Internet DRAFT - draft-zhou-dime-4over6-provisioning
draft-zhou-dime-4over6-provisioning
Internet Engineering Task Force C. Zhou
Internet-Draft Huawei Technologies
Intended status: Standards Track T. Taylor
Expires: March 27, 2015 PT Taylor Consulting
Q. Sun
China Telecom
M. Boucadair
France Telecom
September 23, 2014
Attribute-Value Pairs For Provisioning Customer Equipment Supporting
IPv4-Over-IPv6 Transitional Solutions
draft-zhou-dime-4over6-provisioning-05
Abstract
During the transition from IPv4 to IPv6, customer equipment may have
to support one of the various transition methods that have been
defined for carrying IPv4 packets over IPv6. This document
enumerates the information that needs to be provisioned on a customer
edge router to support a list of transition techniques based on
tunneling IPv4 in IPv6, with a view to defining reusable components
for a reasonable transition path between these techniques. To the
extent that the provisioning is done dynamically, AAA support is
needed to provide the information to the network server responsible
for passing the information to the customer equipment. This document
specifies Diameter (RFC 6733) attribute-value pairs to be used for
that purpose.
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 March 27, 2015.
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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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Description of the Parameters Required By Each Transition
Method . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Parameters For Dual-Stack Lite (DS-Lite) . . . . . . . . 4
2.2. Light Weight IPv4 Over IPv6 (LW4over6) . . . . . . . . . 5
2.3. Port Set Specification . . . . . . . . . . . . . . . . . 5
2.4. Mapping of Address and Port with Encapsulation (MAP-E) . 6
2.5. Parameters For Multicast . . . . . . . . . . . . . . . . 7
2.6. Summary and Discussion . . . . . . . . . . . . . . . . . 7
3. Attribute-Value Pair Definitions . . . . . . . . . . . . . . 8
3.1. IP-Prefix-Length AVP . . . . . . . . . . . . . . . . . . 8
3.2. Border-Router-Name AVP . . . . . . . . . . . . . . . . . 8
3.3. 64-Multicast-Attributes AVP . . . . . . . . . . . . . . . 9
3.3.1. ASM-Prefix64 AVP . . . . . . . . . . . . . . . . . . 9
3.3.2. SSM-Prefix64 AVP . . . . . . . . . . . . . . . . . . 10
3.3.3. Delegated-IPv6-Prefix AVP As uPrefix64 . . . . . . . 10
3.4. Tunnel-Source-Pref-Or-Addr AVP . . . . . . . . . . . . . 10
3.4.1. Delegated-IPv6-Prefix As the IPv6 Binding Prefix . . 11
3.4.2. Tunnel-Source-IPv6-Address AVP . . . . . . . . . . . 11
3.5. Port-Set-Identifier . . . . . . . . . . . . . . . . . . . 11
3.6. LW4over6-Binding . . . . . . . . . . . . . . . . . . . . 12
3.7. MAP-E-Attributes . . . . . . . . . . . . . . . . . . . . 12
3.8. MAP-Mapping-Rule . . . . . . . . . . . . . . . . . . . . 13
3.8.1. Rule-IPv4-Addr-Or-Prefix AVP . . . . . . . . . . . . 14
3.8.2. Rule-IPv6-Prefix AVP . . . . . . . . . . . . . . . . 14
3.8.3. EA-Field-Length AVP . . . . . . . . . . . . . . . . . 15
3.8.4. Port-Set-Identifier AVP . . . . . . . . . . . . . . . 15
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
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7. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Normative References . . . . . . . . . . . . . . . . . . 16
7.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
A number of transition technologies have been defined to allow IPv4
packets to pass between hosts and IPv4 networks over an intervening
IPv6 network while minimizing the number of public IPv4 addresses
that need to be consumed by the hosts. Different operators will
deploy different technologies, and sometimes one operator will use
more than one technology, depending on what is supported by the
available equipment and upon other factors both technical and
economic.
Each technique requires the provisioning of some subscriber-specific
information on the customer edge device. The provisioning may be by
DHCPv6 [RFC3315] or by some other method. This document is
indifferent to the specific provisioning technique used, but assumes
a deployment in which that information is managed by AAA
(Authentication, Authorization, and Accounting) servers. It further
assumes that this information is delivered to intermediate network
nodes for onward provisioning using the Diameter protocol [RFC6733].
