[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02

DOTS                                                           N. Teague
Internet-Draft                                            Verisign, Inc.
Intended status: Standards Track                            A. Mortensen
Expires: August 19, 2017                            Arbor Networks, Inc.
                                                       February 15, 2017


                  DDoS Open Threat Signaling Protocol
                     draft-teague-dots-protocol-02

Abstract

   This document describes Distributed-Denial-of-Service (DDoS) Open
   Threat Signaling (DOTS), a protocol for requesting and managing
   mitigation of DDoS attacks.

   DOTS mitigation requests over the signal channel permit domains to
   signal the need for help fending off DDoS attacks, setting the scope
   and duration of the requested mitigation.  Elements called DOTS
   servers field the signals for help, and enable defensive
   countermeasures to defend against the attack reported by the clients,
   reporting the status of the delegated defense to the requesting
   clients.  DOTS clients additionally may use a reliable data channel
   to manage filters and black- and white-lists to restrict or allow
   traffic to the clients' domains arbitrarily.  The DOTS signal channel
   may operate over UDP [RFC0768] and if necessary TCP [RFC0793].  This
   revision discusses a transport-agnostic approach to this channel,
   focusing on the message exchanges and delegating transport specifics
   to other documents.  Discussion of the reliable data channel may be
   found in [I-D.reddy-dots-data-channel].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 19, 2017.




Teague & Mortensen       Expires August 19, 2017                [Page 1]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


Copyright Notice

   Copyright (c) 2017 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
   (http://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
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Architecture  . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  DOTS Agents . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DOTS Communication Channels . . . . . . . . . . . . . . . . .   5
   4.  Signal Channel  . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Minimum Viable Information  . . . . . . . . . . . . . . .   6
     4.2.  Signal Channel Messages . . . . . . . . . . . . . . . . .   7
       4.2.1.  Messaging Overview  . . . . . . . . . . . . . . . . .   7
       4.2.2.  Message Definition and Serialization  . . . . . . . .   9
       4.2.3.  Client Message Fields . . . . . . . . . . . . . . . .   9
       4.2.4.  Mitigation Request Fields . . . . . . . . . . . . . .  10
       4.2.5.  DOTS Server Message Fields  . . . . . . . . . . . . .  11
       4.2.6.  Server Errors . . . . . . . . . . . . . . . . . . . .  11
       4.2.7.  Server Mitigation Status Fields . . . . . . . . . . .  13
     4.3.  Interactions  . . . . . . . . . . . . . . . . . . . . . .  13
       4.3.1.  Session Initialization  . . . . . . . . . . . . . . .  13
       4.3.2.  Heartbeat . . . . . . . . . . . . . . . . . . . . . .  15
       4.3.3.  Mitigation Request Handling . . . . . . . . . . . . .  18
       4.3.4.  Ancillary Messages  . . . . . . . . . . . . . . . . .  20
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  23
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  23
   7.  Appendix A: Message Schemas . . . . . . . . . . . . . . . . .  23
     7.1.  DOTS Client Message Schema  . . . . . . . . . . . . . . .  23
     7.2.  Mitigation Request Schema . . . . . . . . . . . . . . . .  23
     7.3.  Session Configuration Schema  . . . . . . . . . . . . . .  24
     7.4.  DOTS Server Message Schema  . . . . . . . . . . . . . . .  24
     7.5.  DOTS Redirect Schema  . . . . . . . . . . . . . . . . . .  25
     7.6.  DOTS Mitigation Status Schema . . . . . . . . . . . . . .  26
     7.7.  Server Error Schema . . . . . . . . . . . . . . . . . . .  26
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  27



Teague & Mortensen       Expires August 19, 2017                [Page 2]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  27
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  29

1.  Introduction

   Distributed-Denial-of-Service attack scale and frequency continues to
   increase year over year, and the trend shows no signs of abating
   [WISR].  In response to the DDoS attack trends, service providers and
   vendors have developed various approaches to sharing or delegating
   responsibility for defense, among them ad hoc service relationships,
   filtering through peering relationships [COMMUNITYFS], and
   proprietary solutions ([CLOUDSIGNAL], [OPENHYBRID]).  Such hybrid
   approaches to DDoS defense have proven effective, but the
   heterogeneous methods employed to coordinate DDoS defenses across
   domain boundaries have necessarily limited their scope and
   effectiveness, as the mechanisms in one domain have no traction in
   another.

   The DDoS Open Threat Signaling (DOTS) protocol provides a common
   mechanism to achieve the coordinated attack response previously
   restricted to custom or proprietary solutions.  To meet the needs of
   network operators facing down modern DDoS attacks, DOTS itself is a
   hybrid protocol, consisting of a signal channel and a data channel.
   DOTS uses the signal channel, a lightweight and robust communication
   layer, to signal the need for mitigation regardless of network
   conditions, and uses the reliable data channel as vehicle for
   provisioning, configuration, telemetry, filter management, and other
   unsized or bulk data exchange.

   The DOTS protocol is not intended as a replacement for such protocols
   as BGP Flow Specification [RFC5575] or as a general purpose DDoS
   countermeasure application programming interface (API), but rather as
   an advisory protocol enabling attack response coordination between
   DOTS agents.  Any DOTS-enabled device or service is capable of
   triggering a request for help and shaping the scope and nature of
   that help, with the details of the actual mitigation left to the
   discretion of the operators of the attack mitigators.  DOTS thereby
   permits all participating parties to manage their own attack defenses
   in the manner most appropriate for their own domains.

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].





Teague & Mortensen       Expires August 19, 2017                [Page 3]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   Terms used to define entity relationships, transmitted data, and
   methods of communication are drawn from the terminology defined in
   [I-D.ietf-dots-requirements].

2.  Architecture

   The architecture in which the DOTS protocol operates is assumed to be
   derived from the architectural components and concepts described in
   [I-D.ietf-dots-architecture].

