Internet Engineering Task Force (IETF)                     E. Haleplidis
Request for Comments: 6053                          University of Patras
Category: Informational                                         K. Ogawa
ISSN: 2070-1721                                          NTT Corporation
                                                                 W. Wang
                                           Zhejiang Gongshang University
                                                           J. Hadi Salim
                                                       Mojatatu Networks
                                                           November 2010

Implementation Report for
Forwarding and Control Element Separation (ForCES)

Abstract

   Forwarding and Control Element Separation (ForCES) defines an
   architectural framework and associated protocols to standardize
   information exchange between the control plane and the forwarding
   plane in a ForCES network element (ForCES NE).  RFC 3654 has defined
   the ForCES requirements, and RFC 3746 has defined the ForCES
   framework.

   This document is an implementation report for the ForCES Protocol,
   Model, and the Stream Control Transmission Protocol-based Transport
   Mapping Layer (SCTP TML) documents, and includes a report on
   interoperability testing and the current state of ForCES
   implementations.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6053.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  ForCES Protocol  . . . . . . . . . . . . . . . . . . . . .  4
     1.2.  ForCES Model . . . . . . . . . . . . . . . . . . . . . . .  4
     1.3.  Transport Mapping Layer  . . . . . . . . . . . . . . . . .  4
   2.  Terminology and Conventions  . . . . . . . . . . . . . . . . .  4
     2.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  4
     2.2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Summary  . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
   4.  Methodology  . . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   6.  Detail Section . . . . . . . . . . . . . . . . . . . . . . . .  7
     6.1.  Implementation Experience  . . . . . . . . . . . . . . . .  7
       6.1.1.  ForCES Protocol Features . . . . . . . . . . . . . . .  9
         6.1.1.1.  Protocol Messages  . . . . . . . . . . . . . . . .  9
         6.1.1.2.  MainHeader Handling  . . . . . . . . . . . . . . . 10
         6.1.1.3.  TLV Handling . . . . . . . . . . . . . . . . . . . 11
         6.1.1.4.  Operation Types Supported  . . . . . . . . . . . . 12
         6.1.1.5.  ForCES Protocol Advanced Features  . . . . . . . . 13
       6.1.2.  ForCES Model Features  . . . . . . . . . . . . . . . . 14
         6.1.2.1.  Basic Atomic Types Supported . . . . . . . . . . . 14
         6.1.2.2.  Compound Types Supported . . . . . . . . . . . . . 15
         6.1.2.3.  LFBs Supported . . . . . . . . . . . . . . . . . . 15
       6.1.3.  ForCES SCTP TML Features . . . . . . . . . . . . . . . 19
         6.1.3.1.  TML Priority Ports . . . . . . . . . . . . . . . . 19
         6.1.3.2.  Message Handling at Specific Priorities  . . . . . 19
         6.1.3.3.  TML Security Feature . . . . . . . . . . . . . . . 20
     6.2.  Interoperability Report  . . . . . . . . . . . . . . . . . 20
       6.2.1.  Scenarios  . . . . . . . . . . . . . . . . . . . . . . 21
         6.2.1.1.  Scenario 1 - Pre-Association Setup . . . . . . . . 21
         6.2.1.2.  Scenario 2 - TML Priority Channels Connection  . . 22
         6.2.1.3.  Scenario 3 - Association Setup - Association
                   Complete . . . . . . . . . . . . . . . . . . . . . 22
         6.2.1.4.  Scenario 4 - CE Query  . . . . . . . . . . . . . . 23
         6.2.1.5.  Scenario 5 - Heartbeat Monitoring  . . . . . . . . 23
         6.2.1.6.  Scenario 6 - Simple Config Command . . . . . . . . 23
         6.2.1.7.  Scenario 7 - Association Teardown  . . . . . . . . 24
       6.2.2.  Tested Features  . . . . . . . . . . . . . . . . . . . 25
         6.2.2.1.  ForCES Protocol Features . . . . . . . . . . . . . 25
         6.2.2.2.  ForCES Model Features  . . . . . . . . . . . . . . 28
         6.2.2.3.  ForCES SCTP TML Features . . . . . . . . . . . . . 30
       6.2.3.  Interoperability Results . . . . . . . . . . . . . . . 31
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 33
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 33
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 33
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 33

1. Introduction

   This document is an implementation report for the ForCES protocol,
   model, and the SCTP TML documents, and includes an interoperability
   report.

