< draft-ietf-dots-multihoming-07.txt   draft-ietf-dots-multihoming-08.txt >
Network Working Group M. Boucadair Network Working Group M. Boucadair
Internet-Draft Orange Internet-Draft Orange
Intended status: Standards Track T. Reddy Intended status: Standards Track T. Reddy
Expires: January 7, 2022 McAfee Expires: 28 April 2022 McAfee
W. Pan W. Pan
Huawei Technologies Huawei Technologies
July 6, 2021 25 October 2021
Multi-homing Deployment Considerations for Distributed-Denial-of-Service Multi-homing Deployment Considerations for Distributed-Denial-of-Service
Open Threat Signaling (DOTS) Open Threat Signaling (DOTS)
draft-ietf-dots-multihoming-07 draft-ietf-dots-multihoming-08
Abstract Abstract
This document discusses multi-homing considerations for Distributed- This document discusses multi-homing considerations for Distributed-
Denial-of-Service Open Threat Signaling (DOTS). The goal is to Denial-of-Service Open Threat Signaling (DOTS). The goal is to
provide some guidance for DOTS clients/gateways when multihomed. provide some guidance for DOTS clients/gateways when multihomed.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
skipping to change at page 1, line 36 skipping to change at page 1, line 36
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 7, 2022. This Internet-Draft will expire on 28 April 2022.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Multi-Homing Scenarios . . . . . . . . . . . . . . . . . . . 5 4. Multi-Homing Scenarios . . . . . . . . . . . . . . . . . . . 5
4.1. Multi-Homed Residential Single CPE . . . . . . . . . . . 5 4.1. Multi-Homed Residential Single CPE . . . . . . . . . . . 5
4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream 4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream 4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.4. Multi-homed Enterprise with the Same ISP . . . . . . . . 7 4.4. Multi-homed Enterprise with the Same ISP . . . . . . . . 7
5. DOTS Multi-homing Deployment Considerations . . . . . . . . . 8 5. DOTS Multi-homing Deployment Considerations . . . . . . . . . 7
5.1. Residential CPE . . . . . . . . . . . . . . . . . . . . . 8 5.1. Residential CPE . . . . . . . . . . . . . . . . . . . . . 8
5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream 5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream 5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 12 ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4. Multi-Homed Enterprise: Single ISP . . . . . . . . . . . 13 5.4. Multi-Homed Enterprise: Single ISP . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
skipping to change at page 3, line 25 skipping to change at page 3, line 31
Figure 1: Basic DOTS Architecture Figure 1: Basic DOTS Architecture
[RFC8811] specifies that the DOTS client may be provided with a list [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 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 IP addresses. These addresses may or may not be of the same address
family. The DOTS client establishes one or more DOTS sessions by family. The DOTS client establishes one or more DOTS sessions by
connecting to the provided DOTS server(s) addresses (e.g., by using connecting to the provided DOTS server(s) addresses (e.g., by using
[RFC8973]). [RFC8973]).
DOTS may be deployed within networks that are connected to one single DOTS may be deployed within networks that are connected to one single
upstream provider. It can also be enabled within networks that are upstream provider. DOTS can also be enabled within networks that are
multi-homed. The reader may refer to [RFC3582] for an overview of multi-homed. The reader may refer to [RFC3582] for an overview of
multi-homing goals and motivations. This document discusses DOTS multi-homing goals and motivations. This document discusses DOTS
multi-homing considerations. Specifically, the document aims to: multi-homing considerations. Specifically, the document aims to:
1. Complete the base DOTS architecture with multi-homing specifics. 1. Complete the base DOTS architecture with multi-homing specifics.
Those specifics need to be taken into account because: Those specifics need to be taken into account because:
* Sending a DOTS mitigation request to an arbitrary DOTS server * Sending a DOTS mitigation request to an arbitrary DOTS server
will not necessarily help in mitigating a DDoS attack. will not necessarily help in mitigating a DDoS attack.
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3. Provide guidelines and recommendations for placing DOTS requests 3. Provide guidelines and recommendations for placing DOTS requests
in multi-homed networks, e.g.,: in multi-homed networks, e.g.,:
* Select the appropriate DOTS server(s). * Select the appropriate DOTS server(s).
* Identify cases where anycast is not recommended for DOTS. * Identify cases where anycast is not recommended for DOTS.
