INTERNET-DRAFT Erik Nordmark
Oct 15, 2004 Sun Microsystems
Marcelo Bagnulo
UC3M
Multihoming L3 Shim Approach
<draft-nordmark-multi6dt-shim-00.txt>
Status of this Memo
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and any of which I become aware will be disclosed, in accordance with
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This Internet Draft expires April 15, 2005.
Abstract
This document outlines an approach to solving IPv6 multihoming in
order to stimulate discussion.
The approach is based on using a multi6 shim placed between the IP
endpoint sublayer and the IP routing sublayer, and, at least
initially, using routable IP locators as the identifiers visible
above the shim layer. The approach does not introduce a "stack name"
type of identifier, instead it ensures that all upper layer protocols
can operate unmodified in a multihomed setting while still seeing a
stable IPv6 address.
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This document does not specify the mechanism for authenticating and
authorizing the "rehoming" - this is specified in the HBA document.
Nor does it specify the messages used to establish multihoming state.
The document does not even specify the packet format used for the
data packets. Instead it discusses the issue of receive side
demultiplexing and the different tradeoffs. The resolution of this
issue will effect the packet format for the data packets.
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Contents
1. Introduction............................................. 4
1.1. Non-Goals........................................... 4
2. Terminology.............................................. 5
2.1. Notational Conventions.............................. 6
3. Overview................................................. 6
4. Locators as Upper-layer Identifiers...................... 7
5. Placement of the multi6 shim............................. 7
6. Deferred Context Establishment........................... 10
7. Assumptions about the DNS................................ 10
8. Protocol Walkthrough..................................... 11
8.1. Initial Context Establishment....................... 11
8.2. Locator Change...................................... 11
8.3. Concurrent Context Establishment.................... 12
8.4. Handling Initial Locator Failures................... 12
9. Demultiplexing of data packets in multi6 communications.. 13
9.1. Approaches preventing the existence of ambiguities.. 14
9.1.1. Pre-agreed identifiers......................... 14
9.1.2. N-square addresses............................. 14
9.2. Providing additional information to the receiver.... 15
9.2.1. Flow-label..................................... 15
9.2.2. Extension Header............................... 16
9.3. Host-Pair Context................................... 16
10. IPSEC INTERACTIONS...................................... 17
11. OPEN ISSUES............................................. 17
12. ACKNOWLEDGMENTS......................................... 18
13. REFERENCES.............................................. 18
13.1. Normative References............................... 18
13.2. Informative References............................. 18
AUTHORS' ADDRESSES........................................... 19
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1. Introduction
The goal of the IPv6 multihoming work is to allow a site to take
advantage of multiple attachments to the global Internet without
having a specific entry for the site visible in the global routing
table. Specifically, a solution should allow users to use multiple
attachments in parallel, or to switch between these attachment points
dynamically in the case of failures, without an impact on the upper
layer protocols.
The goals for this approach is to:
o Have no impact on upper layer protocols in general and on
transport protocols in particular.
o Address the security threats in [M6THREATS] through a separate
document [HBA]
o No extra roundtrip for setup; deferred setup.
o Take advantage of multiple locators/addresses for load spreading
so that different sets of communication to a host (e.g., different
connections) might use different locators of the host.
1.1. Non-Goals
The assumption is that the problem we are trying to solve is site
multihoming, with the ability to have the set of site locator
prefixes change over time due to site renumbering. Further, we
assume that such changes to the set of locator prefixes can be
relatively slow and managed; slow enough to allow updates to the DNS
to propagate. This proposal does not attempt to solve, perhaps
related, problems such as host multihoming or host mobility.
This proposal also does not try to provide an IP identifier. Even
though such a concept would be useful to ULPs and applications,
especially if the management burden for such a name space was zero
and there was an efficient yet secure mechanism to map from
identifiers to locators, such a name space isn't necessary (and
furthermore doesn't seem to help) to solve the multihoming problem.
