DHCPv6 Options for configuration of Softwire Address and Port Mapped Clients
draft-ietf-softwire-map-dhcp-06
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7598.
|
|
|---|---|---|---|
| Authors | Tomek Mrugalski , Ole Trøan , Wojciech Dec , Congxiao Bao , Leaf Yeh , Xiaohong Deng | ||
| Last updated | 2013-11-19 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
GENART Last Call review
(of
-08)
by Brian Carpenter
On the Right Track
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 7598 (Proposed Standard) | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-softwire-map-dhcp-06
Softwire WG T. Mrugalski
Internet-Draft ISC
Intended status: Standards Track O. Troan, Ed.
Expires: May 23, 2014 Cisco Systems
W. Dec
Cisco
C. Bao
Tsinghua University
L. Yeh
Freelancer Technologies
X. Deng
November 19, 2013
DHCPv6 Options for configuration of Softwire Address and Port Mapped
Clients
draft-ietf-softwire-map-dhcp-06
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 May 23, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
Mrugalski, et al. Expires May 23, 2014 [Page 1]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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 Softwire 46 DHCPv6 Options . . . . . . . . . . . . . . 4
4.1. S46 Rule Option . . . . . . . . . . . . . . . . . . . . . 4
4.2. S46 BR Option . . . . . . . . . . . . . . . . . . . . . . 6
4.3. S46 DMR Option . . . . . . . . . . . . . . . . . . . . . 7
4.4. S46 IPv4 Address 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 . . . . . . . 10
6. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 11
7. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
A number of architectural solution proposals discussed in the IETF
Softwires Working Group use Address and Port (A+P) as their
technology base in providing IPv4 connectivity service to end users
using CE devices across a service provider's IPv6 network, while
allowing for shared or dedicated IPv4 addressing of the CEs.
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
Mrugalski, et al. Expires May 23, 2014 [Page 2]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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. 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 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 (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,
while MAP-T uses NAT64 [RFC6145] based translation. Lightweight
4over6 is a hub and spoke IPv4 over IPv6 tunnel 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 the softwire IPv4 address, prefix or shared IPv4
Mrugalski, et al. Expires May 23, 2014 [Page 3]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
address, port set and any authorisation 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 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 the all 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 DHCPv6 message, without encapsulating them in the
corresponding container options.
The document is organized with the common sub-options described
first, and then the three container options. Some of the sub-options
are mandatory in some of the containers and some are optional, or not
permitted at all.
4. Common Softwire 46 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 is
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 uses the OPTION_S46_RULE, while for Lightweight 4over6, the
OPTION_S46_IPV4ADDRESS option is used. 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 conveyed via the OPTION_S46_DMR option.
Optionally all mechanisms can include the 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 BMR and FMR.
Mrugalski, et al. Expires May 23, 2014 [Page 4]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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 is explained in Figure 2.
o ea-len: 8 bits long field that specifies the Embedded-Address (EA)
bit length. Values allowed 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. Zero-padded.
o prefix6-len: 8 bits long field expressing the prefix length of the
IPv6 prefix specified in the rule-ipv6-prefix field.
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:
Mrugalski, et al. Expires May 23, 2014 [Page 5]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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 only a BMR. Note: BMR rules can be also FMR
rules by setting the F flag. BMR rules are determined by a match
of the Rule-IPv6-prefix against the CPE's prefix(es).
It is expected that in a typical mesh deployment scenarios, there
will be a single BMR, which could also be designated as an FMR using
the F-Flag.
4.2. S46 BR Option
S46 BR Option is used to convey the IPv6 address of the Border Relay.
Figure 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
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.
Mrugalski, et al. Expires May 23, 2014 [Page 6]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
4.3. S46 DMR Option
S46 DMR Option is used to convey values for Default Mapping Rule.
Figure 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 that specifies the IPv6
prefix or address for the S46 BR. This field is padded with
follow up zeros to the nearest octet boundary when dmr-prefix6-len
is not divisible by 8.
4.4. S46 IPv4 Address Option
The IPv4 address Option MAY be used to specify the full or shared
IPv4 address of the CE.
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_IPV4ADDRESS | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ipv4-address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. S46_IPV4ADDRESS-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: S46 IPv4 address Option
Mrugalski, et al. Expires May 23, 2014 [Page 7]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
o option-code: OPTION_S46_IPV4ADDRESS (TBD4)
o option-length: 4
o ipv4-address: A fixed field of 4 octets specifying an IPv4
address.
o S46_IPV4ADDRESS-options: a variable field that may contain zero or
more options that specify additional parameters e.g. a Port
Parameter 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 detailed description of
MAP algorithm that explains meaning of all parameters.
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
(A-bits), as per section 5.1.1 in [I-D.ietf-softwire-map].
