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Versions: 00 01 02 03 draft-kala-dtcp

Internet Draft                                                D. Cavuto
Intended status: Experimental                                      AT&T
Expires: May 2010                                               M. Apte
                                                       Juniper Networks
                                                                S. Jain
                                                       Juniper Networks
                                                              M. Murthy
                                                       Juniper Networks
                                                      November 10, 2009



                  DTCP: Dynamic Tasking Control Protocol
                         draft-cavuto-dtcp-03.txt



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   the Trust Legal Provisions and are provided without warranty as
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Abstract

   Dynamic Tasking Control Protocol is a message-based interface by
   which an authorized client may connect to a server -- usually a
   network element (NE) or security policy enforcement point (PEP) --
   and issue dynamic requests for data. These tasking requests contain,
   among other parameters, packet matching criteria that may apply to
   certain packets flowing through that network element. The primary
   intent of the tasking request is to instruct that network element to
   send copies of packets matching those criteria to a destination
   (usually via tunneling) for further inspection or other action. The
   protocol contains a security architecture to address client or server
   spoofing as well as replay prevention. The protocol assumes that
   multiple clients may simultaneously control a single server.














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Table of Contents


   1. Introduction...................................................5
      1.1. Operational Modes.........................................5
      1.2. Performance Considerations................................6
      1.3. Conventions used in this document.........................6
   2. Definitions....................................................7
      2.1. Server....................................................7
      2.2. Client....................................................7
      2.3. Control Source............................................7
      2.4. Content Destination.......................................7
      2.5. Criteria..................................................7
   3. Overview of Operation..........................................8
      3.1. Request-Response Paradigm.................................8
      3.2. Asynchronous Notifications................................9
      3.3. Data Delivery Mechanism..................................10
   4. Security Model................................................10
      4.1. No Information Exposure..................................10
      4.2. Independence of Control Sources..........................11
      4.3. Control Source to Content Destination Access Control.....11
      4.4. Per-Message Security Mechanisms..........................11
         4.4.1. Sequence Number.....................................11
            4.4.1.1. Sequence Number Negative Window................12
         4.4.2. Hashing Message Authentication Code (HMAC)..........13
   5. Application-Layer Message Formats.............................14
      5.1. Request General Format...................................14
      5.2. Response General Format..................................15
      5.3. Notification General Format..............................15
      5.4. Add Request..............................................15
         5.4.1. Criteria Timeouts...................................17
      5.5. Add Response.............................................17
      5.6. Delete Request...........................................18
      5.7. Delete Response..........................................19
      5.8. Refresh Request..........................................20
      5.9. Refresh Response.........................................20
      5.10. List Request............................................21
      5.11. List Response...........................................22
      5.12. NoOp Request............................................23
      5.13. NoOp Response...........................................23
      5.14. Restart Notification....................................24
      5.15. Rollover Notification...................................24
      5.16. NoOp Notification.......................................24
      5.17. Timeout Notification....................................24
      5.18. Congestion Notification.................................25
      5.19. CongestionDelete Notification...........................25
      5.20. DuplicatesDropped Notification..........................26
   6. Miscellaneous.................................................26
      6.1. Special treatment of response to List request............26
      6.2. Error or Exception Conditions............................28
      6.3. Extensions in ABNF.......................................29
      6.4. Current Version..........................................29


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      6.5. No specific port.........................................29
      6.6. Unimplemented Protocol Methods and Parameters............29
      6.7. Version Mismatches.......................................30
         6.7.1. DTCP Client version exceeds DTCP Server version.....31
         6.7.2. DTCP Server version exceeds DTCP Client version.....31
   7. Message Payload Examples......................................31
      7.1. Successful ADD Request and Response Payload..............31
   8. Formal Syntax.................................................33
   9. Security Considerations.......................................40
   10. IANA Considerations..........................................40
   11. Conclusions..................................................40
   12. Acknowledgments..............................................40
   APPENDIX A: Prior Implementation.................................41
      A.1. Version Number...........................................41
      A.2. Response to List request.................................41
      A.3. Changes in Response Codes................................41
      A.4. IP Version 6.............................................42
      A.5. Sequence Number Negative Window..........................42
      A.6. Version Mismatches.......................................42
   APPENDIX B: DTCP Vendor-Specific Extensions......................43
      B.1. Juniper Networks: "Flow-Tap".............................43
         B.1.1. "Flow-Tap" DTCP Extensions..........................43
         B.1.2. "Flow-Tap" extension ABNF...........................44
   13. References...................................................46
      13.1. Normative References....................................46
      13.2. Informative References..................................46




























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1. Introduction

   The Dynamic Tasking Control Protocol (DTCP) is a mechanism used to
   dynamically control network elements in the course of performing a
   security or other analysis on a transient network event.

   Network Security personnel typically have little visibility into the
   very networks they are monitoring. Routers and switches have awkward
   mechanisms such as port mirroring and cFlowd to enable personnel some
   meager view into the traffic flowing through a device.

   However, when a security incident does happen to be detected, the
   security analysis staff struggles to gain more insight as to the
   actual content of the incident, via inference from these tools. This
   is a time-consuming and cumbersome task.

   cFlowd [9] and other aggregation mechanisms provide only session-
   level statistics about the event, and fail to provide any view into
   the actual packet data. In contrast, wholesale backhauling of port-
   mirrored data is often cumbersome (and expensive) to set up, since it
   requires pre-provisioned free bandwidth on wide-area links, and often
   additional network hardware to implement.

   The intent of DTCP is to provide a simple mechanism by which a third-
   party device can interact with a network element or security policy-
   enforcement-point (PEP) that normally processes packetized network
   data, and in that interaction cause the PEP to take some action
   (usually copy) on a defined subset of that packet data to be
   forwarded for further inspection and analysis.

          packet     +---+     packet
           data ->---|NE |--->- data
                     +---+
                      ^ |
                      | |
             DTCP ----+ +---> copy of selected packet data

            Figure 1 - DTCP interacting with a network element.


   The Network Element (NE) or PEP may be a firewall or proxy server, or
   some other non-security-specific network element, such as a router or
   a switch. This is illustrated in Figure 1.

1.1. Operational Modes

   The primary operation in DTCP is the specification of the filter
   criteria used to select or filter packets. DTCP is designed to work
   in an IPv4 environment, and accordingly all selection criteria are
   chosen from IPv4 and higher-layer protocol definitions. Note that
   current DTCP syntax is limited to L3 and L4, but could be expanded to
   higher layers. Basic filter criteria definitions have semantic (if


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   not syntactic) similarity to well-known router access-control lists
   (ACLs) or firewall rulesets.

   The primary operational mode of DTCP is the "copy" mode, whereby the
   controlled network element forwards the packet towards its intended
   destination, and also makes a copy of that packet, which it forwards
   towards a preconfigured collection and analysis center. In this mode,
   the original packet flow is not interrupted. DTCP makes no provisions
   for the potential performance impact on the network element when
   performing this function; obviously a negligible impact is most
   desirable.

   DTCP also supports optional modes for purely redirecting the packet
   data (instead of making a copy of it), as well as blocking packet
   data. These modes, if implemented, can provide additional
   functionality for network security personnel, who may have decided
   that particular traffic is disallowed on the network and wishes to
   interrupt the selected flow of traffic.

   Of critical distinction to DTCP is the basic paradigm that DTCP does
   NOT involve a "reprovisioning" or "reconfiguration" of the controlled
   device. DTCP is by its very nature transient; controlled devices
   should not attempt to maintain DTCP state in a non-volatile storage
   system.

1.2. Performance Considerations

   It is envisioned that the controlling side of DTCP will be
   implemented by both human-interactive systems and automated systems.
   Since controlled Network Element MUST be able to respond to automated
   requests at a potentially high rate (due to floods or other attacks),
   the protocol implies a high performance requirement during the
   "criteria specification" phase of the interaction. In particular, the
   response time of the Network Element to respond to the DTCP request
   to monitor data is of considerable importance, as the traffic
   intended to be monitored may be short-lived.

   While concrete performance requirements are outside the scope of this
   document, implementers are urged to focus performance on this part of
   the client-server interaction.

1.3. Conventions used in this document

   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 RFC-2119 [1].








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2. Definitions

   The following sections define terms that have special significance
   within the DTCP context.

2.1. Server

   The DTCP Server is the PEP or network element that controls the data
   of interest. The DTCP Server will be controlled in turn via DTCP. The
   Server is responsible for maintaining state of DTCP Client Requests,
   and forwarding data accordingly. Usually the DTCP Server will be
   implemented on a firewall or router (or an accessory device attached
   to one). The Server generally Responds to Requests, and can also
   initiate Asynchronous Notifications. One Server generally services
   more than one Client.

2.2. Client

   The DTCP Client is an arbitrary host that initiates Requests to the
   Server via DTCP.

2.3. Control Source

   A Control Source is the instantiation of one DTCP Client, with
   respect to a given Server. Each Control Source is preconfigured and
   pre-authorized on a given Server to be able to interact with it via
   DTCP. Control Sources may also receive Asynchronous Notifications.
   There may be many Control Sources configured on a given Server.

   A Control Source MUST NOT be identified by IP address; rather,
   Control Sources are identified by user-configured character strings.

2.4. Content Destination

   A Content Destination is the recipient of the extracted data, once it
   is forwarded by the server. Content Destinations are also
   preconfigured on the server.

   A Content Destination MUST NOT be identified by IP address; rather,
   Content Destinations are identified by user-configured character
   strings.

2.5. Criteria

   The Criteria is the list of matching conditions under which a packet
   is selected and acted upon by the server. Criteria are specified in
   requests from the client to the server, which maintains a list of
   active criteria for each client.






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3. Overview of Operation

   This section describes the basic interaction between the DTCP
   elements, as well as the protocol message flows.

3.1. Request-Response Paradigm

   The basic model for DTCP is a request-response message exchange
   paradigm, where the server waits for messages on a specific UDP port
   from authorized Control Sources. When a request message arrives, the
   server processes the request, performs the necessary internal state
   change as per the request, and then sends a reply message.