2.1.  DOTS Agents

   All protocol communication is between a DOTS client and a DOTS
   server.  The logical agent termed a DOTS gateway is in practice a
   DOTS server placed back-to-back with a DOTS client.  As discussed in
   [I-D.ietf-dots-architecture], any interface enabling the back-to-back
   DOTS server and client to act as a DOTS gateway is implementation-
   specific.  This protocol is therefore concerned only with managing
   one or more bilateral relationships between DOTS clients and the DOTS
   servers, a signaling mode known as Direct Signaling in the DOTS
   architecture.  This is shown in Figure 1 below:

       +-----------+  signal channel  +-----------+
       |           |<---------------->|           |
       |DOTS client|                  |DOTS server|
       |           |<================>|           |
       +-----------+   data channel   +-----------+

                 Figure 1: DOTS protocol direct signaling

   The DOTS architecture anticipates many-to-one and one-to-many
   deployments, in which multiple DOTS clients maintain distinct
   signaling sessions with a single DOTS server or a single DOTS client
   maintains distinct signaling sessions with multiple DOTS servers, as
   shown below in Figure 2:
















Teague & Mortensen       Expires August 19, 2017                [Page 4]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


       +----+      +----+      +----+
       | c1 |      | Sa |------| c2 |
       +----+      +----+      +----+
             \                /
              \              /
               \   +----+   /
                +--| Sb |--+
                   +----+

       DOTS        DOTS        DOTS
       client 1    servers     client 2

                 Figure 2: DOTS protocol direct signaling

   DOTS server Sb has signaling sessions with DOTS clients c1 and c2.
   DOTS client c2 has signaling sessions with DOTS servers Sa and Sb.
   Except where explicitly defined in this protocol, all mechanisms to
   maintain multiple signaling sessions are left to the implementation.

3.  DOTS Communication Channels

   DOTS uses two channels, a signal channel and a data channel.

   The signal channel is the minimal secure communication layer a DOTS
   client uses to request mitigation for resources under the
   administrative control the DOTS client; administrative control may be
   delegated.

   The data channel offers DOTS clients a limited ability to manage
   configuration and attack filtering for requested mitigations.  The
   data channel offers DOTS client operators the limited ability to
   adjust configuration and filtering for their mitigation requests.

   This document describes the DOTS signal channel.  The data channel is
   defined separately in [I-D.reddy-dots-data-channel].

4.  Signal Channel

   The purpose of the signaling channel is to convey DDoS mitigation
   request and status information between participating agents (client
   and server or gateway).  Conditions during a DDoS attack are
   invariably hostile for connection-oriented protocols traversing
   affected paths.  Mechanisms such as Happy Eyeballs [RFC6555] may be
   used to select a transport suitable for a given time and prevailing
   network conditions.

   Implementations are required to support the DOTS signal channel over
   UDP as specified in [I-D.ietf-dots-requirements].  This document



Teague & Mortensen       Expires August 19, 2017                [Page 5]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   therefore assumes the the availability of a transport based upon UDP
   [RFC0768], but also defines the message exchanges agnostic of the
   underlying transport used to convey the signaling.

   Key tenets of DOTS protocol design are low communication overhead and
   efficient message packing to increase the chances of successful
   transmission and receipt.  Desirable side-effects of efficient
   packing are the removal of the possibility of fragmentation in
   addition to a message size that is friendly towards encapsulation
   (e.g via GRE [RFC2784] or MPLS [RFC3031]).  Large UDP packets may
   also be treated adversely by middleboxes with restrictive policies or
   may fall foul of aggressive filtering.

   In support of operational requirements for protocol efficiency,
   backward compatibility and extensibility in
   [I-D.ietf-dots-requirements], the signaling channel uses Protocol
   Buffers [PROTOBUF], also known as Protobufs, to define message
   schemas and serialize messages exchanged between DOTS agents.

   The security requirements described in [I-D.ietf-dots-requirements]
   (peer mutual authentication, message confidentiality and integrity,
   and message replay protection are not discussed here.  However, these
   qualities must be present in the transport over which the DOTS signal
   channel operates.

   Key distribution in support of those security requirements to may be
   achieved via the data channel, via an online mechanism such as DANE
   [RFC6698], Enrollment over Secure Transport [RFC7030], or by out-of-
   band means.  The key distribution mechanism is not specified in this
   document, but operators must take care to ensure the distribution
   provides the same level of security demanded by the signal channel
   itself.

4.1.  Minimum Viable Information

   DOTS is intended to be extensible and to evolve to meet the future
   needs in communicating as yet unknown threats.  However, it must be
   able to convey the minimum information required for an upstream
   mitigation platform to successfully counter a DDoS attack.  A client
   may have limited visibility into the full breadth of an attack and as
   such may not be well placed to provide useful telemetry.  DDoS
   sources may or may not be spoofed and number in the millions.  Once
   mitigation is active, the filtered traffic seen by the DOTS client
   (or elements informing the DOTS client operator's decision to request
   mitigation) may not be representative of the ongoing attack.  This
   provides challenges for the quality and usefulness of telemetry and
   mitigation/countermeasure stipulations and as such this type of
   information if conveyed can only be considered advisory.



Teague & Mortensen       Expires August 19, 2017                [Page 6]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   In these instances the minimum viable information required for the
   majority of mitigations to be activated is that which pertains to the
   resource being targeted by the attack (host, prefix, protocol, port,
   URI etc.), per [I-D.ietf-dots-requirements] (OP-006).  The DOTS
   requirements also identify a mitigation lifetime period (OP-005) and
   mitigation efficacy metric (OP-007).  The former may be considered
   for inclusion in the minimum viable information set, however, the
   latter may only be relevant in updates.  An explicit mitigation
   request/terminate flag is also required: a mitigation MUST be
   explicitly requested by a DOTS client operator.  Finally, each
   message should include a message id or sequence number field as well
   as a field for the last received message id or sequence number.
   These may then be compared by the endpoints to assist in tracking
   state and/or identifying loss.