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2. Terminology
upper layer protocol (ULP)
- a protocol layer immediately above IP. Examples are
transport protocols such as TCP and UDP, control
protocols such as ICMP, routing protocols such as
OSPF, and internet or lower-layer protocols being
"tunneled" over (i.e., encapsulated in) IP such as
IPX, AppleTalk, or IP itself.
interface - a node's attachment to a link.
address - an IP layer name that contains both topological
significance and acts as a unique identifier for an
interface. 128 bits.
locator - an IP layer topological name for an interface or a
set of interfaces. 128 bits. The locators are
carried in the IP address fields as the packets
traverse the network.
identifier - an IP layer identifier for an IP layer endpoint
(stack name in [NSRG]). The transport endpoint is a
function of the transport protocol and would
typically include the IP identifier plus a port
number. NOTE: This proposal does not contain any IP
layer identifiers.
upper-layer identifier (ULID)
- an IP locator which has been selected for
communication with a peer to be used by the upper
layer protocol. 128 bits. This is used for
pseudo-header checksum computation and connection
identification in the ULP. Different sets of
communication to a host (e.g., different
connections) might use different ULIDs in order to
enable load spreading.
address field
- the source and destination address fields in the
IPv6 header. As IPv6 is currently specified this
fields carry "addresses". If identifiers and
locators are separated these fields will contain
locators.
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FQDN - Fully Qualified Domain Name
Host-pair context
- the state that the multi6 shim maintains for a
particular peer. The peer is identified by one or
more ULIDs.
2.1. Notational Conventions
A, B, and C are hosts. X is a potentially malicious host.
FQDN(A) is the domain name for A.
Ls(A) is the locator set for A, which consists of L1(A), L2(A), ...
Ln(A).
ULID(A) is an upper-layer ID for A. In this proposal, ULID(A) is
always one member of A's locator set.
3. Overview
This document specifies certain aspects of the approach, yet leaves
other aspects open.
The main points are about using locators as the ULIDs, and the exact
placement of the multi6 shim in the protocol stack.
The draft also discusses issues about receive side demultiplexing,
which affects the packet format for data packets.
The approach assumes that there are mechanisms (specified in other
drafts) which:
- can prevent redirection attacks [HBA]
- can prevent 3rd party DoS attacks [HBA, M6FUNC]
- can detect whether or not a peer supports the multi6 protocol
[M6FUNC, M6DET]
- can explore all the locator pairs to find a working pair when the
initial pair does not work [M6DET]
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4. Locators as Upper-layer Identifiers
Central to this approach is to not introduce a new identifier name
space but instead use one of the locators as the upper-layer ID,
while allowing the locators used in the address fields to change over
time in response to failures of using the original locator.
This implies that the ULID section is performed as today's default
address selection as specified in [RFC 3484]. Underneath, and
transparently, the multi6 shim selects working locator pairs with the
initial locator pair being the ULID pair. When communication fails
the shim can test and select alternate locators. A subsequent
section discusses the issues when the selected ULID is not initially
working hence there is a need to switch locators up front.
Using one of the locators as the ULID has certain benefits for
applications which have long-lived session state, or performs
callbacks or referrals, because both the FQDN and the 128-bit ULID
work as handles for the applications. However, using a single 128-
bit ULID doesn't provide seamless communication when that locator is
unreachable. See [M6REFER] for further discussion of the application
implications.
There has been some discussion of using non-routable locators, such
as unique-local addresses, as ULIDs in a multihoming solution. While
this approach doesn't currently specify all aspects of this, it is
believed that the approach can be extended to handle such a case.
For example, the protocol probably needs to handle ULIDs that are not
initially reachable. Thus the same mechanism can handle ULIDs that
are permanently unreachable. Note that the hard issues with ULIDs is
how to perform the mappings between them and the locator sets. With
routable ULIDs the AAAA resource record set provides this "mapping".
Non-routable ULIDs would need similar mechanisms, which is probably
feasible for unique local addresses based on prefixes that are
centrally assigned.
