46-Configuration Attribute.
/
/ | 1.Rule-IPv6-Prefix Sub
| | Option
| 1.S46-Rule Sub Option--+ 2.Rule-IPv4-Prefix Sub
| | Option
| 2.S46-BR Sub Option | 3.EA Length Sub Option
S46 Container Option--+ 3.S46-DMR Sub Option \
| 4.S46-v4v6Bind Sub Option
| 5.S46-PORTPARAMS Sub Option
\
Figure 2: S46 Container Option Hierarchy
There are three types of S46 Container Options, namely MAP-E
Container Option, MAP-T Container Option, Lightweight 4over6
Container Option. Each type of S46 Container Option contains a
number of sub options, defined in Section 4.3. The hierarchy of the
S46 Container Option is shown in Figure 2. Section 4.5 describes
which Sub Options are mandatory, optional, or not permitted for each
defined S46 Container Option.
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There are three types of S46-Rule Sub Options, namely Basic Mapping
Rule, Forwarding Mapping Rule, Basic and Forwarding Mapping Rule.
Each type of S46-Rule Sub Option also contains a number of Sub
Options. The Rule-IPv6-Prefix Sub Option is necessary for every type
of S46-Rule Sub Option. It should appear for once and only once.
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 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ Sub Options +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
TBD1 MAP-E Container Option
TBD2 MAP-T Container Option
TBD3 Lightweight 4over6 Container Option
Length
2 + the length of the Sub Options specified in octets
Sub Option
A variable field that contains necessary sub options defined in
Section 4.3 and zero or several optional sub options, defined
in Section 4.4.
NOTE: The Type values for each S46 Container Option are the same
as the S46-option-code values of the corresponding S46 Mechanisms
specified in Section 6.1.
4.3. Sub Options for S46 Container Option
4.3.1. S46-Rule Sub Option
The S46-Rule Sub Option can only be encapsulated in the MAP-E
Container Option or the MAP-T Container Option. Depending on
deployment scenario, one Basic Mapping Rule and zero or more
Forwarding Mapping Rules MUST be included in one MAP-E Container
Option or MAP-T Container Option.
Each type of S46-Rule Sub Option also contains a number of sub
options, including Rule-IPv6-Prefix Sub Option, Rule-IPv4-Prefix Sub
Option, and EA Length Sub Option. The structure of the sub options
for S46-Rule Sub Option is defined in section 4.4.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ Sub Options +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
1 Basic Mapping Rule (Not Forwarding Mapping Rule)
2 Forwarding Mapping Rule (Not Basic Mapping Rule)
3 Basic & Forwarding Mapping Rule
SubLen
2 + the length of the Sub Options specified in octets
Sub Option
A variable field that contains sub options defined in
Section 4.4.
4.3.2. S46-BR Sub Option
The S46-BR Sub Option an only be encapsulated in the MAP-E Container
Option or the Lightweight 4over6 Container Option. There MUST be at
least one S46-BR Sub Option included in each MAP-E Container Option
or Lightweight 4over6 Container Option.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| BR-ipv6-address |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
4 (SubType number, for the S46-BR sub option)
SubLen
18 (the length of the S46-BR sub option)
BR-ipv6-address
a fixed-length field of 16 octets that specifies the IPv6 address
for the S46 BR.
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4.3.3. S46-DMR Sub Option
The S46-DMR Sub Option can only appear in the MAP-T Container Option.
There MUST be exactly one S46-DMR Sub Option included in one MAP-T
Container Option.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen |dmr-prefix6-len| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| dmr-ipv6-prefix |
| (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
5 (SubType number, for the S46-DMR Sub Option)
SubLen
3 + length of dmr-ipv6-prefix specified in octets
dmr-prefix6-len
8 bits long; expresses the bitmask length of the IPv6
prefix specified in the dmr-ipv6-prefix field. Allowed values
range from 0 to 96.
dmr-ipv6-prefix
a variable-length field specifying the IPv6 prefix or address
for the BR. This field is right-padded with zeros to the nearest
octet boundary when dmr-prefix6-len is not divisible by 8.