   Note that although DTCP is specified as a message-based protocol, it
   is designed and specified here to operate via single UDP/IP packets,
   for performance reasons. While it is certainly possible for DTCP to
   be operated over TCP/IP for reliable connections, such use is
   unexplored as yet, and any implementation-specific decisions made are
   unspecified herein. This document is written assuming that UDP will
   be used as the Layer-4 transport mechanism.

   A DTCP Server MUST allocate at least ONE IP address and ONE UDP port
   for inbound connections from clients. Each DTCP Client MUST be
   statically configured with at least ONE IP address and ONE UDP port
   representing the server.

   There is no mechanism defined that ensures proper configuration
   between DTCP Clients and servers for requests and responses.

   In general, each request and each reply are a single UDP message,
   contained within a single IP packet. Since IP packets may be
   fragmented during delivery, each DTCP endpoint MUST be capable of IP
   fragment reassembly.

   An IP packet containing a DTCP Request message from a client to a
   server MUST have the following attributes properly set:

   o  Destination IP Address MUST equal an IP address of a DTCP Server;
   o  IP Protocol MUST equal 17 (UDP);
   o  Destination UDP Port MUST equal a UDP port being listened on by
      the respective DTCP Server.

   The DTCP Server MUST NOT rely on the source IP address or source UDP
   port of inbound request packets for any identification or
   authentication of the message.

   An IP packet containing a DTCP Reply message from a server to a
   client MUST have the following attributes properly set:

   o  Source IP Address MUST equal the Destination IP Address of the IP
      packet containing the Request;



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   o  Destination IP address MUST equal the Source IP Address of the IP
      packet containing the Request;
   o  IP Protocol MUST equal 17 (UDP);
   o  Destination UDP port MUST equal the Source UDP port of the UDP
      message containing the Request;
   o  Source UDP port MUST equal the Destination UDP port of the UDP
      message containing the Request.

   There is no specific UDP port registered for DTCP; rather, each DTCP
   Server SHOULD permit the user to configure the port or set of ports
   on which it will listen for inbound DTCP requests. Additionally, a
   DTCP Server MAY choose to implement address or other filters on the
   source of inbound client requests; however, this is optional and
   implementation specific. (Recall that clients are identified by
   strings, NOT IP addresses.)

3.2. Asynchronous Notifications

   Notifications are sent out by the DTCP Server to a set of statically
   preconfigured DTCP Clients who wish to receive notifications of
   asynchronous events. Such messages are sent to IP addresses that have
   been preconfigured therein.

   A DTCP Client MAY provide a mechanism for accepting and processing
   Notifications. The DTCP Server MUST be preconfigured with an IP
   address and UDP port for each DTCP Client that wishes to receive
   Notifications.

   There is no mechanism defined that ensures proper configuration
   between DTCP Clients and servers for Notifications.

   An IP packet containing a DTCP Notification message from a server to
   a client MUST have the following attributes properly set:

   o  Destination IP address MUST equal the configured DTCP Client IP
      address;
   o  IP Protocol MUST equal 17 (UDP);
   o  Destination UDP port MUST equal the configured DTCP Client UDP
      port.

   A future enhancement to this document may be to provide a mechanism
   for clients to dynamically self-register for notifications.

   A DTCP Server SHOULD include a configuration parameter for each
   configured Control Source to indicate the Notification Version for
   that Control Source. If such a parameter is configured for a given
   Control Source, all Asynchronous Notifications sent from the DTCP
   Server to that Control Source MUST precisely match the Notification
   Version configured for that Control Source. Additionally, if such a
   parameter is configured for a given Control Source, the DTCP Server
   MUST NOT send Asynchronous Notifications to that Control Source that
   do not exist in the DTCP specification indicated for that Control


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   Source. Finally, the DTCP Server MUST ensure that Asynchronous
   Notifications whose formats have been modified in newer versions of
   DTCP are properly formatted to meet the older DTCP specification
   version indicated for that Control Source.

   Note that in general the DTCP Server SHOULD accept requests from a
   DTCP Client using a DTCP Version other than that specified in the
   Notification Version for that client.

   If the DTCP Server is unable to meet these requirements, upon
   receiving a request from a DTCP Client with a mismatching version, it
   MUST return a a "505 DTCP Version not supported" error message *using
   the highest version supported by the DTCP Server*, and discontinue
   processing of that request.

   It is recommended, however, that the DTCP Server reject such a state
   at configuration time rather than at run time.

3.3. Data Delivery Mechanism

   Since the original packet IP header is not originally addressed to
   the intended Content Destination, each DTCP Server implementation
   MUST provide a mechanism for delivery of redirected data packets to
   appropriate Content Destinations. This explicitly includes IP
   checksums and IP TTL, as well as any higher-layer headers -- which
   SHOULD NOT be altered once captured -- but may not include MAC or
   lower-layer checksums.

   DTCP explicitly does not specify the mechanism of data delivery to
   the Content Destination. Such a delivery mechanism is implementation-
   specific, and is outside the scope of this document.

   As an example, Servers could utilize such technologies as VLAN
   tagging or IP tunneling to deliver entire unaltered data packets to
   Content Destinations.



4. Security Model

   Since DTCP is, by design, a security protocol, it is imperative that
   it be resistant to malicious use.

4.1. No Information Exposure

   DTCP was designed with the explicit paradigm that only information
   intentionally available to a given Control Source is ever exposed to
   that Control Source. For example: the existence of other Control
   Sources, or Content Destinations to which it has no access MUST NOT
   be exposed to a given Control Source, e.g. via notifications or error
   messages. Also, the server MUST NOT respond to any message that fails



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   its security checks. This basic paradigm MUST be upheld in DTCP
   Server implementations.

4.2. Independence of Control Sources

   DTCP may be implemented on network elements providing service to
   different customers. If each customer is allowed access to the DTCP
   Server, they MUST NOT be aware that another customer is using the
   DTCP Server. More specifically, neither customer's use (or misuse) of
   the DTCP Server can affect the other customer's use of it.

   Limits on service-affecting actions that may be taken by a DTCP
   Client are outside the scope of this document.

4.3. Control Source to Content Destination Access Control

   A DTCP Server SHOULD provide a mechanism by which each configured
   Control Source is granted access to one or more Content Destinations.

4.4. Per-Message Security Mechanisms

   The primary motivation behind the per-message security mechanisms is
   to provide both message integrity as well as source authenticity.
   Additionally, providing insulation against replay-type attacks is
   also a motivation, though secondary.

   DTCP currently provides no mechanism for confidentiality. If
   confidentiality is required, it is recommended that DTCP messages be
   sent via a secure transport.

          Note: Authentication failures, defined as a failure of
          these per-message security mechanisms, MUST NOT be
          reported to the DTCP Client. They SHOULD be logged on
          the DTCP server, and possibly acted upon by
          administration staff.

4.4.1. Sequence Number

   Every message initiated by a DTCP Client MUST contain a sequence
   number. The request sequence number is an unsigned 64-bit whole
   number chosen arbitrarily by the client and maintained by the server
   persistently for each Control Source. All requests from a given
   Control Source MUST contain a monotonically-increasing sequence
   number. The sequence number for each successive request may increment
   by no more than 256. The stored last-valid sequence number shall only
   be updated upon receipt of a valid, authentic message.

   A reply message to a valid request MUST contain the identical
   sequence number as the associated request.

   Other than as specified below in "Sequence Number Negative Window",
   repetition of the last sequence number, or an invalid (non-


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   monotonically-increasing) sequence number, in an otherwise-valid
   message MUST result in the message being dropped and a security
   violation being logged, except when the sequence number wraps over
   zero due to bit-field-length constraints.

   Rollover of the sequence number shall only be permitted when the MSB
   of the current sequence number is all-ones; otherwise this shall be
   considered a security violation. A rollover of the sequence number
   shall cause both an asynchronous notification message to be sent to
   any configured static address(es) for the respective Control Source
   as well as a log message to be generated.

   It is suggested that clients do whatever possible to persistently
   store the current sequence number as there is no DTCP method by which
   to reset the current sequence number.

   DTCP Servers SHOULD provide some mechanism for manually resetting the
   sequence number for a given client.

   Additionally, DTCP Servers SHOULD implement a Negative Window feature
   as specified in the following section.

4.4.1.1. Sequence Number Negative Window

   Under high load, a multithreaded DTCP client may send multiple
   requests (with properly incrementing sequence numbers) to the DTCP
   Server without waiting for each reply to come back individually.
   Because packets may be reordered through the network, they may arrive
   at the DTCP Server out of order.

   For example, the DTCP client may send:

   o  Request 1 (Seq = 1)
   o  Request 2 (Seq = 2)
   o  Request 3 (Seq = 3)

    But due to network reordering, the DTCP Server may receive:

   o  Request 1 (Seq = 1)
   o  Request 3 (Seq = 3)
   o  Request 2 (INVALID)

   Unfortunately, the specification of the sequence number above will
   make Request 2 invalid, because once Request 3 is processed, the
   stored sequence number in the DTCP Server for that Client has been
   incremented to 3.

   Therefore to correct this problem, the DTCP Server SHOULD include a
   "negative" window as well as the required "positive" window for
   sequence numbers, and keep track of received sequence numbers within
   that negative window. However, in order to maintain the replay-
   protection afforded by the sequence number in the first place, any


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   DTCP Server implementing a negative window MUST also implement
   tracking of particular sequence numbers received within the union of
   both windows, and MUST NOT respond to any requests containing a
   sequence number already received.

   If the received sequence number is in the negative window, the DTCP
   Server would simply store that sequence number as seen from that
   particular DTCP Client and process the packet. If the sequence number
   of the packet is in the positive window, the new positive and
   negative window would begin and end at this packet's sequence number
   respectively with the window sizes remaining the same. So a DTCP
   packet with sequence number within the negative window but that has
   not been seen (or anywhere within the positive window) is valid.

