Internet DRAFT - draft-ietf-dots-multihoming
draft-ietf-dots-multihoming
Network Working Group M. Boucadair
Internet-Draft Orange
Intended status: Informational T. Reddy.K
Expires: 28 October 2022 Akamai
W. Pan
Huawei Technologies
26 April 2022
Multi-homing Deployment Considerations for Distributed-Denial-of-Service
Open Threat Signaling (DOTS)
draft-ietf-dots-multihoming-13
Abstract
This document discusses multi-homing considerations for Distributed-
Denial-of-Service Open Threat Signaling (DOTS). The goal is to
provide some guidance for DOTS clients and client-domain DOTS
gateways when multihomed.
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 https://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 28 October 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
Boucadair, et al. Expires 28 October 2022 [Page 1]
Internet-Draft DOTS Multihoming April 2022
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Multi-Homing Scenarios . . . . . . . . . . . . . . . . . . . 5
4.1. Multi-Homed Residential Single CPE . . . . . . . . . . . 5
4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.4. Multi-homed Enterprise with the Same ISP . . . . . . . . 7
5. DOTS Multi-homing Deployment Considerations . . . . . . . . . 8
5.1. Residential CPE . . . . . . . . . . . . . . . . . . . . . 8
5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4. Multi-Homed Enterprise: Single ISP . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
In many deployments, it may not be possible for a network to
determine the cause of a distributed Denial-of-Service (DoS) attack
[RFC4732]. Rather, the network may just realize that some resources
appear to be under attack. To help with such situations, the IETF
has specified the DDoS Open Threat Signaling (DOTS) architecture
[RFC8811], where a DOTS client can inform an upstream DOTS server
that its network is under a potential attack and that appropriate
mitigation actions are required. The DOTS protocols can be used to
coordinate real-time mitigation efforts which can evolve as the
attacks mutate, thereby reducing the impact of an attack and leading
Boucadair, et al. Expires 28 October 2022 [Page 2]
Internet-Draft DOTS Multihoming April 2022
to more efficient responsive actions. [RFC8903] identifies a set of
scenarios for DOTS; most of these scenarios involve a Customer
Premises Equipment (CPE).
The high-level base DOTS architecture is illustrated in Figure 1
([RFC8811]):
+-----------+ +-------------+
| Mitigator | ~~~~~~~~~~ | DOTS Server |
+-----------+ +-------------+
|
|
|
+---------------+ +-------------+
| Attack Target | ~~~~~~ | DOTS Client |
+---------------+ +-------------+
Figure 1: Basic DOTS Architecture
[RFC8811] specifies that the DOTS client may be provided with a list
of DOTS servers; each of these servers is associated with one or more
IP addresses. These addresses may or may not be of the same address
family. The DOTS client establishes one or more DOTS sessions by
connecting to the provided DOTS server(s) addresses (e.g., by using
[RFC8973]).
DOTS may be deployed within networks that are connected to one single
upstream provider. DOTS can also be enabled within networks that are
multi-homed. The reader may refer to [RFC3582] for an overview of
multi-homing goals and motivations. This document discusses DOTS
multi-homing considerations. Specifically, the document aims to:
1. Complete the base DOTS architecture with multi-homing specifics.
Those specifics need to be taken into account because:
* Sending a DOTS mitigation request to an arbitrary DOTS server
will not necessarily help in mitigating a DDoS attack.
* Randomly replicating all DOTS mitigation requests among all
available DOTS servers is suboptimal.
* Sequentially contacting DOTS servers may increase the delay
before a mitigation plan is enforced.
2. Identify DOTS deployment schemes in a multi-homing context, where
DOTS services can be offered by all or a subset of upstream
providers.
Boucadair, et al. Expires 28 October 2022 [Page 3]
Internet-Draft DOTS Multihoming April 2022
3. Provide guidelines and recommendations for placing DOTS requests
in multi-homed networks, e.g.,:
* Select the appropriate DOTS server(s).
* Identify cases where anycast is not recommended for DOTS.
This document adopts the following methodology:
* Identify and extract viable deployment candidates from [RFC8903].
* Augment the description with multi-homing technicalities, e.g.,
- One vs. multiple upstream network providers
- One vs. multiple interconnect routers
- Provider-Independent (PI) vs. Provider-Aggregatable (PA) IP
addresses
* Describe the recommended behavior of DOTS clients and client-
domain DOTS gateways for each case.