As described below, in the particular case where the Light Weight
IPv4 Over IPv6 (LW4o6) [I-D.ietf-softwire-lw4over6] transition method
has been deployed, per-subscriber-site information almost identical
to that passed to the subscriber site [I-D.ietf-softwire-map-dhcp] or
collected from it [I-D.fsc-softwire-dhcp4o6-saddr-opt] also needs to
be delivered to the border router serving that site. The Diameter
protocol may be used for this purpose too.
This document analyzes the information required to configure the
customer edge equipment for the following set of transition methods:
o Dual-Stack Lite (DS-Lite) [RFC6333],
o Light Weight IPv4 Over IPv6 (LW4over6)
[I-D.ietf-softwire-lw4over6], and
o Mapping of Address and Port with Encapsulation (MAP-E)
[I-D.ietf-softwire-map].
[I-D.softwire-dslite-multicast] specifies a generic solution for
delivery of IPv4 multicast services to IPv4 clients over an IPv6
multicast network. The solution was developed with DS-Lite in mind
but it is however not limited to DS-Lite. As such, it applies also
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for LW4over6 and MAP-E. This document analyzes the information
required to configure the customer edge equipment for the support of
multicast in the context of DS-Lite, MAP, and LW4over6 in particular.
On the basis of those analyses it specifies a number of attribute-
value pairs (AVPs) to allow the necessary subscriber-site-specific
configuration information to be carried in Diameter.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The abbreviation "CE" denotes the equipment at the customer edge that
terminates the customer end of an IPv6 transitional tunnel. This
will usually be a router, but could be a host directly connected to
the network.
The term "tunnel source address" is used to denote the IPv6 source
address used in the outer header of packets sent from the CE through
an LW4over6 transitional tunnel to the border router.
2. Description of the Parameters Required By Each Transition Method
This section reviews the parameters that need to be provisioned for
each of the transition methods listed above. This enumeration
provides the justification for the AVPs defined in the next section.
A means is required to indicate which transition method(s) a given
subscriber is allowed to use. The approach taken in this document is
to specify grouped AVPs specific to LW4over6 and MAP-E. The operator
can control which of these two transition methods a given subscriber
uses by ensuring that AAA passes only the grouped AVP relevant to
that method. A grouped AVP is unnecessary for Dual-Stack Lite, since
(as the next section indicates) AAA has to provide only one
parameter. Hence the absence of either of the grouped AVPs indicates
that the subscriber equipment will use Dual-Stack Lite. Provisioning
of multicast is an orthogonal activity, since it is independent of
the transition method.
2.1. Parameters For Dual-Stack Lite (DS-Lite)
DS-Lite is documented in [RFC6333]. The Basic Bridging BroadBand
(B4) element at the customer premises needs to be provisioned with
the IPv6 address of the AFTR (border router). Optionally, it could
also be configured with the IPv4 address of the B4 interface facing
the tunnel, where the default value in the absence of provisioning is
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192.0.0.2 and valid values are 192.0.0.2 through 192.0.0.7.
Provisioning this information through AAA is problematic because it
is most likely used in a case where multiple B4 instances occupy the
same device. This document therefore assumes that the B4 interface
address is determined by other means (implementation-dependent or
static assignment).
2.2. Light Weight IPv4 Over IPv6 (LW4over6)
Light Weight IPv4 Over IPv6 (LW4over6) is documented in
[I-D.ietf-softwire-lw4over6]. LW4over6 requires four items to be
provisioned to the customer equipment:
o IPv6 address of the border router.
o IPv6 prefix used by the CE to construct the tunnel source address.
In the terminology of [I-D.ietf-softwire-lw4over6], this is the
IPv6 Binding Prefix.
o an IPv4 address to be used on the external side of the CE; and
o if the IPv4 address is shared, a specification of the port set the
subscriber site is allowed to use. Please see the description in
Section 2.3. For LW4over6, all three of the parameters 'a', 'k',
and PSID described in that section are required. The default
value of the offset parameter 'a' is 0.
