DOTS M. Chen
Internet-Draft Li. Su
Intended status: Informational China Mobile
Expires: September 10, 2020 March 9, 2020
A method for dots server deployment
draft-chen-dots-server-hierarchical-deployment-02
Abstract
As DOTS is used for DDoS Mitigation signaling, in practice, there are
different deployment scenarios for DOTS agents deployment depending
on the network deployment mode. This document made an recommandation
for DOTS Server deployment, include ISP and enterprise deployment
scenarios. The goal is to provide some guidance for DOTS agents
deployment.
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 September 10, 2020.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(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 Simplified BSD License text as described in Section 4.e of
Chen & Su Expires September 10, 2020 [Page 1]
Internet-Draft dots server hierarchical deployment March 2020
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. DOTS server Considerations . . . . . . . . . . . . . . . . . 3
4. DOTS server deployment inside an ISP . . . . . . . . . . . . 4
4.1. DOTS Agents Deployment . . . . . . . . . . . . . . . . . 4
4.2. DOTS Agents interfaces . . . . . . . . . . . . . . . . . 6
4.2.1. Bandwidth consuming attack . . . . . . . . . . . . . 7
4.2.2. Host resource consuming attack . . . . . . . . . . . 7
5. DOTS server deployment between ISPs . . . . . . . . . . . . . 8
6. DOTS server deployment for Enterprise . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . 10
10.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
DDoS Open Threat Signaling (DOTS) is a protocol to standardize real-
time signaling, threat-handling
requests[I-D.ietf-dots-signal-channel], when attack target is under
attack, dots client send mitigation request to dots server for help,
If the mitigation request contains enough messages of the attack,
then the mitigator can respond very effectively.
In the architecture draft[I-D.ietf-dots-architecture], when comes to
the deployment topic, it says this does not necessarily imply that
the attack target and the DOTS client have to be co-located in the
same administrative domain, but it is expected to be a common
scenario. Although co-location of DOTS server and mitigator within
the same domain is expected to be a common deployment model, it is
assumed that operators may require alternative models.
In the DOTS server discovery draft[I-D.ietf-dots-server-discovery],
it is says that a key point in the deployment of DOTS is the ability
of network operators to be able to configure DOTS clients with the
correct DOTS server(s) information consistently.
In the DOTS multihoming draft[I-D.ietf-dots-multihoming], it provides
deployment recommendations for DOTS client and DOTS gateway, it is
says when conveying a mitigation request to protect the attack
Chen & Su Expires September 10, 2020 [Page 2]
Internet-Draft dots server hierarchical deployment March 2020
target, the DOTS client among the DOTS servers available Must select
a DOTS server whose network has assigned the prefixes from which
target prefixes and target IP addresses are derived. This implies
that id no appropriate DOTS server is found, the DOTS client must not
send the mitigation request to any DOTS server. So in this document,
we give some dots server deployment consideration as the title
suggests we prefer hierarchical deployment.
This is DOTS server deployment guidance for operators, We've written
about our experience as an ISP, and we hope that other scenarios will
contribute as well.
2. Terminology
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
[RFC2119]
The readers should be familiar with the terms defined in
[I-D.ietf-dots-requirements] [I-D.ietf-dots-use-cases]
The terminology related to YANG data modules is defined in [RFC7950]
In addition, this document uses the terms defined below:
dots svr: abbreviation of dots server.
ISP: Internet service provider.
Orchestrator: With the function of DOTS server that can receive
messages from clients and made decisions for mitigators selection.
netflow/ipfix collector: Flow collector used for DDoS attack
detection.
3. DOTS server Considerations
When take dots server deployment into consideration, one thing must
be involved is mitigator. So far, how many network devices can play
the role of mitigator, we make a summerized list as follows:
o Router.
o Special cleaning equipment, such as flow clean device and clean
center.
o Network security equipment, such as firewall, IPS and WAF.
Chen & Su Expires September 10, 2020 [Page 3]
Internet-Draft dots server hierarchical deployment March 2020
o Servers that websites can hidden behind them.
Whether DOTS server can be deployed, the following conditions need to
be met:
o DOTS server and mitigator are in the same administrative domain.
o DOTS server can go directly to the mitigator which had best go
through without any other DOTS agents.
o DOTS server has the permissions for scheduling on mitigators.
o DOTS server has the ability to know the address of attack target
belong to which mitigator, if DOTS server hasn't matched attack
target to mitigators, DOTS server need to configure default
mitigators.