This document adopts the following methodology: This document adopts the following methodology:
o Identify and extract viable deployment candidates from [RFC8903]. * Identify and extract viable deployment candidates from [RFC8903].
o Augment the description with multi-homing technicalities, e.g., * Augment the description with multi-homing technicalities, e.g.,
* One vs. multiple upstream network providers - One vs. multiple upstream network providers
* One vs. multiple interconnect routers - One vs. multiple interconnect routers
* Provider-Independent (PI) vs. Provider-Aggregatable (PA) IP - Provider-Independent (PI) vs. Provider-Aggregatable (PA) IP
addresses addresses
o Describe the recommended behavior of DOTS clients and gateways for * Describe the recommended behavior of DOTS clients and gateways for
each case. each case.
Multi-homed DOTS agents are assumed to make use of the protocols Multi-homed DOTS agents are assumed to make use of the protocols
defined in [I-D.ietf-dots-rfc8782-bis] and [RFC8783]; no specific defined in [RFC9132] and [RFC8783]; no specific extension is required
extension is required to the base DOTS protocols for deploying DOTS to the base DOTS protocols for deploying DOTS in a multi-homed
in a multi-homed context. context.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119][RFC8174] when, and only when, they appear in all 14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Terminology 3. Terminology
This document makes use of the terms defined in [RFC8811] and This document makes use of the terms defined in [RFC8811] and
[RFC4116]. In particular: [RFC4116]. In particular:
Provider-Aggregatable (PA) addresses are globally-unique addresses Provider-Aggregatable (PA) addresses: are globally-unique addresses
assigned by a transit provider to a customer. The addresses are assigned by a transit provider to a customer. The addresses are
considered "aggregatable" because the set of routes corresponding considered "aggregatable" because the set of routes corresponding
to the PA addresses are usually covered by an aggregate route set to the PA addresses are usually covered by an aggregate route set
corresponding to the address space operated by the transit corresponding to the address space operated by the transit
provider, from which the assignment was made (Section 2 of provider, from which the assignment was made (Section 2 of
[RFC4116]). [RFC4116]).
Provider-Independent (PI) addresses are globally-unique addresses Provider-Independent (PI) addresses: are globally-unique addresses
which are not assigned by a transit provider, but are provided by which are not assigned by a transit provider, but are provided by
some other organisation, usually a Regional Internet Registry some other organisation, usually a Regional Internet Registry
(RIR) (Section 2 of [RFC4116]). (RIR) (Section 2 of [RFC4116]).
IP indifferently refers to IPv4 or IPv6. IP indifferently refers to IPv4 or IPv6.
4. Multi-Homing Scenarios 4. Multi-Homing Scenarios
This section describes some multi-homing scenarios that are relevant This section describes some multi-homing scenarios that are relevant
to DOTS. In the following subsections, only the connections of to DOTS. In the following subsections, only the connections of
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elaborated. elaborated.
This section distinguishes between residential CPEs vs. enterprise This section distinguishes between residential CPEs vs. enterprise
CPEs because PI addresses may be used for enterprises while this is CPEs because PI addresses may be used for enterprises while this is
not the current practice for residential CPEs. not the current practice for residential CPEs.
4.1. Multi-Homed Residential Single CPE 4.1. Multi-Homed Residential Single CPE
The scenario shown in Figure 2 is characterized as follows: The scenario shown in Figure 2 is characterized as follows:
o The home network is connected to the Internet using one single * The home network is connected to the Internet using one single
CPE. CPE.
o The CPE is connected to multiple provisioning domains (i.e., both * The CPE is connected to multiple provisioning domains (i.e., both
fixed and mobile networks). Provisioning domain (PvD) is fixed and mobile networks). Provisioning domain (PvD) is
explained in [RFC7556]. explained in [RFC7556].