As discussed in Section 4 of [I-D.ietf-softwire-lw4over6], it is
necessary to synchronize this configuration with corresponding per-
subscriber configuration at the border router. The border router
information consists of the same public IPv4 address and port set
parameters that are passed to the CE, bound together with the full
/128 IPv6 address (not just the Binding Prefix) configured as the
tunnel source address at the CE.
[I-D.fsc-softwire-dhcp4o6-saddr-opt] proposes a means whereby a
DHCPv6 server can influence the choice of this address and collect it
from the CE. Depending on the provisioning architecture deployed in
a given network, it is possible that the tunnel source address is
passed to AAA as an intermediate step before the binding information
is passed on to the border router.
2.3. Port Set Specification
When an external IPv4 address is shared, LW4over6 and MAP-E restrict
the CE to use of a subset of all available ports on the external
side. Both transition methods use the the algorithm defined in
Appendix B of [I-D.ietf-softwire-map] to derive the values of the
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port numbers in the port set. This algorithm features three
parameters, describing the positioning and value of the Port Set
Identifier (PSID) within each port number of the generated set:
o an offset 'a' from the beginning of the port number to the first
bit of the PSID;
o the length 'k' of the PSID within the port number, in bits; and
o the value of the PSID itself.
2.4. Mapping of Address and Port with Encapsulation (MAP-E)
Mapping of Address and Port with Encapsulation (MAP-E) is described
in [I-D.ietf-softwire-map]. MAP-E requires the provisioning of the
following per-subscriber information at the customer edge device:
o the IPv6 address of one or more border routers, or in MAP-E
terminology, MAP border relays.
o the unique End-user IPv6 prefix for the customer edge device.
This may be provided by AAA or acquired by other means.
o the Basic Mapping Rule for the customer edge device. This
includes the following parameters:
* the rule IPv6 prefix and length;
* the rule IPv4 prefix and length. A prefix length of 0
indicates that the entire IPv4 address or prefix is coded in
the Extended Address (EA) bits of the End-user IPv6 prefix
rather than in the mapping rule.
* the number of EA bits included in the End-user IPv6 prefix;
* port set parameters giving the set of ports the CE is allowed
to use when the IPv4 address is shared. Please see the
description of these parameters in Section 2.3. At a minimum,
the offset parameter 'a' is required. For MAP-E this has the
default value 6. The parameters 'k' and PSID are needed if
they cannot be derived from the mapping rule information and
the EA bits (final case of Section 5.2 of
[I-D.ietf-softwire-map]).
o whether the device is to operate in mesh or hub-and-spoke mode;
o in mesh mode only, zero or more Forwarding Mapping Rules,
described by the same set of parameters as the Basic Mapping Rule;
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As indicated in Section 5, bullet 1 of the MAP-E document, a MAP CE
can be provisioned with multiple End-user IPv6 prefixes, each
associated with its own Basic Mapping Rule. This does not change the
basic requirement for representation of the corresponding information
in the form of Diameter AVPs, but adds a potential requirement for
multiple instances of this information to be present in the Diameter
message, differing in the value of the End-user IPv6 prefix (in
contrast to the Forward Mapping Rule instances).
The border router needs to be configured with the superset of the
Mapping Rules passed to the customer sites it serves. Since this
requirement does not require direct coordination with CE
configuration in the way LW4over6 does, it is out of scope of the
present document. However, the AVPs defined here may be useful if a
separate Diameter application is used to configure the border router.
2.5. Parameters For Multicast
[I-D.softwire-dslite-multicast] specifies a generic solution for
delivery of IPv4 multicast services to IPv4 clients over an IPv6
multicast network. The solution can be in particular deployed in a
DS-Lite context, but is also adaptable to LW4over6 and MAP-E.
