Internet DRAFT - draft-fu-nsis-qos-nslp-statemachine

draft-fu-nsis-qos-nslp-statemachine





NSIS                                                               X. Fu
                                                              B. Schloer
Internet-Draft                                          Univ. Goettingen
Expiration Date: April 3, 2008                             H. Tschofenig
                                                               T. Tsenov
                                                  Nokia Siemens Networks
                                                         October 4, 2007

                         QoS NSLP State Machine
               draft-fu-nsis-qos-nslp-statemachine-06.txt

Status of this Memo

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   This Internet-Draft will expire on April 3, 2008.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This document describes a state machine for the NSIS Signaling Layer
   Protocol for Quality-of-Service signaling (QoS NSLP). A combined
   state machine for QoS NSLP entities at different locations of a flow
   path is presented in order to illustrate how QoS NSLP may be
   implemented.








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Table of Contents

   1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.   Terminology  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.   Notational conventions used in state diagrams  . . . . . . .   3
   4.   State Machine Symbols  . . . . . . . . . . . . . . . . . . .   5
   5.   Common Rules . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1  Common Procedures  . . . . . . . . . . . . . . . . . . . .   7
     5.2  Common Variables . . . . . . . . . . . . . . . . . . . . .   7
     5.3  Events   . . . . . . . . . . . . . . . . . . . . . . . . .   9
     5.4  Assumptions  . . . . . . . . . . . . . . . . . . . . . . .   9
   6.   Basic State Machine Concept  . . . . . . . . . . . . . . . .  11
     6.1  The QoS NSLP Daemon  . . . . . . . . . . . . . . . . . . .  11
     6.2  States, Events and Callback Functions  . . . . . . . . . .  12
     6.3  Timer  . . . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.4  The Toggle Flag  . . . . . . . . . . . . . . . . . . . . .  13
   7. State Machine for QoS NSLP nodes   . . . . . . . . . . . . . .  13
     7.1  State ST_IDLE  . . . . . . . . . . . . . . . . . . . . . .  14
     7.2  State ST_WR    . . . . . . . . . . . . . . . . . . . . . .  16
     7.3  State ST_INST  . . . . . . . . . . . . . . . . . . . . . .  19
   8   Actions and Transitions . . . . . . . . . . . . . . . . . . .  23
     8.1  State ST_IDLE  . . . . . . . . . . . . . . . . . . . . . .  23
     8.2  State ST_WR    . . . . . . . . . . . . . . . . . . . . . .  24
     8.3  State ST_INST  . . . . . . . . . . . . . . . . . . . . . .  26
   9.   Security Considerations  . . . . . . . . . . . . . . . . . .  27
   10.   Open Issues   . . . . . . . . . . . . . . . . . . . . . . .  28
   11.   Change History  . . . . . . . . . . . . . . . . . . . . . .  28
   12.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . .  29
   13.  References . . . . . . . . . . . . . . . . . . . . . . . . .  30
     13.1   Normative References . . . . . . . . . . . . . . . . . .  30
     13.2   Informative References . . . . . . . . . . . . . . . . .  30
   Appendix A.  ASCII versions of the state diagrams . . . . . . . .  31
     A.1    State ST_IDLE  . . . . . . . . . . . . . . . . . . . . .  31
     A.2    State ST_WR    . . . . . . . . . . . . . . . . . . . . .  33
     A.3    State ST_INST  . . . . . . . . . . . . . . . . . . . . .  36
     A.4    Commonly used functions   . . . . . . . . . . .  . . . .  41
        Authors' Addresses . . . . . . . . . . . . . . . . . . . . .  47
        Intellectual Property and Copyright Statements . . . . . . .  48













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1.  Introduction

   This document describes a state machine for QoS NSLP [1], trying to
   show how QoS NSLP can be implemented to support its deployment.  The
   state machine described in this document is illustrative of how the
   QoS NSLP protocol defined in [1] may be implemented for QoS NSLP
   nodes in the flow path. Where there are differences [1] are
   authoritative.  The state machine diagrams are informative only.
   Implementations may achieve the same results using different methods.

   According to [1], there are several possibilities for QoS NSLP
   signaling, at least including the following: - end-to-end signaling
   vs. scoped signaling - sender-initiated signaling vs. receiver-
   initiated signaling.

   The messages used in the QoS NSLP protocol can be summarized as
   follows:

      Requesting message       Responding message
      ------------------------+---------------------------
      RESERVE                 |None or RESERVE or RESPONSE
      QUERY                   |RESERVE or RESPONSE
      RESPONSE                |NONE
      NOTIFY                  |NONE
      ------------------------+---------------------------


2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [2].


3.  Notational conventions used in state diagrams

   The following text is reused from [3] and the state diagrams are
   based on the conventions specified in [4], Section 8.2.1. Additional
   state machine details are taken from [5].

   The complete text is reproduced here:

   State diagrams are used to represent the operation of the protocol by
   a number of cooperating state machines each comprising a group of
   connected, mutually exclusive states. Only one state of each machine
   can be active at any given time.

   All permissible transitions between states are represented by arrows,



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   the arrowhead denoting the direction of the possible transition.
   Labels attached to arrows denote the condition(s) that must be met in
   order for the transition to take place. All conditions are
   expressions that evaluate to TRUE or FALSE; if a condition evaluates
   to TRUE, then the condition is met. The label UCT denotes an
   unconditional transition (i.e., UCT always evaluates to TRUE). A
   transition that is global in nature (i.e., a transition that occurs
   from any of the possible states if the condition attached to the
   arrow is met) is denoted by an open arrow; i.e., no specific state is
   identified as the origin of the transition. When the condition
   associated with a global transition is met, it supersedes all other
   exit conditions including UCT. The special global condition BEGIN
   supersedes all other global conditions, and once asserted remains
   asserted until all state blocks have executed to the point that
   variable assignments and other consequences of their execution remain
   unchanged.