In a typical deployment scenario, these provisioning domains are In a typical deployment scenario, these provisioning domains are
owned by the same provider (see Section 1 of [RFC8803]). Such a owned by the same provider (see Section 1 of [RFC8803]). Such a
deployment is meant to seamlessly use both fixed and cellular deployment is meant to seamlessly use both fixed and cellular
networks for bonding, faster hand-overs, or better resiliency networks for bonding, faster hand-overs, or better resiliency
purposes. purposes.
o Each of these provisioning domains assigns IP addresses/prefixes * Each of these provisioning domains assigns IP addresses/prefixes
to the CPE and provides additional configuration information such to the CPE and provides additional configuration information such
as a list of DNS servers, DNS suffixes associated with the as a list of DNS servers, DNS suffixes associated with the
network, default gateway address, and DOTS server's name network, default gateway address, and DOTS server's name
[RFC8973]. These addresses/prefixes are assumed to be Provider- [RFC8973]. These addresses/prefixes are assumed to be Provider-
Aggregatable (PA). Aggregatable (PA).
o Because of ingress filtering, packets forwarded by the CPE towards * Because of ingress filtering, packets forwarded by the CPE towards
a given provisioning domain must be sent with a source IP address a given provisioning domain must be sent with a source IP address
that was assigned by that domain [RFC8043]. that was assigned by that domain [RFC8043].
+-------+ +-------+ +-------+ +-------+
|Fixed | |Mobile | |Fixed | |Mobile |
|Network| |Network| |Network| |Network|
+---+---+ +---+---+ +---+---+ +---+---+
| | Service Providers | | Service Providers
............|....................|....................... ............|....................|.......................
+---------++---------+ Home Network +---------++---------+ Home Network
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| CPE | | CPE |
+-----+ +-----+
... (Internal Network) ... (Internal Network)
Figure 2: Typical Multi-homed Residential CPE Figure 2: Typical Multi-homed Residential CPE
4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs 4.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs
The scenario shown in Figure 3 is characterized as follows: The scenario shown in Figure 3 is characterized as follows:
o The enterprise network is connected to the Internet using a single * The enterprise network is connected to the Internet using a single
router. router.
o That router is connected to multiple provisioning domains (i.e., * That router is connected to multiple provisioning domains (i.e.,
managed by distinct administrative entities). managed by distinct administrative entities).
Unlike the previous scenario, two sub-cases can be considered for an Unlike the previous scenario, two sub-cases can be considered for an
enterprise network with regards to assigned addresses: enterprise network with regards to assigned addresses:
1. PI addresses/prefixes: The enterprise is the owner of the IP 1. PI addresses/prefixes: The enterprise is the owner of the IP
addresses/prefixes; the same address/prefix is then used when addresses/prefixes; the same address/prefix is then used when
establishing communications over any of the provisioning domains. establishing communications over any of the provisioning domains.
2. PA addresses/prefixes: Each of the provisioning domains assigns 2. PA addresses/prefixes: Each of the provisioning domains assigns
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| | Service Providers | | Service Providers
............|....................|....................... ............|....................|.......................
+---------++---------+ Enterprise Network +---------++---------+ Enterprise Network
|| ||
+--++-+ +--++-+
| rtr | | rtr |
+-----+ +-----+
... (Internal Network) ... (Internal Network)
Figure 3: Multi-homed Enterprise Network (Single CPE connected to Figure 3: Multi-homed Enterprise Network (Single CPE connected to
Multiple Networks) Multiple Networks)
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream ISPs 4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
This scenario is similar to the one described in Section 4.2; the This scenario is similar to the one described in Section 4.2; the
main difference is that dedicated routers are used to connect to each main difference is that dedicated routers are used to connect to each
provisioning domain. provisioning domain.
+------+ +------+ +------+ +------+
| ISP1 | | ISP2 | | ISP1 | | ISP2 |
+---+--+ +--+---+ +---+--+ +--+---+
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This scenario is a variant of Section 4.2 and Section 4.3 in which This scenario is a variant of Section 4.2 and Section 4.3 in which
multi-homing is supported by the same ISP (i.e., same provisioning multi-homing is supported by the same ISP (i.e., same provisioning
domain). domain).
5. DOTS Multi-homing Deployment Considerations 5. DOTS Multi-homing Deployment Considerations
Table 1 provides some sample, non-exhaustive, deployment schemes to Table 1 provides some sample, non-exhaustive, deployment schemes to
illustrate how DOTS agents may be deployed for each of the scenarios illustrate how DOTS agents may be deployed for each of the scenarios
introduced in Section 4. introduced in Section 4.
