Softwire WG T. Mrugalski
Internet-Draft ISC
Intended status: Standards Track O. Troan
Expires: September 14, 2014 Cisco
I. Farrer
Deutsche Telekom AG
S. Perreault
Viagenie
W. Dec
Cisco
C. Bao
Tsinghua University
L. Yeh
CNNIC
X. Deng
Yingke Law Firm
March 13, 2014
DHCPv6 Options for configuration of Softwire Address and Port Mapped
Clients
draft-ietf-softwire-map-dhcp-07
Abstract
This document specifies DHCPv6 options, termed Softwire46 options,
for the provisioning of Softwire46 Customer Edge (CE) devices.
Softwire46 is a collective term used to refer to architectures based
on the notion of IPv4 Address+Port (A+P) for providing IPv4
connectivity across an IPv6 network.
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 September 14, 2014.
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Copyright Notice
Copyright (c) 2014 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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Softwire 46 Overview . . . . . . . . . . . . . . . . . . . . 3
4. Common Softwire46 DHCPv6 Options . . . . . . . . . . . . . . 4
4.1. S46 Rule Option . . . . . . . . . . . . . . . . . . . . . 5
4.2. S46 BR Option . . . . . . . . . . . . . . . . . . . . . . 6
4.3. S46 DMR Option . . . . . . . . . . . . . . . . . . . . . 7
4.4. S46 IPv4/IPv6 Address Binding Option . . . . . . . . . . 7
4.5. S46 Port Parameters Option . . . . . . . . . . . . . . . 8
5. Softwire 46 Container DHCPv6 Options . . . . . . . . . . . . 9
5.1. Softwire46 MAP-E Container Option . . . . . . . . . . . . 9
5.2. Softwire46 MAP-T Container Option . . . . . . . . . . . . 10
5.3. Softwire46 LightWeight 46 Container Option . . . . . . . 11
6. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 11
7. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
A number of architectural solution proposals discussed in the IETF
Softwire Working Group use Address and Port (A+P) as their technology
base for providing IPv4 connectivity to end users using CE devices
across a service provider's IPv6 network, while allowing for shared
or dedicated IPv4 addressing of the CEs.
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An example is Mapping of Address and Port (MAP) defined in
[I-D.ietf-softwire-map]. The MAP solution consists of one or more
MAP Border Relay (BR) routers, responsible for stateless forwarding
between a MAP IPv6 domain and an IPv4 network, and one or more MAP
Customer Edge (CE) routers, responsible for forwarding between a
user's private IPv4 network and the MAP IPv6 network domain.
Collectively, the MAP CE and BR form a domain when configured with
common service parameters. This characteristic is common to all of
the Softwire46 proposals.
To function in such a domain, a CE needs to be provisioned with the
appropriate A+P service parameters for that domain. These consist
primarily of the CE's IPv4 address and transport layer port-range(s).
Furthermore, the IPv6 transport mode (i.e. encapsulation or
translation) needs to be specified. Provisioning of other IPv4
configuration information not derived directly from the A+P service
parameters is not covered in this document. It is expected that
provisioning of other IPv4 configuration will continue to use DHCPv4
[RFC2131].
This memo specifies a set of DHCPv6 [RFC3315] options to provision
Softwire46 information to CE routers. Although the focus is to
deliver IPv4 service to an end-user network (such as a residential
home network), it can equally be applied to an individual host acting
as a CE. Configuration of the BR is out of scope of this document.
2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Softwire 46 Overview
This document describes a set of common DHCPv6 options for
configuring the MAP-E [I-D.ietf-softwire-map], MAP-T
[I-D.ietf-softwire-map-t] and Lightweight 4over6
[I-D.ietf-softwire-lw4over6] mechanisms.