   It follows the outline suggested by [RFC5657].

   ForCES defines an architectural framework and associated protocols to
   standardize information exchange between the control plane and the
   forwarding plane in a ForCES network element (ForCES NE).  [RFC3654]
   has defined the ForCES requirements, and [RFC3746] has defined the
   ForCES framework.

1.1. ForCES Protocol

   The ForCES protocol works in a master-slave mode in which forwarding
   elements (FEs) are slaves and control elements (CEs) are masters.
   The protocol includes commands for transport of Logical Functional
   Block (LFB) configuration information, association setup, status,
   event notifications, etc.  The reader is encouraged to read the
   ForCES Protocol Specification [RFC5810] for further information.

1.2. ForCES Model

   The ForCES Model [RFC5812] presents a formal way to define FE Logical
   Functional Blocks (LFBs) using XML.  LFB configuration components,
   capabilities, and associated events are defined when the LFB is
   formally created.  The LFBs within the FE are accordingly controlled
   in a standardized way by the ForCES protocol.

1.3. Transport Mapping Layer

   The TML transports the protocol layer (PL) messages [RFC5810].  The
   TML is where the issues of how to achieve transport-level
   reliability, congestion control, multicast, ordering, etc. are
   handled.  All ForCES protocol layer implementations MUST be portable
   across all TMLs.  Although more than one TML may be standardized for
   the ForCES protocol, all implementations MUST implement SCTP TML
   [RFC5811].

2. Terminology and Conventions

2.1. Requirements Language

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

2.2. Definitions

   This document follows the terminology defined by the ForCES
   requirements in [RFC3654] and by the ForCES framework in [RFC3746].
   The definitions are repeated below for clarity.

      Control Element (CE) - A logical entity that implements the ForCES
      protocol and uses it to instruct one or more FEs on how to process
      packets.  CEs handle functionality such as the execution of
      control and signaling protocols.

      Forwarding Element (FE) - A logical entity that implements the
      ForCES protocol.  FEs use the underlying hardware to provide
      per-packet processing and handling as directed/controlled by one
      or more CEs via the ForCES protocol.

      LFB (Logical Functional Block) - The basic building block that is
      operated on by the ForCES protocol.  The LFB is a well defined,
      logically separable functional block that resides in an FE and is
      controlled by the CE via the ForCES protocol.  The LFB may reside
      at the FE's datapath and process packets or may be purely an FE
      control or configuration entity that is operated on by the CE.
      Note that the LFB is a functionally accurate abstraction of the
      FE's processing capabilities, but not a hardware-accurate
      representation of the FE implementation.

      LFB Class and LFB Instance - LFBs are categorized by LFB Classes.
      An LFB Instance represents an LFB Class (or Type) existence.
      There may be multiple instances of the same LFB Class (or Type) in
      an FE.  An LFB Class is represented by an LFB Class ID, and an LFB
      Instance is represented by an LFB Instance ID.  As a result, an
      LFB Class ID associated with an LFB Instance ID uniquely specifies
      an LFB existence.

      LFB Metadata - Metadata is used to communicate per-packet state
      from one LFB to another, but is not sent across the network.  The
      FE model defines how such metadata is identified, produced, and
      consumed by the LFBs.  It defines the functionality but not how
      metadata is encoded within an implementation.

      LFB Components - Operational parameters of the LFBs that must be
      visible to the CEs are conceptualized in the FE model as the LFB
      components.  The LFB components include, for example, flags,
      single-parameter arguments, complex arguments, and tables that the
      CE can read and/or write via the ForCES protocol (see below).