Allowed values are between 0 and 16, 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 valid of PSID. Subsequently,
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 2-octets field is 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 formula for
this check is "prefix4-len + ea-len = 32" and serves to ensure that
Mrugalski, et al. Expires May 23, 2014 [Page 8]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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_IPV4ADDRESS 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 | - |
| OPTION_S46_BR | M | - | M |
| OPTION_S46_PORTPARAMS | O | O | O |
| OPTION_S46_DMR | - | M | - |
| OPTION_S46_IPV4ADDRESS | - | - | O |
+------------------------+-------+-------+--------------------+
M - Mandatory, O - Optional, - - Not Applicable
Table 1: Option to Container Mappings
5.1. Softwire46 MAP-E Container Option
This 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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 encapsulates those options that are
specific to this MAP Option. Currently there are two options
specified for the OPTION_S46_CONT_MAPE option, OPTION_S46_RULE and
Mrugalski, et al. Expires May 23, 2014 [Page 9]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
OPTION_S46_BR. There MUST be at least one OPTION_S46_RULE option and
at least one OPTION_S46_BR.
Other options suitable for 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
This 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.
The encapsulated options field encapsulates those options that are
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
This 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) .
. .
Mrugalski, et al. Expires May 23, 2014 [Page 10]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
+---------------------------------------------------------------+
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 encapsulates those options that are
specific to this Lightweight 4over6 Option. Currently there are two
options specified for the OPTION_S46_CONT_LW option,
OPTION_S46_IPV4ADDRESS and OPTION_S46_BR. There MUST be at most one
OPTION_S46_IPV4ADDRESS option and at least one OPTION_S46_BR option.
6. DHCPv6 Server Behavior
RFC 3315 Section 17.2.2 [RFC3315] describes how a DHCPv6 client and
server negotiate configuration values using the ORO. As a
convenience to the reader, we mention here that a server will by
default not reply with a Softwire 46 Container Option if the client
has not explicitly enumerated it 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, it is configured for.
7. DHCPv6 Client Behavior
A S46 CE acting as DHCPv6 client will request S46 configuration to be
assigned by the DHCPv6 server located in the IPv6 network. Such a
client SHOULD include the S46 Container option(s) that it is
interested in, 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.
Mrugalski, et al. Expires May 23, 2014 [Page 11]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
The behavior of a client supporting multiple Softwire 46 mechanisms,
is out of scope of this document. See:
[I-D.ietf-softwire-unified-cpe] for how to prioritise and handle
multiple simulatanous mechanisms in use.
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.
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
completely possible that the configuration is being delivered by a
third party (Man In The Middle). As such, there is no basis to trust
that the access over the MAP can be trusted, and it should not
therefore 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].
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_IPV4ADDRESS, TBD5 for
OPTION_S46_PORTPARAMS, and TBD6 for OPTION_S46_CONT_MAPE, TBD7 for
OPTION_S46_CONT_MAPT and 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
Mrugalski, et al. Expires May 23, 2014 [Page 12]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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.
Authors would like to thank Bernie Volz for his 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.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
11.2. Informative References
[I-D.ietf-dhc-option-guidelines]
Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
draft-ietf-dhc-option-guidelines-14 (work in progress),
September 2013.
[I-D.ietf-dhc-secure-dhcpv6]
Jiang, S. and S. Shen, "Secure DHCPv6 Using CGAs", draft-
ietf-dhc-secure-dhcpv6-07 (work in progress), September
2012.
[I-D.ietf-homenet-arch]
Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil,
"IPv6 Home Networking Architecture Principles", draft-
ietf-homenet-arch-11 (work in progress), October 2013.
[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.
Mrugalski, et al. Expires May 23, 2014 [Page 13]
Internet-Draft DHCPv6 for Softwire 46 CEs 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.
[I-D.mdt-softwire-map-deployment]
Sun, Q., Chen, M., Chen, G., Sun, C., Tsou, T., and S.
Perreault, "Mapping of Address and Port (MAP) - Deployment
Considerations", draft-mdt-softwire-map-deployment-02
(work in progress), June 2012.
[I-D.townsley-troan-ipv6-ce-transitioning]
Townsley, M. and O. Troan, "Basic Requirements for
Customer Edge Routers - multihoming and transition",
draft-townsley-troan-ipv6-ce-transitioning-02 (work in
progress), December 2011.
[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.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165, RFC
6335, August 2011.
Mrugalski, et al. Expires May 23, 2014 [Page 14]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
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/
Ole Troan (editor)
Cisco Systems
Philip Pedersens vei 1
Lysaker 1366
Norway
Email: ot@cisco.com
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
Leaf Y. Yeh
Freelancer Technologies
Shenzhen, Guangdong
P. R. China
Email: leaf.yeh.sdo@gmail.com
Mrugalski, et al. Expires May 23, 2014 [Page 15]
Internet-Draft DHCPv6 for Softwire 46 CEs November 2013
Xiaohong Deng
6 Cordelia St.
South Brisbane QLD 4101
Australia
Phone: +61 3858 3128
Email: dxhbupt@gmail.com
Mrugalski, et al. Expires May 23, 2014 [Page 16]