   On entry to a state, the procedures defined for the state (if any)
   are executed exactly once, in the order that they appear on the page.
   Each action is deemed to be atomic; i.e., execution of a procedure
   completes before the next sequential procedure starts to execute. No
   procedures execute outside of a state block. The procedures in only
   one state block execute at a time, even if the conditions for
   execution of state blocks in different state machines are satisfied,
   and all procedures in an executing state block complete execution
   before the transition to and execution of any other state block
   occurs, i.e., the execution of any state block appears to be atomic
   with respect to the execution of any other state block and the
   transition condition to that state from the previous state is TRUE
   when execution commences. The order of execution of state blocks in
   different state machines is undefined except as constrained by their
   transition conditions. A variable that is set to a particular value
   in a state block retains this value until a subsequent state block
   executes a procedure that modifies the value.

   On completion of all of the procedures within a state, all exit
   conditions for the state (including all conditions associated with
   global transitions) are evaluated continuously until one of the
   conditions is met. The label ELSE denotes a transition that occurs if
   none of the other conditions for transitions from the state are met
   (i.e., ELSE evaluates to TRUE if all other possible exit conditions
   from the state evaluate to FALSE). Where two or more exit conditions
   with the same level of precedence become TRUE simultaneously, the
   choice as to which exit condition causes the state transition to take
   place is arbitrary.

   In addition to the above notation, there are a couple of
   clarifications specific to this document. First, all boolean



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   variables are initialized to FALSE before the state machine execution
   begins. Second, the following notational shorthand is specific to
   this document:

   <variable> = <expression1> | <expression2> | ...

      Execution of a statement of this form will result in <variable>
      having a value of exactly one of the expressions. The logic for
      which of those expressions gets executed is outside of the state
      machine and could be environmental, configurable, or based on
      another state machine such as that of the method.


4.  State Machine Symbols

   ( )
      Used to force the precedence of operators in Boolean expressions
      and to delimit the argument(s) of actions within state boxes.

   ;
      Used as a terminating delimiter for actions within state boxes.
      Where a state box contains multiple actions, the order of
      execution follows the normal English language conventions for
      reading text.

   =
      Assignment action. The value of the expression to the right of the
      operator is assigned to the variable to the left of the operator.
      Where this operator is used to define multiple assignments, e.g.,
      a = b = X the action causes the value of the expression following
      the right-most assignment operator to be assigned to all of the
      variables that appear to the left of the right-most assignment
      operator.

   !
      Logical NOT operator.

   &&
      Logical AND operator.

   ||
      Logical OR operator.

   if...then...
      Conditional action. If the Boolean expression following the if
      evaluates to TRUE, then the action following the then is executed.

   { statement 1, ... statement N }



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      Compound statement. Braces are used to group statements that are
      executed together as if they were a single statement.

   !=
      Inequality. Evaluates to TRUE if the expression to the left of the
      operator is not equal in value to the expression to the right.

   ==
      Equality. Evaluates to TRUE if the expression to the left of the
      operator is equal in value to the expression to the right.

   >
      Greater than. Evaluates to TRUE if the value of the expression to
      the left of the operator is greater than the value of the
      expression to the right.

   <=
      Less than or equal to. Evaluates to TRUE if the value of the
      expression to the left of the operator is either less than or
      equal to the value of the expression to the right.

   ++
      Increment the preceding integer operator by 1.

   +
      Arithmetic addition operator.

   &
      Bitwise AND operator.






















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5.  Common Rules

   Throughout the document we use terms defined in the [1], such as flow
   sender, flow receiver, QUERY, RESERVE or RESPONSE.


5.1  Common Procedures

   tx_reserve():
      Transmit RESERVE message

   tx_response():
      Transmit RESPONSE message

   tx_query():
      Transmit QUERY message

   tx_notify():
      Transmit NOTIFY message

   install_qos_state():
      Install the local QoS state.

   delete_qos_state():
      Delete the local QoS state.

   send_info_to_app():
      Report information to the application.

   RMF():
      Performs Resource Management Function and returns the following
      values{AVAIL, NO_AVAIL}.

   is_local(RII):
      Checks the RII object of received RESPONSE message if it is
      requested by current node or other upstream node. Returns values
      {true, false}.

   is_local(RSN):
      Checks The RSN object of the received RESPONSE message if it is
      requested by current node. Returns values {true, false}.

   process_query():
      Processes a Query message and provides the requested info

5.2 Common Variables

   RII:



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      Request Identification Information (RII) object.

   RSN:
      Reservation Sequence Number (RSN) object.

   INFO:
      Info_Spec object. Takes values:
      - 0x02 - Success values
      - 0x04 - Transient Failure values

   QSPEC:
      QoS specification object.

   T-Flag:
      Tear flag. Indicates to tear down reservation state. Takes values
      {true, false}.

   Q-Flag:
      Request Reduced Refreshes flag of common message header. Takes
      values {true, false}.

   R-Flag:
      Reserve-Init flag (QUERY) or Replace flag (RESERVE). Indicates a
      Receiver Initiated Reservation request in a QUERY message or an
      replacing RESERVE in a RESERVE message. Takes values {true,
      false}.

   S-Flag:
      Scoping flag of common message header. Takes values
      {true="Next_hop", false="Whole_path"}.

   setRII:
      If set a RII object will be included into the message. Takes
      values {true, false}.

   ReducedRefresh:
      Keeps information if Reduced refresh method may be used for
      refreshing a installed QoS state. Takes value {"On","Off"}.

   FlowID:
      Flow ID kept by the installed QoS state.

   Nodepos:
      Position of the QoS NSLP node. Takes values {"QNI", "QNE", "QNR"}.

   Toggle:
      Flag to indicate whether the direction of a new message has to be
      changed compared to the direction of a received one. Takes values



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      {true, false}.

   Direction:
      Direction, in which the message has to be sent. Takes values
      {DOWNSTREAM, UPSTREAM}.

   SII:
      Source Identification Information entry. Takes values:
      - CurrSII - SII entry stored for current installed QoS state.
      (Assumed to be the one for the direction where the message comes
      from e.g.Upstream/Downstream)
      - newSII - SII of the received message is different from the SII
      stored for the current installed QoS state.

5.3  Events

   EV_TG_QUERY:
      External trigger to send a QUERY message.

   EV_RX_QUERY:
      QUERY message received

   EV_RX_NOTIFY:
      NOTIFY message received

   EV_TG_RESERVE:
      External trigger to send a RESERVE message.