      ForCES Protocol - While there may be multiple protocols used
      within the overall ForCES architecture, the term "ForCES protocol"
      and "protocol" refer to the "Fp" reference points in the ForCES
      framework in [RFC3746].  This protocol does not apply to CE-to-CE
      communication, FE-to-FE communication, or to communication between
      FE and CE managers.  Basically, the ForCES protocol works in a
      master-slave mode in which FEs are slaves and CEs are masters.

      ForCES Protocol Transport Mapping Layer (ForCES TML) - A layer in
      ForCES protocol architecture that uses the capabilities of
      existing transport protocols to specifically address protocol
      message transportation issues, such as how the protocol messages
      are mapped to different transport media (like TCP, IP, ATM,
      Ethernet, etc.), and how to achieve and implement reliability,
      multicast, ordering, etc.  The ForCES TML specifications are
      detailed in separate ForCES documents, one for each TML.

3. Summary

   Three independent implementations, NTT Japan, the University of
   Patras, and Zhejiang Gongshang University, were surveyed and found to
   already implement all the major features.  All implementors mentioned
   they will be implementing all missing features in the future.

   An interop test was conducted in July 2009 for all three
   implementations.  Two other organizations, Mojatatu Networks and
   Hangzhou Baud Information and Networks Technology Corporation, which
   independently extended two different well known public domain
   protocol analyzers, Ethereal/Wireshark and tcpdump, also participated
   in the interop for a total of five independent organizations
   implementing.  The two protocol analyzers were used to verify the
   validity of ForCES protocol messages (and in some cases semantics).

   There were no notable difficulties in the interoperability test, and
   almost all issues were code bugs that were dealt with mostly on site;
   tests repeated successfully, as stated in Section 6.2.3.

4. Methodology

   This report describes an implementation experience survey as well as
   the results of the interoperability test.

   The survey information was gathered after implementors answered a
   brief questionnaire regarding all ForCES Protocol, Model, and SCTP
   TML features.  The results can be seen in Section 6.1.

   The interoperability results were part of the interoperability test.
   Extended Ethereal and extended tcpdump were used to verify the
   results.  The results can be seen in Section 6.2.

5. Exceptions

   The core features of the ForCES Protocol, Model, and SCTP TML were
   implemented and assessed in an interop test in July 2009.  The
   intention of the interop testing was to validate that all the main
   features of the three core documents were interoperable amongst
   different implementations.  The tested features can be seen in
   Section 6.2.2.

   Different organizations surveyed have implemented certain features
   but not others.  This approach is driven by the presence of different
   LFBs that the different organizations currently implement.  All
   organizations surveyed have indicated their intention to implement
   all outstanding features in due time.  The implemented features can
   be seen in Section 6.1.

   The mandated TML security requirement, IP security (IPsec), was not
   validated during the interop and is not discussed in this document.
   Since IPsec is well known and widely deployed, not testing in the
   presence of IPsec does not invalidate the tests done.  Note that
   Section 6.1.3.3 indicates that none of the implementations reporting
   included support for IPsec, but all indicated their intention to
   implement it.

   Although the SCTP priority ports have changed since the
   interoperability test with the version of the SCTP TML draft
   available prior to the publication of RFC 5811, the change has no
   impact on the validity of the interoperability test.

6. Detail Section

6.1. Implementation Experience

   Three different organizations have implemented the ForCES Protocol,
   Model, and SCTP TML and answered a questionnaire.  These are:

   o  NTT Japan

   o  University of Patras

   o  Zhejiang Gongshang University

   Extensions to protocol analyzers capable of understanding ForCES
   protocol messages are considered part of an implementation, since
   these analyzers can now understand and validate ForCES protocol
   message that have been exchanged.  Two such extensions have been
   created:

   o  Extension to Ethereal/Wireshark [ethereal].

   o  Extension to tcpdump [tcpdump].