4.2.  Signal Channel Messages

4.2.1.  Messaging Overview

   The signal channel requirements in [I-D.ietf-dots-requirements]
   demand a protocol capable of operating despite significant link
   congestion between DOTS agents.  In an effort to maximize the
   probability of signal delivery between DOTS agents, all DOTS signal
   channel messages in the DOTS protocol are conceptually unidirectional
   heartbeats sent between DOTS agents.

   The result is a form of scheduled messaging between DOTS agents, in
   contrast to a conventional request-response model.  Once a signal
   channel is established, a DOTS client begins sending unidirectional
   heartbeats to the DOTS server, separated by the configured session
   heartbeat interval (see Section 4.3.1 below).  To request mitigation,
   a DOTS client merely adds the requested mitigation parameters to its
   heartbeat, and maintains that request until a heartbeat from the DOTS
   server indicates receipt of that mitigation request.  The DOTS server
   likewise sends its unidirectional heartbeat on the schedule interval,
   augmenting the content of the heartbeat with mitigation request
   status.

   A simple exchange between DOTS agents with an established signaling
   session is shown below in Figure 3.











Teague & Mortensen       Expires August 19, 2017                [Page 7]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   Client                           Server
     |                                 |  // Active signaling session
     |<==== Signal Channel Active ====>|  // with heartbeat interval of
     |                                 |  // 15 seconds, +/- jitter.
     |                                 |
     |----------Heartbeat------------->|  // Client heartbeat
     |                                 |
     |<---------Heartbeat--------------|  // Server heartbeat
     |                                 |
     \                                 \  // 15 seconds elapse, during
     /                                 /  // which client adds request
     \                                 \  // for mitigation.
     |                                 |
     |----------HeartBeat------------->|  // Client heartbeat now has
     |          + MitigationRequest    |  // mitigation request params.
     |                                 |
     |<---------HeartBeat--------------|  // Server heartbeat now has
     |          + MitigationPending    |  // pending mitigation request
     |                                 |  // status.
     |                                 |
     \                                 \
     /                                 /  // 15s elapse, +/- jitter.
     \                                 \
     |                                 |
     |----------HeartBeat------------->|  // Client heartbeat maintains
     |          + MitigationRequest    |  // request as it waits for
     |                                 |  // mitigation to begin.
     |                                 |
     |     X----HeartBeat--------------|  // Mitigation enabled, but
     |          + MitigationRunning    |  // server heartbeat is dropped
     |                                 |
     \                                 \
     /                                 /  // 15s elapse, +/- jitter.
     \                                 \
     |                                 |
     |----------HeartBeat------------->|  // Client heartbeat maintains
     |          + MitigationRequest    |  // request as it waits for
     |                                 |  // mitigation to begin.
     |                                 |
     |<---------HeartBeat--------------|  // Server heartbeat, status of
     |          + MitigationRunning    |  // running mitigation
     |                                 |  // delivered to client.

            Figure 3: Signaling Session with Mitigation Request

   All messages are variations of this scheduled heartbeat model.  See
   Section 4.3 below for detailed discussion of the message exchanges
   between DOTS agents.



Teague & Mortensen       Expires August 19, 2017                [Page 8]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


4.2.2.  Message Definition and Serialization

   The DOTS protocol signal channel uses Protobufs [PROTOBUF] as an
   interface definition language (IDL) for signal channel messaging
   between DOTS agent, reducing the number of discrete messages to just
   a single message superset per direction, with function defined by the
   chosen fields contained within the message.

   Protobufs schemas are used to define the messages sent in either
   direction, from which code may be generated for specific language
   implementations of DOTS.  As Protobufs serialization relies on
   numbered fields, signal channel messaging permits the introduction of
   new numbered fields arbitrarily, adding the requisite extensibility
   to the protocol while retaining backward compatibility.  Future
   revisions of or extensions to the protocol may use the data channel
   to provide a mechanism by which schema updates or expansions may be
   communicated during provisioning/session establishment.

4.2.3.  Client Message Fields

   Only the seqno and last_svr_seqno fields are required in every
   message, as they are the minimum required for the heartbeat.  Subsets
   of the other fields are used to convey a given signal message type.

   The fields in the DOTS client signal channel message have the
   following functions:

   seqno:  a client-generated sequence number unique to the message.
      The client increments the seqno value by one for each message sent
      over the signal channel.

   last_svr_seqno:  the sequence number of the last message received
      from the server, provided to the server as a simple way to detect
      lost messages.

   mitigations:  a list of mitigations requested or withdrawn by the
      client.  The mitigation schema fields are described below.

   active:  indicates a request for a list of active mitigations and
      their detail that are current on the DOTS server.

   ping:  an operator initiated heartbeat like message which will elicit
      a response from the DOTS server.  This may be used to prove bi-
      directional communications on an ad-hoc basis.  For example, a
      DOTS ping may be used to prove keying material on the DOTS client
      is valid and may be used to establish signaling sessions with the
      DOTS server.




Teague & Mortensen       Expires August 19, 2017                [Page 9]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   extensions:  these fields may be used to communicate implementation
      specific details.  An example would be the dissemination of
      filters between DOTS client and DOTS server.

4.2.3.1.  Client Message Schema

   The DOTS client message schema is detailed in Section 7.1.

4.2.4.  Mitigation Request Fields

   The fields in a mitigation request are as follows:

   eventid:  an opaque client generated identifier that distinguishes a
      unique event or incident.  May be used by the client as a
      reference to the specific event triggering a mitigation request,
      or for other implementation-specific purposes.

   requested:  signals the need for mitigation to the DOTS server.  If
      true, the DOTS client is requesting mitigation for the provided
      scope.  If false, the DOTS client is indicating it does not
      require mitigation, and the DOTS server MUST cease the mitigation
      for the provided scope.

   scope:  the scope of the mitigation requested, which may be any of
      the types described in [I-D.ietf-dots-requirements], such as
      Classless Internet Domain Routing (CIDR) [RFC1518],[RFC1519]
      prefixes, DNS names, or aliases defined by the DOTS client
      operator through the data channel.

   lifetime:  the lifetime in seconds a mitigation request should be
      considered valid.

   efficacy:  a metric to convey to a DOTS server the perceived efficacy
      of an active mitigation, per operational requirements in
      [I-D.ietf-dots-requirements].  The mitigation efficacy is
      represented as a floating point value between 0 and 1, with
      smaller values indicating lesser efficacy, and larger greater
      efficacy.

   extensions:  these fields may be used to provide implementation-
      specific mitigation details.