   EV_RX_RESERVE:
      RESERVE message received

   EV_RX_RESPONSE:
      RESPONSE message received

   EV_TIMEOUT_RESPONSE:
      Wait-Response interval timer expiration

   EV_TIMEOUT_REFRESH:
      Refresh interval timer expiration

   EV_TIMEOUT_STATE_LIFETIME:
      State lifetime timer expiration


5.4  Assumptions

   - For simplification not all included objects in a message are shown.
      Only those that are significant for the case are shown.  The State



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      Machine does not present handling of messages that are not
      significant for management of the states such as certain NOTIFY
      and QUERY messages.
   - The State Machine represents handling of messages of the same
      Session ID and with no protocol errors. Separate parallel
      instances of the state machines should handle messages for
      different Session IDs.
   - Default message handling should be defined for messages with
      different Session IDs that have impact on current session state
      and error messages. This is not included in the current version.









































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6 Basic State Machine Concept

6.1 The QoS NSLP Daemon

   The QoS NSLP Daemon (qosd) listens for incoming messages from the
   local application and for messages coming over the network from GIST.
   For each new SessionID (SID) a new State Machine (FSM) is created as
   shown in the diagram below.

   Incoming messages from the client application are checked for the
   type of the message (QUERY or RESERVE) and for the SID. A table is
   searched for the given SID. If it is not found, a new FSM is created
   and its address together with the SID is added to the table. If the
   type of the message is a QUERY with set R-Bit, a Receiver Initiated
   Reservation is requested and the node position is QNR, in all other
   cases the node position is QNI. If the SID is found, the address of
   the FSM is returned. Now the FSM is triggered with the corresponding
   event of the message (EV_TG_QUERY, EV_TG_RESERVE). If the FSM returns
   to the qosd in ST_IDLE, it is deleted together with its table entry.

   For a message arriving from GIST, the procedure is almost the same.
   The table is searched for the given SID. If it is not found, then the
   IP-address of the MRI is compared to the local IP-address. If the
   arriving message is requesting a Receiver Initiated Reservation and
   the destination address is equal to the local address then the node
   position is QNR. If the addresses are equal and no Receiver Initiated
   Reservation is requested then the node position is QNI. If the
   addresses are not the same, a new FSM for a QNE is created. Also
   here, the corresponding FSM is triggered with the event according to
   the arrived message and deleted when returning in ST_IDLE.


                 +-------+     +-------+     +-------+
                 |       |     |       |     |       |
                 | FSM 1 |     | FSM 2 |     | FSM n |
                 |       |     |       |     |       |
                 +-------+     +-------+     +-------+
                          \        |        /
                           \       |       /
                            \      |      /
                             \     |     /
                              \    |    /
                               +-------+
                               |       |
                               | qosd  |
                               |       |
                               +-------+




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                                Figure 1

6.2 States, Events and Callback Functions

   Three States are defined: ST_IDLE, ST_WR and ST_INST. A new created
   FSM is starting automatically in ST_IDLE. In this state no
   reservation state is installed no responses to previously sent
   messages are expected. In ST_WR the FSM is waiting for a response to
   a previously sent message, but no reservation state is installed. In
   ST_INST reservation state has been installed and incoming messages
   are processed.

   The following table provides to a given state and a triggered event
   the function which has to be executed by the FSM. Example: when
   EV_RX_QUERY is triggered in state ST_IDLE, the function
   idle__rx_query is executed.

+-----------+----------------------------+-------------------------------+
|  State    |  Event                     |  Executed Function            |
+-----------+----------------------------+-------------------------------+
|  ST_IDLE  |  EV_RX_QUERY               | idle__rx_query                |
|  ST_IDLE  |  EV_RX_NOTIFY              | idle__rx_notify               |
|  ST_IDLE  |  EV_RX_RESERVE             | idle__rx_reserve              |
|  ST_IDLE  |  EV_RX_RESPONSE            | idle__rx_response             |
|  ST_IDLE  |  EV_RX_RMF_MSG             | idle__rx_rmf_msg              |
+-----------+----------------------------+-------------------------------+
|  ST_WR    |  EV_RX_QUERY               | wr__rx_query                  |
|  ST_WR    |  EV_RX_NOTIFY              | wr__rx_notify                 |
|  ST_WR    |  EV_RX_RESERVE             | wr__rx_reserve                |
|  ST_WR    |  EV_RX_RESPONSE            | wr__rx_response               |
|  ST_WR    |  EV_RX_RMF_MSG             | wr__rx_rmf_msg                |
|  ST_WR    |  EV_TIMEOUT_WAITRESP       | wr__timeout_response          |
|  ST_WR    |  EV_TIMEOUT_STATELIFETIME  | wr__timeout_statelifetime     |
+-----------+----------------------------+-------------------------------+
|  ST_INST  |  EV_RX_QUERY               | inst__rx_query                |
|  ST_INST  |  EV_RX_NOTIFY              | inst__rx_notify               |
|  ST_INST  |  EV_RX_RESERVE             | inst__rx_reserve              |
|  ST_INST  |  EV_RX_RESPONSE            | inst__rx_response             |
|  ST_INST  |  EV_RX_RMF_MSG             | inst__rx_rmf_msg              |
|  ST_INST  |  EV_TIMEOUT_WAITRESP       | inst__timeout_response        |
|  ST_INST  |  EV_TIMEOUT_REFRESH        | inst__timeout_refresh         |
|  ST_INST  |  EV_TIMEOUT_STATELIFETIME  | inst__timeout_statelifetime   |
|  ST_INST  |  EV_SII_CHANGED            | inst__sii_changed             |
|  ST_INST  |  EV_NETWORK_NOTIFICATION   | inst__network_notification    |
+-----------+----------------------------+-------------------------------+






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                                Figure 2


6.3 Timer

   The Response Timer at QNI and QNE is started when a RESPONSE message
   is expected to a sent QUERY or RESERVE. When a reservation is set up,
   the Refresh Timer are started at QNI and QNE and the StateLife Timer
   are started at QNE and QNR. When the Refresh Timer times out, a
   refreshing RESERVE is sent peer to peer towards the QNR and the
   Response Timer are started because a confirmation is expected. On
   arrival the StateLife Timer is restarted.