4.4.2. Hashing Message Authentication Code (HMAC)

   A DTCP Server MUST store a statically-provisioned secret key for each
   configured client. This key is manually shared with each DTCP Client.
   Each request and response message MUST contain, as the last entry, a
   parameter called Authentication-Info, whose value is the HMAC
   algorithm specified in RFC-2104 [2] of the rest of the message
   payload (including the sequence number) generated using a SHA-1 [3]
   digest and the secret key. This digest is expressed in hexadecimal
   notation ([0-9a-f]), using 40 UTF-8 [4] characters to express the
   160-bit SHA-1 hash.

         Original Message:    text
         Secret Key:          K
         HMAC:                hash = SHA1HMAC(K, text)
         New Message:         text + "Authentication-Info: " + hash

     Figure 2 - Generating the message HMAC from the original message.


   The shared secret key MUST NOT be sent in any DTCP message.

   The precise algorithm, excerpted here from RFC-2104 for reference
   purposes (using SHA-1 as the hashing function H and byte length B=64)
   is as follows:

      We define two fixed and different strings ipad and opad as follows
      (the 'i' and 'o' are mnemonics for inner and outer):
                     ipad = the byte 0x36 repeated B times
                     opad = the byte 0x5C repeated B times.

      To compute HMAC over the data `text' we perform
                       H(K XOR opad, H(K XOR ipad, text))







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5. Application-Layer Message Formats

   In general, the best source for the message formats is the Formal
   Syntax specified below. The following prose is provided for
   informational purposes and implementation guidelines. Where apparent
   syntactic conflicts exist, the Formal Syntax is defined to be
   correct.

   DTCP messages are formatted in human-readable CRLF-delimited UTF-8
   text format, using a mechanism similar to HTTP [5] or SIP [6]. Each
   message begins with an initial "command" line, followed by an
   optional series of parameter-value lines. Each token in the command
   line as well as each option line is separated by one or more white
   space characters. The entire message MUST end with two CRLFs.

   The final token in any line MAY have whitespace before its
   terminating CRLF, but is not so required, and is not so reflected in
   the ABNF. DTCP servers SHOULD ignore extra whitespace between the
   final token and the terminating CRLF, but MUST return a Syntax Error
   otherwise.

   Parameter names are specified in mixed case, but MUST be matched
   regardless of case.

   Control characters or other unprintable characters in the parameter
   value may be indicated by a backslash (\) followed by precisely three
   digits indicating the UTF-8 value for the character, possibly
   including leading zeros. The backslash notation may be used to
   express any character, including whitespace. Backslash notation is
   explicitly forbidden from being interpreted as either an inter-token
   delimiter or an inter-parameter delimiter.

   DTCP Clients and server MUST NOT rely upon the order of parameters
   within the DTCP message, since it is not guaranteed (other than the
   final "Authentication-Info" parameter as noted below).

   Every DTCP message MUST contain the "Authentication-Info" parameter,
   and it MUST be the final parameter in the message. Any parameters in
   any DTCP message following the Authentication-Info parameter MUST be
   disregarded.

   If a parameter appears multiple times, the behavior is undefined and
   not guaranteed; however, if a parameter does show up multiple times,
   the endpoint SHOULD take the value of the first occurrence and
   disregard any successive occurrences.

5.1. Request General Format

   Each client-to-server message in DTCP begins with a single request
   command line with the following format:

      <command>  <protocol-version-specifier> CRLF


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   The command line is followed by one or more parameter-value pairs,
   comprising the message body. The message is terminated by two CRLFs.

   A DTCP request MUST contain the Sequence Number and the Control
   Source ID parameters.

5.2. Response General Format

   Each server-to-client response message in DTCP shall begin with a
   single response line with the following format:

   <protocol-version-specifier> <response-code> <response-text> CRLF

   where the response-code is a three-digit numeric value, and the
   response-text is an arbitrary-length text string intended to be
   human-readable. The response line is followed by one or more
   parameter-value pairs comprising the message body. The message is
   terminated by two CRLFs.

   Responses to successful requests MUST contain the response-code "200"
   and the response-text "OK".

   A DTCP response MUST contain the Sequence Number parameter. A DTCP
   response MUST also contain the Timestamp parameter.

5.3. Notification General Format

   Each server-to-client notification message in the control protocol
   shall begin with a single response line with the following format:

   <protocol-version-specifier> <response-code> <response-text> CRLF

   where the response-code is a three-digit numeric value, and the
   response-text is an arbitrary-length text string intended to be
   human-readable. The response line is followed by one or more
   parameter-value pairs comprising the message body. The message is
   terminated by two CRLFs.

   A DTCP notification message MUST contain the Timestamp parameter.

5.4. Add Request

   The Add request specifies a new filter criteria to be merged with the
   existing tasking list for a given Control Source and Content
   Destination (regardless of order added). Any missing parameters in
   the request will inferred to be a wildcard or "don't care". The Add
   request MAY be accompanied by one or more of the following required
   filter criterion parameters:

   o  Source IP address, range or IP + bitmask, or wildcard
   o  Destination IP address, range, or IP + bitmask, or wildcard
   o  IP Protocol or range, or wildcard


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   o  Source Layer-4 Port or range, or wildcard (parameter only
      meaningful when IP protocol range includes protocols 6 or 17)
   o  Destination Layer-4 Port or range, or wildcard (parameter only
      meaningful when IP protocol range includes 6 or 17)
   o  ICMP Type or range, or wildcard (parameter only meaningful when IP
      protocol range includes protocol 1)
   o  ICMP Code or range, or wildcard (parameter only meaningful when IP
      protocol range includes protocol 1)

   A wildcard in a given field implies that any value will match it
   (i.e. "don't care").

   Additionally, the Add request MUST contain one or more of the
   following parameters:

   o  Timeout specified in seconds idle (maximum one day)
   o  Timeout specified in seconds total (maximum one day)
   o  Timeout specified in packets (maximum 64 bits)
   o  Timeout specified in bytes (maximum 64 bits)
   o  Flag: Static, which indicates that this criterion will never
      timeout and persist until explicitly deleted. All other timeouts
      shall be ignored if a STATIC flag is present.

   Additionally, the Add request may contain one or more of the
   following parameters:

   o  Relative Priority (unsigned integer, minimum value 1) (optional,
      defaults to 1)
   o  Flag: Send Timeout Async (optional), which will cause the server
      to send a Asynchronous Notification when the criterion times out
      for any reason.
   o  Action (optional), which specifies whether the packet stream
      identified by the criterion will be a) copied to the Content
      Destination and also forwarded to its original intended
      destination ("Copy"), b) copied but not forwarded ("Redirect"), or
      c) not copied and not forwarded ("Block"). By default, Action is
      "Copy".

   Finally, the Add request MUST contain the following control protocol
   parameters:

   o  Control Source Identifier
   o  Content Destination Identifier
   o  Sequence number (MUST be monotonically increasing for each request
      from a given Control Source)
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Although not explicitly expressed in the request, the DTCP Server
   MUST maintain the date/time of each filter criterion successfully
   added. This time is the local DTCP Server time, either maintained
   independently by the server or synchronized via NTP.



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5.4.1. Criteria Timeouts

   Timeouts are required for each filter criterion added. These timeouts
   may be specified in any of four formats: seconds-idle, seconds-total,
   bytes, or packets. Any combination of these four timeouts may be used
   in a filter criterion as long as at least one is used.

   Once a criterion is added, the timeouts will begin decrementing as
   appropriate. Only the timeouts that are specified in the request will
   be used for timing-out that criterion. When any active timeout is
   decremented to zero, the DTCP Server will automatically delete the
   filter criterion. For each Control Source, if enabled, when a
   criterion times-out and is deleted, timeout notifications will be
   sent to any statically-configured Notification Destination(s)
   associated with that Control Source.

   A criterion may be added as STATIC. Any such criterion shall persist
   in the active state unless and until explicitly deleted or deleted
   due to congestion, provided the DTCP Server maintains its normal
   operational state. (See section 5.18 Congestion Notification for more
   information on congestion and timeouts.)

   If all timeout values are zero and the criterion is not marked
   STATIC, the DTCP Server MUST return Error 433 (Improper Timeout
   Specification) and the criterion must not be added. For STATIC
   criteria, the DTCP Server MUST ignore the all timeout values.

   If the server fails, STATIC rules may be lost. Any Control Source
   that uses STATIC criteria SHOULD attempt to ensure that such criteria
   are still up and active following any maintenance or failure event on
   the server.

5.5. Add Response

   The response to a successful Add request will consist of the
   following parameters:

   o  Criteria ID

   The Criteria ID will be persistent for the duration of that request,
   until it is removed explicitly by the client, or is removed
   implicitly by either timeout or some failure of the DTCP Server. The
   Criteria ID MUST uniquely identify that particular filter criterion
   for that particular Control Source (and be agnostic to the Content
   Destination).

   DTCP Servers MUST ensure that generated Criteria ID are unique for
   all currently-active requests for a given Control Source.

   Ideally, the Criteria ID SHOULD be globally unique across Control
   Sources, but this is not strictly required (since all requests will
   always be from a particular Control Source).


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   DTCP Servers SHOULD provide unique Criteria IDs for new requests,
   even if old ones have been deleted resulting in a fragmented ID
   space. This prevents race conditions that can cause inconsistent
   behavior e.g., a criterion specified in an Add request gets the same
   Criterion Id as a recently deleted criterion (deleted due to
   timeout), and before the delete notification could reach the Control
   Source, it sends out an explicit delete request for the old
   criterion, which when received by the DTCP Server would delete the
   recently added criterion, which is clearly undesirable.

   This response MUST also include the following parameters:

   o  Timestamp
   o  Sequence number (MUST match the sequence number for the request)
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Responses to unsuccessful Add requests may take any of the following
   forms:

   o  Syntax Error
   o  Improper Filter Criterion Specification
   o  Unknown Destination Identifier
   o  Invalid Timeout Specification
   o  Improper Authentication (logged, but never sent to client)
   o  Invalid Sequence Number (logged, but never sent to client)
   o  Unknown Control Source Identifier (logged, but never sent to
      client)

5.6. Delete Request

   The Delete request removes a particular filter criterion (or
   optionally all filter criteria) for the particular Control Source.
   The Delete request MUST take precisely one of the following
   parameters:

   o  Criteria ID or list of ranges of Criteria IDs
   o  Content Destination Identifier

   Additionally, the Delete request may contain one or more of the
   following parameters:

   o  Flag: Static, which indicates that criteria added as STATIC should
      be deleted as well. (optional) If this flag is omitted, STATIC
      criteria MUST NOT be deleted.