4.2.4.1.  Mitigation Request Schema

   The DOTS client message schema is detailed in Section 7.2.






Teague & Mortensen       Expires August 19, 2017               [Page 10]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


4.2.5.  DOTS Server Message Fields

   DOTS server messages use a subset of the available fields to convey
   the given signal type, including additional relevant fields as
   necessary.  The only fields which may be common to all signals are
   seqno and last_client_seqno which may be used to detect message loss
   or out-of-order delivery.  When conveying mitigation information, the
   server schema may bundle multiple mitigation status datasets into a
   single message, provided this does not violate the required sub-MTU
   message size [I-D.ietf-dots-requirements].

   The fields in the DOTS server signal channel message schema have the
   following functions:

   seqno:  a server generated sequence number unique to the message.

   last_cli_seqno:  the seqno of the last message received from the
      client.

   ping:  an operator-initiated heartbeat like message which will elicit
      a response from the DOTS client.  This may be used to prove bi-
      directional communications on an ad-hoc basis.

   error:  details of an error caused by a DOTS client request.

   redirect:  Populated with the details of the redirection target DOTS
      server, if the DOTS server is redirecting the DOTS client to
      another DOTS server.

   mitigations:  a list containing the status of mitigations requested
      by the DOTS client.  The fields in the mitigation status schema
      are described below.

   extensions:  these fields may be used to communicate implementation
      specific details.  An example would be the communication of DNS
      mitigation vip to the DOTS client by the DOTS server.

4.2.5.1.  DOTS Server Message Schema

   The server message schema is detailed in Section 7.4.

4.2.6.  Server Errors

   If a DOTS client message cannot be processed by the DOTS server, or
   for any other reason causes an error, the DOTS server MUST populate
   the error field in any response to the message causing the error.  As
   the error response itself may be lost, a DOTS client may continue
   sending problematic messages regardless of the DOTS server's error



Teague & Mortensen       Expires August 19, 2017               [Page 11]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   notifications.  DOTS server implementations MAY terminate the
   signaling session after client-triggered errors exceed a threshold
   during a time period equivalent to three times the session heartbeat
   interval.

   The DOTS client message triggering the error condition is indicated
   in the last_client_seqno value of the DOTS server message containing
   the error.

   Error codes MUST be one of the following types:

   NOERROR:  Indicates the DOTS server has detected no error resulting
      from a DOTS client message.  Implementations MAY omit the error
      field entirely when no error condition is present.  This value is
      included in the schema largely to adhere to the convention that an
      error status of 0 indicates success.

   INVALID_VALUE:  Indicates the DOTS client included an invalid value
      for a field in the client message most recently received from the
      client.  The DOTS server SHOULD include specifics of the invalid
      value in the details field of the error.

   MITIGATION_UNAVAILABLE:  Indicates the DOTS server is unable to
      provide mitigation in response to a mitigation request from the
      DOTS client.

   MITIGATION_CONFLICT:  Indicates a mitigation request conflicts with
      an existing mitigation from the client.  The DOTS server SHOULD
      populate the error details field with the status information of
      the mitigation conflicting with the requested mitigation.

   MALFORMED_MESSAGE:  Indicates the DOTS client message is malformed
      and cannot be processed.

4.2.6.1.  Server Error Fields

   code:  a numeric code categorizing the error type detected by the
      DOTS server.

   details:  specific information about the reason for the detected
      error.

4.2.6.2.  Server Error Schema

   The server error schema is detailed in Section 7.7.






Teague & Mortensen       Expires August 19, 2017               [Page 12]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


4.2.7.  Server Mitigation Status Fields

   The DOTS server message contains zero or more mitigation status
   messages, the fields of which have the following functions:

   eventid:  an opaque client generated identifier that distinguishes a
      unique event or incident.

   ttl:  the remaining lifetime of the mitigation, in seconds.

   bytes_dropped:  the total dropped byte count for the mitigation
      associated with eventid.

   bps_dropped:  the dropped bytes per second for the mitigation
      associated with eventid.  This value is expected to be calculated
      by the mitigator, and as such is implementation-specific.

   pkts_dropped:  the total dropped packet count for the mitigation
      associated with eventid..

   pps_dropped:  the dropped packets per second for the mitigation
      associated with eventid.  This value is expected to be calculated
      by the mitigator, and as such is implementation-specific.

   blacklist_enabled:  Indicates whether a blacklist of prohibited
      traffic sources is enabled for the mitigation associated with
      eventid.  The blacklist is managed through the data channel.

   whitelist_enabled:  Indicates whether a whitelist of sources from
      which traffic must always be allowed is enabled.  The whitelist is
      managed through the data channel.

   filters_enabled:  Indicates whether client-specified traffic filters
      are enabled for the mitigation associated with eventid.

4.3.  Interactions

4.3.1.  Session Initialization

   Signaling sessions are initiated by the DOTS client.  Session
   initialization begins when the DOTS client connects to the DOTS
   server port, 4646.  After connecting, the DOTS client establishes the
   channel security context, including all necessary cryptographic
   exchanges between the two DOTS agents.

   This signal channel specification is transport-agnostic, and
   delegates the details of transport, including transport security, to
   transport-specific documents.  Regardless of transport, DOTS



Teague & Mortensen       Expires August 19, 2017               [Page 13]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   implementations nonetheless MUST provide signal channel security
   meeting the requirements in [I-D.ietf-dots-requirements].