[I-D.ietf-softwire-multicast-prefix-option] specifies how DHCPv6
[RFC3315] can be used to provision multicast-related information,
particularly:
o ASM_mPrefix64: the IPv6 multicast prefix to be used to synthesize
the IPv4-embedded IPv6 addresses of the multicast groups in the
ASM mode.
o SSM_mPrefix64: the IPv6 multicast prefix to be used to synthesize
the IPv4-embedded IPv6 addresses of the multicast groups in the
SSM mode.
o uPrefix64: the IPv6 unicast prefix to be used in SSM mode for
constructing the IPv4-embedded IPv6 addresses representing the
IPv4 multicast sources in the IPv6 domain. uPrefix64 may also be
used to extract the IPv4 address from the received multicast data
flows. The address mapping follows the guidelines documented in
[RFC6052].
2.6. Summary and Discussion
It appears that two items are common to the different transition
methods and the corresponding AVPs to carry them can be reused:
o a representation of the IPv6 address of a border router;
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o A set of prefixes for delivery of multicast services to IPv4
clients over an IPv6 multicast network.
[RFC6519] sets a precedent for representation of the IPv6 address of
a border router as an FQDN. This can be dereferenced to one or more
IP addresses by the provisioning system before being passed to the
customer equipment, or left as an FQDN as it as in [RFC6334].
The remaining requirements are transition-method-specific:
o for LW4over6, a representation of a binding between (1) either the
IPv6 Binding Prefix or a full /128 IPv6 address, (2) a public IPv4
address, and (3) (if the IPv4 address is shared) a port set
identifier;
o for MAP-E, a representation of the unique End-user IPv6 prefix for
the CE, if not provided by other means;
o for MAP-E, a representation of a Mapping Rule;
o for MAP-E, an indication of whether mesh mode or hub-and-spoke
mode is to be used.
3. Attribute-Value Pair Definitions
This section provides the specifications for the AVPs needed to meet
the requirements summarized in Section 2.6. Within the context of
their usage, all of these AVPs MUST have the M bit set and the V bit
cleared.
3.1. IP-Prefix-Length AVP
The IP-Prefix-Length AVP (AVP code TBD00) is of type Unsignedint. It
provides the length of an IPv4 or IPv6 prefix. Valid values are from
0 to 32 for IPv4, and from 0 to 128 for IPv6. Tighter limits are
given below for particular contexts of use of this AVP.
3.2. Border-Router-Name AVP
Following on the precedent set by [RFC6334] and [RFC6519], this
document identifies a border router using an FQDN rather than an
address. The Border-Router-Name AVP (AVP Code TBD01) is of type
OctetString. The rules for encoding the FQDN are the same as those
for the FQDN variant of the derived type DiameterIdentity
(Section 4.3.1 of [RFC6733]).
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3.3. 64-Multicast-Attributes AVP
The 64-Multicast-Attributes AVP (AVP Code TBD02) is of type Grouped.
It contains the multicast-related prefixes needed for providing IPv4
multicast over IPv6 using DS-Lite, MAP-E, or LW4over6, as specified
in [I-D.softwire-dslite-multicast].
The syntax is shown in Figure 1.
64-Multicast-Attributes ::= < AVP Header: TBD02 >
[ ASM-Prefix64 ]
[ SSM-Prefix64 ]
[ Delegated-IPv6-Prefix ]
*[ AVP ]
Figure 1: 64-Multicast-Attributes AVP
If either ASM-Prefix64 or SSM-Prefix64 or both are present,
Delegated-IPv6-Prefix MUST also be present.
3.3.1. ASM-Prefix64 AVP
The ASM-Prefix64 AVP (AVP Code TBD03) conveys the value of
ASM_mPrefix64 as identified in Section 2.1 and specified in
[I-D.softwire-dslite-multicast]. The ASM-Prefix64 AVP is of type
Grouped, as shown in Figure 2.
ASM-Prefix64 ::= < AVP Header: TBD03 >
{ IP-Address }
{ IP-Prefix-Length }
*[ AVP ]
Figure 2: ASM-Prefix64 AVP
IP-Address (AVP code 518) is defined in [RFC5777] and is of type
Address. Within the ASM-Prefix64 AVP, it provides the value of an
IPv6 prefix. The AddressType field in IP-Address MUST have value 2
(IPv6). The conveyed multicast IPv6 prefix MUST belong to the ASM
range. Unused bits in IP-Address beyond the actual prefix MUST be
set to zeroes by the sender and ignored by the receiver.