MAP-E, MAP-T and Lightweight 4over6 are essentially providing the
same functionality: IPv4 service to a CE router over an IPv6 only
access network. MAP-E and MAP-T may embed parts of the IPv4 address
in IPv6 prefixes, thereby supporting many clients with a fixed set of
mapping rules and mesh mode (direct CE to CE communication). MAP-E
and MAP-T CEs may also be provisioned in hub and spoke mode, and in
1:1 mode (with no embedded address bits). The difference between
MAP-E and MAP-T is that they use different means to connect to the
IPv6 domain. MAP-E uses RFC2473 [RFC2473] IPv4 over IPv6 tunnelling,
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while MAP-T uses NAT64 [RFC6145] based translation. Lightweight
4over6 is a hub and spoke IPv4 over IPv6 tunneling mechanism, with
complete independence of IPv4 and IPv6 addressing (zero embedded
address bits).
The DHCP options described here tie the provisioning parameters, and
hence the IPv4 service itself, to the End-user IPv6 prefix lifetime.
The validity of a softwire's IPv4 address, prefix or shared IPv4
address, port set and any authorization and accounting are tied to
the lifetime of its associated End-user IPv6 prefix.
To support more than one mechanism at a time and to allow for a
possibility of transition between them, the Option Request Option
DHCPv6 [RFC3315] function is used. Each mechanism has a
corresponding DHCPv6 container option. A DHCPv6 client can request a
particular mechanism by including the option code for a particular
container option in its ORO option. The provisioning parameters for
that mechanism are expressed by embedding the common format options
within the respective container.
This approach implies that all of the provisioning options MUST
appear only within the container options. The client MUST NOT
request any of the provisioning options directly within an ORO.
Likewise, the server MUST NOT send the provisioning options directly
within a DHCPv6 message, without encapsulation in the corresponding
container option.
The document is organized with the common sub-options described
first, followed by the three container options. Some sub-options are
mandatory in some containers, some are optional and some are not
permitted at all.
4. Common Softwire46 DHCPv6 Options
The DHCPv6 protocol is used for Softwire46 CE provisioning following
regular DHCPv6 notions, with the CE assuming the role of a DHCPv6
client, and the DHCPv6 server providing options following typical
DHCPv6 server side policies. The format and usage of the options are
defined in the following sub-sections.
Each CE needs to be provisioned with enough information to calculate
its IPv4 address, IPv4 prefix or shared IPv4 address. MAP-E and
MAP-T use the OPTION_S46_RULE, while Lightweight 4over6 uses the
OPTION_S46_V4V6BIND option. A CE that needs to communicate outside
of the A+P domain also needs the address or prefix of the BR. MAP-E
and Lightweight 4over6 use the OPTION_S46_BR option to communicate
the IPv6 address of the BR. MAP-T forms an IPv6 destination address
by embedding an IPv4 destination address into the BR's IPv6 prefix
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conveyed via the OPTION_S46_DMR option. Optionally, all mechanisms
can include OPTION_S46_PORTPARAMS to specify parameters and port sets
for the port range algorithm.
4.1. S46 Rule Option
Figure 1 shows the format of the S46 Rule option used for conveying
the Basic Mapping Rule (BMR) and Forwarding Mapping Rule (FMR).
A server MAY send more than one S46 Rule Option in a container, if it
is configured to do so. Clients MUST NOT send a S46 Rule 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_RULE | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags | ea-len | prefix4-len | ipv4-prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| (continued) | prefix6-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ipv6-prefix |
| (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. S46_RULE-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: S46 Rule Option
o option-code: OPTION_S46_RULE (TBD1)
o option-length: length of the option, excluding option-code and
option-length fields, including length of all encapsulated
options, expressed in bytes.
o flags: 8 bits long field carrying flags applicable to the rule.