   Once the signal channel security context is established, the DOTS
   client sends a channel initialization message to the DOTS server,
   optionally including signaling session configuration values; if the
   session configuration values are excluded, defaults MUST be used for
   the signaling session.  An example initialization message setting the
   acceptable signal loss and heartbeat interval for the signaling
   sessions is described in Figure 4 below:

       message DOTSClientMessage {
         1 (seqno) = %;
         2 (last_svr_seqno) = %;
         6 (config) = {
           1 (loss_limit) = %;
           3 (heartbeat_interval) = %;
         };
       }

              Figure 4: Signal Channel Initialization Message

   The DOTS server MUST respond immediately by sending a heartbeat (see
   Section 4.3.2 below) to the DOTS client.  The signal channel is
   active when the DOTS client receives a heartbeat from the DOTS server
   with a last_client_seqno of a signal channel initialization message.
   Both DOTS agents MUST begin sending heartbeats on the interval for
   the signaling session once the session is active.

   The following example assumes a DOTS implementation using UDP as the
   transport and DTLS1.2 [RFC6347].  In Figure 5 below, the DOTS client
   uses the default values for acceptable signal loss, maximum
   mitigation lifetime, and heartbeat interval.  The initial DOTS server
   heartbeat is lost, so the DOTS client sends another channel
   initialization message after waiting for the minimum heartbeat
   interval defined below in Section 4.3.2:















Teague & Mortensen       Expires August 19, 2017               [Page 14]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   Client                           Server
     |                                 |
     |<- - - - DTLS1.2 handshake - - ->|  // Server listens on UDP:4646.
     |                                 |  // Client initiates DTLS
     |                                 |  // handshake.
     |                                 |
     |----------ChannelInit----------->|  // Client sends signal
     |          seqno = 1              |  // channel init message
     |          last_svr_seqno = 0     |
     |                                 |
     |     X----HeartBeat--------------|  // Server immediately sends
     |          seqno = 1              |  // heartbeat reply, which
     |          last_client_seqno = 1  |  // is lost.
     |                                 |
     \                                 \  // Session heartbeat interval
     /                                 /  // elapses.
     \                                 \
     |----------ChannelInit----------->|  // Client retries signal
     |          seqno = 2              |  // channel init message.
     |          last_svr_seqno = 0     |
     |                                 |
     |<---------HeartBeat--------------|  // Server immediately sends
     |          seqno = 2              |  // heartbeat reply
     |          last_client_seqno = 2  |
     |                                 |
     |<==== Signal Channel Active ====>|

                  Figure 5: Signal Channel Initialization

4.3.1.1.  Session Initialization Error Handling

   If the DOTS client specifies invalid values for the signal channel
   configuration, the DOTS server replies with an error, and may
   ultimately terminate the connection if the client fails to correct
   the invalid values, as described in [I-D.ietf-dots-architecture].

4.3.1.2.  Mis-Sequencing

   In the event that the DOTS agent receives messages containing invalid
   seqno, last_client_seqno or last_svr_seqno these should be discarded
   and ignored.

4.3.2.  Heartbeat

   The most common message exchanged between a DOTS client and a DOTS
   server is a heartbeat (OP-002 [I-D.ietf-dots-requirements]), which
   maintains and monitors the health of the DOTS session.  This is
   achieved with simple, loosely-coupled bi-directional messages



Teague & Mortensen       Expires August 19, 2017               [Page 15]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   containing the sending DOTS agent's message sequence number and the
   sequence number the sending DOTS agent last received from its peer.
   Due to the stress volumetric DDoS impose upon a network, a degree of
   loss during attacks is to be expected.  Message loss tolerance may be
   set on signal channel establishment.

   The default heartbeat interval is 20 seconds, plus or minus a number
   of milliseconds between 50 and 2000.  The number of milliseconds MUST
   be randomized in order to introduce jitter into the heartbeat
   interval, as recommended by [RFC5405].  The default interval is
   derived from the recommendations in [RFC5405] regarding middlebox
   traversal, to maintain NAT bindings in the path between DOTS agents.

   The interval between heartbeats is may also be set by the client when
   establishing the signal channel.  The minimum heartbeat interval is
   15 seconds, plus the random number of milliseconds as described
   above.  The maximum heartbeat interval is 120 seconds (two minutes),
   minus the random number of milliseconds described above.

   Heartbeats are loosely-coupled, meaning each DOTS agent in a
   bilateral signaling session sends DOTS heartbeats on the specified
   interval, but asynchronously, without acknowledgement.  Each DOTS
   agent tracks heartbeats received from its peer, and includes the
   sequence number of the last heartbeat received from the peer agent in
   the next heartbeat sent, as shown in Figure 6:


























Teague & Mortensen       Expires August 19, 2017               [Page 16]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


     Client                           Server
       |                                 |
       |----------HeartBeat------------->|  // Client heartbeat
       |          seqno = 1              |
       |          last_svr_seqno = 0     |
       |                                 |
       |<---------HeartBeat--------------|  // Server heartbeat
       |          seqno = 1              |
       |          last_client_seqno = 1  |
       |                                 |
       |----------HeartBeat------------->|  // Client heartbeat
       |          seqno = 2              |
       |          last_svr_seqno = 1     |
       |                                 |
       |      X---HeartBeat--------------|  // Server heartbeat lost
       |          seqno = 2              |
       |          last_client_seqno = 2  |
       |                                 |
       |----------HeartBeat------------->|  // Client heartbeat,
       |          seqno = 3              |  // last_svr_seqno remains 1,
       |          last_svr_seqno = 1     |  // indicating lost heartbeat
       |                                 |
       |<---------HeartBeat--------------|  // Server heartbeat resumes
       |          seqno = 3              |
       |          last_client_seqno = 3  |
       |                                 |
       |----------HeartBeat------------->|  // Client heartbeat
       |          seqno = 4              |
       |          last_svr_seqno = 3     |
       |                                 |

                 Figure 6: Heartbeats Between DOTS agents

   The DOTS client heartbeat has the following format:

       message DOTSClientMessage {
         1 (seqno) = %;
         2 (last_svr_seqno) = %;
       }

   The DOTS server heartbeat is identical aside from the schema type:

       message DOTSServerMessage {
         1 (seqno) = %;
         2 (last_svr_seqno) = %;
       }





Teague & Mortensen       Expires August 19, 2017               [Page 17]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   Should the number of signals lost exceed the acceptable lossiness
   value for the signaling session, the agent detecting the signal loss
   may consider the signaling session lost.  The default value for
   acceptable signal loss is 9, which, when coupled with the default
   heartbeat interval, amounts to lack of heartbeat from the peer DOTS
   agent for 180 seconds (three minutes).