+---------------------------+-------------------------+-------------+ +============================+=======================+==============+
| Scenario | DOTS client | DOTS | | Scenario | DOTS client | DOTS |
| | | gateway | | | | gateway |
+---------------------------+-------------------------+-------------+ +============================+=======================+==============+
| Residential CPE | CPE | N/A | | Residential CPE | CPE | N/A |
+---------------------------+-------------------------+-------------+ +----------------------------+-----------------------+--------------+
| Single CPE, Multiple | Internal hosts or CPE | CPE | | Single CPE, Multiple | Internal hosts or CPE | CPE |
| provisioning domains | | | | provisioning domains | | |
+---------------------------+-------------------------+-------------+ +----------------------------+-----------------------+--------------+
| Multiple CPEs, Multiple | Internal hosts or all | CPEs (rtr1 | | Multiple CPEs, Multiple | Internal hosts or all | CPEs (rtr1 |
| provisioning domains | CPEs (rtr1 and rtr2) | and rtr2) | | provisioning domains | CPEs (rtr1 and rtr2) | and rtr2) |
+---------------------------+-------------------------+-------------+ +----------------------------+-----------------------+--------------+
| Multi-homed enterprise, | Internal hosts or all | CPEs (rtr1 | | Multi-homed enterprise, | Internal hosts or all | CPEs (rtr1 |
| Single provisioning | CPEs (rtr1 and rtr2) | and rtr2) | | Single provisioning domain | CPEs (rtr1 and rtr2) | and rtr2) |
| domain | | | +----------------------------+-----------------------+--------------+
+---------------------------+-------------------------+-------------+
Table 1: Sample Deployment Cases Table 1: Sample Deployment Cases
These deployment schemes are further discussed in the following These deployment schemes are further discussed in the following
subsections. subsections.
5.1. Residential CPE 5.1. Residential CPE
Figure 5 depicts DOTS sessions that need to be established between a 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 DOTS client (C) and two DOTS servers (S1, S2) within the context of
the scenario described in Section 4.1. the scenario described in Section 4.1.
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For example, a mitigation request to protect target resources bound For example, a mitigation request to protect target resources bound
to a PA IP address/prefix cannot be satisfied by a provisioning to a PA IP address/prefix cannot be satisfied by a provisioning
domain other than the one that owns those addresses/prefixes. domain other than the one that owns those addresses/prefixes.
Consequently, if a CPE detects a DDoS attack that spreads over all Consequently, if a CPE detects a DDoS attack that spreads over all
its network attachments, it MUST contact both DOTS servers for its network attachments, it MUST contact both DOTS servers for
mitigation purposes. mitigation purposes.
The DOTS client MUST be able to associate a DOTS server with each The DOTS client MUST be able to associate a DOTS server with each
provisioning domain. For example, if the DOTS client is provisioned provisioning domain. For example, if the DOTS client is provisioned
with S1 using DHCP when attaching to a first network and with S2 with S1 using DHCP when attaching to a first network and with S2
using Protocol Configuration Option (PCO) when attaching to a second using Protocol Configuration Option (PCO) [TS.24008] when attaching
network, the DOTS client must record the interface from which a DOTS to a second network, the DOTS client must record the interface from
server was provisioned. DOTS signaling session to a given DOTS which a DOTS server was provisioned. DOTS signaling session to a
server must be established using the interface from which the DOTS given DOTS server must be established using the interface from which
server was provisioned. the DOTS server was provisioned.
+--+ +--+
----------|S1| ----------|S1|
/ +--+ / +--+
/ DOTS Server Domain #1 / DOTS Server Domain #1
/ /
+---+/ +---+/
| C | | C |
+---+\ +---+\
\ \
\ \
\ +--+ \ +--+
----------|S2| ----------|S2|
+--+ +--+
DOTS Server Domain #2 DOTS Server Domain #2
Figure 5: DOTS Associations for a Multihomed Residential CPE Figure 5: DOTS Associations for a Multihomed Residential CPE
5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs 5.2. Multi-Homed Enterprise: Single CPE, Multiple Upstream ISPs
Figure 6 illustrates a first set of DOTS associations that can be Figure 6 illustrates a first set of DOTS associations that can be
established with a DOTS gateway, which is enabled within the context established with a DOTS gateway, which is enabled within the context
of the scenario described in Section 4.2. This deployment is of the scenario described in Section 4.2. This deployment is
characterized as follows: characterized as follows:
o One of more DOTS clients are enabled in hosts located in the * One of more DOTS clients are enabled in hosts located in the
internal network. internal network.
o A DOTS gateway is enabled to aggregate and then relay the requests * A DOTS gateway is enabled to aggregate and then relay the requests
towards upstream DOTS servers. towards upstream DOTS servers.