The IP-Prefix-Length AVP provides the actual length of the prefix
contained in the IP-Address AVP. Within the ASM-Prefix64 AVP, valid
values of the IP-Prefix-Length AVP are from 24 to 96.
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3.3.2. SSM-Prefix64 AVP
The SSM-Prefix64 AVP (AVP Code TBD04) conveys the value of
SSM_mPrefix64 as identified in Section 2.1 and specified in
[I-D.softwire-dslite-multicast]. The SSM-Prefix64 AVP is of type
Grouped, as shown in Figure 3.
SSM-Prefix64 ::= < AVP Header: TBD04 >
{ IP-Address }
{ IP-Prefix-Length }
*[ AVP ]
Figure 3: SSM-Prefix64 AVP
IP-Address (AVP code 518) provides the value of an IPv6 prefix. The
AddressType field in IP-Address MUST have value 2 (IPv6). The
conveyed multicast IPv6 prefix MUST belong to the SSM range. Unused
bits in IP-Address beyond the actual prefix MUST be set to zeroes by
the sender and ignored by the receiver.
The IP-Prefix-Length AVP provides the actual length of the prefix
contained in the IP-Address AVP. With regard to prefix length, note
that Section 6 of [RFC3306] requires that bits 33-95 of an SSM
address in the FF3x range be set to zero, meaning that the prefix
length for an SSM prefix is effectively 96. However, Section 1 of
[RFC4607] suggests that the lower limit of 32 bits be preserved to
allow potential future use of bits 33-95. Hence applications SHOULD
accept prefix lengths between 32 and 96 inclusive.
3.3.3. Delegated-IPv6-Prefix AVP As uPrefix64
Within the 64-Multicast-Attributes AVP, the Delegated-IPv6-Prefix AVP
(AVP Code 123) conveys the value of uPrefix64, a unicast IPv6 prefix,
as identified in Section 2.1 and specified in
[I-D.softwire-dslite-multicast]. The Delegated-IPv6-Prefix AVP is
defined in [RFC4818]. As specified by [RFC6052], the value in the
Prefix-Length field MUST be one of 32, 48, 56, 64 or 96.
3.4. Tunnel-Source-Pref-Or-Addr AVP
The Tunnel-Source-Pref-Or-Addr AVP (AVP Code TBD05) conveys either
the IPv6 Binding Prefix or the tunnel source address on the CE, as
described in Section 2.2. The Tunnel-Source-Pref-Or-Addr AVP is of
type Grouped, with syntax as shown in Figure 4. One of the
Delegated-IPv6-Prefix AVP or the Tunnel-Source-IPv6-Address AVP MUST
be present.
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Tunnel-Source-Pref-Or-Addr ::= < AVP Header: TBD05 >
[ Delegated-IPv6-Prefix ]
[ Tunnel-Source-IPv6-Address ]
*[ AVP ]
Figure 4: Tunnel-Source-Pref-Or-Addr AVP
This AVP is defined separately from the LW4over6-Binding AVP (which
includes it) to provide flexibility in the transport of the tunnel
source address from the provisioning system to AAA while also
supporting the provision of a complete binding to the LW4over6 border
router.
3.4.1. Delegated-IPv6-Prefix As the IPv6 Binding Prefix
The Delegated-IPv6-Prefix AVP (AVP code 123) is of type Octetstring,
and is defined in [RFC4818]. Within the Tunnel-Source-Pref-Or-Addr
AVP, it conveys the IPv6 Binding Prefix assigned to the CE. Valid
values in the Prefix-Length field are from 0 to 128 (full address),
although a more restricted range is obviously more reasonable.
3.4.2. Tunnel-Source-IPv6-Address AVP
The Tunnel-Source-IPv6-Address AVP (AVP code TBD06) is of type
Address. It provides the address that the CE has assigned to its end
of an LW4over6 tunnel. The AddressType field in this AVP MUST be set
to 2 (IPv6). The DHCP 4o6 server described in
[I-D.fsc-softwire-dhcp4o6-saddr-opt] can use the Tunnel-Source-
IPv6-Address AVP to report the address to AAA after Step 3 of the
binding flow shown in Section 4 of that document.