The meaning of specific bits are explained in Figure 2.
o ea-len: 8 bits long field that specifies the Embedded-Address (EA)
bit length. Allowed values range from 0 to 48.
o prefix4-len: 8 bits long field expressing the prefix length of the
IPv4 prefix specified in the rule-ipv4-prefix field. Valid values
0 to 32.
o ipv4-prefix: a fixed length 32 bit field that specifies the IPv4
prefix for the S46 rule. The bits in the prefix after prefix4-len
number of bits are reserved and MUST be initialized to zero by the
sender and ignored by the receiver.
o prefix6-len: 8 bits long field expressing the length of the IPv6
prefix specified in the rule-ipv6-prefix field.
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o ipv6-prefix: a variable length field that specifies the IPv6
domain prefix for the S46 rule. The field is padded with follow
up zero bits up to the nearest octet boundary when prefix6-len is
not divisible by 8.
o S46_RULE-options: a variable field that may contain zero or more
options that specify additional parameters for this S46 rule, e.g.
a Port Parameter Option.
The Format of the S46 Rule Flags field is:
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|Reserved |F|
+-+-+-+-+-+-+-+-+
Figure 2: S46 Rule Flags
o Reserved: 7-bits reserved for future use as flags.
o F-Flag: 1 bit field that specifies whether the rule is to be used
for forwarding (FMR). If set, this rule is used as a FMR, if not
set this rule is a BMR. Note: A BMR rule can also be an FMR rule
by setting the F flag. The BMR rule is determined by a match of
the Rule-IPv6-prefix against the CPE's prefix(es).
It is expected that in a typical mesh deployment scenario, there will
be a single BMR, which could also be designated as an FMR using the
F-Flag.
4.2. S46 BR Option
The S46 BR Option is used to convey the IPv6 address of the Border
Relay. Figure 4 shows the format of the BR 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_BR | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| br-ipv6-address |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: S46 DMR Option
o option-code: OPTION_S46_BR (TBD2)
o option-length: 16
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o br-ipv6-address: a fixed length field of 16 octets that specifies
the IPv6 address for the S46 BR.
BR redundancy can be implemented by using an anycast address for the
BR IPv6 address. Multiple BR options MAY be included in the
container; this document does not further explore the use of multiple
BR IPv6 addresses.
4.3. S46 DMR Option
The S46 DMR Option is used to convey values for the Default Mapping
Rule (DMR). Figure 4 shows the format of the MAP Rule option used
for conveying a DMR.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_DMR | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|dmr-prefix6-len| dmr-ipv6-prefix |
+-+-+-+-+-+-+-+-+ (variable length) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: S46 DMR Option
o option-code: OPTION_S46_DMR (TBD3)
o option-length: 1 + length of dmr-ipv6-prefix specified in bytes.
o dmr-prefix6-len: 8 bits long field expressing the bit mask length
of the IPv6 prefix specified in the dmr-ipv6-prefix field.
o dmr-ipv6-prefix: a variable length field specifying the IPv6
prefix or address for the S46 BR. This field is right padded with
zeros to the nearest octet boundary when dmr-prefix6-len is not
divisible by 8.
4.4. S46 IPv4/IPv6 Address Binding Option
The IPv4 address Option MAY be used to specify the full or shared
IPv4 address of the CE. The IPv6 prefix field is used by the CE to
identify the correct prefix to use for the tunnel source.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_V4V6BIND | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ipv4-address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|bindprefix6-len| bind-ipv6-prefix |
+-+-+-+-+-+-+-+-+ (variable length) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. S46_V4V6BIND-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: S46 IPv4/IPv6 Address Binding Option
o option-code: OPTION_S46_V4V6BIND (TBD4)
o option-length: 4
o ipv4-address: A fixed field of 4 octets specifying an IPv4
address.
o bindprefix6-len: 8 bits long field expressing the bit mask length
of the IPv6 prefix specified in the bind-ipv6-prefix field.
o bind-ipv6-prefix: a variable length field specifying the IPv6
prefix or address for the S46. This field is right padded with
zeros to the nearest octet boundary when bindprefix6-len is not
divisible by 8.
o S46_V4V6BIND-options: a variable field that may contain zero or
more options that specify additional parameters e.g. a Port
Parameters Option.