5. Placement of the multi6 shim
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-----------------------
| Transport Protocols |
-----------------------
------ ------- -------------- ------------- IP endpoint
| AH | | ESP | | Frag/reass | | Dest opts | sub-layer
------ ------- -------------- -------------
---------------------
| multi6 shim layer |
---------------------
------ IP routing
| IP | sub-layer
------
Figure 1: Protocol stack
The proposal uses an multi6 shim layer between IP and the ULPs as
shown in figure 1, in order to provide ULP independence.
Conceptually the multi6 shim layer behaves as if it is associated
with an extension header, which would be ordered immediately after
any hop-by-hop options in the packet. However, the amount of data
that needs to be carried in an actual multi6 extension header is
close to zero, thus it might not be necessary to add bytes to each
packet. See section 9.
We refer to packets that at least conceptually have this extension
header, i.e., packets that should be processed by the multi6 shim on
the receiver, as "multi6 packets" (analogous to "ESP packets" or "TCP
packets").
Layering AH and ESP above the multi6 shim means that IPsec can be
made to be unaware of locator changes the same way that transport
protocols can be unaware. Thus the IPsec security associations
remain stable even though the locators are changing. Layering the
fragmentation header above the multi6 shim makes reassembly robust in
the case that there is broken multi-path routing which results in
using different paths, hence potentially different source locators,
for different fragments. Thus, effectively the multi6 shim layer is
placed between the IP endpoint sublayer, which handles fragmentation,
reassembly, and IPsec, and the IP routing sublayer, which on a host
selects which default router to use etc.
Applications and upper layer protocols use ULIDs which the multi6
layer will map to/from different locators. The multi6 layer
maintains state, called host-pair context, in order to perform this
mapping. The mapping is performed consistently at the sender and the
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receiver, thus from the perspective of the upper layer protocols,
packets appear to be sent using ULIDs from end to end, even though
the packets travel through the network containing locators in the IP
address fields, and even though those locators might be changed by
the transmitting multi6 shim layer.
The context state in this approach is maintained per remote ULID i.e.
approximately per peer host, and not at any finer granularity. It
might make sense to merge the context state for multiple ULIDs
assigned to the same peer host, but this is for further study.
---------------------------- ----------------------------
| Sender A | | Receiver B |
| | | |
| ULP | | ULP |
| | src ULID(A)=L1(A) | | ^ |
| | dst ULID(B)=L1(B) | | | src ULID(A)=L1(A) |
| v | | | dst ULID(B)=L1(B) |
| multi6 shim | | multi6 shim |
| | src L2(A) | | ^ |
| | dst L3(B) | | | src L2(A) |
| v | | | dst L3(B) |
| IP | | IP |
---------------------------- ----------------------------
| ^
-------- cloud with some routers -------
Figure 2: Mapping with changed locators.
The result of this consistent mapping is that there is no impact on
the ULPs. In particular, there is no impact on pseudo-header
checksums and connection identification.
Conceptually one could view this approach as if both ULIDs and
locators are being present in every packet, but with a header
compression mechanism applied that removes the need for the ULIDs
once the state has been established. In order for the receiver to
recreate a packet with the correct ULIDs there might be a need to
include some "compression tag" in the data packets. This would serve
to indicate the correct context to use for decompression when the
locator pair in the packet is insufficient to uniquely identify the
context.
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6. Deferred Context Establishment
The protocol will use some context establishment exchange in order to
setup multi6 state at the two endpoints. Similar to MAST [MAST] this
initial exchange can be performed asynchronously with data packets
flowing between the two hosts; until context state has been
established at both ends the packets would flow just as for
unmodified IPv6 hosts i.e., without the ability for the hosts to
switch locators. This approach allows the hosts to have some local
policy on when to attempt to establish multi6 state with a peer;
perhaps based on the transport protocols and port numbers, or perhaps
based on the number of packets that have flowed to/from the peer.