3.5. Port-Set-Identifier
The Port-Set-Identifier AVP (AVP Code TBD07) is a structured
OctetString with four octets of data, hence a total AVP length of 12.
The description of the structure which follows refers to refers to
the parameters described in Section 2.3.
o The first (high-order) octet is the Offset field. It is
interpreted as an 8-bit unsigned integer giving the offset 'a'
from the beginning of a port number to the beginning of the port
set identifier (PSID) to which that port belongs. Valid values
are from 0 to 15.
o The next octet, the PSIDLength, is also interpreted as an 8-bit
unsigned integer and gives the length 'k' in bits of the port set
identifier (PSID). Valid values are from 0 to (16 - a). A value
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of 0 indicates that the PSID is not present (probable case for
MAP-E, see Section 2.4), and the PSIDValue field MUST be ignored.
o The final two octets contain the PSIDValue field. They give the
value of the PSID itself, right-justified within the field. That
is, the value of the PSID occupies the 'k' lowest-order bits of
the PSIDValue field.
3.6. LW4over6-Binding
The LW4over6-Binding AVP (AVP Code TBD08) is of type Grouped. It
contains the elements of configuration that constitute the binding
between an LW4over6 tunnel and IPv4 packets sent through that tunnel,
as described in Section 2.2.
LW4over6-Binding ::= < AVP Header: TBD08 >
{ Tunnel-Source-Pref-Or-Addr }
{ LW4over6-External-IPv4-Addr }
[ Port-Set-Identifier ]
*[ AVP ]
Figure 5
The Tunnel-Source-Pref-Or-Addr AVP is defined in Section 3.4 and
provides either the Binding Prefix or the full IPv6 tunnel source
address. This AVP MUST be present.
The LW4over6-External-IPv4-Addr AVP (AVP Code TBD09) uses the Address
derived data format defined in Section 4.3.1 of [RFC6733]. It
provides the CE's external IPv4 address within the LW4over6 tunnel
associated with the given binding. The AddressType field MUST be set
to 1 (IPv4), and the total length of the AVP MUST be 14 octets. This
AVP MUST be present.
The Port-Set-Identifier AVP is defined in Section 3.5. It identifies
the specific set of ports assigned to the LW4over6 tunnel, when the
IPv4 address is being shared.
3.7. MAP-E-Attributes
The MAP-E-Attributes AVP (AVP Code TBD10) is of type Grouped. It
contains the configuration data identified in Section 2.4 for all of
the mapping rules (Basic and Forwarding) in a single MAP domain.
Multiple instances of this AVP will be present if the CE belongs to
multiple MAP domains.
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MAP-E-Attributes ::= < AVP Header: TBD06 >
1*{ Border-Router-Name }
1*{ MAP-Mapping-Rule }
[ MAP-Mesh-Mode ]
[ Delegated-IPv6-Prefix ]
*[ AVP ]
Figure 6
The Border-Router-Name AVP is defined in Section 3.2. It provides
the FQDN of a MAP border relay at the edge of the MAP domain to which
the containing MAP-E-Attributes AVP relates. At least one instance
of this AVP MUST be present.
The MAP-Mapping-Rule AVP is defined in Section 3.8. At least one
instance of this AVP MUST be present. If the MAP-E domain supports
mesh mode (indicated by the presence of the MAP-Mesh-Mode AVP),
additional MAP-Mapping-Rule instances MAY be present. If the MAP-E
domain is operating in hub-and-spoke mode, additional MAP-Mapping-
Rule instances MUST NOT be present.
The MAP-Mesh-Mode AVP (AVP Code TBD11) uses the OctetString data
format but has no data. Hence the AVP length is always 8. The
absence of the mesh mode indicator attribute indicates that the CE is
required to operate in hub-and-spoke mode.
The Delegated-IPv6-Prefix AVP (AVP Code 123) provides the End-user
IPv6 prefix assigned to the CE for the MAP domain to which the
containing MAP-E-Attributes AVP relates. The AVP is defined in
[RFC4818]. Valid values of the Prefix-Length field range from 0 to
128.