4. DOTS server deployment inside an ISP
4.1. DOTS Agents Deployment
From the internal structure of ISP, the whole network can divide into
backbone and metropolitan area networks logically. There are two
most important routers: backbone router, man(metropolitan area
network) router. It's worth noting that there are usually Internet
Data Centers(IDC), high bandwidth demand customers(such as online
game companies) and VIP customer centers(such as financial clients)
distributed in metropolitan area networks. When a ddos attack
occurs, it must be one of the three cases as follows, and the
corresponding mitigator will responsible for mitigation.
o DDoS attacks occur inside the LAN or the attack source inside
metropolitan area network launched an attack against the target in
local area network, the lan network detected the attack, dots
server3 will receive mitigation request, and mitigator3 will act
as the first responsible mitigator.
o DDoS attacks occur inside the MAN or the attack source inside
backbone network launched an attack against the target in
metropolitan area network, the man network detected the attack,
dots server2 will receive mitigation request, then mitigator2 will
act as the first responsible mitigator.
o DDoS attacks from other ISPs, the backbone network detected the
attack, dots server1 will receive mitigation request, then
mitigator1 will act as the first responsible mitigator.
Chen & Su Expires September 10, 2020 [Page 4]
Internet-Draft dots server hierarchical deployment March 2020
If attacks on the same attack target are found both in adjacent
areas, there are two strategies for the mitigators' selection, then
found the best mitigation node for different scenes.
o Near Attack Source Mitigation(NASM), NASM means that the
mitigation is performed closest to the source of the attack, this
usually happens at the entrance to the edge of the network. This
approach can block attack flow at the source and protect network
bandwidth maximumly, but requires the ability to operate the
entire network. This principle is more suitable for large-traffic
attack mitigation.
o Near Attack Target Mitigation(NATM), NATM means that the
mitigation is performed closest to the attack target, This is the
easiest and most direct way, but it will cause the attack flow
long-distance transmission, occupy the bandwidth along the link,
more likely to cause link congestion. This principle is more
suitable for low-traffic attack mitigation.
According to the NATM, the lower network mitigator will act as the
first responsible mitigator. for example, dots server1 and dots
server2 both received the mitigation request from attack target by
dots client, mitigator2 will responsible for ddos
disposition(priority ranking: mitigator3, mitigator2, mitigator1),
but according to the NASM the priority will be reverse.
Normally, The lower network the target in, the easier it is to alert.
Because the higher network the attack target in, the greater the
bandwidth of the pipeline. As shown in the following figure,
Orchestrator take on the role for scheduling. Because the importance
of the orchestrator, it is suggested to consider bakeup mechanisms or
heartbeat technology to ensure continuity and security.
How does DOTS client can find DOTS servers, we can reference the DOTS
server discovery draft[I-D.ietf-dots-server-discovery], Static
configuration or dynamic discovery depends on the actual scenario and
the size of the network.
Chen & Su Expires September 10, 2020 [Page 5]
Internet-Draft dots server hierarchical deployment March 2020
+----------+
|other ISPs|
+----------+
|
+-----------+
|dots client|
======|==========================
| Backbone Network
+---------------+ +----------+
|backbone router|-----|mitigator1|
+---------------+ +----------+
|dots svr1|
+---------+
........|........................
| MAN
+----------+ +----------+
|man router|-------|mitigator2|
+----------+ +----------+
|dots svr2|
+---------+
.......|........................
| LAN
+----------+ +----------+
|IDC router|------|mitigator3|
+----------+ +----------+
|dots svr3|
+------------+
|Orchestrator|
+------------+
|
+-----------+ +--------------+ +-------------+
|dots client|----|flow collector|---|attack target|
+-----------+ +--------------+ +-------------+
*MAN is for metropolitan area network
*LAN is for local area network
*flow collector is for netflow/ipfix collector
Figure 1: hierarchical deployment for DOTS servers
4.2. DOTS Agents interfaces
In the dots use case draft[I-D.ietf-dots-use-cases], it is says the
orchestrator analyses the various information it receives from DDoS
telemetry system, and initiates one or multiple DDoS mitigation
strategies. In the telemetry draft, all the telemetry informations
are contained and some parameters can be used to make decisions.
Chen & Su Expires September 10, 2020 [Page 6]
Internet-Draft dots server hierarchical deployment March 2020
This section made a discussion on which attributes could be used in
orchestrator for scheduling.
We suggest orchestrator has three capabilities and reuse the method
of registration and notification in signal channel to know all the
related mitigators capability and residue capability:
1.Can get the neflow/ipfix collector's telemetry informations.
2.Can get the capabilities of each mitigator, it means the initial
capacity, this means that with each addition of mitigator there needs
to be a protocol that can push this information to orchestrator, we
recommend using DOTS signal channel to transfer initial capacity.
3.When mitigation finished, mitigator can inform orchestrator that
mitigation is finished and capacity has been released, also we
recommend using DOTS signal channel to transfer.
4.2.1. Bandwidth consuming attack
The following parameters will be required by orchestrator:
o top-talker
o source-prefix
o total-traffic
o total-attack-traffic
o total-pipe-capability
The recommended approach here is to redirect traffic and flow
cleaning.
4.2.2. Host resource consuming attack
The following parameters will be required by orchestrator:
o top-talker
o source-prefix
The recommended approach here is to use router for disposition.