Once the initial exchange has completed there is host-pair context
state at both hosts, and both ends know a set of locators for the
peer that are acceptable as the source in received packets. This
will trigger some verification of the set of locators, which is the
subject of the security scheme.
7. Assumptions about the DNS
This approach assumes that hosts in multihomed sites have multiple
AAAA records under a single name, in order to allow initial
communication to try all the locators. For multi6 capable hosts, the
content of those records are the locators (which also serve as
ULIDs).
However, the approach does not assume that all the AAAA records for a
given name refer to the same host. Instead the context establishment
allows each host to pass its locators to the peer. This set could be
either smaller or larger (or neither) than the AAAA record set.
The approach makes no assumption about the reverse tree since the
approach does not use it. However, applications might rely on the
reverse tree whether multi6 is used or not.
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8. Protocol Walkthrough
8.1. Initial Context Establishment
Here is the sequence of events when A starts talking to B:
1. A looks up FQDN(B) in the DNS which returns a locator set which
includes some locators for B. (The set could include locators
for other hosts since e.g., www.example.com might include AAAA
records for multiple hosts.) The application would typically
try to connect using the first locator in the set i.e., ULID(B)
= L1(B). The application is prepared to try the other locators
should the first one fail.
2. The ULP creates "connection" state between ULID(A)=L1(A) and
ULID(B) and sends the first packet down to the IP/multi6 shim
layer on A. L1(A) was picked using regular source address
selection mechanisms.
3. The packet passes through the multi6 layer, which has no state
for ULID(B). A local policy will be used to determine when, if
at all, to attempt to setup multi6 state with the peer. Until
this state triggers packets pass back and forth between A and B
as they do in unmodified IPv6 today.
When the policy is triggers, which could be on either A or B, an
initial context establishment takes place. This exchange might
fail should the peer not support the multi6 protocol. If it
succeeds it results in both ends receiving the locator sets from
their respective peer, and the security mechanism provides some
way to verify these sets.
At this point in time it is possible for the hosts to change to
a different locator in the set. But until they have exhanged
the locator sets, and probably until they rehome the context to
use different locators, they continue sending and receiving IPv6
packets as before.
8.2. Locator Change
When a host detects that communication is no longer working it can
try to switch to a different locator pair. A host might suspect that
communication isn't working due to
- lack of positive advise from the ULP (akin to the NUD advise in
[RFC 2461]
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- negative advise from the ULP
- failure of some explicit multi6 "heartbeat" messages
- local indications such as the local locator becoming invalid [RFC
2462] or the interface being disabled
Given that each host knows the locator set for its peer, the host can
just switch to using a different locator pair. It might make sense
for the host to test the locator pair before using it for ULP
traffic, both to verify that the locator pair is working and to
verify that it is indeed the peer that is present at the other end;
the latter to prevent 3rd party DoS attacks. Such testing needs to
complete before using the locator as a destination in order to
prevent 3rd party DoS attacks [M6THREATS].
8.3. Concurrent Context Establishment
Should both A and B attempt to contact each other at about the same
time using the same ULIDs for each other, the context establishment
should create a single host-pair context.
However, if different ULIDs are used this would result in two
completely independent contexts between the two hosts following the
basic content establishment above.
8.4. Handling Initial Locator Failures
Should not all locators be working when the communication is
initiated some extra complexity arises, because the ULP has already
been told which ULIDs to use. If the locators that where selected to
be ULIDs are not working and the multi6 shim does not know of
alternate locators, it has to choice than to have the application try
a different ULID.
Thus the simplest approach is to always punt initial locator failures
up the stack to the application. However, this might imply
significant delays while transport protocol times out.
It is possible to optimize this case when the multi6 shim already has
alternate locators for the peer. This might be the case when the two
hosts have already communicated, and it might be possible to have the
DNS resolver library provide alternate locators to the shim in the
speculation that they might be useful. However, those are
optimizations and not required for the protocol to work.