4.3.4. S46-V4V6Bind Sub Option
The S46-V4V6Bind Sub Option can only be encapsulated in the
Lightweight 4over6 Container Option. There MUST be at most one
S46-V4V6Bind Sub Option included in each Lightweight 4over6 Container
Option.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | ipv4-address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (Continued) |bindprefix6-len| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| bind-ipv6-prefix |
| (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
6 (SubType number, for the S46-V4V6Bind sub option)
SubLen
the length of the S46-V4V6Bind sub option expressed in octets
ipv4-address
a 32-bits field that specifies an IPv4 address that appears in
the V4V6Bind Option
bindprefix6-len
8 bits long; expresses the bitmask length of the IPv6 prefix
specified in the bind-ipv6-prefix field. Allowed values range from
0 to 96.
bind-ipv6-prefix
a variable-length field specifying the IPv6 prefix or address for
the S46 CE. This field is right-padded with zeros to the nearest
octet boundary when bindprefix6-len is not divisible by 8.
4.3.5. S46-PORTPARAMS Sub Option
The S46-PORTPARAMS Sub Option specifies optional port set information
that MAY be provided to CEs. The S46-PORTPARAMS sub option can be
included optionally by each type of S46 Container Option.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | PSID-Offset | PSID-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
7 (SubType number, for the S46-PORTPARAMS Sub Option sub option)
SubLen
6 (the length of the S46-PORTPARAMS Sub Option sub option)
PSID Offset
8 bits long field that specifies the numeric value for the S46
algorithm's excluded port range/ offset bits (a bits), as per
Section 5.1 of RFC7597. Allowed values are between 0 and 15.
Default values for this field are specific to the Softwire
mechanism being implemented and are defined in the relevant
specification document.
PSID-len
8 bits long; specifies the number of significant bits in the PSID
field. (also known as 'k'). When set to 0, the PSID field is to
be ignored. After the first 'a' bits, there are k bits in the
port number representing valid of PSID. Subsequently, the
address sharing ratio would be 2 ^k.
PSID (Port-set ID)
Explicit 16-bit (unsigned word) PSID value. The PSID value
algorithmically identifies a set of ports assigned to a CE. The
first k-bits on the left of this 2-octets field is the PSID
value. The remaining (16-k) bits on the right are padding zeros.
4.4. Sub Options for S46-Rule Sub Option
4.4.1. Rule-IPv6-Prefix Sub Option
The Rule-IPv6-Prefix Sub Option is necessary for every S46-RULE sub
option. There MUST be exactly one S46-IPv6-Prefix Sub Option
encapsulated in each type of S46-Rule Sub Option.
The IPv6 Prefix sub option is followed the framed IPv6 prefix
designed in [RFC3162].
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | Reserved | prefix6-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| rule-ipv6-prefix |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
8 (SubType number, for the Rule-IPv6-Prefix Sub Option)
SubLen
20 (the length of the Rule-IPv6-Prefix Sub Option)
Reserved
Reserved for future usage. It should be set to all zero.
prefix6-len
the length of IPv6 prefix, specified in the rule-ipv6-prefix
field, expressed in bits.
rule-ipv6-prefix
a 128-bits field that specifies an IPv6 prefix that appears in
a MAP rule.
4.4.2. Rule-IPv4-Prefix Sub Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | Reserved | prefix4-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| rule-ipv4-prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
9 (SubType number, for the Rule-IPv4-Prefix sub option)
SubLen
8 (the length of the Rule-IPv4-Prefix sub option)
Reserved
Reserved for future usage. It should be set to all zero
Prefix4-len
the length of IPv4 prefix, specified in the rule-ipv4-prefix
field, expressed in bits.
rule-ipv4-prefix
a 32-bits field that specifies an IPv4 prefix that appears in
a MAP rule.