   If the confirmation is not sent back, then the refreshing RESERVEs
   are resent up to MAX_RETRY. After MAX_RETRY has been reached,
   reservation state is removed and a RESERVE with set T-Flag is sent to
   the QNR to remove reservation state along the path. When no
   refreshing RESERVE arrive at QNE and QNR, then the StateLife Timer
   expires and reservation state is also removed and a RESERVE with set
   T-Flag is sent towards the QNR.


      +-----------------+-------------------+-------------------+
      |  QNI            |  QNE              |  QNR              |
      +-----------------+-------------------+-------------------+
      |  Refresh Timer  |  Refresh Timer    |  StateLife Timer  |
      |  Response Timer |  Response Timer   |                   |
      |                 |  StateLife Timer  |                   |
      +-----------------+-------------------+-------------------+

                                Figure 3

6.4 The Toggle Flag

   The Toggle Flag manipulates the direction of the message. When set,
   the message is sent in the opposite direction compared to the
   received one.  The boolean operation XOR is used. Example, where true
   is the toggle flag: DOWNSTREAM XOR true = UPSTREAM (0 XOR 1 = 1).

7.  State machine

   The following section presents the state machine diagrams of QoS
   NSLP. Please note that stateless nodes do not perform transitions to
   other states than ST_IDLE. A C-like pseudo code example for
   update_rsn() and for send_rmf() is presented in Appendix A.4. The
   send_rmf function is located in the RMF code and update_rsn() is part
   of the FSM code.




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7.1  State ST_IDLE

              (see the .pdf version for missing diagram or
           refer to Appendix A.1 if reading the .txt version)



                                Figure 4











































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              (see the .pdf version for missing diagram or
           refer to Appendix A.1 if reading the .txt version)



                                Figure 5













































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7.2  State ST_WR

              (see the .pdf version for missing diagram or
           refer to Appendix A.2 if reading the .txt version)



                                Figure 6











































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              (see the .pdf version for missing diagram or
           refer to Appendix A.2 if reading the .txt version)



                                Figure 7













































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              (see the .pdf version for missing diagram or
           refer to Appendix A.2 if reading the .txt version)



                                Figure 8













































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7.3  State ST_INST
              (see the .pdf version for missing diagram or
           refer to Appendix A.3 if reading the .txt version)



                                Figure 9












































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              (see the .pdf version for missing diagram or
           refer to Appendix A.3 if reading the .txt version)



                               Figure 10













































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              (see the .pdf version for missing diagram or
           refer to Appendix A.3 if reading the .txt version)



                               Figure 11













































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              (see the .pdf version for missing diagram or
           refer to Appendix A.3 if reading the .txt version)



                               Figure 12













































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8. Actions and Transitions

   This chapter describes the operation of the FSM.

8.1 State ST_IDLE


8.1.1 idle__rx_query

   This function is executed when a QUERY message has arrived over the
   network from GIST and the FSM is in State ST_IDLE. If a receiver
   initiated reservation has been requested and the node position is
   QNI, Direction is set to upstream and the message is passed to the
   RMF.  Transition is made to ST_WR. In all other cases a resource
   query has been received, the message is passed to the RMF and
   transition is done to ST_WR.

8.1.2 idle__rx_notify

   A NOTIFY message has been received. If the node position is not the
   final destination for this message, it is passed further along the
   path.


8.1.3 idle__rx_reserve

   A RESERVE from the network in ST_IDLE has arrived. If the T-Flag is
   set, then the message is passed to the RMF to tear down the
   reservation.  Transition is made to ST_IDLE.

   In the other case where a reservation request has arrived, Direction
   is set to UPSTREAM at QNR's. On statefull nodes the state timer is
   started. In any case the message is passed to the RMF and transition
   is made to ST_WR.

8.1.4 idle__rx_response

   In ST_IDLE the node is not expecting a RESPONSE message. It is
   forwarded further to the final destination. The state ST_IDLE is
   kept.

8.1.5 idle__rx_rmf_msg

   If the RMF is triggering a RESPONSE message and the containing
   INFO_SPEC object indicates either a reservation failure or that the
   teardown was successful the message is passed further and transition
   is done to ST_IDLE.




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   If a QUERY message has been triggered, it is checked whether the R-
   Flag is set or an RII object is present. In this case the response
   timer is started and transition is made to ST_WR. If a normal QUERY
   containing no R-Flag and no RII object has been triggered, no
   response timer is started and transition is made to ST_IDLE.

   In case the RMF has triggered a RESERVE message at statefull
   intermediate nodes the state timer is started. If it contains no RII
   object, then no response is triggered and the refresh timer is
   started immediately to frequently refresh the session. If an RII
   object is included in the message the response timer is started
   instead of the refresh timer.  The message is sent further along the
   path.

   At the QNI no state timer is started as this is the node which takes
   care of the refreshes. It does not receive any refreshes which would
   restart the state timer. The message is sent further along the path.

   The QNR is starting only the state timer. As this is the end node it
   does not propagate the message any further. No responses are expected
   and no refresh messages will be sent.

   Transition is made to ST_INST.

8.2 State ST_WR

8.2.1 wr__rx_query

   A QUERY message has arrived over the network from GIST and the FSM is
   in State ST_WR. The message is entirely passed to the RMF using
   sendrmf(). Transition is made to ST_WR.

8.2.2 wr__rx_notify

   If the node is not the final destination of the NOTIFY message it is
   sent further along the path and transition is made to ST_WR.

8.2.3 wr__rx_reserve

   If a reserve message with set T-Flag has been received, the message
   is passed to the RMF to tear down the reservation and to construct a
   new tearing reserve message. If no confirmation of state removal has
   been requested, i.e. no RII object is present, transition is done to
   ST_IDLE. QNR's and stateless nodes also go directly to ST_IDLE.

   If the RII object in the tearing reserve is present, statefull nodes
   except QNR's start the state timer for one refresh period and pass
   the message to the RMF to remove reservation state. Transition is



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   done to ST_WR .

   If the received message is requesting a reservation the state timer
   is started.  The message is passed to the RMF to install reservation
   state and transition is made to ST_WR. If the node position is QNR
   then this is the requested RESERVE message for the Receiver Initiated
   Reservation. The Response Timer is stopped.  The state ST_WR is kept.