4.3.2.1.  Ping

   There may be cases where a DOTS client or server operator wishes to
   trigger an immediate heartbeat response in order to validate bi-
   directional communication (e.g. during provisioning).  This ad-hoc
   triggering may be achieved by setting the ping field set to TRUE.
   When DOTS agent receives a message on the signal channel with the
   ping field set to TRUE, it MUST immediately send heartbeat back to
   the ping sender.  A ping reply MUST consist of only the senders
   sequence number and the sequence number of the received ping.
   [[EDITOR'S NOTE: rate limiting of pings required?]]

   A ping is identical to a standard heartbeat, but with the ping field
   included and set to true:

          message DOTSClientMessage {
            1 (seqno) = %;
            2 (last_svr_seqno) = %;
            5 (ping) = true;
          }

4.3.3.  Mitigation Request Handling

   The mitigation request is the crux of the DOTS protocol, and is
   comprised of the minimum viable information described in Section 4.1.
   The request may be augmented with additional implementation specific
   extensions where these do not result in undue packet bloat.  The DOTS
   client may send repeated requests until it receives a suitable
   response from the DOTS server by which it may interpret successful
   receipt.














Teague & Mortensen       Expires August 19, 2017               [Page 18]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


          message DOTSClientMessage {
            1 (seqno) = %;
            2 (last_svr_seqno) = %;
            3 (mitigations) = [
              {
                1 (eventid) = %;
                2 (requested) = %;
                3 (scope) = %;
                4 (lifetime) = %;
              }
            ];
          }

   The DOTS server is expected to respond to confirm that it has
   accepted and or rejected the mitigation request.  Upon receipt of the
   response the DOTS client should cease sending additional initial
   requests for the same eventid.  If these do not cease then the server
   may assume that the response was possibly lost and should resend
   accordingly.  Acceptance status is communicated by the DOTS server
   replying with the corresponding eventid and the enabled field set to
   1 for acceptance and 0 for rejection.  A rejection by the DOTS server
   should be accompanied with an extension field detailing succinctly
   the reason (e.g. out of contract, conflict, maintenance etc. ).

         message DOTSServerMessage {
           1 (seqno) = %;
           2 (last_cli_seqno) = %;
           4 (mitigations) = [
             {
               1 (eventid) = %;
               2 (enabled) = true; // Mitigation request accepted
             }
           ]
         }

   After a period of time the mitigation request may expire and the DOTS
   server may end the mitigation.  Alternately, the DOTS client may
   explicitly terminate the active mitigation by sending a message to
   the server that contains a mitigation value with the eventid and that
   has the requested field set to false, as shown below:











Teague & Mortensen       Expires August 19, 2017               [Page 19]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


         message DOTSClientMessage {
           1 (seqno) = %;
           2 (last_svr_seqno) = %;
           3 (mitigations) = [
             {
               1 (eventid) = %;
               2 (requested) = false; // Terminate mitigation
             }
           ];
         }

   The server must explicitly acknowledge the termination with a
   response message with the enabled field now set to false:

         message DOTSServerMessage {
           1 (seqno) = %;
           2 (last_cli_seqno) = %;
           6 (mitigations) = [
             {
               1 (eventid) = %;
               2 (enabled) = false; // Mitigation terminated
             }
           ];
         }

   The life cycle of a DOTS mitigation request resembles the following:

          Client                        Server
            |                              |
            |---Request(M=true)----------->|  // Mitigation request
            |                              |
            |<---------MitigationActive----|  // Server acceptance
            |                              |
            |< - - - - MitigationFeedback -|
            |                              |
            |---Terminate(M=false)-------->|  // Mitigation termination
            |                              |
            |<---------MitigationEnded-----|  // Server termination ack

4.3.4.  Ancillary Messages

   In addition to the basic interaction, additional messages may be
   exchanged throughout the lifetime of the mitigation.  The following
   message types are defined to provide requisite information between
   DOTS agents during an active signaling session.






Teague & Mortensen       Expires August 19, 2017               [Page 20]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


4.3.4.1.  Mitigation Feedback

   The DOTS server MUST update the client with current mitigation
   status.  This MUST include the eventid, and SHOULD include available
   dropped attack traffic statistics provided by the mitigator.  A DOTS
   server MAY provide feedback for more than one mitigation in a single
   message, provided the resulting message meets the sub-MTU size
   requirements in [I-D.ietf-dots-requirements].

   The DOTS client SHOULD use the feedback from the DOTS server when
   deciding to update or terminate a mitigation request.  For example,
   if the DOTS client learns from DOTS server mitigation feedback that
   the dropped_pps rate is low, the DOTS client might decide to
   terminate upstream mitigation and handle the attack locally.

   A mitigation feedback message from the DOTS server would resemble the
   following format, assuming an active mitigation request from the DOTS
   client:

         message DOTSServerMessage {
           1 (seqno) = %;
           2 (last_client_seqno) = %;
           6 (mitigations) = [
             {
               1 (eventid) = %;
               2 (enabled) = %;
               3 (ttl) = %;
               4 (bytes_dropped) = %;
               5 (bps_dropped) = %;
               6 (pkts_dropped) = %;
               7 (pps_dropped) = %;
               10 (filters_enabled) = true;
             },
           ];
         }

4.3.4.2.  Mitigation Lifetime Update

   The DOTS client may wish to update the mitigation during its
   lifetime.  Updates may be to alter the lifetime to extend the
   mitigation, or an update may communicate the perceived efficacy of
   the mitigation.  The former may be as a result of the DOTS sever
   feedback which may suggest that an attack shows no sign of abating.
   The latter may be to notify the DOTS server whether the
   countermeasures deployed are perceived as effective or not.