The Delegated-IPv6-Prefix AVP is optional because, depending on
deployment, the End-user IPv6 prefix may be provided by AAA or by
other means. If multiple instances of the MAP-E-Attributes AVP
containing the Delegated-IPv6-Prefix AVP are present, each instance
of the latter MUST have a different value.
3.8. MAP-Mapping-Rule
The MAP-Mapping-Rule AVP (AVP Code TBD12) is of type Grouped, and is
used only in conjunction with MAP-based transition methods. Mapping
rules are required both by the MAP border relay and by the CE. The
components of the MAP-Mapping-Rule AVP provide the contents of a
mapping rule as described in Section 2.4.
The syntax of the MAP-Mapping-Rule AVP is as follows:
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MAP-Mapping-Rule ::= < AVP Header: TBD12 >
{ Rule-IPv4-Addr-Or-Prefix }
{ Rule-IPv6-Prefix }
{ EA-Field-Length }
{ Port-Set-Identifier }
*[ AVP ]
Figure 7
The Rule-IPv4-Addr-Or-Prefix, Rule-IPv6-Prefix, EA-Field-Length, and
Port-Set-Identifier AVPs MUST all be present.
3.8.1. Rule-IPv4-Addr-Or-Prefix AVP
The Rule-IPv4-Addr-Or-Prefix AVP (AVP Code TBD13) conveys the rule
IPv4 prefix and length as described in Section 2.4. The Rule-IPv4-
Addr-Or-Prefix AVP is of type Grouped, as shown in Figure 8.
Rule-IPv4-Addr-Or-Prefix ::= < AVP Header: TBD13 >
{ IP-Address }
{ IP-Prefix-Length }
*[ AVP ]
Figure 8: Rule-IPv4-Addr-Or-Prefix AVP
IP-Address (AVP code 518) is defined in [RFC5777] and is of type
Address. Within the Rule-IPv4-Addr-Or-Prefix AVP, it provides the
value of a unicast IPv4 address or prefix. The AddressType field in
IP-Address MUST have value 1 (IPv4). Unused bits in IP-Address
beyond the actual prefix MUST be set to zeroes by the sender and
ignored by the receiver.
The IP-Prefix-Length AVP provides the actual length of the prefix
contained in the IP-Address AVP. Within the Rule-IPv4-Addr-Or-Prefix
AVP, valid values of the IP-Prefix-Length AVP are from 0 to 32 (full
address), based on the different cases identified in Section 5.2 of
[I-D.ietf-softwire-map].
3.8.2. Rule-IPv6-Prefix AVP
The Rule-IPv6-Prefix AVP (AVP Code TBD14) conveys the rule IPv6
prefix and length as described in Section 2.4. The Rule-IPv6-Prefix
AVP is of type Grouped, as shown in Figure 9.
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Rule-IPv6-Prefix ::= < AVP Header: TBD14 >
{ IP-Address }
{ IP-Prefix-Length }
*[ AVP ]
Figure 9: Rule-IPv6-Prefix AVP
IP-Address (AVP code 518) is defined in [RFC5777] and is of type
Address. Within the Rule-IPv6-Prefix AVP, it provides the value of a
unicast IPv6 prefix. The AddressType field in IP- Address MUST have
value 2 (IPv6). Unused bits in IP-Address beyond the actual prefix
MUST be set to zeroes by the sender and ignored by the receiver.
This AVP MUST be present.
The IP-Prefix-Length AVP provides the actual length of the prefix
contained in the IP-Address AVP. Within the Rule-IPv6-Prefix AVP,
the minimum valid prefix length is 0. The maximum value is bounded
by the length of the End-user IPv6 prefix associated with the mapping
rule, if present in the form of the Delegated-IPv6-Prefix AVP in the
enclosing MAP-E-Attributes AVP. Otherwise the maximum value is 128.
This AVP MUST be present.
3.8.3. EA-Field-Length AVP
The EA-Field-Length AVP (AVP Code TBD15) is of type Unsigned32.
Valid values range from 0 to 48. See Section 5.2 of
[I-D.ietf-softwire-map] for a description of the use of this
parameter in deriving IPv4 address and port number configuration.
This AVP MUST be present.