8.2.4 wr__rx_response

   In ST_WR a RESPONSE message has arrived. If the node is configured as
   QNE_Egress the message is forwarded with the BYPASS_STATELESS_ID as
   nslp_id that stateless nodes do not intercept this message. If an
   Ingress node receives a response with the BYPASS_STATELESS_ID, the
   nslp_id is translated to the QOS_NSLP_ID and the message is forwarded
   up to the requesting node. Normal QNE's just forward the response
   message. At this point no state transition is done. The relevant
   checkings follow in the next paragraph.

   If the received RII is from the local node the response timer is
   stopped. If there are no more outstanding RII's, either from the
   local node or from foreign nodes transition is done to ST_IDLE
   otherwise ST_WR. If the received RII was from a foreign node the same
   transitions are done depending on the outstanding RII's. For a stored
   foreign RII no response timer was started and therefore no response
   timer has to be stopped.

8.2.5 wr__rx_rmf_msg

   See the section 8.1.5 where a RESERVE message has been triggered.
   Transition is made to ST_INST.


8.2.6 wr__timeout_response

   A Response Timer has timed out while in ST_WR. If the maximum number
   of retries has been reached, transition is done to ST_IDLE, if no
   more response timers are pending, otherwise transition is done to
   ST_WR. If the maximum number of retransmissions has not been reached,
   then the query message is resent. The response timer is restarted and
   transition is made to ST_WR.

8.2.7 wr__timeout_statelifetime

   If the state timer in ST_WR times out the confirmation message for
   state removal has not been sent. In this case no retransmissions of
   the message is done and transition is done to ST_IDLE after stopping
   all timers.



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8.2.8 wr__rx_rmf_msg

   In ST_WR any triggered message from the RMF is forwarded and the same
   state is kept.

8.3 State ST_INST

8.3.1 inst__rx_query

   See wr__rx_query. Transition is made to ST_INST.

8.3.2 inst__rx_notify

   Reduced Refreshes are the default for refreshing RESERVEs. Notify
   messages are checked whether the next peer accepts reduced refreshes
   or not. The state ST_INST is kept.

8.3.3 inst__rx_reserve

   All incoming RESERVEs are checked for their RSN value. if it is
   smaller than the stored peer RSN the message is rejected. If the
   value is the same to the stored one the reservation is refreshed.
   Larger RSN value modify the reservation state.

   A tearing reserve is passed to the RMF to remove the existing
   reservation state.  If no confirmation is requested, i.e. no RII
   object is present, transition is done to ST_IDLE. If a confirmation
   is requested, the state timer is started for one refresh interval and
   transition is done to ST_WR.

   If no T_Flag is set the message is passed to the RMF to install or
   modify the reservation if the RSN value is larger than the stored
   peer RSN. The state timer is restarted for equal and larger RSN
   values. The state ST_INST is kept.

8.3.4 inst__rx_response

   In ST_INST a RESPONSE message has arrived. If the node position is
   QNE and no Scoping Flag is set, then the RESPONSE message is
   forwarded. If the RII value matches, then the Response Timer is
   stopped. If the received Error Code of the INFO object is SUCCESS,
   then the Response Timer is started. Transition is done to ST_INST.

   If the Error Code is FAILURE, then the reservation state is deleted
   and pending timers are stopped. Transition is made to ST_IDLE.

8.3.5 inst__timeout_response




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   A Response Timer has timed out while in ST_INST. If the maximum
   number of retries has been reached, then all pending timer are
   stopped and the RMF is informed to remove existing reservation state.
   Transition is made to ST_IDLE. If maximum numbers of retransmissions
   has not been reached, then previously sent message is resent. The
   Response Timer is restarted and the state ST_INST is kept.

8.3.6 inst__timeout_refresh

   A refreshing RESERVE message is created. If Reduced Refreshes are
   accepted, no QSPEC object is added. The refresh timer is being
   restarted. Transition is made to ST_INST.

8.3.7 inst__timeout_statelifetime

   The Statelife Timer timed out in ST_INST. All active timer are
   stopped and existing reservations are removed. The RMF is informed to
   teardown reservation state and to trigger a teardown message.
   Transition is done to ST_IDLE.


8.3.8 inst__sii_changed

   A different SII-Handle indicates that a route change has occurred. A
   full reserve including QSPEC is sent on the new path. The reservation
   on the old path is torn down using the old SII-Handle. The state
   ST_INST is kept.

8.3.9 inst__network_notification

   A network notification from GIST is indicating that a route change
   has occurred. A full RESERVE including QSPEC is sent on the new path.
   The state ST_INST is kept.

8.3.10 inst__rx_rmf_msg

   See idle__rx_rmf_msg for details.


9.  Security Considerations

   This document does not raise new security considerations. Any
   security concerns with QoS NSLP are likely reflected in security
   related NSIS work already (such as [1] or [6]).

   For the time being, the state machine described in this document does
   not consider the security aspect of QoS NSLP protocol itself.




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10.  Open Issues

   This document tries to describe possible states and transitions for
   QoS NSLP according to its current specification [1], Section 5. We
   found some issues during the development of the state machines.

   1. Bi-directional reservation is difficult to support as the state
      machine becomes quite complex (note at one particular point in
      time the protocol state engine can be only in one state).
   2. How to signal unsuccessful reservation for Receiver initiated
      reservation (No RII included; a resulting Response(RSN) cannot be
      forwarded further than the next peer). We use NOTIFY message.
   3. The case of unsuccessful reservation at a QNE node and no RII
      specified by upstream nodes. According to the spec RESPONSE(RSN)
      should not be forwarded further than the next peer. Currently we
      use NOTIFY(RSN) that is sent further to the upstream nodes.
   4. We assume that handling of QoS state lifetime expiration event is
      based on the local policy of the node. NOTIFY/Reserve(Ton)
      messages might be sent to other peers.
   5. The draft states that RESERVE message MUST be sent only towards
      the QNR. This is not the case when re-routing procedure is done
      and RESERVE(Ton) message should be sent from merging QNE node for
      deleting the old branch. We believe this is towards the QNI.
   6. Re-routing functionality described in this document is not
      complete and need further consideration.