   All implementors were asked about the ForCES features they have
   implemented.  For every item listed, the respondents indicated
   whether they had implemented, will implement, or won't implement at
   all.

6.1.1. ForCES Protocol Features

6.1.1.1. Protocol Messages

6.1.1.2. MainHeader Handling

6.1.1.3. TLV Handling

6.1.1.4. Operation Types Supported

6.1.1.5. ForCES Protocol Advanced Features

6.1.2. ForCES Model Features

6.1.2.1. Basic Atomic Types Supported

6.1.2.2. Compound Types Supported

6.1.2.3. LFBs Supported

6.1.2.3.1. FE Protocol LFB

6.1.2.3.2. FE Object LFB

6.1.3. ForCES SCTP TML Features

6.1.3.1. TML Priority Ports

6.1.3.2. Message Handling at Specific Priorities

6.1.3.3. TML Security Feature

6.2. Interoperability Report

   The interoperability test took place at the University of Patras, in
   the Department of Electrical and Computer Engineering.

   There were two options for participation in the interoperability
   test.

   1.  Locally, on the University of Patras premises.

   2.  Remotely, via Internet.

   Implementations from NTT and the University of Patras were present
   locally on the University of Patras premises in Greece, while the
   implementation from Zhejiang Gongshang University, which was behind a
   NAT, connected remotely from China.

   The interoperability test validated the basic functionality of the
   ForCES protocol, mainly message exchanging and handling.

   The following scenarios were tested.

6.2.1. Scenarios

   The main goal of the interoperability test was to validate the basic
   protocol functionality; the test parameters were limited.

   1.  In the Association Setup message, all report messages were
       ignored.

   2.  In the Association Setup stage, the FEO OperEnable Event (FE to
       CE), Config FEO Adminup (CE to FE), and FEO Config-Resp (FE to
       CE) messages were ignored.  The CEs assumed that the FEs were
       enabled once the LFB selectors had been queried.

   3.  Only FULLDATA-TLVs were used and not SPARSEDATA-TLVs.

   4.  There were no transaction operations.

   5.  Each message had only one LFBSelect-TLV, one OPER-TLV, and one
       PATH-DATA-TLV per message when these were used.

6.2.1.1. Scenario 1 - Pre-Association Setup

   While the pre-association setup is not in the ForCES current scope,
   it is an essential step before CEs and FEs communicate.  As the first
   part in a successful CE-FE connection, the participating CEs and FEs
   had to be configurable.

   In the pre-association phase, the following configuration items were
   set up regarding the CEs:

   o  The CE ID.

   o  The FE IDs that were connected to this CE.

   o  The IP addresses of the FEs that connected to the CE.

   o  The TML priority ports.

   In the pre-association phase, the following configuration items were
   set up regarding the FEs:

   o  The FE ID.

   o  The CE ID to which this FE was connecting.

   o  The IP address of the CE to which this FE was connecting.

   o  The TML priority ports.

6.2.1.2. Scenario 2 - TML Priority Channels Connection

   For the interoperability test, the SCTP was used as TML.  The TML
   connection with the associating element was needed for Scenario 2 to
   be successful.

   SCTP TML [RFC5811] defines three priority channels, with specific
   ports:

   o  High priority - Port number: 6704

   o  Medium priority - Port number: 6705

   o  Lower priority - Port number: 6706

   However, at the time of the interoperability test, the SCTP ports of
   the three priority channels were the following:

   o  High priority - Port number: 6700

   o  Medium priority - Port number: 6701

   o  Lower priority - Port number: 6702

   As specified in Section 5, "Exceptions", this does not invalidate the
   results of the interoperability test.