   If a single Criteria ID or list of ranges Criteria IDs is specified,
   the respective criterion/criteria is/are removed from the list of
   filter conditions that apply for that Control Source.

   If a Content Destination Identifier is specified, all criteria are
   removed from the list of filter conditions to that particular Content
   Destination for that Control Source, except for STATIC criteria --


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   unless the STATIC flag is specified. (Note that any other criteria
   specified by any other Control Sources MUST remain unaffected.)

   Additionally, the Delete request MUST contain the following
   parameters:

   o  Control Source Identifier
   o  Sequence number (MUST be monotonically increasing for each request
      from a given Control Source)
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.7. Delete Response

   The response to a successful Delete will consist of the following
   parameter:

   o  Number of Criteria Deleted

   This parameter is an integer specifying the total number of filter
   criteria that were actually deleted. The number will be precisely 1
   if a single, valid Criteria ID is supplied in the Delete request. If
   multiple valid Criteria IDs are supplied, the number of criteria
   actually deleted will be returned.

   If any individual Criteria ID is invalid, the entire response will
   return an error and no action shall be taken by the server for any
   supplied Criteria ID. If a Content Destination Identifier is
   supplied, the number of criteria deleted shall be equal to the total
   number of active filter criteria from the requesting Control Source
   to that particular Content Destination. If no such criteria exist,
   the DTCP Server will return a successful delete response (with
   criteria deleted parameter set to zero).

   When a range is specified, any existing criteria matching the
   Criteria ID in that range (inclusive) will be deleted and the true
   number of criteria deleted (including possibly zero) will be
   returned.

   Trying to delete a STATIC criterion without the STATIC flag in the
   Delete request will result in that criterion NOT being deleted. Such
   a deletion attempt will return a success (non-error) response,
   including the actual number of criteria deleted (which may be zero).

   This response MUST also include the following parameters:

   o  Timestamp
   o  Sequence number (MUST match the sequence number for the request)
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Responses to unsuccessful Delete requests may take any of the
   following forms:



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   o  Syntax Error
   o  Unknown Criteria ID
   o  Unknown Destination Identifier
   o  Improper Authentication (logged, but never sent to client)
   o  Invalid Sequence Number (logged, but never sent to client)
   o  Unknown Control Source Identifier (logged, but never sent to
      client)

5.8. Refresh Request

   The Refresh request updates the timeout for a particular filter
   criterion or set of filter criteria (or optionally all filter
   criteria) for the particular Control Source assigned to a particular
   Content Destination. This is used to maintain active criteria that
   are in danger of timing-out based on the original Add request. The
   updated timeout will replace the current remaining timeout, NOT be
   added to it.  The Refresh request MUST take precisely one of the
   following parameters:

   o  Criteria ID or list of ranges of Criteria IDs
   o  Content Destination Identifier

   Additionally, the Refresh request MUST contain one or more of the
   following parameters:

   o  Timeout specified in seconds total
   o  Timeout specified in seconds idle
   o  Timeout specified in packets
   o  Timeout specified in bytes

   (Note that a Refresh request MUST NOT be used to make an existing
   filter criterion STATIC. A criterion MUST be added explicitly as
   STATIC in its original Add.)

   Finally, the Refresh request MUST contain the following parameters:

   o  Control Source Identifier
   o  Sequence number (MUST be monotonically increasing for each request
      from a given Control Source)
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.9. Refresh Response

   The response to a successful Refresh will consist of the following
   parameters:

   o  Number of Criteria Refreshed

   This parameter is an integer specifying the total number of filter
   criteria that were actually updated. The number will be precisely 1
   if a single, valid Criteria ID is supplied. If multiple valid
   Criteria ID are supplied, the number of criteria updated will be


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   returned, and that will equal the number of supplied Criteria IDs. If
   any Criteria ID is invalid, the entire response will return an error
   and no action shall be taken by the server for any supplied Criteria
   ID. If a Content Destination Identifier is supplied, the number of
   criteria updated shall be equal to the total number of active filter
   criteria from the requesting Control Source to that particular
   Content Destination, including zero (which will NOT return an error).

   This response MUST also include the following parameters:

   o  Timestamp
   o  Sequence number (MUST match the sequence number for the request)
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Responses to unsuccessful Refresh requests may take any of the
   following forms:

   o  Syntax Error
   o  Invalid Timeout Specification
   o  Unknown Criteria ID
   o  Unknown Destination Identifier
   o  Improper Authentication (logged, but never sent to client)
   o  Invalid Sequence Number (logged, but never sent to client)
   o  Unknown Control Source Identifier (logged, but never sent to
      client)

5.10. List Request

   The List request makes no change on the DTCP Server, but returns a
   list of all criteria that a particular Control Source has added. The
   Control Source may request this list on the basis of Content
   Destination, Criteria ID, or overall (for that particular Control
   Source). The List request takes the following parameters:

   o  Content Destination Identifier (optional)
   o  Criteria ID or List of ranges of Criteria IDs (optional)
   o  Flag: Statistics / Criteria / All

   If neither of the optional parameters is included, the server MUST
   reply with the full set of criteria associated with that Control
   Source.

   Additionally, the List request MUST contain the following parameters:

   o  Control Source Identifier
   o  Sequence number (MUST be monotonically increasing for each request
      from a given Control Source)
   o  HMAC authenticator (MUST span message payload, plus secret key)






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5.11. List Response

   The response to a successful List will consist of a formatted list --
   essentially a table -- of filter criteria and related parameters.

   Fields will be included and excluded depending on the presence and
   the value of Stats/Criteria/All entry in the request as noted in
   square brackets [] following the value listed below. Each entry in
   the List list shall contain the following fields as specified in the
   original criteria:

   o  Control Source Identifier
   o  Control Source IP Address
   o  Content Destination Identifier
   o  Criteria ID
   o  Date/Time added
   o  Specified Source IP address, range or IP + bitmask , or wildcard
      [Criteria]
   o  Specified Destination IP address, range, or IP + bitmask, or
      wildcard [Criteria]
   o  IP Protocol or range, or wildcard [Criteria]
   o  Source Layer-4 Port or range, or wildcard (parameter only
      meaningful when IP protocol range includes protocols 6 or 17)
      [Criteria]
   o  Destination Layer-4 Port or range, or wildcard (parameter only
      meaningful when IP protocol range includes 6 or 17) [Criteria]
   o  ICMP Type or range, or wildcard (parameter only meaningful when IP
      protocol range includes protocol 1) [Criteria]
   o  ICMP Code or range, or wildcard (parameter only meaningful when IP
      protocol range includes protocol 1) [Criteria]
   o  Timeout specified in seconds total [Criteria]
   o  Timeout specified in seconds idle [Criteria]
   o  Timeout specified in packets [Criteria]
   o  Timeout specified in bytes [Criteria]

   The List list shall also contain the following statistical
   information based on each criterion:

   o  An ordinal counter to specify the position of this entry in the
      context of the list
   o  An integer specifying the total number of entries in the list
   o  Timeout remaining in seconds total [Stats]
   o  Timeout remaining in seconds idle [Stats]
   o  Timeout remaining in packets [Stats]
   o  Timeout remaining in bytes [Stats]
   o  An indication if the timeout is STATIC
   o  Last 10-second average bandwidth, in bits/second [Stats]
   o  Total number of packets that have matched this Criteria  [Stats]
   o  Total number of bytes that have matched this Criteria [Stats]
   o  Total times this rule has been Refreshed [Stats]
   o  Date/Time of last Refresh  [Stats]



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   This response MUST also include the following parameters:

   o  Timestamp
   o  Sequence number (MUST match the sequence number for the request)
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Responses to unsuccessful List requests may take any of the following
   forms:

   o  Syntax Error
   o  Unknown Destination Identifier
   o  Unknown Criteria ID
   o  Improper Authentication (logged, but never sent to client)
   o  Invalid Sequence Number (logged, but never sent to client)
   o  Unknown Control Source Identifier (logged, but never sent to
      client)

   Important Note: the response to the List message, in particular all
   entries in the generated table, SHOULD be internally consistent and
   atomic, regardless of the activity in progress at the time of and
   during the course of transmission of the message. The data SHOULD
   represent a snapshot of the relevant information at the quantum in
   time that the List message is processed.

5.12. NoOp Request

   This request takes no action on the server whatsoever, other than
   returning a successful response. The sole purpose of this command is
   to verify the end-to-end application-layer connectivity between a
   Control Source and the DTCP Server. The NoOp request may contain the
   following parameter:

   o  Flag: SendAsync

   See 5.13 NoOp Response for a description of the SendAsync flag.

   Additionally, the NoOp request MUST contain the following parameters:

   o  Control Source Identifier
   o  Sequence number (MUST be monotonically increasing for each request
      from a given Control Source)
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.13. NoOp Response

   The response to a successful NoOp will consist of a successful
   response message indicator, and contain the following parameters:

   o  Timestamp
   o  Sequence number (MUST match the sequence number for the request)
   o  HMAC authenticator (MUST span message payload, plus secret key)



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   If the SendAsync parameter is specified in the NoOp request, the
   server shall cause an asynchronous notification message to be sent to
   any configured notification destinations for that particular Control
   Source.