11.  Change History

11.1  Changes in Version -01

   1. Notation of the nodes changed to QNI, QNE and QNR.
   2. Description of soft state refresh functionality.
   3. Support of ACK flag in the common header.
   4. Include of QoS NSLP objects, flags from the common header and
      entries stored with the installed QoS state in a node: ACK,
      Replace, RSN, Error_SPEC, QSPEC, FlowID, SII.
   5. Initial description of Re-routing functionality.
   6. For support of all listed changes, some notations are changed.


11.2  Changes in Version -02

   1. Switch to .pdf format of the draft and include graphic diagrams.
   2. Update notation from "Summary refresh" to "Reduced refresh"
   3. Description of QoS reservation update/upgrade

11.3 Changes in Version -03



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   1. Deep review of the state machine architecture

11.4  Changes in Version -04

   1. Reduced the three state machines of QNI, QNE and QNR to one for
      all nodes.
   2. Introduced new flags to have a finer control of the direction of
      the message to be sent.

11.5  Changes in Version -05

   1. Combined ST_WR2 and ST_INST into ST_INST
   2. Support for Q-Flag in common header
   3. Explanations on the execution of the State Machine added

11.6  Changes in Version -06

   1. Interaction with RMF added
   2. Trigger from local application removed


12.  Acknowledgments

   The authors would like to thank Sven Van den Bosch and Christian
   Dickmann for their feedback.


























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13. References

13.1. Normative References

   [1]         Manner, J., Karagiannis, G. and McDonald, A., "NSLP for
               Quality-of-Service Signaling", Internet draft, draft-
               ietf-nsis-qos-nslp-15 (work in progress), July 2007.

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

13.2. Informative References

   [3]         Vollbrecht, J., Eronen, P., Petroni, N., and Y. Ohba,
               "State Machines for Extensible Authentication Protocol
               (EAP) Peer and Authenticator", RFC 4137, August 2005.

   [4]         Institute of Electrical and Electronics Engineers, "DRAFT
                Standard for Local and Metropolitan Area Networks: Port-
               Based
                Network Access Control (Revision)", IEEE 802-1X-REV/D11,
               July 2004.

   [5]         Ohba, Y., "State Machines for Protocol for Carrying
               Authentication for Network Access (PANA)",
                draft-ohba-pana-statemachine-01 (work in progress),
               February 2005.

   [6]         Tschofenig, H. and D. Kroeselberg, "Security Threats for
               NSIS", RFC 4081, June 2005.





















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Appendix A. ASCII versions of state diagrams

   This appendix contains the state diagrams in ASCII format. Please use
   the PDF version whenever possible: it is much easier to understand.

   The notation is as follows: for each state there is a separate table
   that lists in each row:
   - an event that triggers a transition,
   - actions taken as a result of the incoming event,
   - and the new state at which the transitions ends.


A.1.  State ST_IDLE



ST_IDLE::EV_RX_QUERY
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!(R-Flag && QNI)) {                                  |  ST_WR    |
|    sendrmf();                                           |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(R-Flag && QNI) {                                     |  ST_WR    |
|    Direction=UPSTREAM;                                  |           |
|    sendrmf();                                           |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 13


ST_IDLE::EV_RX_NOTIFY
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!QNI) tx_notify(Toggle=false);                       |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 14




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ST_IDLE::EV_RX_RESERVE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(T-Flag) sendrmf();                                   |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!T-Flag) {                                           |  ST_WR    |
|    if(QNR) {                                            |           |
|       Direction=UPSTREAM;                               |           |
|       startStateTimer();                                |           |
|    sendrmf();                                           |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 15


ST_IDLE::EV_RX_RESPONSE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!QNI) tx_response(Toggle=false);                     |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 16


ST_IDLE::EV_RX_RMF_MSG
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(rx_response && !QNI) tx_response(Toggle=false);      |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(rx_query && (R-Flag || RII)) {                       |  ST_WR    |
|    startResponseTimer();                                |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |



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| if(rx_reserve && !T-Flag)                               |  ST_INST  |
|    if(QNE || QNE_Ingress || QNE_Egress) {               |           |
|       startStateTimer();                                |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNI) {                                     |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNR) {                                     |           |
|       startStateTimer();                                |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 17


A.2.  State ST_WR


ST_WR::EV_RX_QUERY
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| sendrmf();                                              |  ST_WR    |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 18


ST_WR::EV_RX_NOTIFY
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!QNI) tx_notify(Toggle=false);                       |  ST_WR    |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 19






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ST_WR::EV_RX_RESERVE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(T-Flag && (!RII || QNR || STATELESS)) {              |  ST_IDLE  |
|    send_rmf();                                          |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(T-Flag && RII && (STATEFULL && !QNR)) {              |  ST_WR    |
|    startStateTimer(REFRESH_PERIOD);                     |           |
|    send_rmf();                                          |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!T-Flag && QNR) {                                    |  ST_WR    |
|    if(QNR) stopResponseTimer();                         |           |
|    startStateTimer();                                   |           |
|    sendrmf();                                           |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 20


ST_WR::EV_RX_RESPONSE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(QNE_Egress) {                                        |           |
|    tx_response(Toggle=false, BYPASS_STATELESS_ID);      |           |
| } else if(QNE ||                                        |           |
|       (QNE_Ingress && nslp_id==BYPASS_STATELESS_ID)) {  |           |
|    tx_response(Toggle=false, QOS_NSLP_ID);              |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(is_local(RII)==true && !outstanding_foreign_rii) {   |  ST_IDLE  |
|    stopResponseTimer();                                 |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+



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|                                                         |           |
| if(is_local(RII)==true && outstanding_foreign_rii) {    |  ST_WR    |
|    stopResponseTimer();                                 |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(is_foreign(RII)==true && !outstanding_local_rii)     |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(is_foreign(RII)==true && outstanding_local_rii)      |  ST_WR    |
|                                                         |           |
+---------------------------------------------------------+-----------+


                               Figure 21


ST_WR::EV_TIMEOUT_RESPONSE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(MAX_RETRY && !TIMER_PENDING)                         |  ST_IDLE  |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(MAX_RETRY && TIMER_PENDING)                          |  ST_WR    |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!MAX_RETRY) {                                        |  ST_WR    |
|    tx_query(Direction);                                 |           |
|    restartResponseTimer();                              |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 22