Multi-homed DOTS agents are assumed to make use of the protocols
defined in [RFC9132] and [RFC8783]. This document does not require
any specific extension to the base DOTS protocols for deploying DOTS
in a multi-homed context.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terminology
This document makes use of the terms defined in [RFC8811], [RFC8612],
and [RFC4116]. In particular:
Provider-Aggregatable (PA) addresses: globally-unique addresses
assigned by a transit provider to a customer. The addresses are
considered "aggregatable" because the set of routes corresponding
to the PA addresses are usually covered by an aggregate route set
corresponding to the address space operated by the transit
provider, from which the assignment was made (Section 2 of
[RFC4116]).
Boucadair, et al. Expires 28 October 2022 [Page 4]
Internet-Draft DOTS Multihoming April 2022
Provider-Independent (PI) addresses: globally-unique addresses that
are not assigned by a transit provider, but are provided by some
other organisation, usually a Regional Internet Registry (RIR)
(Section 2 of [RFC4116]).
IP indifferently refers to IPv4 or IPv6.
4. Multi-Homing Scenarios
This section describes some multi-homing scenarios that are relevant
to DOTS. In the following subsections, only the connections of
border routers are shown; internal network topologies are not
elaborated.
A multihomed network may enable DOTS for all or a subset of its
upstream interconnection links. In such a case, DOTS servers can be
explicitly configured or dynamically discovered by a DOTS client
using means such as those discussed in [RFC8973]. These DOTS servers
can be owned by the upstream provider, managed by a third-party
(e.g., mitigation service provider), or a combination thereof.
If a DOTS server is explicitly configured, it is assumed that an
interface is also provided to bind the DOTS service to an
interconnection link. If no interface is provided, this means that
the DOTS server can be reached via any active interface.
This section distinguishes between residential CPEs vs. enterprise
CPEs because PI addresses may be used for enterprises while this is
not the current practice for residential CPEs.
In the following subsections, all or a subset of interconnection
links are associated with DOTS servers.
4.1. Multi-Homed Residential Single CPE
The scenario shown in Figure 2 is characterized as follows:
* The home network is connected to the Internet using one single
CPE.
* The CPE is connected to multiple provisioning domains (i.e., both
fixed and mobile networks). Provisioning domain (PvD) is
explained in [RFC7556].
Boucadair, et al. Expires 28 October 2022 [Page 5]
Internet-Draft DOTS Multihoming April 2022
In a typical deployment scenario, these provisioning domains are
owned by the same provider (see Section 1 of [RFC8803]). Such a
deployment is meant to seamlessly use both fixed and cellular
networks for bonding, faster hand-overs, or better resiliency
purposes.
* Each of these provisioning domains assigns IP addresses/prefixes
to the CPE and provides additional configuration information such
as a list of DNS servers, DNS suffixes associated with the
network, default gateway address, and DOTS server's name
[RFC8973]. These addresses/prefixes are assumed to be Provider-
Aggregatable (PA).
* Because of ingress filtering, packets forwarded by the CPE towards
a given provisioning domain must be sent with a source IP address
that was assigned by that domain [RFC8043].
+-------+ +-------+
|Fixed | |Mobile |
|Network| |Network|
+---+---+ +---+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Home Network
||
+--++-+
| CPE |
+-----+
... (Internal Network)
Figure 2: Typical Multi-homed Residential CPE
4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs
The scenario shown in Figure 3 is characterized as follows:
* The enterprise network is connected to the Internet using a single
router.
* That router is connected to multiple provisioning domains managed
by distinct administrative entities.
Unlike the previous scenario, two sub-cases can be considered for an
enterprise network with regards to assigned addresses:
1. PI addresses/prefixes: The enterprise is the owner of the IP
addresses/prefixes; the same address/prefix is then used when
establishing communications over any of the provisioning domains.