5.14. Restart Notification

   The Restart notification shall be sent from the server to any
   configured notification-recipient when the system experiences a
   failure such that all the filter criteria are lost. The Restart
   notification shall contain the following parameters:

   o  Restart Reason, a text string indicating the reason for the
      restart, if known
   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.15. Rollover Notification

   The Rollover notification shall be sent from the server to any
   configured notification-recipient when the server experiences a
   sequence-number rollover. The Rollover notification shall contain the
   following parameters:

   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.16. NoOp Notification

   The NoOp notification shall be sent from the server to any configured
   notification-recipient when the DTCP Server receives a NoOp message
   with the SendAsync parameter present. The NoOp notification shall
   contain the following parameters:

   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.17. Timeout Notification

   The Timeout notification shall be sent from the server to the
   appropriate notification-recipient(s) when the server times out a
   filter criterion on any one of its configured timeout parameters and
   the criterion contains a SendTimeoutAsync parameter.

   The Timeout notification shall contain the following parameters:

   o  Criteria ID, to indicate the particular criteria that has timed
      out
   o  Timeout specified in seconds total  [omit if unconfigured]
   o  Timeout remaining in seconds total  [omit if unconfigured]
   o  Timeout specified in seconds idle  [omit if unconfigured]
   o  Timeout remaining in seconds idle [omit if unconfigured]


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   o  Timeout specified in packets  [omit if unconfigured]
   o  Timeout remaining in packets  [omit if unconfigured]
   o  Timeout specified in bytes  [omit if unconfigured]
   o  Timeout remaining in bytes  [omit if unconfigured]
   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

5.18. Congestion Notification

   The Congestion notification shall be sent from the server to any
   configured notification-recipient when the total 10-second average
   data rate (in bits/second) summed over all active filter criteria to
   a configured Content Destination exceeds the configured soft limit
   for that destination.  The Congestion notification shall contain the
   following parameters:

   o  Content Destination ID, to indicate the particular destination
      experiencing excessive bandwidth
   o  Current total 10-second average Bandwidth, in bits/second
   o  Configured SoftLimit Threshold, in bits/second
   o  Configured HardLimit Threshold, in bits/second
   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

   Note that since multiple Control Sources may be responsible for this
   overload, this Notification MUST be sent to all configured Control
   Sources that have currently-active filter criteria to this particular
   Content Destination.

5.19. CongestionDelete Notification

   The CongestionDelete notification shall be sent from the server to
   any configured notification-recipient when the total 10-second
   average data rate (in bits/second) summed over all active filter
   criteria to a configured Content Destination exceeds the configured
   hard limit for that destination, causing the DTCP Server to begin
   purging filter criteria.  The CongestionDelete notification shall
   contain the following parameters:

   o  Content Destination ID
   o  List of Criteria ID purged
   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

   CongestionDelete messages MUST be specifically and uniquely sent to
   all configured notification-recipients for the Control Sources to
   which they apply. To be clear: a given Control Source notification-
   recipient MUST only receive CongestionDelete messages containing
   Criteria ID created by that Control Source.





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5.20. DuplicatesDropped Notification

   The DuplicatesDropped notification shall be sent from the server to
   any configured notification-recipient when capacity has been exceeded
   in such a way as to cause packets matching criteria added by the
   corresponding Control Source to be dropped. This notification will be
   sent periodically as long as packets continue to be dropped. The
   DuplicatesDropped notification shall contain the following
   parameters:

   o  Content Destination ID
   o  Applicable CriteriaID pertaining to Dropped Packets
   o  Total Number of Dropped Packets
   o  Sum of Bytes contained in Dropped Packets
   o  Timestamp
   o  HMAC authenticator (MUST span message payload, plus secret key)

   DuplicatesDropped messages MUST be specifically and uniquely sent to
   all configured notification-recipients for the Control Sources to
   which they apply.



6. Miscellaneous

6.1. Special treatment of response to List request

   The List request inherently provides unique functionality with
   respect to the messaging architecture of DTCP. All other requests
   result in reasonably terse replies, which can be encapsulated in, at
   worst, a few IP packets.

   However, the List request will generate an arbitrary amount of reply
   data, since it could contain all requests that are still active, up
   to the limit of the device. This section specifically describes how
   responses to the List request are sent.

   a) The full reply to the List request MAY consist of multiple
   packets. Each packet will contain a single "Response" element;
   therefore, each packet will have a single Status-Line and a single
   trailer (Authentication-Info) terminated by 2xCRLF. A UDP packet MUST
   NOT contain more than ONE "Response" element.

   b) A "Response" element in each packet shall contain zero or more
   "List-Resp-Entry" elements (in "List-Resp-Parameters"). Each filter
   criteria is encoded into a single "List-Resp-Entry" element. The
   sequence number MUST be identical for all "Response" elements in a
   multi-packet reply.

   c) Each "List-Resp-Entry" element MUST contain the following two
   elements: "Criteria-Num" and "Criteria-Count". "Criteria-Num" MUST be
   valued as an enumeration starting with 1 (one) and incrementing by


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   one for each "List-Resp-Entry" sent. "Criteria-Count" SHOULD be set
   to the total number of matching Criteria in the given particular LIST
   response (see below for potential exceptions).

   d) Therefore, a full reply to the List request shall consist of as
   many "List-Resp-Entry" elements as necessary to fully transmit the
   List, divided into multiple packets as described above.

   e) DTCP Servers SHOULD ensure that each "List-Resp-Entry" element is
   not divided across multiple IP packets.

   f) DTCP Clients can use the simple test (Criteria-Num==Criteria-
   Count) to determine if they've received the last packet in the
   series. However, in order to ensure that all packets were received
   (and, respectively, all List-Resp-Entry elements), the DTCP Client
   MUST traverse through the list of Criteria-Count to ensure it's
   complete from 1 to XX where XX==Criteria-Num==Criteria-Count.

   g) At the UDP layer, all packets in the response MUST contain
   identical UDP port numbers. DTCP Clients SHOULD maintain their socket
   open until either all expected Response messages are received, or a
   timeout occurs.

   h) If the List request matches no criteria, but does not supply
   invalid Criteria-IDs, the "Response" element will contain zero "List-
   Resp-Entry" elements.

   i) DTCP Servers MAY simplify their implementation by only including a
   single "List-Resp-Entry" element in each "Response" element (and
   therefore in each packet).

   j) DTCP Servers MAY simplify their implementation by transmitting the
   "Criteria-Count" element in each List-Resp-Entry element as ZERO (0)
   until the final element is sent, whereupon it is set to the proper
   value.

   A List response that matches 3 criteria may look as follows:

   =============== First UDP packet
   DTCP header
   Seq: A
   criteria-id: x    ; this is the first List-Resp-Entry element
   ...
   criteria-num: 1
   criteria-count: 3
   criteria-id: y   ; this is the second List-Resp-Entry element
   ...
   criteria-num: 2
   criteria-count: 3
   HMAC
   ================



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   =============== Second UDP packet
   DTCP header
   Seq: A
   criteria-id: z   ; this is the third List-Resp-Entry element
   ...
   criteria-num: 3
   criteria-count: 3
   HMAC
   ================

   If the list request matches no criteria, it will look as follows:

   =============== First UDP packet
   DTCP header
   Seq: B
   HMAC
   ================

6.2. Error or Exception Conditions

   Errors in DTCP requests are reported in response messages via any
   Response-Code other than "200" (OK). When such error or exception
   condition exists, the server SHOULD attempt to indicate the precise
   nature of the error or exception using the Error-Parameters element.
   This behavior, though helpful, is not strictly required by the
   protocol.

   For example, if a Delete request contained a specific Criteria-ID not
   currently active in the server, the response error message MUST begin
   with a 431 - Unknown Criteria ID response line. The server SHOULD
   also add the Criteria-ID parameter indicating the unknown Criteria
   ID.

   Again, note that authentication failures MUST NOT be reported in
   response messages; they MUST be silently dropped.

   The DTCP Server MUST attempt to provide the most specific error
   message to report the specific error or exception condition. When the
   request message meets any of the following conditions, if no such
   specific error message exists, the server MAY return a 400 (Bad
   Request) error:

   o  Missing required fields
   o  Parse failure
   o  Parameters beyond range

   In these cases, the server SHOULD include the specific line from the
   request that caused the condition using the Error-Parameters element.






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6.3. Extensions in ABNF

   Extension placeholders are provided in the formal syntax for the
   definition of future methods, parameters, and response-codes. Vendors
   SHOULD NOT define implementation-specific extensions; rather, such
   extensions SHOULD be brought to the DTCP working group for inclusion
   into the protocol, to ensure interoperability.

   However, in order to provide faster extensions to the protocol, the
   "X-" extension parameter construct has been borrowed from other
   protocols, including SIP and SMTP.

   The DTCP Server or the DTCP Client MAY include an arbitrary
   parameter-value pair, as long as the parameter is preceded by the
   character string "X-", and all other parameter-value conventions are
   followed.

   The sender of such extension parameters MUST NOT rely on the
   recipient correctly processing those values.

   The recipient of such extension parameters MAY process the values as
   appropriate upon receipt, but MUST discard without error those
   extension parameters that it does not recognize.

6.4. Current Version

   The current version string for this release of the DTCP protocol is:

      DTCP/0.7

6.5. No specific port

   While it is common practice to register and/or publish a TCP or UDP
   port for applications that define them as a layer-4 transport, DTCP
   has no specific UDP ports predefined. This is intended both to allow
   flexibility for implementers and users, as well as to make it more
   difficulty to detect DTCP messages on untrusted networks.

6.6. Unimplemented Protocol Methods and Parameters

   Some DTCP Server vendors have indicated their interest in supporting
   a subset of the functionality specified here, due to their position
   in the security space. Additionally, some constructs (arbitrary
   lists, in particular) add complexity to implementations that may not
   require that complexity.

   To address this need, rather than adding complexity by changing the
   grammar to indicate optional sections, specific error messages have
   been added to indicate to the client that the server cannot process
   the request in its current format. Depending on the request, the
   client might be able to reformat that request into one that the
   server implementation is able to process.