When PA addresses/prefixes are in use, the same considerations When PA addresses/prefixes are in use, the same considerations
discussed in Section 5.1 need to be followed by the DOTS gateway to discussed in Section 5.1 need to be followed by the DOTS gateway to
contact its DOTS server(s). The DOTS gateways can be reachable from contact its DOTS server(s). The DOTS gateways can be reachable from
DOTS clients by using an unicast address or an anycast address. DOTS clients by using an unicast address or an anycast address.
Nevertheless, when PI addresses/prefixes are assigned, the DOTS Nevertheless, when PI addresses/prefixes are assigned, the DOTS
gateway MUST send mitigation requests to all its DOTS servers. gateway MUST send mitigation requests to all its DOTS servers.
Otherwise, the attack traffic may still be delivered via the ISP Otherwise, the attack traffic may still be delivered via the ISP
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+---+ +-+-+/ +---+ +-+-+/
| C3|------| G | | C3|------| G |
+---+ +-+-+\ +---+ +-+-+\
+---+ | \ +---+ | \
| C2|----+ \ | C2|----+ \
+---+ \ +--+ +---+ \ +--+
----------|S2| ----------|S2|
+--+ +--+
DOTS Server Domain #2 DOTS Server Domain #2
Figure 6: Multiple DOTS Clients, Single DOTS Gateway, Multiple DOTS Figure 6: Multiple DOTS Clients, Single DOTS Gateway, Multiple
Servers DOTS Servers
An alternate deployment model is depicted in Figure 7. This An alternate deployment model is depicted in Figure 7. This
deployment assumes that: deployment assumes that:
o One or more DOTS clients are enabled in hosts located in the * One or more DOTS clients are enabled in hosts located in the
internal network. These DOTS clients may use [RFC8973] to internal network. These DOTS clients may use [RFC8973] to
discover their DOTS server(s). discover their DOTS server(s).
o These DOTS clients communicate directly with upstream DOTS * These DOTS clients communicate directly with upstream DOTS
servers. servers.
If PI addresses/prefixes are in use, the DOTS client MUST send a If PI addresses/prefixes are in use, the DOTS client MUST send a
mitigation request to all the DOTS servers. The use of anycast mitigation request to all the DOTS servers. The use of anycast
addresses to reach the DOTS servers is NOT RECOMMENDED. addresses to reach the DOTS servers is NOT RECOMMENDED.
If PA addresses/prefixes are used, the same considerations discussed If PA addresses/prefixes are used, the same considerations discussed
in Section 5.1 need to be followed by the DOTS clients. Because DOTS in Section 5.1 need to be followed by the DOTS clients. Because DOTS
clients are not embedded in the CPE and multiple addreses/prefixes clients are not embedded in the CPE and multiple addreses/prefixes
may not be assigned to the DOTS client (typically in an IPv4 may not be assigned to the DOTS client (typically in an IPv4
skipping to change at page 11, line 25 skipping to change at page 11, line 29
|S2|------|C3|------|S1| |S2|------|C3|------|S1|
+--+ . +--+ . +--+ +--+ . +--+ . +--+
| . . | | . . |
| . +--+ . | | . +--+ . |
+--------|C2|--------+ +--------|C2|--------+
. +--+ . . +--+ .
.......... ..........
DOTS Client DOTS Client
Domain Domain
Figure 7: Multiple DOTS Clients, Multiple DOTS Servers Figure 7: Multiple DOTS Clients, Multiple DOTS Servers
Another deployment approach is to enable many DOTS clients; each of Another deployment approach is to enable many DOTS clients; each of
them is responsible for handling communications with a specific DOTS them is responsible for handling communications with a specific DOTS
server (see Figure 8). server (see Figure 8).
.......... ..........
. +--+ . . +--+ .
+--------|C1| . +--------|C1| .
| . +--+ . | . +--+ .
+--+ . +--+ . +--+ +--+ . +--+ . +--+
skipping to change at page 11, line 51 skipping to change at page 12, line 7
Figure 8: Single Homed DOTS Clients Figure 8: Single Homed DOTS Clients
Each DOTS client SHOULD be provided with policies (e.g., a prefix Each DOTS client SHOULD be provided with policies (e.g., a prefix
filter that will be against DDoS detection alarms) that will trigger filter that will be against DDoS detection alarms) that will trigger
DOTS communications with the DOTS servers. Such policies will help DOTS communications with the DOTS servers. Such policies will help
the DOTS client to select the appropriate destination DOTS server. the DOTS client to select the appropriate destination DOTS server.