Boucadair, et al. Expires 28 October 2022 [Page 6]
Internet-Draft DOTS Multihoming April 2022
2. PA addresses/prefixes: Each of the provisioning domains assigns
IP addresses/prefixes to the enterprise network. These
addresses/prefixes are used when communicating over the
provisioning domain that assigned them.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Enterprise Network
||
+--++-+
| CPE |
+-----+
... (Internal Network)
Figure 3: Multi-homed Enterprise Network (Single CPE connected to
Multiple Networks)
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
This scenario is similar to the one described in Section 4.2; the
main difference is that dedicated routers (CPE1 and CPE2) are used to
connect to each provisioning domain.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
......................|..........|.......................
| | Enterprise Network
+---+--+ +--+---+
| CPE1 | | CPE2 |
+------+ +------+
... (Internal Network)
Figure 4: Multi-homed Enterprise Network (Multiple CPEs, Multiple
ISPs)
4.4. Multi-homed Enterprise with the Same ISP
This scenario is a variant of Sections 4.2 and 4.3 in which multi-
homing is supported by the same ISP (i.e., same provisioning domain).
Boucadair, et al. Expires 28 October 2022 [Page 7]
Internet-Draft DOTS Multihoming April 2022
5. DOTS Multi-homing Deployment Considerations
Table 1 provides some sample, non-exhaustive, deployment schemes to
illustrate how DOTS agents may be deployed for each of the scenarios
introduced in Section 4.
+=========================+=======================+===============+
| Scenario | DOTS client | Client-domain |
| | | DOTS gateway |
+=========================+=======================+===============+
| Residential CPE | CPE | N/A |
+-------------------------+-----------------------+---------------+
| Single CPE, Multiple | Internal hosts or CPE | CPE |
| provisioning domains | | |
+-------------------------+-----------------------+---------------+
| Multiple CPEs, Multiple | Internal hosts or all | CPEs (CPE1 |
| provisioning domains | CPEs (CPE1 and CPE2) | and CPE2) |
+-------------------------+-----------------------+---------------+
| Multi-homed enterprise, | Internal hosts or all | CPEs (CPE1 |
| Single provisioning | CPEs (CPE1 and CPE2) | and CPE2) |
| domain | | |
+-------------------------+-----------------------+---------------+
Table 1: Sample Deployment Cases
These deployment schemes are further discussed in the following
subsections.
5.1. Residential CPE
Figure 5 depicts DOTS sessions that need to be established between a
DOTS client (C) and two DOTS servers (S1, S2) within the context of
the scenario described in Section 4.1. As listed in Table 1, the
DOTS client is hosted by the residential CPE.
Boucadair, et al. Expires 28 October 2022 [Page 8]
Internet-Draft DOTS Multihoming April 2022
+--+
----------|S1|
/ +--+
/ DOTS Server Domain #1
/
+---+/
| C |
+---+\
CPE \
\
\ +--+
----------|S2|
+--+
DOTS Server Domain #2
Figure 5: DOTS Associations for a Multihomed Residential CPE
The DOTS client MUST resolve the DOTS server's name provided by each
provisioning domain using either the DNS servers learned from the
respective provisioning domain or from the DNS servers associated
with the interface(s) for which a DOTS server was explicitly
configured (Section 4). IPv6-capable DOTS clients MUST use the
source address selection algorithm defined in [RFC6724] to select the
candidate source addresses to contact each of these DOTS servers.
DOTS sessions MUST be established and MUST be maintained with each of
the DOTS servers because the mitigation scope of each of these
servers is restricted. The DOTS client MUST use the security
credentials (a certificate, typically) provided by a provisioning
domain to authenticate itself to the DOTS server(s) provided by the
same provisioning domain. How such security credentials are provided
to the DOTS client is out of the scope of this document. The reader
may refer to Section 7.1 of [RFC9132] for more details about DOTS
authentication methods.
When conveying a mitigation request to protect the attack target(s),
the DOTS client MUST select an available DOTS server whose network
has assigned the IP prefixes from which target prefixes/addresses are
derived. This implies that if no appropriate DOTS server is found,
the DOTS client MUST NOT send the mitigation request to any other
available DOTS server.
For example, a mitigation request to protect target resources bound
to a PA IP address/prefix cannot be satisfied by a provisioning
domain other than the one that owns those addresses/prefixes.
Consequently, if a CPE detects a DDoS attack that spreads over all
its network attachments, it MUST contact all DOTS servers for
mitigation purposes.