3.8.4. Port-Set-Identifier AVP
The Port-Set-Identifier AVP provides information to identify the
specific set of ports assigned to the CE. For more information see
Section 2.4 and Section 2.3. The Port-Set-Identifier AVP is defined
in Section 3.5. It MUST be present.
4. Acknowledgements
Huawei Technologies funded Tom Taylor's work on earlier versions of
this document.
5. IANA Considerations
This memo requests to IANA to register the following Diameter AVP
codes:
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+-------+-----------------------------+---------------+
| Code | Attribute Name | Reference |
+-------+-----------------------------+---------------+
| TBD00 | IP-Prefix-Length | This document |
| TBD01 | Border-Router-Name | This document |
| TBD02 | 64-Multicast-Attributes | This document |
| TBD03 | ASM-Prefix64 | This document |
| TBD04 | SSM-Prefix64 | This document |
| TBD05 | Tunnel-Source-Pref-Or-Addr | This document |
| TBD06 | Tunnel-Source-IPv6-Address | This document |
| TBD07 | Port-Set-Identifier | This document |
| TBD08 | LW4over6-Binding | This document |
| TBD09 | LW4over6-External-IPv4-Addr | This document |
| TBD10 | MAP-E-Attributes | This document |
| TBD11 | MAP-Mesh-Mode | This document |
| TBD12 | MAP-Mapping-Rule | This document |
| TBD13 | Rule-IPv4-Addr-Or-Prefix | This document |
| TBD14 | Rule-IPv6-Prefix | This document |
| TBD15 | EA-Field-Length | This document |
+-------+-----------------------------+---------------+
Table 1
6. Security Considerations
The AVPs defined in this document face two threats, both dependent on
man-in-the-middle attacks on the Diameter delivery path. The more
serious threat is denial of service through modification of the AVP
contents leading to misconfiguration. The lesser threat is
disclosure of subscriber addresses allowing the attacker to track
subscriber activity.
Diameter security is currently provided on a hop-by-hop basis (see
Section 2.2 of [RFC6733]). The Diameter end-to-end security problem
has not been solved, so man-in-the-middle attacks on Diameter peers
along the path are possible. The present document does not propose
to solve that general problem, but simply warn that it exists.
7. References
7.1. Normative References
[I-D.ietf-softwire-lw4over6]
Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
Farrer, "Lightweight 4over6: An Extension to the DS-Lite
Architecture (work in progress)", March 2014.
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[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) (work in progress)", January
2014.
[I-D.softwire-dslite-multicast]
Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q.
Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients
over an IPv6 Multicast Network (work in progress)", March
2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, August 2002.
[RFC4818] Salowey, J. and R. Droms, "RADIUS Delegated-IPv6-Prefix
Attribute", RFC 4818, April 2007.
[RFC5777] Korhonen, J., Tschofenig, H., Arumaithurai, M., Jones, M.,
and A. Lior, "Traffic Classification and Quality of
Service (QoS) Attributes for Diameter", RFC 5777, February
2010.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011.
[RFC6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
"Diameter Base Protocol", RFC 6733, October 2012.
7.2. Informative References
[I-D.fsc-softwire-dhcp4o6-saddr-opt]
Farrer, I., Sun, Q., and Y. Cui, "DHCPv4 over DHCPv6
Source Address Option (Work in progress)", June 2014.
[I-D.ietf-softwire-map-dhcp]
Mrugalski, T., Troan, O., Farrer, I., Perrault, S., Dec,
W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
configuration of Softwire Address and Port Mapped Clients
(Work in progress)", March 2014.
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[I-D.ietf-softwire-multicast-prefix-option]
Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", draft-ietf-softwire-multicast-prefix-option-07
(work in progress), September 2014.
[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.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, August 2006.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010.
[RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
RFC 6334, August 2011.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, February 2012.
Authors' Addresses
Cathy Zhou
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
P.R. China
Email: cathy.zhou@huawei.com
T. Taylor
PT Taylor Consulting
Ottawa
Canada
Email: tom.taylor.stds@gmail.com
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Qiong Sun
China Telecom
P.R.China
Phone: 86 10 58552936
Email: sunqiong@ctbri.com.cn
M. Boucadair
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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