4.5. S46 Port Parameters Option
The Port Parameters Option specifies optional Rule Port Parameters
that MAY be provided as part of the Mapping Rule for CEs using the
MAP algorithm.
See [I-D.ietf-softwire-map], Section 5.1 for a description of MAP
algorithm, explaining all of the parameters in detail.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_PORTPARAMS | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| offset | PSID-len | PSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: S46 Port Parameters Option
o option-code: OPTION_S46_PORTPARAMS (TBD5)
o option-length: 4
o offset: (PSID offset) 8 bits long field that specifies the numeric
value for the S46 algorithm's excluded port range/offset bits
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(A-bits), as per section 5.1.1 of [I-D.ietf-softwire-map].
Allowed values are between 0 and 15, with the default value being
6.
o PSID-len: Bit length value of 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 the value of the Port Set
Identifier (PSID). Consequently, the address sharing ratio would
be 2^k.
o PSID: 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 field contain the PSID value.
The remaining (16-k) bits on the right are padding zeros.
When receiving the Port Parameters option with an explicit PSID, the
client MUST use this explicit PSID in configuring its MAP interface.
If the conveyed IPv4 address is not 32 bit-long, the option MUST be
discarded. The formula for this check is "prefix4-len + ea-len = 32"
and serves to ensure that the explicit PSID is only applied to
configurations with a completely formed IPv4 address.
The OPTION_S46_PORTPARAMS option MUST be encapsulated in a
OPTION_S46_RULE option or an OPTION_S46_V4V6BIND option. It MUST NOT
appear directly within a container option.
5. Softwire 46 Container DHCPv6 Options
+-----------------------+-------+-------+--------------------+
| Option | MAP-E | MAP-T | Lightweight 4over6 |
+-----------------------+-------+-------+--------------------+
| OPTION_S46_RULE | M | M | N/A |
| OPTION_S46_BR | M | N/A | M |
| OPTION_S46_PORTPARAMS | O | O | O |
| OPTION_S46_DMR | N/A | M | N/A |
| OPTION_S46_V4V6BIND | N/A | N/A | O |
+-----------------------+-------+-------+--------------------+
M - Mandatory, O - Optional, N/A - Not Applicable
Table 1: Option to Container Mappings
5.1. Softwire46 MAP-E Container Option
The MAP-E Container Option specifies the container used to group all
rules and optional port parameters for a specified domain.
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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_CONT_MAPE | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. encapsulated-options (variable length) .
. .
+---------------------------------------------------------------+
Figure 7: MAP-E Container Option
o option-code: OPTION_S46_CONT_MAPE (TBD6)
o option-length: Length of encapsulated options
o encapsulated-options: options associated with this Softwire46
MAP-E domain.
The encapsulated options field conveys options specific to this MAP
Option. Currently there are two options specified for the
OPTION_S46_CONT_MAPE option, OPTION_S46_RULE and OPTION_S46_BR.
There MUST be at least one OPTION_S46_RULE option and at least one
OPTION_S46_BR.
Other options applicable to a domain may be defined in the future. A
DHCP message MAY include multiple S46 MAPE Container Options
(representing multiple domains).
5.2. Softwire46 MAP-T Container Option
The MAP-T Container Option specifies the container used to group all
rules and optional port parameters for a specified domain.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_CONT_MAPT | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. encapsulated-options (variable length) .
. .
+---------------------------------------------------------------+
Figure 8: MAP-E Container Option
o option-code: OPTION_S46_CONT_MAPT (TBD7)
o option-length: Length of encapsulated options
o encapsulated-options: options associated with this Softwire46
MAP-T domain.
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The encapsulated options field conveys options specific to this MAP
Option. Currently there are two options specified for the
OPTION_S46_CONT_MAPT option, OPTION_S46_RULE and OPTION_S46_DMR
options. There MUST be at least one OPTION_S46_RULE option and
exactly one OPTION_S46_DMR.