   A DOTS client may update the lifetime of multiple mitigations in a
   single request as long as the message size meets the sub-MTU



Teague & Mortensen       Expires August 19, 2017               [Page 21]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   requirement per [I-D.ietf-dots-requirements].  The lifetime update
   message has the following format:

          message DOTSClientMessage {
            1 (seqno) = %;
            2 (last_svr_seqno) = %;
            3 (mitigations) = [
              {
                1 (eventid) = %;
                2 (requested) = true;
                4 (lifetime) = %;
              }
            ];
          }

   Upon receipt of the mitigation lifetime update, the DOTS server
   replace the current mitigation expiration time with the new value.
   The updated lifetime MUST be visible in the ttl field in subsequent
   mitigation feedback messages.  When updating a mitigation lifetime,
   the DOTS client SHOULD continue sending the lifetime update request
   at the heartbeat interval until the DOTS server's mitigation feedback
   shows an updated ttl for the updated mitigation.

4.3.4.3.  Mitigation Efficacy Updates

   When a mitigation is active, a DOTS client MUST periodically
   communicate the locally perceived efficacy of the mitigation to the
   DOTS server.  This gives the DOTS server a rough sense of whether the
   DOTS client perceives the mitigator's deployed countermeasures as
   effective.  The efficacy update update message has the following
   format:

         message DOTSClientMessage {
           1 (seqno) = %;
           2 (last_svr_seqno) = %;
           3 (mitigations) = [
             {
               1 (eventid) = %;
               6 (efficacy) = %;
             }
           ];
         }

   The DOTS server SHOULD consider the efficacy update an indication of
   the effectiveness of any ongoing mitigations related to the eventid
   provided by the DOTS client.  The DOTS server nonetheless MAY treat
   any efficacy update from the client as advisory, and is under no
   obligation to alter the mitigation strategy in response.



Teague & Mortensen       Expires August 19, 2017               [Page 22]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


5.  IANA Considerations

   The DOTS protocol requires a well-known port to which DOTS client
   messages are sent.  The DOTS server listens on the well-known port
   for client messages.  The DOTS client binds to an ephemeral port per
   Section 4.3.1 above.  This document selects port 4646 (the ASCII
   decimal values for "..": "DOTS") as the well-known port.

6.  Security Considerations

   The DOTS protocol controls mitigation request and withdrawal and as
   such care must be taken to protect against concerns outlined in the
   security considerations of [I-D.ietf-dots-architecture].

7.  Appendix A: Message Schemas

7.1.  DOTS Client Message Schema

       syntax = "proto3";
       import "google/protobuf/any.proto";

       message DOTSClientMessage {
         // Client generated sequence number
         uint64 seqno = 1;

         // Sequence number of last received server message
         uint64 last_svr_seqno = 2;

         repeated DOTSMitigation mitigations = 3;

         // Request active mitigation list from server
         bool active = 4;

         // Ping request (operator initiated)
         bool ping = 5;

         DOTSSessionConfig config = 6;

         repeated google.protobuf.Any extensions = 999;
       }

                   Figure 7: DOTS Client Message Schema

7.2.  Mitigation Request Schema







Teague & Mortensen       Expires August 19, 2017               [Page 23]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


       message DOTSMitigation {
         // Opaque client-generated event identifier
         string eventid = 1;

         // Toggle mitigation for the above scope
         bool requested = 2;

         // Mitigation scope as described in I-D.ietf-dots-requirements
         string scope = 3;

         // Lifetime of the requested mitigation.
         uint32 lifetime = 4;

         // Mitigation efficacy score as a float value between 0 and 1
         float efficacy = 5;

         repeated google.protobuf.Any extensions = 999;
       }

              Figure 8: DOTS Client Mitigation Request Schema

7.3.  Session Configuration Schema

         // Per session configuration sent on signaling session init
         message DOTSSessionConfig {
           // Acceptable signal loss
           uint32 loss_limit = 1;

           // Maximum mitigation lifetime in seconds
           uint32 lifetime_max = 2;

           // Heartbeat interval in milliseconds
           uint32 heartbeat_interval = 3;
         }

               Figure 9: DOTS Session Conifiguration Schema

7.4.  DOTS Server Message Schema













Teague & Mortensen       Expires August 19, 2017               [Page 24]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


       syntax = "proto3";
       import "google/protobuf/any.proto";

       message DOTSServerMessage {
         // Server generated sequence number
         uint64 seqno = 1;

         // Sequence number of last received Client message
         uint64 last_client_seqno = 2;

         // Request immediate heartbeat response from client.
         bool ping = 3;

         // Server error details, if available
         DOTSServerError error = 4;

         DOTSRedirect redirect = 5;

         // Mitigation data, limited by MTU
         repeated DOTSMitigationStatus mitigations = 6;
       }

                   Figure 10: DOTS Server Message Schema

7.5.  DOTS Redirect Schema

       message DOTSRedirect {
         // Redirection target DOTS server address
         string target = 1;

         // Address family of redirection target
         enum RedirectionTargetType {
           DNSNAME = 0;
           IPV4 = 4;
           IPV6 = 6;
         }
         RedirectionTargetType target_type = 2;

         // Port on which to contact redirection target.
         // XXX Protobufs has no uint16 type, implementations
         // will need to sanity check.
         uint32 port = 3;
       }








Teague & Mortensen       Expires August 19, 2017               [Page 25]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


7.6.  DOTS Mitigation Status Schema

     syntax = "proto3";
     import "google/protobuf/any.proto";

     message DOTSMitigationStatus {
       // Opaque Client generated event identifier, used by DOTS client
       // to associate a mitigation status with the event triggering the
       // mitigation request.
       string eventid = 1;

       // Mitigation state
       bool enabled = 2;

       // Mitigation time-to-live (lifetime - (now - start))
       uint32 ttl = 3;