ST_WR::EV_TIMEOUT_STATELIFETIME
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| stopTimers();                                           |  ST_IDLE  |



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|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 23


ST_WR::EV_RX_RMF_MSG
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(rx_reserve && !T-Flag)                               |  ST_INST  |
|    if(QNE || QNE_Ingress || QNE_Egress) {               |           |
|       startStateTimer();                                |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNI) {                                     |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNR) {                                     |           |
|       startStateTimer();                                |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 24


A.3.  State ST_INST


ST_INST::EV_RX_QUERY
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| sendrmf();                                              |  ST_INST  |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 25


ST_INST::EV_RX_NOTIFY
+---------------------------------------------------------+-----------+



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| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(ErrorClass==ERRORCLASS_INFO) {                       |  ST_INST  |
|    if(ErrorCode==RR_NOT_SUPPORTED) {                    |           |
|       ReducedRefreshes = false;                         |           |
|    } else if(ErrorCode==RR_SUPPORTED) {                 |           |
|       ReducedRefreshes = true;                          |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 26


ST_INST::EV_RX_RESERVE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(T-Flag && !RII) {                                    |  ST_IDLE  |
|    if(rsn>peer_rsn) {                                   |           |
|       update_rsn();                                     |           |
|       sendrmf();                                        |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(T-Flag && RII) {                                     |  ST_WR    |
|    if(rsn>peer_rsn) {                                   |           |
|       update_rsn();                                     |           |
|       sendrmf();                                        |           |
|       start_statetimer(REFRESH_RELOAD);                 |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!T-Flag) {                                           |  ST_INST  |
|    if(rsn>=peer_rsn) {                                  |           |
|       if(rsn>peer_rsn) {                                |           |
|          update_rsn();                                  |           |
|          sendrmf();                                     |           |
|       }                                                 |           |
|    restart_statetimer();                                |           |
|    }                                                    |           |



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| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+


                               Figure 27


ST_INST::EV_RX_RESPONSE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(QNE_Egress) {                                        |           |
|    tx_response(toggle=false, BYPASS_STATELESS_ID);      |           |
| } else if(QNE ||                                        |           |
|       (QNE_Ingress && nslp_id==BYPASS_STATELESS_ID)) {  |           |
|    tx_response(toggle=false, QOS_NSLP_ID);              |           |
| }                                                       |           |
| if(is_local_rii) stopResponseTimer();                   |           |
| startRefreshTimer();                                    |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(INFO==SUCCESS)                                       |  ST_INST  |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(INFO==FAILURE) {                                     |  ST_IDLE  |
|    sendrmf();                                           |           |
|    stop_timers();                                       |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 28


ST_INST::EV_RX_RMF_MSG
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(rx_response && (fail || tear_successful)) {          |  ST_IDLE  |
|    tx_response();                                       |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+



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|                                                         |           |
| if(rx_response && success) {                            |  ST_INST  |
|    tx_response();                                       |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(rx_reserve && !T-Flag)                               |  ST_INST  |
|    if(QNE || QNE_Ingress || QNE_Egress) {               |           |
|       startStateTimer();                                |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNI) {                                     |           |
|       if(RII) startResponseTimer();                     |           |
|       else startRefreshTimer();                         |           |
|       tx_reserve();                                     |           |
|    } else if(QNR) {                                     |           |
|       startStateTimer();                                |           |
|    }                                                    |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 29



ST_INST::EV_TIMEOUT_RESPONSE
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(MAX_RETRY) {                                         |  ST_IDLE  |
|    sendrmf();                                           |           |
|    stopTimers();                                        |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(!MAX_RETRY) {                                        |  ST_INST  |
|    tx_reserve(Direction);                               |           |
|    restartResponseTimer()                               |           |
| }                                                       |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 30



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ST_INST::EV_TIMEOUT_REFRESH
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| if(ReducedRefreshes) {                                  |  ST_INST  |
|    tx_reserve(RSN, Direction);                          |           |
| } else {                                                |           |
|    tx_reserve(RSN, QSPEC, Direction);                   |           |
| }                                                       |           |
| restartRefreshTimer();                                  |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 31


ST_INST::EV_TIMEOUT_STATELIFETIME
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| stopTimers();                                           |  ST_IDLE  |
| sendrmf();                                              |           |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 32


ST_INST::EV_SII_CHANGED
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| tx_reserve(RII, RSN, QSPEC, SII);                       |  ST_INST  |
|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 33


ST_INST::EV_NETWORK_NOTIFICATION
+---------------------------------------------------------+-----------+
| Action                                                  | new State |
+---------------------------------------------------------+-----------+
|                                                         |           |
| tx_reserve(RII, RSN, QSPEC);                            |  ST_INST  |



Fu, et al.                                                     [Page 40]

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|                                                         |           |
+---------------------------------------------------------+-----------+

                               Figure 34

A.4 Commonly used functions:

A.4.1 update_rsn()



  1 void update_rsn() {
  2    if((STATEFULL && !QNE_Egress) ||
  3       (QNE_Egress && nslp_id==BYPASS_STATELESS_ID)) {
  4       peer_rsn=rsn;
  5    }
  6 }
  7

                               Figure 35


This function is used to update the rsn value only on statefull peers. At
the egress node the rsn is updated when a message arrives with the nslp_id
BYPASS_STATELESS_ID.


A.4.2 send_rmf()


  1 void sendrmf() {
  2
  3    switch(message_type) {
  4
  5       case QOS_MESSAGETYPE_RESERVE:
  6
  7          switch(nodepos) {
  8
  9             case QNI:
 10
 11                if(T-Flag) {
 12                   free_qos();
 13                   recv_rmf(reserve, DO_NOT_TOGGLE);
 14
 15                } else {
 16                   qos_available = reserve_qos();
 17                   if(qos_available) recv_rmf(reserve, DO_NOT_TOGGLE);
 18                   else recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);



Fu, et al.                                                     [Page 41]