5.3. Softwire46 LightWeight 46 Container Option
The LW46 Container Option specifies the container used to group all
rules and optional port parameters for a specified domain.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_S46_CONT_LW | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ encapsulated-options (variable length) .
. .
+---------------------------------------------------------------+
Figure 9: LW46 Container Option
o option-code: OPTION_S46_CONT_LW (TBD8)
o option-length: Length of encapsulated options
o encapsulated-options: options associated with this Softwire46
domain.
The encapsulated options field conveys options specific to this
Lightweight 4over6 Option. Currently there are two options specified
for the OPTION_S46_CONT_LW option, OPTION_S46_V4V6BIND and
OPTION_S46_BR. There MUST be at most one OPTION_S46_V4V6BIND option
and at least one OPTION_S46_BR option.
6. DHCPv6 Server Behavior
[RFC3315] Section 17.2.2 describes how a DHCPv6 client and server
negotiate configuration values using the ORO. As a convenience to
the reader, we mention here that by default, a server will not reply
with a Softwire 46 Container Option if the client has not explicitly
enumerated one in its Option Request Option.
A CE router may support several (or all) of the mechanisms mentioned
here. In the case where a client requests multiple mechanisms in its
ORO option, the server SHOULD reply with all the corresponding
Softwire 46 Container options, enumerated in the Option Request
Option, the the server is configured for.
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7. DHCPv6 Client Behavior
An S46 CE acting as DHCPv6 client will request S46 configuration
parameters from the DHCPv6 server located in the IPv6 network. Such
a client SHOULD include the S46 Container option(s) that it is
configured for in its ORO in SOLICIT, REQUEST, RENEW, REBIND and
INFORMATION-REQUEST messages.
When processing received S46 container options the following
behaviour is expected:
o A client MUST support processing multiple received OPTION_S46_RULE
options in a container OPTION_S46_CONT_MAPE or
OPTION_S46_CONT_MAPT option
o A client receiving an unsupported S46 option, or an invalid
parameter value SHOULD discard that S46 Container option and log
the event.
The behavior of a client supporting multiple Softwire 46 mechanisms,
is out of scope of this document. [I-D.ietf-softwire-unified-cpe]
describes client behaviour for the prioritization and handling of
multiple mechanisms simultaneously.
Note that system implementing CE functionality may have multiple
network interfaces, and these interfaces may be configured
differently; some may be connected to networks that call for MAP, and
some may be connected to networks that are using normal dual stack or
other means. The CE system should approach this specification on an
interface-by-interface basis. For example, if the CE system is MAP
capable and is attached to multiple networks that provide the MAP
Mapping Rule Option, then the CE system MUST configure a MAP service
(i.e. a translation or encapsulation) for each interface separately
as each MAP provides IPv4 connectivity for each distinct interface.
The means to bind a MAP configuration to a given interface in a
multiple interfaces device are out of scope of this document.
8. Security Considerations
Implementation of this document does not present any new security
issues, but as with all DHCPv6-derived configuration state, it is
possible that configuration is actually being delivered by a third
party (Man In The Middle). As such, there is no basis on which
access over MAP or lw4o6 can be trusted. Therefore, softwires should
not bypass any security mechanisms such as IP firewalls.
Readers concerned with security of MAP provisioning over DHCPv6 are
encouraged to read [I-D.ietf-dhc-secure-dhcpv6].
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Section 11 of [I-D.ietf-softwire-map] discusses security issues of
the MAP mechanism.
Section 23 of [RFC3315] discusses DHCPv6-related security issues.