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Should the multi6 shim know alternate locators for the peer, it needs
to perform the multi6 protocol before upper layer protocol packets
are exchanged. This means that the context establishment can not be
deferred, and that there is a rehoming event, with the necessary
security checks, before the first ULP packets can be successfully
exchanged.
9. Demultiplexing of data packets in multi6 communications
The mechanisms for preserving established communications through
outages that reside in the M6 shim layer manage the multiple
addresses available in the multihomed node so that a reachable
address is used in the communication. Since reachability may vary
during the communication lifetime, different addresses may have to be
used in order to keep packets flowing. However, the addresses
presented by the M6 shim layer to the upper layer protocols must
remain constant through the locator changes, so that received packets
are recognized by the upper layer protocols as belonging to the
established communication. In other words, in order to preserve
established communications through outages, the M6 shim layer will
use different locators for exchanging packets while presenting the
same identifiers for the upper layer protocols. This means that upon
the reception of an incoming packet with a pair of locators, the M6
shim layer will need to translate the received locators to the
identifiers that are being used by the upper layer protocols in the
particular communication. This operation is called demultiplexing.
For example, if a host has address A1 and A2 and starts communicating
with a peer with addresses B1 and B2, then some communication
(connections) might use the pair <A1, B1> as upper-layer identifiers
and others might use e.g., <A2, B2>. Initially there are no failures
so these address pairs are used as locators i.e. in the IP address
fields in the packets on the wire. But when there is a failure the
multi6 shim on A might decide to send packets that used <A1, B1> as
upper-layer identifiers using <A2, B2> as the locators. In this case
B needs to be able to rewrite the IP address field for some packets
and not others, but the packets all have the same locator pair.
Either we must prevent this from happening, or provide some
additional information to B so that it can tell which packets need to
have the IP address fields rewritten.
In this section, we will analyze different approaches to perform the
demultiplexing operation. The possible approaches can be classified
into two categories: First, the approaches that prevent the existence
of ambiguities on the demultiplexing operation i.e. each received
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locator corresponds to one and only one ULP identifier. Second, the
approaches that use a context tag to provide additional information
to the receiver that indicates the identifiers that correspond to the
locators contained in the packets.
9.1. Approaches preventing the existence of ambiguities
9.1.1. Pre-agreed identifiers
The simplest approach of this type is to designate one of the
available addresses as the identifier to be used for all the
communications while the remaining addresses will only be used as
locators. This means that the upper layer protocols will only be
aware of a single address, the one used as identifier, and all the
remaining addresses that are used as locators will remain invisible
to them. Consequently, only the address that is being used as
identifier can be returned by the resolver to the applications. The
addresses used as locators cannot be returned to the applications by
the resolver. So, if no additional information about the role of the
addresses is placed in the DNS, only the identifier-address can be
published in the DNS. This configuration has reduced fault tolerance
capabilities during the initial contact, since the initiator will
have only one address available to reach the receiver. If the
identifier address placed in the DNS is not reachable, the
communication will fail. It would be possible to overcome this
limitation by defining a new DNS record for storing information about
address that can be only used as locators. If such record is
defined, the initiator can use an alternative locator, even for
initial contact, while still presenting the address designated as
identifier to the upper layer protocols. However, this approach
requires support form the initiator node, implying that only upgraded
nodes will obtain improves fault tolerance while legacy nodes that
don't support the new DNS record will still obtain reduced fault
tolerance capabilities.
9.1.2. N-square addresses
In order to overcome the limitations presented by the previous
scheme, it is possible to create additional addresses that have a
pre-determined role. In this approach, each multihomed node that has
n prefixes available, will create n^2 addresses, or in other words,
the node will have n sets of n addresses each. Each set will contain
one address per prefix. So, in each set, one address will be
designated as identifier while the remaining addresses will be
designated as locators. The addresses designated as identifiers will
have different prefixes in the different sets. The result is that
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there will be n addresses designated as identifiers, one per
available prefix, and each identifier-address will have an associated
set of n-1 addresses that can only be used as locators. The
addresses designated as identifiers will be published in the DNS
while the addresses used as locators must not be AAAA records in the
DNS to prevent them from every being used as ULIDs. The applications
will only have knowledge of the first ones, and only the M6 shim
layer will deal with locators. The resulting configuration has full
fault tolerance capabilities since n addresses (one per prefix) will
be published in the DNS, allowing the usage of different addresses to
make the initial contact.