The CPE MUST select the appropriate source IP address when forwarding The CPE MUST select the appropriate source IP address when forwarding
DOTS messages received from an internal DOTS client. If anycast DOTS messages received from an internal DOTS client. If anycast
addresses are used to reach DOTS servers, the CPE may not be able to addresses are used to reach multiple DOTS servers, the CPE may not be
select the appropriate provisioning domain to which the mitigation able to select the appropriate provisioning domain to which the
request should be forwarded. As a consequence, the request may not mitigation request should be forwarded. As a consequence, the
be forwarded to the appropriate DOTS server. request may not be forwarded to the appropriate DOTS server.
5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream ISPs 5.3. Multi-Homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
The deployments depicted in Figures 7 and 8 also apply to the The deployments depicted in Figures 7 and 8 also apply to the
scenario described in Section 4.3. One specific problem for this scenario described in Section 4.3. One specific problem for this
scenario is to select the appropriate exit router when contacting a scenario is to select the appropriate exit router when contacting a
given DOTS server. given DOTS server.
An alternative deployment scheme is shown in Figure 9: An alternative deployment scheme is shown in Figure 9:
o DOTS clients are enabled in hosts located in the internal network. * DOTS clients are enabled in hosts located in the internal network.
o A DOTS gateway is enabled in each CPE (rtr1, rtr2). * A DOTS gateway is enabled in each CPE (rtr1, rtr2).
o Each of these DOTS gateways communicates with the DOTS server of * Each of these DOTS gateways communicates with the DOTS server of
the provisioning domain. the provisioning domain.
When PI addresses/prefixes are used, DOTS clients MUST contact all When PI addresses/prefixes are used, DOTS clients MUST contact all
the DOTS gateways to send a DOTS message. DOTS gateways will then the DOTS gateways to send a DOTS message. DOTS gateways will then
relay the request to the DOTS server. Note that the use of anycast relay the request to the DOTS server. The use of anycast addresses
addresses is NOT RECOMMENDED to establish DOTS sessions between DOTS to establish DOTS sessions between DOTS clients and DOTS gateways is
clients and DOTS gateways. not an option.
When PA addresses/prefixes are used, but no filter rules are provided When PA addresses/prefixes are used, but no filter rules are provided
to DOTS clients, the latter MUST contact all DOTS gateways to DOTS clients, the latter MUST contact all DOTS gateways
simultaneously to send a DOTS message. Upon receipt of a request by simultaneously to send a DOTS message. Upon receipt of a request by
a DOTS gateway, it MUST check whether the request is to be forwarded a DOTS gateway, it MUST check whether the request is to be forwarded
upstream (if the target IP prefix is managed by the upstream server) upstream (if the target IP prefix is managed by the upstream server)
or rejected. or rejected.
When PA addresses/prefixes are used, but specific filter rules are When PA addresses/prefixes are used, but specific filter rules are
provided to DOTS clients using some means that are out of scope of provided to DOTS clients using some means that are out of scope of
skipping to change at page 13, line 16 skipping to change at page 13, line 16
+------------| C1|----+ +------------| C1|----+
| +---+ | | +---+ |
+--+ +-+-+ +---+ +-+-+ +--+ +--+ +-+-+ +---+ +-+-+ +--+
|S2|------|G2 |------| C3|------|G1 |------|S1| |S2|------|G2 |------| C3|------|G1 |------|S1|
+--+ +-+-+ +---+ +-+-+ +--+ +--+ +-+-+ +---+ +-+-+ +--+
| +---+ | | +---+ |
+------------| C2|----+ +------------| C2|----+
+---+ +---+
Figure 9: Multiple DOTS Clients, Multiple DOTS Gateways, Multiple Figure 9: Multiple DOTS Clients, Multiple DOTS Gateways, Multiple
DOTS Servers DOTS Servers
5.4. Multi-Homed Enterprise: Single ISP 5.4. Multi-Homed Enterprise: Single ISP
The key difference of the scenario described in Section 4.4 compared 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 to the other scenarios is that multi-homing is provided by the same
ISP. Concretely, that ISP can decide to provision the enterprise ISP. Concretely, that ISP can decide to provision the enterprise
network with: network with:
o The same DOTS server for all network attachments. * The same DOTS server for all network attachments.
o Distinct DOTS servers for each network attachment. These DOTS * Distinct DOTS servers for each network attachment. These DOTS
servers need to coordinate when a mitigation action is received servers need to coordinate when a mitigation action is received
from the enterprise network. from the enterprise network.