Boucadair, et al. Expires 28 October 2022 [Page 9]
Internet-Draft DOTS Multihoming April 2022
The DOTS client MUST be able to associate a DOTS server with each
provisioning domain it serves. For example, if the DOTS client is
provisioned with S1 using DHCP when attaching to a first network and
with S2 using Protocol Configuration Option (PCO) [TS.24008] when
attaching to a second network, the DOTS client must record the
interface from which a DOTS server was provisioned. A DOTS signaling
session to a given DOTS server must be established using the
interface from which the DOTS server was provisioned. If a DOTS
server is explicitly configured, DOTS signaling with that server must
be established via the interfaces that are indicated in the explicit
configuration or via any active interface if no interface is
configured.
5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs
Figure 6 illustrates the DOTS sessions that can be established with a
client-domain DOTS gateway (hosted within the CPE as per Table 1),
which is enabled within the context of the scenario described in
Section 4.2. This deployment is characterized as follows:
* One or more DOTS clients are enabled in hosts located in the
internal network.
* A client-domain DOTS gateway is enabled to aggregate and then
relay the requests towards upstream DOTS servers.
+--+
.................... ----------|S1|
. +---+ . / +--+
. | C1|----+ ./ DOTS Server Domain #1
. +---+ | .
. | /.
.+---+ +-+-+/ .
.| C3|------| G | .
.+---+ +-+-+\ .
. CPE \.
. +---+ | .
. | C2|----+ .\
. +---+ . \ +--+
'..................' ----------|S2|
+--+
DOTS Client Domain DOTS Server Domain #2
Figure 6: Multiple DOTS Clients, Single DOTS Gateway, Multiple
DOTS Servers
Boucadair, et al. Expires 28 October 2022 [Page 10]
Internet-Draft DOTS Multihoming April 2022
When PA addresses/prefixes are in use, the same considerations
discussed in Section 5.1 need to be followed by the client-domain
DOTS gateway to contact its DOTS server(s). The client-domain DOTS
gateways can be reachable from DOTS clients by using a unicast
address or an anycast address (Section 3.2.4 of [RFC8811]).
Nevertheless, when PI addresses/prefixes are assigned and absent any
policy, the client-domain DOTS gateway SHOULD send mitigation
requests to all its DOTS servers. Otherwise, the attack traffic may
still be delivered via the ISP that hasn't received the mitigation
request.
An alternate deployment model is depicted in Figure 7. This
deployment assumes that:
* One or more DOTS clients are enabled in hosts located in the
internal network. These DOTS clients may use [RFC8973] to
discover their DOTS server(s).
* These DOTS clients communicate directly with upstream DOTS
servers.
..........
. +--+ .
+--------|C1|--------+
| . +--+ . |
| . . |
+--+ . +--+ . +--+
|S2|------|C3|------|S1|
+--+ . +--+ . +--+
| . . |
| . +--+ . |
+--------|C2|--------+
. +--+ .
'........'
DOTS Client
Domain
Figure 7: Multiple DOTS Clients, Multiple DOTS Servers
If PI addresses/prefixes are in use, the DOTS client MUST send a
mitigation request to all the DOTS servers. The use of the same
anycast addresses to reach these DOTS servers is NOT RECOMMENDED. If
a well-known anycast address is used to reach multiple DOTS servers,
the CPE may not be able to select the appropriate provisioning domain
to which the mitigation request should be forwarded. As a
consequence, the request may not be forwarded to the appropriate DOTS
server.
Boucadair, et al. Expires 28 October 2022 [Page 11]
Internet-Draft DOTS Multihoming April 2022
If PA addresses/prefixes are used, the same considerations discussed
in Section 5.1 need to be followed by the DOTS clients. Because DOTS
clients are not embedded in the CPE and multiple addresses/prefixes
may not be assigned to the DOTS client (typically in an IPv4
context), some issues may arise in how to steer traffic towards the
appropriate DOTS server by using the appropriate source IP address.
These complications discussed in [RFC4116] are not specific to DOTS.
Another deployment approach is to enable many DOTS clients; each of
them is responsible for handling communications with a specific DOTS
server (see Figure 8).
..........
. +--+ .
+--------|C1| .
| . +--+ .
+--+ . +--+ . +--+
|S2| . |C2|------|S1|
+--+ . +--+ . +--+
'........'
DOTS Client
Domain
Figure 8: Single Homed DOTS Clients
For both deployments depicted in Figures 7 and 8, each DOTS client
SHOULD be provided with policies (e.g., a prefix filter that is used
to filter DDoS detection alarms) that will trigger DOTS
communications with the DOTS servers. Such policies will help the
DOTS client to select the appropriate destination DOTS server. The
CPE MUST select the appropriate source IP address when forwarding
DOTS messages received from an internal DOTS client.