9.2. Providing additional information to the receiver
When two nodes establish a multi6 enabled communication, a context is
created at the M6 shim layers of each node. The context stores
information about the addresses that are used as identifiers for the
upper layer protocols and also about the locator set available for
each node. In this approach, data packets carry a context tag that
allows the receiver determine which is the context that has to be
used to perform the demultiplexing operation. There are several ways
to carry the context tag within the data packets. In this section we
will explore the following options: the Flow Label, and an Extension
Header.
9.2.1. Flow-label
A possible approach is to carry the context tag in the Flow Label
field of the IPv6 header. This means that when a multi6 context is
established, a Flow Label value is associated with this context.
When a packet is received, the Flow Label value is used as a key to
determine the context to be used for the demultiplexing operation,
hence determining the identifiers that have to be presented to the
upper layers. Because this approach overloads the Flow Label field,
it is necessary to have an additional information to determine
whether the Flow Label field is actually being used as a context tag
or not. In other words, additional information is needed to identify
multi6 packets from regular IPv6 packets. This is because, the same
Flow Label value that is being used as context tag in multi6 enabled
communication can be used for other purposes by a non-multi6 enabled
host, resulting in two communications using the same Flow Label
value. The result of this situation would be that packets of the
non-multi6 enabled communication would be demultiplexed using the
context associated to the Flow Label value carried in the packets. A
possible approach to solve this issue it to use an additional bit to
identify data packets that belong to multi6 capable communications
and that have to be demultiplexed using the Flow Label value.
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However, there are no obvious choices for that bit, since all bits of
the IPv6 header are currently in use. A possibility would be to use
new Next Header values to indicate that the packet belongs to a
multi6 enabled communication and that the Flow Label carries context
information as proposed in [NOID].
Another approach is to extend the context tag to include additional
fields of the IPv6 header. The obvious choice would be to extend the
context tag to the combination of Flow Label, Source Address and
Destination Address. In this case, the context tag is composed of
these three values and it will be used to identify the context. The
limitation imposed by this approach is that all the potential source
and destination addresses have to be known beforehand by the receiver
in order to be recognized. This means that before sending packets
with a new address, the sender has to inform the receiver about the
new address.
9.2.2. Extension Header
Another approach is to define a new Extension Header to carry the
context tag. This context tag is agreed between the involved parties
during the multi6 protocol initial negotiation. Following data
packets will be demultiplexed using the tag carried in the Extension
Header. This seems a clean approach since it does not overload
existing fields. However, it introduces additional overhead in the
packet due to the additional header. The additional overhead
introduced is 8 octets. However, it should be noted that the context
tag is only required when an address other than the one used as
identifier for upper layer protocols is contained in the packet.
Packets carrying the addresses that have to be used as identifier for
the upper layer protocols do not require a context tag, since the
address contained in the packets is the address presented to the
upper layers. This approach would reduce the overhead. On the other
hand, this approach would cause changes in the available MTU, since
packets that include the Extension Header will have an MTU 8 octets
shorter.
9.3. Host-Pair Context
The host-pair context is established on each end of the communication
when one of the endpoints performs the multi6 signaling (the 4-way
handshake referred to in [M6FUNC].
This context is accessed differently in the transmit and receive
paths. In the transmit path when the ULP passes down a packet the
key to the context state is the tuple <ULID(local), ULID(peer)>; this
key must identify at most one state record. In the receive path the
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context must be found based on what is in the packet, be it just the
locators, or the locators plus some additional "context tag" as
discussed above, or just a "context tag".