       // Dropped byte count
       uint64 bytes_dropped = 4;

       // Dropped bits per second
       uint64 bps_dropped = 5;

       // Dropped packet count
       uint64 pkts_dropped = 6;

       // Dropped packets per second
       uint64 pps_dropped = 7;

       // Blacklist enabled through data channel
       bool blacklist_enabled = 8;

       // Whitelist enabled through data channel
       bool whitelist_enabled = 9;

       // Filters enabled through data channel
       bool filters_enabled = 10;

       repeated google.protobuf.Any extensions = 999;
     }

              Figure 11: DOTS Server Mitigation Status Schema

7.7.  Server Error Schema







Teague & Mortensen       Expires August 19, 2017               [Page 26]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


       syntax = "proto3";
       import "google/protobuf/any.proto";

       message DOTSServerError {
         enum ErrorCode {
           NOERROR = 0;
           INVALID_VALUE = 1;
           MITIGATION_UNAVAILABLE = 2;
           MITIGATION_CONFLICT = 3;
           MALFORMED_MESSAGE = 4;
         }
         ErrorCode code = 1;

         // Error details, returned as a blob
         google.protobuf.Any details = 2;
       }

                    Figure 12: DOTS Server Error Schema

8.  References

8.1.  Normative References

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768, DOI
              10.17487/RFC0768, August 1980,
              <http://www.rfc-editor.org/info/rfc768>.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7, RFC
              793, DOI 10.17487/RFC0793, September 1981,
              <http://www.rfc-editor.org/info/rfc793>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
              RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              DOI 10.17487/RFC2784, March 2000,
              <http://www.rfc-editor.org/info/rfc2784>.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, DOI 10.17487/
              RFC3031, January 2001,
              <http://www.rfc-editor.org/info/rfc3031>.






Teague & Mortensen       Expires August 19, 2017               [Page 27]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   [RFC5405]  Eggert, L. and G. Fairhurst, "Unicast UDP Usage Guidelines
              for Application Designers", BCP 145, RFC 5405, DOI
              10.17487/RFC5405, November 2008,
              <http://www.rfc-editor.org/info/rfc5405>.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012, <http://www.rfc-editor.org/info/rfc6347>.

   [RFC6555]  Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
              Dual-Stack Hosts", RFC 6555, DOI 10.17487/RFC6555, April
              2012, <http://www.rfc-editor.org/info/rfc6555>.

   [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
              of Named Entities (DANE) Transport Layer Security (TLS)
              Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
              2012, <http://www.rfc-editor.org/info/rfc6698>.

   [RFC7030]  Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
              "Enrollment over Secure Transport", RFC 7030, DOI
              10.17487/RFC7030, October 2013,
              <http://www.rfc-editor.org/info/rfc7030>.

   [I-D.ietf-dots-architecture]
              Mortensen, A., Andreasen, F., Reddy, T.,
              christopher_gray3@cable.comcast.com, c., Compton, R., and
              N. Teague, "Distributed-Denial-of-Service Open Threat
              Signaling (DOTS) Architecture", draft-ietf-dots-
              architecture-01 (work in progress), October 2016.

   [I-D.ietf-dots-requirements]
              Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed
              Denial of Service (DDoS) Open Threat Signaling
              Requirements", draft-ietf-dots-requirements-03 (work in
              progress), October 2016.

   [PROTOBUF]
              Google, Inc., "Protocol Buffers", 2016,
              <https://developers.google.com/protocol-buffers/>.

8.2.  Informative References

   [I-D.reddy-dots-data-channel]
              Reddy, T., Boucadair, M., Nishizuka, K., Xia, L., and P.
              Patil, "Distributed Denial-of-Service Open Threat
              Signaling (DOTS) Data Channel", draft-reddy-dots-data-
              channel-03 (work in progress), December 2016.




Teague & Mortensen       Expires August 19, 2017               [Page 28]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   [RFC1518]  Rekhter, Y. and T. Li, "An Architecture for IP Address
              Allocation with CIDR", RFC 1518, DOI 10.17487/RFC1518,
              September 1993, <http://www.rfc-editor.org/info/rfc1518>.

   [RFC1519]  Fuller, V., Li, T., Yu, J., and K. Varadhan, "Classless
              Inter-Domain Routing (CIDR): an Address Assignment and
              Aggregation Strategy", RFC 1519, DOI 10.17487/RFC1519,
              September 1993, <http://www.rfc-editor.org/info/rfc1519>.

   [RFC5575]  Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
              and D. McPherson, "Dissemination of Flow Specification
              Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
              <http://www.rfc-editor.org/info/rfc5575>.

   [CLOUDSIGNAL]
              Arbor Networks, Inc., "Cloud Signaling: A Faster,
              Automated Way to Mitigate DDoS Attacks", 2011,
              <https://www.arbornetworks.com/cloud-signaling-a-faster-
              automated-way-to-mitigate-ddos-attacks>.

   [COMMUNITYFS]
              Team Cymru, Inc., "Community FlowSpec", 2011,
              <https://www.cymru.com/jtk/misc/community-fs.html>.

   [OPENHYBRID]
              Verisign, Inc., "Verisign OpenHybrid", 2016,
              <http://www.verisign.com/en_US/security-services/ddos-
              protection/open-api/index.xhtml>.

   [WISR]     Arbor Networks, Inc., "Worldwide Infrastructure Security
              Report", 2016,
              <https://www.arbornetworks.com/images/documents/
              WISR2016_EN_Web.pdf>.

Authors' Addresses

   Nik Teague
   Verisign, Inc.
   12061 Bluemont Way
   Reston, VA  20190
   United States

   Email: nteague@verisign.com








Teague & Mortensen       Expires August 19, 2017               [Page 29]


Internet-Draft     DDoS Open Threat Signaling Protocol     February 2017


   Andrew Mortensen
   Arbor Networks, Inc.
   2727 S. State St
   Ann Arbor, MI  48104
   United States

   Email: amortensen@arbor.net












































Teague & Mortensen       Expires August 19, 2017               [Page 30]


Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/