5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
The deployments depicted in Figures 7 and 8 also apply to the
scenario described in Section 4.3. One specific problem for this
scenario is to select the appropriate exit router when contacting a
given DOTS server.
An alternative deployment scheme is shown in Figure 9:
* DOTS clients are enabled in hosts located in the internal network.
* A client-domain DOTS gateway is enabled in each CPE (CPE1 and CPE2
per Table 1).
Boucadair, et al. Expires 28 October 2022 [Page 12]
Internet-Draft DOTS Multihoming April 2022
* Each of these client-domain DOTS gateways communicates with the
DOTS server of the provisioning domain.
.................................
. +---+ .
. +------------| C1|----+ .
. | +---+ | .
. | | .
+--+ . +-+-+ +---+ +-+-+ . +--+
|S2|------|G2 |------| C3|------|G1 |------|S1|
+--+ . +-+-+ +---+ +-+-+ . +--+
. CPE2 CPE1 .
. | +---+ | .
. +------------| C2|----+ .
. +---+ .
'...............................'
DOTS Client Domain
Figure 9: Multiple DOTS Clients, Multiple DOTS Gateways, Multiple
DOTS Servers
When PI addresses/prefixes are used, DOTS clients MUST contact all
the client-domain DOTS gateways to send a DOTS message. Client-
domain DOTS gateways will then relay the request to the DOTS servers
as a function of local policy. Note that (same) anycast addresses
cannot be used to establish DOTS sessions between DOTS clients and
client-domain DOTS gateways because only one DOTS gateway will
receive the mitigation request.
When PA addresses/prefixes are used, but no filter rules are provided
to DOTS clients, the latter MUST contact all client-domain DOTS
gateways simultaneously to send a DOTS message. Upon receipt of a
request by a client-domain DOTS gateway, it MUST check whether the
request is to be forwarded upstream (if the target IP prefix is
managed by the upstream server) or rejected.
When PA addresses/prefixes are used, but specific filter rules are
provided to DOTS clients using some means that are out of scope of
this document, the clients MUST select the appropriate client-domain
DOTS gateway to reach. The use of the same anycast addresses is NOT
RECOMMENDED to reach client-domain DOTS gateways.
5.4. Multi-Homed Enterprise: Single ISP
The key difference of the scenario described in Section 4.4 compared
to the other scenarios is that multi-homing is provided by the same
ISP. Concretely, that ISP can decide to provision the enterprise
network with:
Boucadair, et al. Expires 28 October 2022 [Page 13]
Internet-Draft DOTS Multihoming April 2022
* The same DOTS server for all network attachments.
* Distinct DOTS servers for each network attachment. These DOTS
servers need to coordinate when a mitigation action is received
from the enterprise network.
In both cases, DOTS agents enabled within the enterprise network MAY
decide to select one or all network attachments to send DOTS
mitigation requests.
6. Security Considerations
A set of security threats related to multihoming are discussed in
[RFC4218].
DOTS-related security considerations are discussed in Section 4 of
[RFC8811].
DOTS clients should control the information that they share with peer
DOTS servers. In particular, if a DOTS client maintains DOTS
sessions with specific DOTS servers per interconnection link, the
DOTS client SHOULD NOT leak information specific to a given link to
DOTS servers on different interconnection links that are not
authorized to mitigate attacks for that given link. Whether this
constraint is relaxed is deployment-specific and must be subject to
explicit consent from the DOTS client domain administrator. How to
seek for such consent is implementation- and deployment-specific.
7. IANA Considerations
This document does not require any action from IANA.
8. Acknowledgements
Thanks to Roland Dobbins, Nik Teague, Jon Shallow, Dan Wing, and
Christian Jacquenet for sharing their comments on the mailing list.
Thanks to Kirill Kasavchenko for the comments.
Thanks to Kathleen Moriarty for the secdir review, Joel Jaeggli for
the opsdir review, Mirja Kuhlewind for the tsvart review, and Dave
Thaler for the Intdir review.
Many thanks to Roman Danyliw for the careful AD review.
Thanks to Lars Eggert, Robert Wilton, Paul Wouters, Erik Kline, and
Eric Vyncke for the IESG review.