10. IPSEC INTERACTIONS
As specified, all of ESP, AH, and key management is layered above the
multi6 layer. Thus they benefit from the stable ULIDs provided above
the multi6 layer. This means the IPsec security associations are
unaffected by switching locators.
The alternative would be to layer multi6 above IPsec, but that
doesn't seem to provide any benefits and it would add the need to
create different IPsec SAs when the locators change due to rehoming.
A result of layering multi6 above IPsec is that the multi6 protocol
can potentially be used to redirect IPsec protected traffic as a
selective DoS mechanism. If we somehow could require IPsec for the
multi6 protocol packets when the ULP packets between the same hosts
use IPsec, then we could prevent such attacks.
However, due to the richness in IPsec policy, this would be a bit
tricky. If only some protocols or port numbers/selectors are to be
protected by IPsec per a host's IPsec policy, then how would one
determine whether multi6 traffic needs to be protected? Should one
take the conservative approach that if any packets between the
hosts/ULIDs need to be protected, then the multi6 traffic should also
be protected?
For this to be useful both communicating hosts would need to make the
same policy decisions, so if we are to take this path there would
need to some standardization in this area.
11. OPEN ISSUES
Receive side demultiplexing issue as described above.
Is it possible to facilitate transition to multi6 using some "multi6
proxy" at site boundaries until all important hosts in a site have
been upgraded to support multi6? Would would be the properties of
such a proxy? Would it place any additional requirements on the
protocol itself?
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12. ACKNOWLEDGMENTS
This document was originally produced of a MULTI6 design team
consisting of (in alphabetical order): Jari Arkko, Iljitsch van
Beijnum, Marcelo Bagnulo Braun, Geoff Huston, Erik Nordmark, Margaret
Wasserman, and Jukka Ylitalo.
The idea to use a set of locators and not inventing a new identifier
name space, as well as using the DNS for verification of the
locators, was first brought up by Tony Li.
13. REFERENCES
13.1. Normative References
[M6THREATS] Nordmark, E., and T. Li, "Threats relating to IPv6
multihoming solutions", draft-ietf-multi6-multihoming-
threats-00.txt, July 2004.
[ADDR-ARCH] S. Deering, R. Hinden, Editors, "IP Version 6
Addressing Architecture", RFC 3513, April 2003.
[IPv6] S. Deering, R. Hinden, Editors, "Internet Protocol, Version
6 (IPv6) Specification", RFC 2461.
[M6FUNC] Functional decomposition of the M6 protocol, draft-dt-
multi6-functional-dec-00.txt
[HBA] Hash Based Addresses (HBA), draft-bagnulo-multi6dt-hba-00.txt
[M6DET] Jari Arkko, Failure Detection and Locator Selection in
Multi6, draft-multi6dt-failure-detection-00.txt
13.2. Informative References
[NSRG] Lear, E., and R. Droms, "What's In A Name: Thoughts from the
NSRG", draft-irtf-nsrg-report-09.txt (work in progress),
March 2003.
[ULA] R. Hinden, and B. Haberman, Centrally Assigned Unique Local
IPv6 Unicast Addresses, draft-ietf-ipv6-ula-central-00.txt
[MAST] D. Crocker, "MULTIPLE ADDRESS SERVICE FOR TRANSPORT (MAST):
AN EXTENDED PROPOSAL", draft-crocker-mast-protocol-01.txt,
October, 2003.
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[RFC3041] T. Narten, R. Draves, "Privacy Extensions for Stateless
Address Autoconfiguration in IPv6", RFC 3041, January 2001.
AUTHORS' ADDRESSES
Erik Nordmark
Sun Microsystems, Inc.
17 Network Circle
Mountain View, CA
USA
phone: +1 650 786 2921
fax: +1 650 786 5896
email: erik.nordmark@sun.com
Marcelo Bagnulo
Universidad Carlos III de Madrid
Av. Universidad 30
Leganes, Madrid 28911
SPAIN
Phone: 34 91 6249500
EMail: marcelo@it.uc3m.es
URI: http://www.it.uc3m.es
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