6.2.1.3. Scenario 3 - Association Setup - Association Complete

   Once the pre-association phase in the previous two scenarios had
   completed, CEs and FEs would be ready to communicate using the ForCES
   protocol and enter the Association Setup stage.  In this stage, the
   FEs would attempt to join the NE.  The following ForCES protocol
   messages would be exchanged for each CE-FE pair in the specified
   order:

   o  Association Setup message (from FE to CE)

   o  Association Setup Response message (from CE to FE)

   o  Query message: FEO LFB selectors (from CE to FE)

   o  Query Response: FEO LFB selectors response (from FE to CE)

6.2.1.4. Scenario 4 - CE Query

   Once the Association Setup stage had completed, the FEs and CEs would
   enter the Established stage.  In this stage, the FE will be
   continuously updated or queried.  The CE should query the FE for a
   specific value from the FE Object LFB and from the FE Protocol LFB.
   An example from the FE Protocol LFB is the FE Heartbeat Interval
   (FEHI), and an example from the FE Object LFB is the state of the LFB
   (FEState).

   The following ForCES protocol messages were exchanged:

   o  Query message

   o  Query Response message

6.2.1.5. Scenario 5 - Heartbeat Monitoring

   The Heartbeat (HB) message is used for one ForCES element (FE or CE)
   to asynchronously notify one or more other ForCES elements in the
   same ForCES NE of its liveness.  The default configuration of the
   Heartbeat Policy of the FE is set to 0, which means that the FE
   should not generate any Heartbeat messages.  The CE is responsible
   for checking FE liveness by setting the PL header ACK flag of the
   message it sends to AlwaysACK.  In this scenario, the CE will send a
   Heartbeat message with the ACK flag set to AlwaysACK, and the FE
   should respond.

   The following type of ForCES protocol message was exchanged:

   o  Heartbeat message

6.2.1.6. Scenario 6 - Simple Config Command

   A Config message is sent by the CE to the FE to configure LFB
   components in the FE.  A simple Config command, easily visible and
   metered, would be to change the Heartbeat configuration.  This was
   done in two steps:

   1.  Change the FE Heartbeat Policy (FEHBPolicy) to value 1, to force
       the FE to send heartbeats.

   2.  After some heartbeats from the FE, the FE Heartbeat Interval
       (FEHI) was changed.

   The following ForCES protocol messages were exchanged:

   o  Config message

   o  Config Response message

6.2.1.7. Scenario 7 - Association Teardown

   In the end, the association must be terminated.  There were three
   scenarios by which the association was terminated:

   1.  Normal teardown, by exchanging an Association Teardown message.

   2.  Irregular teardown, by stopping heartbeats from an FE or a CE.

   3.  Irregular teardown, by externally shutting down/rebooting an FE
       or a CE.

   All scenarios were investigated in the interoperability test.

   The following type of ForCES protocol message was exchanged:

   o  Association Teardown message

6.2.2. Tested Features

The features that were tested are:

6.2.2.1. ForCES Protocol Features

6.2.2.1.1. Protocol Messages

6.2.2.1.2. MainHeader Handling

6.2.2.1.3. TLV Handling

6.2.2.1.4. Operation Types Supported

                             +--------------+
                             |   Operation  |
                             +--------------+
                             |      SET     |
                             |              |
                             | SET-RESPONSE |
                             |              |
                             |      GET     |
                             |              |
                             | GET-RESPONSE |
                             |              |
                             |    REPORT    |
                             +--------------+

                         Operation Types Supported

   o  PASS: All implementations handled these operations, and all
      protocol analyzers captured them.

6.2.2.1.5. ForCES Protocol Advanced Features

                              +------------+
                              |   Feature  |
                              +------------+
                              |  Batching  |
                              |            |
                              | Heartbeats |
                              +------------+

                     ForCES Protocol Advanced Features

   Although batching was not initially intended to be tested, it was
   assessed during the interoperability test.

   o  PASS: Two implementations handled batching, and all handled
      heartbeats.  The protocol analyzers captured both.