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 19                }
 20                break;
 21
 22             case QNE:
 23
 24                if(T-Flag) {
 25                   free_qos();
 26                   if(!S-Flag) recv_rmf(reserve, new_rsn, DO_NOT_TOGGLE);
 27                   else if(rii) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 28
 29                } else {
 30                   qos_available = reserve_qos();
 31                   if(!qos_available) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 32                   else if(!S-Flag) recv_rmf(reserve, DO_NOT_TOGGLE);
 33                   else recv_rmf(response, INFOSPEC=SUCCESS, DO_TOGGLE);
 34                   if(rr_supported) recv_rmf(notify, DO_TOGGLE);
 35                }
 36                break;
 37
 38             case QNE_Ingress:
 39
 40                if(T-Flag) {
 41                   free_qos();
 42                   recv_rmf(reserve, BYPASS_STATELESS_ID, DO_NOT_TOGGLE);
 43                   recv_rmf(reserve, new_rsn, new_rii, DO_NOT_TOGGLE);
 44                } else {
 45                   qos_available = reserve_qos();
 46                   if(!qos_available) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 47                   else {
 48                      recv_rmf(reserve, BYPASS_STATELESS_ID, DO_NOT_TOGGLE);
 49                      recv_rmf(reserve, DO_NOT_TOGGLE);
 50                   }
 51                   if(rr_supported) recv_rmf, notify(DO_TOGGLE);
 52                }
 53                break;
 54
 55             case QNE_Interior:
 56
 57                if(T-Flag) {
 58                   free_qos();
 59                   recv_rmf(reserve(new_rsn, DO_NOT_TOGGLE));
 60
 61                } else {
 62                   qos_available = reserve_qos();
 63                   if(!qos_available) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 64                   else recv_rmf(reserve, DO_NOT_TOGGLE);
 65                }
 66                break;



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 67
 68             case QNE_Egress:
 69
 70                if(T-Flag) {
 71                   free_qos();
 72                   if(nslp_id==QOS_NSLP_ID && rii)
 73                      recv_rmf(response(new_rsn, new_rii, DO_NOT_TOGGLE));
 74                } else {
 75                   qos_available = reserve_qos();
 76                   if(!qos_available) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 77                   if (nslp_id==QOS_NSLP_ID) {
 78                       if(rii) recv_rmf(response, INFOSPEC=SUCCESS, QOS_NSLP_ID);
 79                       if(rr_supported) recv_rmf(notify, QOS_NSLP_ID);
 80                   } else if (nslp_id==BYPASS_STATELESS_NODE && rr_supported)
 81                       recv_rmf(notify, BYPASS_STATELESS_NODE);
 82                }
 83                break;
 84
 85             case QNR:
 86
 87                if(T-Flag) {
 88                   free_qos();
 89                   if(rii) recv_rmf(response(DO_TOGGLE));
 90                } else {
 91                   qos_available = reserve_qos();
 92                   if(!qos_available) recv_rmf(response, INFOSPEC=FAIL, DO_TOGGLE);
 93                   if(rii) recv_rmf(response, INFOSPEC=SUCCESS, DO_TOGGLE);
 94                   if(rr_supported) recv_rmf(notify, INFOSPEC=RR_SUPPORTED, DO_TOGGLE);
 95                }
 96                break;
 97
 98          }
 99          break;
100
101       case QOS_MESSAGETYPE_QUERY:
102
103          if (QNI && R-Flag) {
104             reserve_qos();
105             send_rmf(reserve, new_rii, new_rsn, new_qspec);
106
107          } else if (QNR && R-Flag) {
108
109             query_rmf();
110             send_rmf(query, R-Flag, PC, QSPEC, Direction=DOWNSTREAM);
111
112          } else {
113
114             query_rmf();



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115             if(QNR) send_rmf(response);
116             else send_rmf(query);
117
118          }
119          break;
120
121       case QOS_MESSAGETYPE_RESPONSE:
122
123          break;
124
125       case QOS_MESSAGETYPE_NOTIFY:
126
127          break;
128
129    }
130
131 }
132

                               Figure 36



Message Type Reserve

   At the QNI if the message has set the T-Flag the reservation is torn
   down and a new reserve message is triggered using the API-call
   recv_rmf(). If no T-Flag was set in the reserve message, reservation
   state is installed. If successful a new reserve message is triggered
   to be sent further along the path.

   At QNE's the (tearing) reserve is sent further if the scoping flag is
   not set.  Otherwise this node triggers a response if an RII object is
   present. If a reservation request fails a response is triggered to
   inform the initiator about the failure. If reduced refreshes are
   supported a notify message is sent back to the previous peer.

   Ingress nodes trigger two new (tearing) reserve message, one with the
   old nslp_id and one with the BYPASS_STATELESS_ID to bypass stateless
   nodes. No special treatment of the messages is done at interior
   nodes.

   The egress node triggers a response message, if a response was
   requested by including an RII object and if the nslp_id of the
   received message is QOS_NSLP_ID. If a requested reservation fails, a
   response is sent back in any case. Notify message for reduced
   refreshes are sent with the corresponding nslp_id.




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   The QNR as the destination of the message echoes a response if the
   reservation fails or if a response was requested by including an RII
   object. Also here a notify message is sent back to the previous node,
   if reduced refreshes are accepted.















































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Message Type QUERY

   If a QUERY message with set R-Flag arrives at the QNI, the RMF
   triggers a new RESERVE message to be sent towards the QNR. Resource
   query messages are sent further after updating the QSPEC. The QNR
   triggers a response message containing the QSPEC.













































Fu, et al.                                                     [Page 46]

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Authors' Addresses

   Xiaoming Fu
   University of Goettingen
   Telematics Group
   Lotzestrasse 16-18
   Goettingen  37083
   Germany

   Email: fu@cs.uni-goettingen.de


   Hannes Tschofenig
   Nokia Siemens Networks
   Otto-Hahn-Ring 6
   Munich, Bayern  81739
   Germany

   Email: Hannes.Tschofenig@nsn.com
   URI:   http://www.tschofenig.com

   Tseno Tsenov
   Nokia Siemens Networks
   Otto-Hahn-Ring 6
   Munich, Bayern  81739
   Germany

   Email: tseno.tsenov@mytum.de


   Bernd Schloer
   University of Goettingen
   Telematics Group
   Lotzestrasse 16-18
   Goettingen  37083
   Germany

   Email: bschloer@cs.uni-goettingen.de













Fu, et al.                                                     [Page 47]

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Full Copyright Statement

   Copyright (C) The IETF Trust (2007).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
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