Boucadair, et al. Expires 28 October 2022 [Page 14]
Internet-Draft DOTS Multihoming April 2022
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
<https://www.rfc-editor.org/info/rfc6724>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8811] Mortensen, A., Ed., Reddy.K, T., Ed., Andreasen, F.,
Teague, N., and R. Compton, "DDoS Open Threat Signaling
(DOTS) Architecture", RFC 8811, DOI 10.17487/RFC8811,
August 2020, <https://www.rfc-editor.org/info/rfc8811>.
9.2. Informative References
[RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site-
Multihoming Architectures", RFC 3582,
DOI 10.17487/RFC3582, August 2003,
<https://www.rfc-editor.org/info/rfc3582>.
[RFC4116] Abley, J., Lindqvist, K., Davies, E., Black, B., and V.
Gill, "IPv4 Multihoming Practices and Limitations",
RFC 4116, DOI 10.17487/RFC4116, July 2005,
<https://www.rfc-editor.org/info/rfc4116>.
[RFC4218] Nordmark, E. and T. Li, "Threats Relating to IPv6
Multihoming Solutions", RFC 4218, DOI 10.17487/RFC4218,
October 2005, <https://www.rfc-editor.org/info/rfc4218>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006,
<https://www.rfc-editor.org/info/rfc4732>.
[RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain
Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
<https://www.rfc-editor.org/info/rfc7556>.
Boucadair, et al. Expires 28 October 2022 [Page 15]
Internet-Draft DOTS Multihoming April 2022
[RFC8043] Sarikaya, B. and M. Boucadair, "Source-Address-Dependent
Routing and Source Address Selection for IPv6 Hosts:
Overview of the Problem Space", RFC 8043,
DOI 10.17487/RFC8043, January 2017,
<https://www.rfc-editor.org/info/rfc8043>.
[RFC8612] Mortensen, A., Reddy, T., and R. Moskowitz, "DDoS Open
Threat Signaling (DOTS) Requirements", RFC 8612,
DOI 10.17487/RFC8612, May 2019,
<https://www.rfc-editor.org/info/rfc8612>.
[RFC8783] Boucadair, M., Ed. and T. Reddy.K, Ed., "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Data
Channel Specification", RFC 8783, DOI 10.17487/RFC8783,
May 2020, <https://www.rfc-editor.org/info/rfc8783>.
[RFC8803] Bonaventure, O., Ed., Boucadair, M., Ed., Gundavelli, S.,
Seo, S., and B. Hesmans, "0-RTT TCP Convert Protocol",
RFC 8803, DOI 10.17487/RFC8803, July 2020,
<https://www.rfc-editor.org/info/rfc8803>.
[RFC8903] Dobbins, R., Migault, D., Moskowitz, R., Teague, N., Xia,
L., and K. Nishizuka, "Use Cases for DDoS Open Threat
Signaling", RFC 8903, DOI 10.17487/RFC8903, May 2021,
<https://www.rfc-editor.org/info/rfc8903>.
[RFC8973] Boucadair, M. and T. Reddy.K, "DDoS Open Threat Signaling
(DOTS) Agent Discovery", RFC 8973, DOI 10.17487/RFC8973,
January 2021, <https://www.rfc-editor.org/info/rfc8973>.
[RFC9132] Boucadair, M., Ed., Shallow, J., and T. Reddy.K,
"Distributed Denial-of-Service Open Threat Signaling
(DOTS) Signal Channel Specification", RFC 9132,
DOI 10.17487/RFC9132, September 2021,
<https://www.rfc-editor.org/info/rfc9132>.
[TS.24008] 3GPP, "Mobile radio interface Layer 3 specification; Core
network protocols; Stage 3 (Release 16)", December 2019,
<http://www.3gpp.org/DynaReport/24008.htm>.
Authors' Addresses
Mohamed Boucadair
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
Boucadair, et al. Expires 28 October 2022 [Page 16]
Internet-Draft DOTS Multihoming April 2022
Tirumaleswar Reddy.K
Akamai
Embassy Golf Link Business Park
Bangalore 560071
Karnataka
India
Email: kondtir@gmail.com
Wei Pan
Huawei Technologies
Email: william.panwei@huawei.com
Boucadair, et al. Expires 28 October 2022 [Page 17]