Chen & Su Expires September 10, 2020 [Page 7]
Internet-Draft dots server hierarchical deployment March 2020
5. DOTS server deployment between ISPs
Because of global connectivity, the coexistence of different
operators is very common, coordination between operators across
networks is very important. Interdomain attacks occur frequently, We
recommend deploying the DOTS server at the access point.
o DDoS attack from one of other ISPs, for example, ISP A received
DDoS attack from ISP B or ISP C, then dots server C or dots server
B will receive the mitigation request.
o DDoS attacks from two or more of other ISPs,for example, ISP A and
ISP B both start ddos attack to ISP C, then dots server A and dots
server B will both receive mitigation request from dots client C.
+-------------+ +-------------+
| ISP A | | ISP B |
| +---------+ | | +---------+ |
| |dots svrA| | | |dots svrB| |
+-------------+ +-------------+
| |
+-------+===========+-------+
|dots client|
+===========+
|
|
+-------------+
| |dots svrC| |
| +---------+ |
| ISP C |
+-------------+
Figure 2: DOTS Server Deployment between different ISPs
It is obvious from the figure 2 that there is a super DOTS client in
the middle, this also means that there will be corresponding netflow/
ipfix collector on the link between different ISPs, the final
location of the DOTS client according to the actual network topology.
When an DDoS attack occurs, depending on the direction of the attack,
the corresponding server is required for mitigation, DOTS server can
use call home to find the source of the DDoS
attacks[I-D.ietf-dots-signal-call-home]
Chen & Su Expires September 10, 2020 [Page 8]
Internet-Draft dots server hierarchical deployment March 2020
6. DOTS server deployment for Enterprise
In addition to operators taking advantage of the pipeline to make a
contribution to DDoS attack mitigation, there are also enterprise-
level DDoS attack mitigation solutions. It's usually a cloud service
and a large number of distributed nodes are deployed to protect their
customers from DDoS attack, customers' websites can be hidden behind
the nodes, usually the internet game companies and the live streaming
company will choose this way.
+-------------+
| ISP |
| +---------+ |
| |dots svr | |
+-------------+
|
|
+-------------+
| Anti-D Node |
+-------------+
|dots client|
+-----------+
|
|
+-------------+
|attack target|
+-------------+
*Anti-D is for Anti-DDoS
Figure 3: DOTS Server Deployment for Enterprise and ISP
When enterprise-level anti-DDos nodes are unable to mitigate the DDoS
attack, they can trigger DOTS client which integrated in the Anti-D
Node to send mitigation request to ISP's DOTS server.
7. Security Considerations
TBD
8. IANA Considerations
TBD
Chen & Su Expires September 10, 2020 [Page 9]
Internet-Draft dots server hierarchical deployment March 2020
9. Acknowledgement
TBD
10. References
10.1. 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>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
10.2. Informative References
[I-D.ietf-dots-architecture]
Mortensen, A., Reddy.K, T., Andreasen, F., Teague, N., and
R. Compton, "Distributed-Denial-of-Service Open Threat
Signaling (DOTS) Architecture", draft-ietf-dots-
architecture-15 (work in progress), March 2020.
[I-D.ietf-dots-multihoming]
Boucadair, M., Reddy.K, T., and W. Pan, "Multi-homing
Deployment Considerations for Distributed-Denial-of-
Service Open Threat Signaling (DOTS)", draft-ietf-dots-
multihoming-03 (work in progress), January 2020.
[I-D.ietf-dots-requirements]
Mortensen, A., K, R., and R. Moskowitz, "Distributed
Denial of Service (DDoS) Open Threat Signaling
Requirements", draft-ietf-dots-requirements-22 (work in
progress), March 2019.
[I-D.ietf-dots-server-discovery]
Boucadair, M. and T. Reddy.K, "Distributed-Denial-of-
Service Open Threat Signaling (DOTS) Agent Discovery",
draft-ietf-dots-server-discovery-10 (work in progress),
February 2020.
[I-D.ietf-dots-signal-call-home]
Reddy.K, T., Boucadair, M., and J. Shallow, "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Signal
Channel Call Home", draft-ietf-dots-signal-call-home-07
(work in progress), November 2019.
Chen & Su Expires September 10, 2020 [Page 10]
Internet-Draft dots server hierarchical deployment March 2020
[I-D.ietf-dots-signal-channel]
Reddy.K, T., Boucadair, M., Patil, P., Mortensen, A., and
N. Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-41 (work in progress), January
2020.
[I-D.ietf-dots-use-cases]
Dobbins, R., Migault, D., Moskowitz, R., Teague, N., Xia,
L., and K. Nishizuka, "Use cases for DDoS Open Threat
Signaling", draft-ietf-dots-use-cases-20 (work in
progress), September 2019.
Authors' Addresses
Meiling Chen
China Mobile
32, Xuanwumen West
BeiJing
,
BeiJing
100053
China
Email:
chenmeiling@chinamobile.com
Chen & Su Expires September 10, 2020 [Page 11]
Internet-Draft dots server hierarchical deployment March 2020
Li Su
China Mobile
32, Xuanwumen West
BeiJing
100053
China
Email:
suli@chinamobile.com
Chen & Su Expires September 10, 2020 [Page 12]