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4.4.3. EA Length Sub Option
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SubType | SubLen | EA-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
SubType
10 (SubType number, for the EA Length Sub Option)
SubLen
4 (the length of the EA Length Sub Option)
EA-len
16 bits long field that specifies the Embedded-Address (EA)
bit length. Allowed values range from 0 to 48.
4.5. Softwire46 Sub Options Encapsulation
The table below shows which encapsulated Sub Options are mandatory,
optional, or not permitted for each defined S46 Container Option.
+----------------+-------+-------+--------------------+
| Sub Option | MAP-E | MAP-T | Lightweight 4over6 |
+----------------+-------+-------+--------------------+
| S46-BR | M | N/P | M |
+----------------+-------+-------+--------------------+
| S46-Rule | M | M | N/P |
+----------------+-------+-------+--------------------+
| S46-DMR | N/P | M | N/P |
+----------------+-------+-------+--------------------+
| S46-V4V6Bind | N/P | N/P | O |
+----------------+-------+-------+--------------------+
| S46-PORTPARAMS | O | O | O |
+----------------+-------+-------+--------------------+
M - Mandatory, O - Optional, N/P - Not Permitted
4.6. Softwire46-Priority Attribute
The S46-Priority Attribute is structured as follows:
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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 | S46-option-code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | S46-option-code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
TBD
Length
2 + the length of the S46-option-code(s) specified in octets
S46-option-code
16-bit IANA-registered option code of the DHCPv6 option that
is used to identify the softwire mechanisms. S46 mechanisms
are prioritized in the appearance order of the S46-option-code(s)
in the Softwire46-Priority Attribute. A Softwire46-Priority
Attribute MUST contain at least one S46-option-code. The option
codes of the corresponding S46 mechanisms are listed in
Section 6.1.
4.7. Table of attributes
The following table provides a guide to which attributes may be found
in which kinds of packets, and in what quantity.
Request Accept Reject Challenge Accounting # Attribute
Request
0-1 0-1 0 0 0-1 TBD1 Softwire46-
Configuration
0-1 0-1 0 0 0-1 TBD2 Softwire46-
Priority
0-1 0-1 0 0 0-1 1 User-Name
0-1 0 0 0 0 2 User-Password
0-1 0-1 0 0 0-1 6 Service-Type
0-1 0-1 0-1 0-1 0-1 80 Message-Authenticator
The following table defines the meaning of the above table entries.
0 This attribute MUST NOT be present in packet.
0+ Zero or more instances of this attribute MAY be present in
packet.
0-1 Zero or one instance of this attribute MAY be present in
packet.
1 Exactly one instance of this attribute MUST be present in
packet.
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5. Diameter Considerations
S46 Configuration using Diameter [RFC6733] is specified in [RFC7678].
6. IANA Considerations
This document requires the assignment of two new RADIUS Attribute
Type in the "Radius Types" registry (currently located at
http://www.iana.org/assignments/radius-types for the following
attributes:
o Softwire46-Configuration Attribute TBD1
o Softwire46-Priority Attribute TBD2
IANA should allocate the numbers from the standard RADIUS Attributes
space using the "IETF Review" policy [RFC5226].
6.1. S46 Mechanisms and Their Identifying Option Codes
The Softwire46-Priority Attribute defines a 16-bit S46-option-code
field, for which IANA is to create and maintain a new registry
entitled "Option Codes Permitted in the Softwire46-Priority
Attribute". This document requires IANA to register four option
codes of the Softwire46 mechanisms permitted to be included in the
Softwire46-Priority Attribute. Additional options may be added to
this list in the future using the IETF Review process described in
Section 4.1 of [RFC5226].