6.2.2.2. ForCES Model Features

6.2.2.2.1. Basic Atomic Types Supported

6.2.2.2.2. Compound Types Supported

6.2.2.2.3. LFBs Supported

6.2.2.2.3.1. FE Protocol LFB

6.2.2.2.3.2. FE Object LFB

                           +------------------+
                           | Object Datatypes |
                           +------------------+
                           |   FEStateValues  |
                           |                  |
                           |  LFBSelectorType |
                           +------------------+

                          FE Object LFB Datatypes

   o  PASS: All implementations handled these FE Object LFB datatypes.

                           +-------------------+
                           | Object Components |
                           +-------------------+
                           |    LFBSelectors   |
                           |                   |
                           |      FEState      |
                           +-------------------+

                         FE Object LFB Components

   o  PASS: All implementations handled these FE Object LFB components.

6.2.2.3. ForCES SCTP TML Features

6.2.2.3.1. TML Priority Ports

                        +------------------------+
                        |          Port          |
                        +------------------------+
                        |  High priority (6700)  |
                        |                        |
                        | Medium priority (6701) |
                        |                        |
                        |   Low priority (6702)  |
                        +------------------------+

                              Priority Ports

   o  PASS: All implementations opened and connected to all the SCTP
      priority ports.  The protocol analyzers captured all ports and
      their corresponding priority.

6.2.2.3.2. Message Handling at Specific Priorities

                            +----------------+
                            | ForCES Message |
                            +----------------+
                            |   Heartbeats   |
                            +----------------+

               Message Handling at Low-Priority (6702) Port

   o  PASS: All implementations handled these messages at this SCTP
      priority port.  The protocol analyzers captured these messages at
      this priority port.

6.2.3. Interoperability Results

   All implementations were found to be interoperable with each other.

   All scenarios were tested successfully.

   The following issues were found and dealt with.

   1.   Some messages were sent on the wrong priority channels.  There
        were some ambiguities in the SCTP TML document regarding how to
        deal with such a situation.  The possibilities were an FE
        response on the same (wrong) channel as a CE query; an FE
        response on the correctly documented channel for the message; or
        simply dropping the packet.  This has been corrected by
        mandating the message-to-channel mapping to be a MUST in the
        SCTP TML document [RFC5811] before it was published as an RFC.

   2.   At some point, a CE sent a Teardown message to the FE.  The CE
        expected the FE to shut down the connection, and the FE waited
        for the CE to shut down the connection; both were then caught in
        a deadlock.  This was a code bug and was fixed.

   3.   Sometimes, only when the CE and FE were remote to each other
        (one being in China and another in Greece), the Association
        Setup message was not received by the CE side, and therefore an
        association never completed.  This was not an implementation
        issue but rather a network issue.  This issue was solved with
        the retransmission of the non-delivered messages.

   4.   An implementation did not take into account that the padding in
        TLVs MUST NOT be included in the length of the TLV.  This was a
        code bug and was fixed.

   5.   The Execution Mode flag was set to Reserved by a CE and was not
        ignored by the FE.  This was a code bug and was fixed.

6. After the FEHBPolicy was set to 1, the FE didn't send any
heartbeats. This was a code bug and was fixed.

   7.   Some FEs sent heartbeats with the ACK flag set to a value other
        than NoACK.  The CE responded.  This was a code bug and was
        fixed.

   8.   When a cable was disconnected, none of the TML implementations
        detected it.  The association was eventually dropped due to
        heartbeat detection; this test was a success, but this is an
        implementation issue that implementors should keep in mind.
        This is an SCTP options issue.  Nothing needed to be done.

9. A CE crashed due to unknown LFB selector values. This was a
code bug and was fixed.

   10.  With the remote connection from China (which was behind a NAT)
        to Greece, there were a lot of ForCES packet retransmissions.
        The problem was that packets like heartbeats were retransmitted.
        This was an implementation issue regarding SCTP usage that
        implementors should keep in mind.  The SCTP-PR option needed to
        be used.  Nothing needed to be done.