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   In order to be compliant with this protocol, the following rules
   apply:

   a) If a vendor chooses not to implement one or more DTCP Methods,
   when responding to a request containing one of the unsupported
   methods, the DTCP Server MUST send a "501 Not Implemented" Response
   error message, and discontinue processing of that request.

   b) If a vendor chooses not to implement a list element, when
   responding to a request containing such a list, the DTCP Server MUST
   send a "501 Not Implemented" Response error message, and discontinue
   processing of that request.

   c) If a vendor chooses not to implement one or more specific
   parameters or parameter value options in a request, the DTCP Server
   MUST send a "501 Not Implemented" Response error message, and
   discontinue processing of that request.

   d) The DTCP Server SHOULD include the method, parameter, or value
   which caused the "501 Not Implemented" error to be sent, within the
   error response message (to be consistent with 6.4 above)

   e) The DTCP Server SHOULD support prior versions of DTCP. However, if
   the vendor chooses not to implement prior versions of the protocol,
   the DTCP Server MUST send a "505 DTCP Version not supported" error
   message, and discontinue processing of that request.

   The onus is on the client to determine if it can reformat the message
   to make it acceptable to the particular DTCP Server implementation.

6.7. Version Mismatches

   The intent of this section is to clarify any ambiguity arising from
   mismatches between DTCP versions supported by the DTCP Client and the
   DTCP Server. In practice is has been observed that unintended
   consequences have arisen by leaving the implementation vague, so it
   was decided that clarifing at least a set of reccomendations, if not
   rising to the level of requirements, will help guide DTCP
   implementations and help ensure interoperability.

   Two possible cases of mismatch exist: when the client exceeds the
   server version, and when the server exceeds the client version. They
   are handled separately, but the motivation in each case is to permit
   maximum compatibility.

   In this case, versions are compared numerically, with a single digit
   after decimal point. For example: 0.4 is greater than 0.2, 1.9 is
   greater than 1.4, and 3.1 is greater than 2.9






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6.7.1. DTCP Client version exceeds DTCP Server version

   If the DTCP Client attempts to make a request to a DTCP Server using
   a DTCP version greater than that supported by the DTCP Server, the
   DTCP Server MUST return a "505 DTCP Version not supported" error
   message using the GREATEST DTCP version supported by the DTCP Server,
   and discontinue processing of that request. It has not way of knowing
   what new parameters might exist in a newer version of the protocol
   and simply has to abandon processing altogether.


   In this case, the onus is on the DTCP Client to revert to an older
   version of the protocol specification to talk with this DTCP Server
   to ensure that its request is properly handled.

6.7.2. DTCP Server version exceeds DTCP Client version

   It is expected that a given DTCP Server will support a range of DTCP
   protocol specification versions, for interoperability purposes.

   If the DTCP Server receives a request from a DTCP Server using a DTCP
   version lesser than the most current version supported by the DTCP
   Server, the server SHOULD attempt to process that response using the
   semantics of the earlier specification, and MUST reply using the
   precise DTCP version included in the request.

   If the DTCP server is unable to do this, the DTCP Server MUST return
   a "505 DTCP Version not supported" error message using the LEAST DTCP
   version supported by the DTCP Server, and discontinue processing of
   that request

   Asynchronous Notifications sent to a client using an earlier version
   are addressed in Section 3.2 (Asynchronous Notifications).



7. Message Payload Examples

   Note: These are only examples of message payloads, and are not
   intended to illustrate the full breadth of the protocol. Also, please
   note that the Authentication-Info shown are correct if each line is
   terminated with CRLF as specified and the key "secret" is used.
   (Terminating CRLFs are not shown.)

7.1. Successful ADD Request and Response Payload

   Following is an example of the UDP payload for an Add request:







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      ADD DTCP/0.6
      Source-Address: 192.168.10.4
      Dest-Address: 10.1.1.1-10.1.1.10
      Protocol: 6,17
      Dest-Port: 53
      Timeout-Idle: 600
      Action: Copy
      Priority: 2
      Flags: SendAsync
      Cdest-ID: cdst_b
      Csource-ID: csrc_a
      Seq: 3827443
      Authentication-Info: 28eb606458ba46160d7a59da48763020f5aef9f5

   Following is the UDP payload of one potential successful response to
   that Add request:

      DTCP/0.6 200 OK
      Criteria-ID: 38224
      Seq: 3827443
      Timestamp: 2005-01-01 12:01:01.111
      Authentication-Info: 38099d03fcb5b12a849b36f9bdccc757303fafd0

   7.2 Unsuccessful DELETE Request and Response Payload

   Following is an example of the UDP payload for an Delete request:

      DELETE DTCP/0.6
      Criteria-ID: 55331
      Csource-ID: csrc_d
      Flags: Static
      Seq: 2655371
      Authentication-Info: 6af62247a2b59a2a06e0ca08ec5a80a644e2cd67

   Following is the UDP payload of one potential unsuccessful response
   to that Delete request:

         DTCP/0.6 431 Unknown Criteria ID
         Criteria-ID: 55331
         Seq: 2655371
         Timestamp: 2005-02-02 12:02:02.222
         Authentication-Info: 5de4552e98832c2d2c3a9ffa8a2958c967b4e1e8

   This delete request was unsuccessful because the Criteria ID supplied
   did not exist. Note that the error-causing parameter is included
   within the reply to assist in debugging.








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8. Formal Syntax

   All of the mechanisms specified in this document are described in
   both prose and an Augmented Backus-Naur Form (ABNF) defined in RFC
   4234 [7]. Section 6.1 of RFC 4234 defines a set of core rules that
   are used by this specification, and not repeated here.  Implementers
   need to be familiar with the notation and content of RFC 4234 in
   order to understand this specification.  Certain basic rules are in
   uppercase, such as SP, LWS, HTAB, CRLF, DIGIT, ALPHA, etc.

   Note that while much of this syntax is taken from the Session
   Initiation Protocol (SIP), some of its constructs have been
   simplified for this application here. Where appropriate, these
   digressions have been noted with comments.

   The following core definitions appear throughout the formal syntax:

   COL            =  *(WSP) ":" *(WSP) ;  used in parameter-value pair
   NPCHAR         =  "\" 3DIGIT        ;  used to express ctrl-chars
   DSTRING        =  *(VCHAR / NPCHAR) ;  no embedded whitespace
   WC             =  "*"            ;  wildcard character for matching
   NOT            =  "!"            ;  invert character for matching
   N64BITNUM         =  1*20DIGIT
   N32BITNUM         =  1*10DIGIT
   N16BITNUM         =  1*5DIGIT
   N8BITNUM       =  1*3DIGIT
   DAYSEC         =  1*5DIGIT
   IPv4address    =  1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT
   TEXT           =  1*(1*(VCHAR) WSP) ; includes whitespace
   DTCP-Time      =  4DIGIT "-" 2DIGIT "-" 2DIGIT SP 2DIGIT ":"
                     2DIGIT ":" 2DIGIT "." 3DIGIT
                     ; This is ISO date/time: YYYY-MM-DD sp HH:MM:SS.TTT

   Additionally, the following definitions are excerpted from RFC 3986
   [8]:

         IPv6address =                            6( h16 ":" ) ls32
                     /                       "::" 5( h16 ":" ) ls32
                     / [               h16 ] "::" 4( h16 ":" ) ls32
                     / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
                     / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
                     / [ *3( h16 ":" ) h16 ] "::"    h16 ":"   ls32
                     / [ *4( h16 ":" ) h16 ] "::"              ls32
                     / [ *5( h16 ":" ) h16 ] "::"              h16
                     / [ *6( h16 ":" ) h16 ] "::"

         ls32        = ( h16 ":" h16 ) / IPv4address
                     ; least-significant 32 bits of address

         h16         = 1*4HEXDIG
                     ; 16 bits of address represented in hexadecimal



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   Here begins the formal syntax:

   DTCP-Message   =  Request / Response / Notification

   Request        =  Request-Line
                     ( Add-Req-Parameters
                  /  Delete-Req-Parameters
                  /  Refresh-Req-Parameters
                  /  List-Req-Parameters
                  /  Noop-Req-Parameters)
                     *(extension-parameter)
                     Csource-ID
                     Seq
                     Authentication-Info
                     CRLF

   Response       =  Status-Line
                     ( ( Add-Resp-Parameters
                  /  Delete-Resp-Parameters
                  /  Refresh-Resp-Parameters
                  /  List-Resp-Parameters
                  /  Noop-Resp-Parameters) / Error-Parameters )
                     *(extension-parameter)
                     Timestamp
                     Seq                  ; note absence of Csource-ID
                     Authentication-Info
                     CRLF

   Notification   =  Status-Line
                     ( Restart-Notif-Parameters
                  /  Rollover-Notif-Parameters
                  /  Noop-Notif-Parameters
                  /  Timeout-Notif-Parameters
                  /  Congestion-Notif-Parameters
                  /  CongDel-Notif-Parameters )
                     *(extension-parameter)
                     Timestamp
                     Authentication-Info  ;  note absence of Seq
                     CRLF

   DTCP-Version   =  "DTCP" "/" 1*DIGIT "." 1*DIGIT

   Status-Line    =  DTCP-Version SP Status-Code SP Reason-Phrase CRLF
   Request-Line   =  Method SP DTCP-Version CRLF

   Method         =  "ADD" / "DELETE" / "REFRESH" / "LIST" / "NOOP"
                     / extension-method

   extension-method  =  DSTRING

   Status-Code    =  Provisional
                  /  Success


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                  /  Redirection
                  /  Request-Failure
                  /  Server-Failure
                  /  Global-Failure
                  /  extension-code

   Reason-Phrase  =  TEXT  ; differs from SIP
   extension-code =  3DIGIT

   Provisional       =  "130" ;  Sequence Number Rollover (Notif)
                     /  "131" ;  NoOp Notification (Notif)
   Success           =  "200" ;  OK
   Redirection       =  "390" ;  Criterion Timeout Delete (Notif)
   Request-Failure   =  "400" ;  Bad Request
                     /  "430" ;  Unknown Content Destination
                     /  "431" ;  Unknown Criteria ID
                     /  "432" ;  Improper Filter Specification
                     /  "433" ;  Improper Timeout Specification
                     /  "497" ;  Invalid Authentication
                              ;  (never sent to client)
                     /  "498" ;  Invalid Sequence Number
                              ;  (never sent to client)
                     /  "499" ;  Unknown Control Source Identifier
                              ;  (never sent to client)
   Server-Failure    =  "500" ;  Server Internal Error
                     /  "501" ;  Not Implemented
                     /  "505" ;  DTCP Version not supported
                     /  "550" ;  Max Criteria Limit Exceeded
                     /  "551" ;  Max Content Destination Exceeded
                     /  "580" ;  Congestion (Notif)
                     /  "598" ;  Duplicate Packets Dropped (Notif)
                     /  "599" ;  Server Restart (Notif)
   Global-Failure    =  "680" ;  Criterion Congestion Delete (Notif)