The following table shows the option codes that are required and the
S46 mechanisms that they represent. The option code for DS-Lite is
derived from the IANA allocated RADIUS Attribute Type value for DS-
Lite [RFC6519]. The option codes for MAP-E, MAP-T and Lightweight
4over6 need to be determined. The option codes for MAP-E, MAP-T, and
Lightweight 4over6 should also be used as the option Type values for
the MAP-E, MAP-T, and Lightweight 4over6 Container Options defined in
Section 4.2.
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+-------------+------------------+-----------+
| Option Code | S46 Mechanism | Reference |
+-------------+------------------+-----------+
| TBD1 | MAP-E | RFC7597 |
+-------------+------------------+-----------+
| TBD2 | MAP-T | RFC7599 |
+-------------+------------------+-----------+
| TBD3 |Lightweight 4over6| RFC7596 |
+-------------+------------------+-----------+
| 144 | DS-Lite | RFC6519 |
+--------------------------------+-----------+
Table 1: Option Codes to S46 Mechanisms
7. Security Considerations
Known security vulnerabilities of the RADIUS protocol are discussed
in [RFC2607], [RFC2865], and[RFC2869]. Use of IPsec [RFC4301] for
providing security when RADIUS is carried in IPv6 is discussed in
[RFC3162].
A malicious user may use MAC address spoofing on the shared password
that has been preconfigured on the DHCPv6 server to get unauthorized
configuration information.
Security considerations for MAP specific between the MAP CE and the
BNG are discussed in [RFC7597]. Security considerations for
Lightweight 4over6 are discussed in [RFC7596]. Security
considerations for DHCPv6-Based S46 Prioritization Mechanism are
discussed in [RFC8026]. Furthermore, generic DHCPv6 security
mechanisms can be applied DHCPv6 intercommunication between the CE
and the BNG.
Security considerations for the Diameter protocol are discussed in
[RFC6733].
8. Acknowledgements
The authors would like to thank the valuable comments made by Peter
Lothberg, Wojciech Dec, Ian Farrer and Suresh Krishnan for this
document. This document was merged with draft-sun-softwire-lw4over6-
radext-01, thanks to everyone who contributed to this draft.
This document was produced using the xml2rfc tool [RFC7991].
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9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<http://www.rfc-editor.org/info/rfc2865>.
[RFC3162] Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6",
RFC 3162, DOI 10.17487/RFC3162, August 2001,
<http://www.rfc-editor.org/info/rfc3162>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>.
[RFC5080] Nelson, D. and A. DeKok, "Common Remote Authentication
Dial In User Service (RADIUS) Implementation Issues and
Suggested Fixes", RFC 5080, DOI 10.17487/RFC5080, December
2007, <http://www.rfc-editor.org/info/rfc5080>.
[RFC6158] DeKok, A., Ed. and G. Weber, "RADIUS Design Guidelines",
BCP 158, RFC 6158, DOI 10.17487/RFC6158, March 2011,
<http://www.rfc-editor.org/info/rfc6158>.
[RFC6929] DeKok, A. and A. Lior, "Remote Authentication Dial In User
Service (RADIUS) Protocol Extensions", RFC 6929,
DOI 10.17487/RFC6929, April 2013,
<http://www.rfc-editor.org/info/rfc6929>.
[RFC8026] Boucadair, M. and I. Farrer, "Unified IPv4-in-IPv6
Softwire Customer Premises Equipment (CPE): A DHCPv6-Based
Prioritization Mechanism", RFC 8026, DOI 10.17487/RFC8026,
November 2016, <http://www.rfc-editor.org/info/rfc8026>.
9.2. Informative References
[RFC2607] Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
Implementation in Roaming", RFC 2607,
DOI 10.17487/RFC2607, June 1999,
<http://www.rfc-editor.org/info/rfc2607>.
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[RFC2869] Rigney, C., Willats, W., and P. Calhoun, "RADIUS
Extensions", RFC 2869, DOI 10.17487/RFC2869, June 2000,
<http://www.rfc-editor.org/info/rfc2869>.