9. IANA Considerations
IANA is kindly requested to allocate the following DHCPv6 option
codes:
TBD1 for OPTION_S46_RULE
TBD2 for OPTION_S4_BR
TBD3 for OPTION_S46_DMR
TBD4 for OPTION_S46_V4V6BIND
TBD5 for OPTION_S46_PORTPARAMS
TBD6 for OPTION_S46_CONT_MAPE
TBD7 for OPTION_S46_CONT_MAPT
TBD8 for OPTION_S46_CONT_LW
All values should be added to the DHCPv6 option code space defined in
Section 24.3 of [RFC3315].
10. Acknowledgements
This document was created as a product of a MAP design team.
Following people were members of that team: Congxiao Bao, Mohamed
Boucadair, Gang Chen, Maoke Chen, Wojciech Dec, Xiaohong Deng, Jouni
Korhonen, Xing Li, Satoru Matsushima, Tomasz Mrugalski, Tetsuya
Murakami, Jacni Qin, Necj Scoberne, Qiong Sun, Tina Tsou, Dan Wing,
Leaf Yeh and Jan Zorz.
The authors would like to thank Bernie Volz and Tom Taylor for their
insightful comments and suggestions.
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
11.2. Informative References
[I-D.ietf-dhc-secure-dhcpv6]
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Internet-Draft DHCPv6 for Softwire 46 CEs March 2014
Jiang, S. and S. Shen, "Secure DHCPv6 Using CGAs", draft-
ietf-dhc-secure-dhcpv6-07 (work in progress), September
2012.
[I-D.ietf-softwire-lw4over6]
Cui, Y., Qiong, Q., Boucadair, M., Tsou, T., Lee, Y., and
I. Farrer, "Lightweight 4over6: An Extension to the DS-
Lite Architecture", draft-ietf-softwire-lw4over6-03 (work
in progress), November 2013.
[I-D.ietf-softwire-map-t]
Li, X., Bao, C., Dec, W., Troan, O., Matsushima, S., and
T. Murakami, "Mapping of Address and Port using
Translation (MAP-T)", draft-ietf-softwire-map-t-04 (work
in progress), September 2013.
[I-D.ietf-softwire-map]
Troan, O., Dec, W., Li, X., Bao, C., Matsushima, S.,
Murakami, T., and T. Taylor, "Mapping of Address and Port
with Encapsulation (MAP)", draft-ietf-softwire-map-08
(work in progress), August 2013.
[I-D.ietf-softwire-unified-cpe]
Boucadair, M., Farrer, I., Perreault, S., and S.
Sivakumar, "Unified IPv4-in-IPv6 Softwire CPE", draft-
ietf-softwire-unified-cpe-01 (work in progress), May 2013.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, December 1998.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
Authors' Addresses
Tomasz Mrugalski
Internet Systems Consortium, Inc.
950 Charter Street
Redwood City, CA 94063
USA
Phone: +1 650 423 1345
Email: tomasz.mrugalski@gmail.com
URI: http://www.isc.org/
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Ole Troan
Cisco Systems, Inc.
Philip Pedersens vei 1
Lysaker 1366
Norway
Email: ot@cisco.com
Ian Farrer
Deutsche Telekom AG
CTO-ATI, Landgrabenweg 151
Bonn, NRW 53227
Germany
Email: ian.farrer@telekom.de
Simon Perreault
Viagenie
246 Aberdeen
Quebec, QC G1R 2E1
Canada
Phone: +1 418 656 9254
Email: simon.perreault@viagenie.ca
Wojciech Dec
Cisco Systems, Inc.
The Netherlands
Email: wdec@cisco.com
URI: http://cisco.com
Congxiao Bao
CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University
Beijing 100084
CN
Phone: +86 10-62785983
Email: congxiao@cernet.edu.cn
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Leaf Y. Yeh
CNNIC
4, South 4th Street, Zhong_Guan_Cun
Beijing 100190
P. R. China
Email: leaf.yeh.sdo@gmail.com
Xiaohong Deng
Yingke Law Firm
6 Floor, C Block, DaCheng International Center Chaoyang District
Beijing 100124
China
Phone: +61 3858 3128
Email: dxhbupt@gmail.com
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