   Error-Parameters  =  Cdest-ID
                     /  Criteria-ID
                     /  Filter-Block
                     /  Timeout-Block

   Add-Req-Parameters   =  Filter-Block Timeout-Block [Action]
                           Option-Block [Flags] Cdest-ID

   Filter-Block               =  *(Filter-Element)
   Timeout-Block              =  *(Timeout-Element)
   TRemaining-Block           =  *(TRemaining-Element)
   Option-Block               =  *(Option-Element)
   Timeout-Required-Block     =  1*(Timeout-Element)
   TRemaining-Required-Block  =  1*(TRemaining-Element)


   Filter-Element    =  Source-Address
                     /  Dest-Address


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                     /  Protocol
                     /  Source-Port
                     /  Dest-Port
                     /  ICMP-Type
                     /  ICMP-Code

   Timeout-Element   =  Timeout-Idle
                     /  Timeout-Total
                     /  Timeout-Packets
                     /  Timeout-Bytes

   TRemaining-Element   =  Remaining-Idle
                        /  Remaining-Total
                        /  Remaining-Packets
                        /  Remaining-Bytes

   Option-Element    =  Priority

   Add-Resp-Parameters  =  Criteria-ID

   Delete-Req-Parameters   =  ( (Criteria-ID / Criteria-ID-Filter)
                              Cdest-ID ) [Flags]
   Delete-Resp-Parameters  =  Criteria-Count

   Refresh-Req-Parameters  =  ( (Criteria-ID / Criteria-ID-Filter)
                              Cdest-ID ) Timeout-Required-Block
   Refresh-Resp-Parameters =  Criteria-Count

   List-Req-Parameters  =  [ ( (Criteria-ID / Criteria-ID-Filter)
                              Cdest-ID ) ] [Flags]

   List-Resp-Parameters =  *(List-Resp-Entry CRLF)

   List-Resp-Entry   =  Criteria-Count Criteria-Num Main-List
                        [Criteria-List] [Stats-List]

   Main-List            =  Csource-ID Csource-Address Cdest-ID
                           Criteria-ID Timestamp
   Criteria-List        =  *(Filter-Element) *(Timeout-Element) [Flags]
   Stats-List           =  TRemaining-Block Stats-Block

   Stats-Block       =  Average-Bandwidth Matching-Packets
                        Matching-Bytes Num-Refresh Last-Refresh

   Noop-Req-Parameters  =  [Flags]
   Noop-Resp-Parameters =  []    ;  no parameters

   Restart-Notif-Parameters      =  Alert-Info
   Rollover-Notif-Parameters     =  []       ; no parameters
   Noop-Notif-Parameters         =  []       ; no parameters
   Timeout-Notif-Parameters      =  Criteria-ID
                                 /  Timeout-Required-Block


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                                 /  TRemaining-Required-Block
   Congestion-Notif-Parameters   =  Cdest-ID Average-Bandwidth
                                    Alert-Bandwidth Max-Bandwidth
   CongDel-Notif-Parameters      =  Cdest-ID Criteria-ID-Filter

   extension-parameter  =  "X-" DSTRING COL DSTRING CRLF

   Csource-ID           =  "Csource-ID" COL DSTRING CRLF
   Seq                  =  "Seq" COL N64BITNUM CRLF
   Authentication-Info  =  "Authentication-Info" COL 40HEXDIG CRLF
   ID-List              =  DSTRING *("," DSTRING)
   Cdest-ID             =  "Cdest-ID" COL ID-List CRLF
   Source-Address       =  "Source-Address" COL IPFilter CRLF
   Dest-Address         =  "Dest-Address" COL IPFilter CRLF
   Protocol             =  "Protocol" COL ProtFilter CRLF
   Source-Port          =  "Source-Port" COL PortFilter CRLF
   Dest-Port            =  "Dest-Port" COL PortFilter CRLF
   ICMP-Type            =  "ICMP-Type" COL ICMPFilter CRLF
   ICMP-Code            =  "ICMP-Code" COL ICMPFilter CRLF
   Timeout-Idle         =  "Timeout-Idle" COL DAYSEC CRLF
   Timeout-Total        =  "Timeout-Total" COL DAYSEC CRLF
   Timeout-Packets      =  "Timeout-Packets" COL N32BITNUM CRLF
   Timeout-Bytes        =  "Timeout-Bytes" COL N64BITNUM CRLF
   Priority             =  "Priority" COL N8BITNUM CRLF
   Criteria-ID          =  "Criteria-ID" COL N32BITNUM CRLF
   Criteria-ID-Filter   =  "Criteria-ID" COL CritFilter CRLF
   Criteria-Count       =  "Criteria-Count" COL N32BITNUM CRLF
   Criteria-Num         =  "Criteria-Num" COL N32BITNUM CRLF
   Csource-Address      =  "Csource-Address" COL (IPv4address /
                           IPv6address) CRLF
   Timestamp            =  "Timestamp" COL DTCP-Time CRLF
   Remaining-Idle       =  "Remaining-Idle" COL DAYSEC CRLF
   Remaining-Total      =  "Remaining-Total" COL DAYSEC CRLF
   Remaining-Packets    =  "Remaining-Packets" COL N32BITNUM CRLF
   Remaining-Bytes      =  "Remaining-Bytes" COL N64BITNUM CRLF
   Average-Bandwidth    =  "Average-Bandwidth" COL N64BITNUM CRLF
   Matching-Packets     =  "Matching-Packets" COL N64BITNUM CRLF
   Matching-Bytes       =  "Matching-Bytes" COL N64BITNUM CRLF
   Num-Refresh          =  "Num-Refresh" COL N32BITNUM CRLF
   Last-Refresh         =  "Last-Refresh" COL DTCP-Time CRLF
   Alert-Info           =  "Alert-Info" COL TEXT CRLF
   Alert-Bandwidth      =  "Alert-Bandwidth" COL N64BITNUM CRLF
   Max-Bandwidth        =  "Max-Bandwidth" COL N64BITNUM CRLF
   Action               =  "Action" COL ActionEntry CRLF

   ActionEntry          =  "Copy"
                        /  "Block"
                        /  "Redirect"
                        /  extension-action

   extension-action     =  DSTRING



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   Flags                = "Flags" COL FlagEntry *("," FlagEntry) CRLF

   FlagEntry            =  "Static"
                        /  "SendAsync"
                        /  "Stats"
                        /  "Criteria"
                        /  "Both"

   IPFilter    =  [NOT] IPEntry *("," [WSP] [NOT] IPEntry)

   ProtFilter  =  [NOT] ProtEntry *("," [WSP] [NOT] ProtEntry)

   PortFilter  =  [NOT] PortEntry *("," [WSP] [NOT] PortEntry)

   ICMPFilter  =  [NOT] ICMPEntry *("," [WSP] [NOT] ICMPEntry)

   CritFilter  =  [NOT] CritEntry *("," [WSP] [NOT] CritEntry)

   IPEntry     =  IPv4Entry
               /  IPv6Entry


   IPv4Entry   =  IPv4address                   ;  Single Entry
               /  IPv4address "/" N8BITNUM      ;  Address/mask
               /  IPv4address "-" IPv4address   ;  Range
               /  IPv4address "-" WC            ;  Range to UBOUND
               /  WC "-" IPv4address            ;  LBOUND to Range
               /  WC                            ;  Pure Wildcard

   IPv6Entry   =  IPv6address                   ;  Single Entry
               /  IPv6address "/" N8BITNUM      ;  Address/mask
               /  IPv6address "-" IPv6address   ;  Range
               /  IPv6address "-" WC            ;  Range to UBOUND
               /  WC "-" IPv6address            ;  LBOUND to Range
               /  WC                            ;  Pure Wildcard

   PortEntry   =  N16BITNUM                        ;  Single Entry
               /  N16BITNUM "-" N16BITNUM          ;  Range
               /  N16BITNUM "-" WC                 ;  Range to UBOUND
               /  WC "-" N16BITNUM                 ;  LBOUND to Range
               /  WC                            ;  Pure Wildcard

   ProtEntry   =  N8BITNUM                      ;  Single Entry
               /  N8BITNUM "-" N8BITNUM         ;  Range
               /  N8BITNUM "-" WC               ;  Range to UBOUND
               /  WC "-" N8BITNUM               ;  LBOUND to Range
               /  WC                            ;  Pure Wildcard

   ICMPEntry   =  N8BITNUM                      ;  Single Entry
               /  N8BITNUM "-" N8BITNUM         ;  Range
               /  N8BITNUM "-" WC               ;  Range to UBOUND
               /  WC "-" N8BITNUM               ;  LBOUND to Range


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               /  WC                            ;  Pure Wildcard

   CritEntry   =  N64BITNUM                        ;  Single Entry
               /  N64BITNUM "-" N64BITNUM          ;  Range
               /  N64BITNUM "-" WC                 ;  Range to UBOUND
               /  WC "-" N64BITNUM                 ;  LBOUND to Range
               /  WC                            ;  Pure Wildcard















































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9. Security Considerations

   DTCP empowers network security personnel to monitor packet data
   transitioning through a network element. As such, it is a powerful
   protocol that can cause any network data to be redirected to a
   arbitrary location for inspection. Consequently, it is of greatest
   criticality that any DTCP Servers fully implement the security model
   outlined in this draft. Failure to do so could result in malicious
   individuals either obtaining unauthorized access to data or
   interruption of data transmission.