In both cases, DOTS agents enabled within the enterprise network MAY In both cases, DOTS agents enabled within the enterprise network MAY
decide to select one or all network attachments to send DOTS decide to select one or all network attachments to send DOTS
mitigation requests. mitigation requests.
6. Security Considerations 6. Security Considerations
DOTS-related security considerations are discussed in Section 4 of DOTS-related security considerations are discussed in Section 4 of
skipping to change at page 14, line 41 skipping to change at page 14, line 41
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8811] Mortensen, A., Ed., Reddy.K, T., Ed., Andreasen, F., [RFC8811] Mortensen, A., Ed., Reddy.K, T., Ed., Andreasen, F.,
Teague, N., and R. Compton, "DDoS Open Threat Signaling Teague, N., and R. Compton, "DDoS Open Threat Signaling
(DOTS) Architecture", RFC 8811, DOI 10.17487/RFC8811, (DOTS) Architecture", RFC 8811, DOI 10.17487/RFC8811,
August 2020, <https://www.rfc-editor.org/info/rfc8811>. August 2020, <https://www.rfc-editor.org/info/rfc8811>.
9.2. Informative References 9.2. Informative References
[I-D.ietf-dots-rfc8782-bis]
Boucadair, M., Shallow, J., and T. Reddy.K, "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Signal
Channel Specification", draft-ietf-dots-rfc8782-bis-06
(work in progress), March 2021.
[RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site- [RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site-
Multihoming Architectures", RFC 3582, Multihoming Architectures", RFC 3582,
DOI 10.17487/RFC3582, August 2003, DOI 10.17487/RFC3582, August 2003,
<https://www.rfc-editor.org/info/rfc3582>. <https://www.rfc-editor.org/info/rfc3582>.
[RFC4116] Abley, J., Lindqvist, K., Davies, E., Black, B., and V. [RFC4116] Abley, J., Lindqvist, K., Davies, E., Black, B., and V.
Gill, "IPv4 Multihoming Practices and Limitations", Gill, "IPv4 Multihoming Practices and Limitations",
RFC 4116, DOI 10.17487/RFC4116, July 2005, RFC 4116, DOI 10.17487/RFC4116, July 2005,
<https://www.rfc-editor.org/info/rfc4116>. <https://www.rfc-editor.org/info/rfc4116>.
skipping to change at page 15, line 44 skipping to change at page 15, line 39
[RFC8903] Dobbins, R., Migault, D., Moskowitz, R., Teague, N., Xia, [RFC8903] Dobbins, R., Migault, D., Moskowitz, R., Teague, N., Xia,
L., and K. Nishizuka, "Use Cases for DDoS Open Threat L., and K. Nishizuka, "Use Cases for DDoS Open Threat
Signaling", RFC 8903, DOI 10.17487/RFC8903, May 2021, Signaling", RFC 8903, DOI 10.17487/RFC8903, May 2021,
<https://www.rfc-editor.org/info/rfc8903>. <https://www.rfc-editor.org/info/rfc8903>.
[RFC8973] Boucadair, M. and T. Reddy.K, "DDoS Open Threat Signaling [RFC8973] Boucadair, M. and T. Reddy.K, "DDoS Open Threat Signaling
(DOTS) Agent Discovery", RFC 8973, DOI 10.17487/RFC8973, (DOTS) Agent Discovery", RFC 8973, DOI 10.17487/RFC8973,
January 2021, <https://www.rfc-editor.org/info/rfc8973>. January 2021, <https://www.rfc-editor.org/info/rfc8973>.
Authors' Addresses [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 Mohamed Boucadair
Orange Orange
Rennes 35000 35000 Rennes
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy Tirumaleswar Reddy
McAfee, Inc. McAfee, Inc.
Embassy Golf Link Business Park Embassy Golf Link Business Park
Bangalore, Karnataka 560071 Bangalore 560071
Karnataka
India India
Email: TirumaleswarReddy_Konda@McAfee.com Email: TirumaleswarReddy_Konda@McAfee.com
Wei Pan Wei Pan
Huawei Technologies Huawei Technologies
Email: william.panwei@huawei.com Email: william.panwei@huawei.com
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