   The interoperability test went so well that an additional extended
   test was added to check for batching messages.  This test was also
   done successfully.

7.  Acknowledgements

   The authors would like to give thanks to Professors Odysseas
   Koufopavlou and Spyros Denazis, and the Department of Electrical and
   Computer Engineering at the University of Patras, who hosted the
   ForCES interoperability test.

   The authors would also like to give thanks to Chuanhuang Li, Ming
   Gao, and other participants from Zhejiang Gongshang University, which
   connected remotely.  This allowed the discovery of a series of issues
   that would have been uncaught otherwise.

   The authors would also like to thank Hideaki Iwata and Yoshinobu
   Morimoto of NTT Japan for participating locally at the
   interoperability test; as well as Hiroki Date and Hidefumi Otsuka,
   also of NTT Japan, for contributing to the interoperability test.

   Additionally, thanks are given to Xinping Wang for her help in
   writing the interoperability document and to Fenggen Jia for
   extending the Ethereal protocol analyzer.

8. Security Considerations

   No security elements of the protocol or the SCTP TML [RFC5811]
   specification were tested.

   The survey indicated that no security elements were implemented, but
   all participants indicated their intention to implement them.

   For security considerations regarding the ForCES protocol and SCTP
   TML, please see [RFC5810] and [RFC5811].

9.  References

9.1. Normative References

   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5810]   Doria, A., Hadi Salim, J., Haas, R., Khosravi, H., Wang,
               W., Dong, L., Gopal, R., and J. Halpern, "Forwarding and
               Control Element Separation (ForCES) Protocol
               Specification", RFC 5810, March 2010.

   [RFC5811]   Hadi Salim, J. and K. Ogawa, "SCTP-Based Transport
               Mapping Layer (TML) for the Forwarding and Control
               Element Separation (ForCES) Protocol", RFC 5811,
               March 2010.

   [RFC5812]   Halpern, J. and J. Hadi Salim, "Forwarding and Control
               Element Separation (ForCES) Forwarding Element Model",
               RFC 5812, March 2010.

9.2. Informative References

   [RFC3654]   Khosravi, H. and T. Anderson, "Requirements for
               Separation of IP Control and Forwarding", RFC 3654,
               November 2003.

   [RFC3746]   Yang, L., Dantu, R., Anderson, T., and R. Gopal,
               "Forwarding and Control Element Separation (ForCES)
               Framework", RFC 3746, April 2004.

   [RFC5657]   Dusseault, L. and R. Sparks, "Guidance on Interoperation
               and Implementation Reports for Advancement to Draft
               Standard", BCP 9, RFC 5657, September 2009.

   [ethereal]  "Ethereal is a protocol analyzer.  The specific Ethereal
               that was used is an updated Ethereal, by Fenggen Jia,
               that can analyze and decode the ForCES protocol
               messages", <http://www.ietf.org/mail-archive/web/forces/
               current/msg03687.html>.

   [tcpdump]   "tcpdump is a Linux protocol analyzer.  The specific
               tcpdump that was used is a modified tcpdump, by Jamal
               Hadi Salim, that can analyze and decode the ForCES
               protocol messages", <http://www.ietf.org/mail-archive/
               web/forces/current/msg03811.html>.

Authors' Addresses

   Evangelos Haleplidis
   University of Patras
   Patras
   Greece

   EMail: ehalep@ece.upatras.gr

   Kentaro Ogawa
   NTT Corporation
   Tokyo
   Japan

   EMail: ogawa.kentaro@lab.ntt.co.jp

   Weiming Wang
   Zhejiang Gongshang University
   18, Xuezheng Str., Xiasha University Town
   Hangzhou,   310018
   P.R. China

   Phone: +86-571-28877721
   EMail: wmwang@mail.zjgsu.edu.cn

   Jamal Hadi Salim
   Mojatatu Networks
   Ottawa, Ontario
   Canada

   Phone:
   EMail: hadi@mojatatu.com