[RFC3580] Congdon, P., Aboba, B., Smith, A., Zorn, G., and J. Roese,
"IEEE 802.1X Remote Authentication Dial In User Service
(RADIUS) Usage Guidelines", RFC 3580,
DOI 10.17487/RFC3580, September 2003,
<http://www.rfc-editor.org/info/rfc3580>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <http://www.rfc-editor.org/info/rfc4301>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011,
<http://www.rfc-editor.org/info/rfc6333>.
[RFC6346] Bush, R., Ed., "The Address plus Port (A+P) Approach to
the IPv4 Address Shortage", RFC 6346,
DOI 10.17487/RFC6346, August 2011,
<http://www.rfc-editor.org/info/rfc6346>.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, DOI 10.17487/RFC6519, February
2012, <http://www.rfc-editor.org/info/rfc6519>.
[RFC6733] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
Ed., "Diameter Base Protocol", RFC 6733,
DOI 10.17487/RFC6733, October 2012,
<http://www.rfc-editor.org/info/rfc6733>.
[RFC7596] Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
Farrer, "Lightweight 4over6: An Extension to the Dual-
Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
July 2015, <http://www.rfc-editor.org/info/rfc7596>.
[RFC7597] Troan, O., Ed., Dec, W., Li, X., Bao, C., Matsushima, S.,
Murakami, T., and T. Taylor, Ed., "Mapping of Address and
Port with Encapsulation (MAP-E)", RFC 7597,
DOI 10.17487/RFC7597, July 2015,
<http://www.rfc-editor.org/info/rfc7597>.
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[RFC7598] Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
Configuration of Softwire Address and Port-Mapped
Clients", RFC 7598, DOI 10.17487/RFC7598, July 2015,
<http://www.rfc-editor.org/info/rfc7598>.
[RFC7599] Li, X., Bao, C., Dec, W., Ed., Troan, O., Matsushima, S.,
and T. Murakami, "Mapping of Address and Port using
Translation (MAP-T)", RFC 7599, DOI 10.17487/RFC7599, July
2015, <http://www.rfc-editor.org/info/rfc7599>.
[RFC7678] Zhou, C., Taylor, T., Sun, Q., and M. Boucadair,
"Attribute-Value Pairs for Provisioning Customer Equipment
Supporting IPv4-Over-IPv6 Transitional Solutions",
RFC 7678, DOI 10.17487/RFC7678, October 2015,
<http://www.rfc-editor.org/info/rfc7678>.
[RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
RFC 7991, DOI 10.17487/RFC7991, December 2016,
<http://www.rfc-editor.org/info/rfc7991>.
Additional Authors
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Qiong Sun
China Telecom
Beijing China
Email: sunqiong@ctbri.com.cn
Qi Sun
Tsinghua University
Department of Computer Science, Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: sunqibupt@gmail.com
Cathy Zhou
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
Email: cathy.zhou@huawei.com
Tina Tsou
Huawei Technologies(USA)
2330 Central Expressway
Santa Clara, CA 95050
USA
Email: Tina.Tsou.Zouting@huawei.com
ZiLong Liu
Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-6278-5822
Email: liuzilong8266@126.com
Yong Cui
Tsinghua University
Beijing 100084
P.R.China
Phone: +86-10-62603059
Email: yong@csnet1.cs.tsinghua.edu.cn
Authors' Addresses
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Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: jiangsheng@huawei.com
Yu Fu
CNNIC
No.4 South 4th Street, Zhongguancun
Hai-Dian District, Beijing, 100190
P.R. China
Email: fuyu@cnnic.cn
Bing Liu
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: leo.liubing@huawei.com
Peter Deacon
IEA Software, Inc.
P.O. Box 1170
Veradale, WA 99037
USA
Email: peterd@iea-software.com
Chongfeng Xie
China Telecom
Beijing
P.R. China
Email: xiechf.bri@chinatelecom.cn
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Tianxiang Li
Tsinghua University
Beijing 100084
P.R.China
Email: peter416733@gmail.com
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