10. IANA Considerations

   This document has no actions for IANA.

11. Conclusions

   This protocol has undergone extensive testing and several rounds of
   refinements. The resulting protocol is highly effective at meeting
   its goals of providing a real-time mechanism to inspect raw packets
   containing security-related events traversing a network in real-time.

12. Acknowledgments

   Thanks to all at AT&T and Juniper Networks who provided testing and
   support for this experimental protocol!

   The authors would specifically like to thank Joju Chevookaran, and
   Saravanan Deenadayalan from Juniper since they have not only worked
   hard on the implementation, but also on the some of the enhancements
   (specially VRF support, input/out interface filters etc).

   Also, Rick Suntag, Michael Nanashko, and Michael St. Angelo from AT&T
   all deserve special note for extensive testing as well as excellent
   protocol definition suggestions and corrections.

   This document was prepared using 2-Word-v2.0.template.dot.
















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APPENDIX A: Prior Implementation

   This document fully and accurately describes the operation of
   DTCP/0.7 implementations. However, in development of this protocol,
   some implementations with working versions of the protocol were
   released. This appendix describes the differences between the
   DTCP/0.7 protocol specification documented herein and the prior
   DTCP/0.5 and DTCP/0.6 protocol specifications.

   Other than the changes documented in this appendix, the older
   protocol specifications precisely follow DTCP/0.7 described herein.
   This appendix is provided for backward-compatibility purposes only;
   all new implementations should ignore this appendix.

A.1. Version Number

   (Modifies section 6.4 Current Version)

   o  The prior supported version string was exactly:
    DTCP/0.6

A.2. Response to List request

   (Modifies sections 5.11 List Response, 6.1 Special treatment of
   response to List request and 8 Formal Syntax)

   The following changes apply only to the elements involved in the
   Response message used in reply to the List action. Changes are both
   syntactic and semantic in nature.

   o  The ABNF element called "Criteria-Num" in DTCP/0.7 did not exist
      in DTCP/0.5 and was not included in any DTCP message.
   o  The ABNF element called "Criteria-Count" in DTCP/0.7 was called
      "Num-Criteria" in DTCP/0.5.
   o  The "Num-Criteria" element was only included in the final UDP
      packet sent. This signals the end of the List response.

A.3. Changes in Response Codes

   1. 550: Max Criteria Limit Exceeded

   This error message is sent when the number of DTCP ADD requests
   received by the server exceeds the allowed limit. Error code 500 used
   in the earlier Flow-Tap implementations was not clear enough.

   2. 551: Max Content Destination Exceeded

   Server allows only a certain number of Content Destinations at any
   given time, and generates this error message when the server receives
   a DTCP ADD request that contains a new content destination after the
   number of Content Destinations on that server has already exceeded
   the allowable limit.


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   3. 432: Improper Filter Specification

   Generated when an ADD request contains a combination of X-JTap-VRF-
   Name, X-JTap-Input-Interface, and X-JTap-Output-Interface fields.

A.4. IP Version 6

   The formal ABNF syntax has been updated to include IP Version 6 in
   parallel with IP Version 4 both in the filter criteria specification
   as well as ancillary addressing information. The intent was to permit
   the protocol to operate largely unmodified while allowing the use of
   IP Version 6 addressing information. Some implementations may not
   support this addressing mode.

A.5. Sequence Number Negative Window

   The Negative Window sequence number concept has been added to this
   version of DTCP to address empirical errors found when testing with a
   high rate of DTCP "ADD" messages over a non-trivial network.

A.6. Version Mismatches

   The section on Version Mismatches was added, to account for specific
   problems encountered during upgrade of either the client or the
   server. In particular, the draft was ambiguous on how the DTCP Server
   should behave when servicing clients of various versions.




























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APPENDIX B: DTCP Vendor-Specific Extensions

B.1. Juniper Networks: "Flow-Tap"

B.1.1. "Flow-Tap" DTCP Extensions

   In support of Flow-Tap functionality, the DTCP grammar has been
   extended to include new parameters defined below. In general, the
   purpose of these parameters is to allow a content destination to be
   configured on-demand, rather than pre-configured. General DTCP
   grammar does not provide this functionality, so we extend it herein.

   Note that "JTap-Failure" below is not a grammar tag; it just defines
   a new error value "901' that will be used to indicate any problems
   with the X-JTap parameters.

   1. X-JTap-Cdest-Dest-Address

   IP address(es) of Content destination(s) where the matching packets
   need to be sent out. User may specify maximum two IP addresses
   separated by a comma. This field MUST be present in the ADD request
   otherwise "JTAP-Failure" error will be generated.

   2. X-JTap-Cdest-Dest-Port

   UDP port number(s) of Content destination(s) where the matching
   packets need to be sent out. User may specify maximum two port
   numbers separated by a comma.  This field MUST be present in the ADD
   request otherwise "JTAP-Failure" error will be generated.

   3. X-JTap-Cdest-TTL

   TTL value to be used in the forwarded packet. This is an optional
   field and default of 255 will be used if not specified

   4. X-JTap-Cdest-Source-Address

   Source IP address from which the forwarded packet needs to besent
   from This field MUST be present in the ADD request and "JTap-Failure"
   error will be generated if this is not specified

   5. X-JTap-Cdest-Source-Port

   Source UDP port from which the forwarded packet needs to be sent from

   This field MUST be present in the ADD request and "JTap-Failure"
   error will be generated if this is not specified.

   6. Changes in Cdest-ID

   Cdest-ID field enables you to specify more than one content
   destination by using a comma separated list. Currently, only two


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   content destinations are supported. However, note that the number of
   entries in all the three fields, Cdest-ID, X-JTap-Cdest-Dest-Address
   and X-JTap-Cdest-Dest-Port, must be the same. That is, if you have
   only one entry in one of the fields, the other two can have only one
   entry each. Error message 432 is generated if the number of entries
   in these fields does not match with each other.

   7. X-JTap-VRF-Name

   OPTIONAL field to specify a VRF name. If it is specified, only the
   packets coming to the specified VRF will be monitored. "JTap-Failure"
   error will be generated if the VRF is not configured

   8. X-JTap-Input-Interface

   OPTIONAL field to specify a list of interfaces. If it is specified,
   it will be attached to respective input interface(s) instead of
   global Flow-Tap filters. This list may contain maximum 8 interfaces
   separated by comma. If the unit name of an interface is not
   specified, System will assume it as unit 0. "JTap-Failure" error will
   be generated if any one of the interfaces in the list is not
   configured

   9. X-JTap-Output-Interface

   OPTIONAL field to specify a list of interfaces. If it is specified,
   the filter will be attached to respective output interface(s) instead
   of global Flow-Tap filters. This list may contain maximum 8
   interfaces separated by comma. If the unit name of an interface is
   not specified, System will assume it as unit 0. "JTap-Failure" error
   will be generated if any one of the interfaces in the list is not
   configured

B.1.2. "Flow-Tap" extension ABNF

   IP-4-OR-6                 = (IPv4address / IPv6address)
   ADDR-LIST                 = IP-4-OR-6 1*("," IP-4-OR-6)
   PORT-LIST                 = N16BITNUM 1*("," N16BITNUM)
   IFL   = 3CHAR "-" 2*DIGIT "/" 1*DIGIT "/" 1*DIGIT ["." N16BITNUM]
   IFL-LIST8 = IFL 7*("," IFL)

   X-JTap-Cdest-Dest-Address = "X-JTap-Cdest-Dest-Address" COL ADDR-LIST
   CRLF
   X-JTap-Cdest-Dest-Port    = "X-JTap-Cdest-Dest-Port" COL PORT-LIST
   CRLF
   X-JTap-Cdest-TTL = "X-JTap-Cdest-TTL" COL N8BITNUM CRLF
   X-JTap-Cdest-Source-Address = "X-JTap-Cdest-Source-Address" COL
   (IPv4address / IPv6address) CRLF
   X-JTap-Cdest-Source-Port = "X-JTap-Cdest-Source-Port" COL N16BITNUM
   CRLF
   X-JTap-VRF-Name = "X-JTap-VRF-Name" COL DSTRING CRLF
   X-JTap-Input-Interface = "X-JTap-Input-Interface" COL IFL-LIST8 CRLF


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   X-JTap-Output-Interface = "X-JTap-Output-Interface" COL IFL-LIST8
   CRLF




















































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13. References

13.1. Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Krawczyk, H. et. al., "RFC 2104: HMAC: Keyed-Hashing for
         Message Authentication", RFC 2104, February 1997

   [3]   FIPS 180-1, "Secure Hash Standard". May 10995.
         (http://www.itl.nist.gov/fipspubs/fip180-1.htm)

   [4]   Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC
         3629, November 2003

   [5]   Berners-Lee, T., Fielding, R. and H. Frystyk, "Hypertext
         Transfer Protocol -- HTTP/1.0", RFC 1945, May 10996

   [6]   Rosenberg, et al. "SIP: Session Initiation Protocol", RFC 3261,
         June 2002

   [7]   Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax
         Specifications: ABNF", RFC 5234, January 2008

   [8]   Berners-Lee, T., Fielding, R. , Masinter L., "Uniform Resource
         Identifier (URI): Generic Syntax", RFC 3986, January 2005

13.2. Informative References

   [9]   "CAIDA: The Cooperative Association for Internet Data Analysis"
         (http://www.caida.org/tools/measurement/cflowd/)






















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Authors' Addresses

   David J. Cavuto
   AT&T
   200 Laurel Ave South #C2-3B10
   Middletown, NJ 07748
   USA

   Email: dcavuto@att.com


   Manoj S. Apte
   Juniper Networks
   1194 North Mathilda Avenue
   Sunnyvale, CA 94089
   USA

   Email: mapte@juniper.net


   Sandeep Jain
   Juniper Networks
   1194 North Mathilda Avenue
   Sunnyvale, CA 94089
   USA

   Email: sjain@juniper.net


   Muku Murthy
   Juniper Networks
   1194 North Mathilda Avenue
   Sunnyvale, CA 94089
   USA

   Email: muku@juniper.net


















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