NSIS T. Tsenov Internet-Draft H. Tschofenig Expires: May 11, 2005 Siemens X. Fu I. Juchem Univ. Goettingen November 10, 2004 GIMPS State Machine draft-fu-nsis-ntlp-statemachine-00.txt Status of this Memo This document is an Internet-Draft and is subject to all provisions of section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 11, 2005. Copyright Notice Copyright (C) The Internet Society (2004). Abstract This document describes the state machines for the General Internet Messaging Protocol for Signaling (GIMPS). The states of GIMPS nodes for a given flow and their transitions are presented in order to illustrate how GIMPS may be implemented. Tsenov, et al. Expires May 11, 2005 [Page 1] Internet-Draft GIMPS State Machine November 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Notational conventions used in state diagrams . . . . . . . . 5 4. State Machine Symbols . . . . . . . . . . . . . . . . . . . . 7 5. Common Rules . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Common Procedures . . . . . . . . . . . . . . . . . . . . 8 5.2 Common Variables . . . . . . . . . . . . . . . . . . . . . 8 5.3 Constants . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Default state machines for soft state refreshes and teardowns . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.1 State machine for soft state refreshes . . . . . . . . . . 10 6.2 State machine for soft state teardowns . . . . . . . . . . 10 7. State machine for the first GIMPS node in the flow path . . . 12 8. State machine for intermediate GIMPS nodes . . . . . . . . . . 14 9. State machine for the last GIMPS node in the flow path . . . . 18 10. Security Considerations . . . . . . . . . . . . . . . . . . 20 11. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . 21 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 22 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 13.1 Normative References . . . . . . . . . . . . . . . . . . . . 23 13.2 Informative References . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 23 Intellectual Property and Copyright Statements . . . . . . . . 25 Tsenov, et al. Expires May 11, 2005 [Page 2] Internet-Draft GIMPS State Machine November 2004 1. Introduction This document describes the state machines for GIMPS [1], trying to show how GIMPS can be implemented to support its deployment. The state machines described in this document are illustrative of how the GIMPS protocol defined in [1] may be implemented for the GIMPS nodes in different locations of a flow path. Where there are differences [1] are authoritative. The state machines are informative only. Implementations may achieve the same results using different methods. There are 3 types of possible entities for GIMPS signaling: The first node that speaks GIMPS in the path from FlowSender to the FlowReceiver (it is assumed that it has only downstream RoutingState or MessagingAssociation for the given flow); Intermediate GIMPS node; The last node that speaks GIMPS in the path from the FlowSender to the FlowReceiver (it is assumed that it has only upstream RoutingState or MessagingAssociation for the given flow). We describe a set of state machines for these entities to illustrate how GIMPS may be implemented. Tsenov, et al. Expires May 11, 2005 [Page 3] Internet-Draft GIMPS State Machine November 2004 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]. Tsenov, et al. Expires May 11, 2005 [Page 4] Internet-Draft GIMPS State Machine November 2004 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, 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 Tsenov, et al. Expires May 11, 2005 [Page 5] Internet-Draft GIMPS State Machine November 2004 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 variables are initialized to FALSE before the state machine execution begins. Second, the following notational shorthand is specific to this document: = | | ... Execution of a statement of this form will result in 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. Tsenov, et al. Expires May 11, 2005 [Page 6] Internet-Draft GIMPS State Machine November 2004 4. State Machine Symbols *_up means the message is sent in upstream direction or received from upstream direction *_down means the message is sent in downstream direction or received from downstream direction MA means "Messaging Association" RS means "Routing State" ( ) 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 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 \} 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. Tsenov, et al. Expires May 11, 2005 [Page 7] Internet-Draft GIMPS State Machine November 2004 5. Common Rules Throughout the document we use terms defined in the [1], such as Query, Response, Confirm. 5.1 Common Procedures Tg_SendMsg: NSLP/GIMPS API message that request transmission of a NSLP message Tg_SetStateLifetime(time_period): NSLP/GIMPS API message providing info for the Lifetime of an RS, required by the application. "Time_period = 0" represents the cancellation of established RSs/MAs (invoked by NSLP application). Tg_MessageDeliveryError: NSLP/GIMPS API message informing NSLP application of unsuccessful delivery of a message Tg_RecvMsg: NSLP/GIMPS API message that provides received message to the NSLP Tg_NetworkNotification: NSLP/GIMPS API message that informs NSLP for change in RS Tx_Query_Dmode: Transmit of Query message in Dmode Tx_Response_Dmode: Transmit of Response message in Dmode Rx_Response_Dmode: Receive of Response message in Dmode Tx_Confirm_Cmode: Transmit of Confirm message in Cmode (via MA) Rx_Query_Dmode: Receive of Query message in Dmode Rx_Confirm_Cmode: Receive of Confirm message in Cmode (via MA) Queue NSLP msg info: Save NLSP messages in a queue until a required MA association is established Tx_Msg_Cmode: Transmit message in Cmode (via MA) TIMEOUT_MAState: Expiration of an established MA state lifetime timer. TIMEOUT_RSState: Expiration of an established RS state lifetime timer. TIMEOUT_Refresh: Refresh interval timer expiration ESTABLISH RS: Establish Downstream/Upstream Routing State at the node ESTABLISH MA: Establish Downstream/Upstream Message Association at the node REFRESH RS: Refreshes established RS 5.2 Common Variables It is assumed that the type of mode and destination info (which need to be taken from the application parameters and local GIMPS policy) is provided. This is represented by the common variables Dmode, Cmode, MArequest, MAinfo, MApresent and Refresh. Dmode: The message MUST be transmitted in Dmode. This is specified by "Message transfer attributes" set to the following values: Tsenov, et al. Expires May 11, 2005 [Page 8] Internet-Draft GIMPS State Machine November 2004 Reliability: is set to FALSE Security: is set to values that do not request special security handling of a message. Local processing: is set to values that do not require services offered by Cmode [1] Cmode: The message MUST be transmitted in Cmode. This is specified by "Message transfer attributes" set to any of the following values: Reliability: is set to TRUE Security: is set to values that request secure handling of a message. Local processing: is set to values that require services offered by Cmode (e.g., congestion control) [1] MApresent: Used for re-use of MAs. It shows that there is a perfect match between the Node Addressing Object (NAO) of an existing association and the NAO provided in the GIMPS Query Dmode message (section 4.4.2 of [1]). MArequest: Request for MA establishment. Its mapping to specific GIMPS message parameters is left for future version of the document. MAinfo: Information for establishment of the requested MA. Its mapping to specific GIMPS message parameters is left for future version of the document. NSLPinfo: NSLP application information Refresh: This variable specifies that the message is for refresh purposes Downstream: Specifies that message must be sent in downstream direction Upstream: Specifies that message must be sent in upstream direction. 5.3 Constants Tsenov, et al. Expires May 11, 2005 [Page 9] Internet-Draft GIMPS State Machine November 2004 6. Default state machines for soft state refreshes and teardowns This section presents the state machines for any "established state" in a GIMPS nodes. Whenever possible, they are not repeated in subsequent sections for simplicity. Note: since in GIMPS there can be different combinations of RS (established or not) and MA (etablished or not) states in both DIRECTIONs (up- and downstream), there are 8 sub-states in total, all being soft states (subject to expiration unless refreshes), thus yield the state machine presented in this section (and the combination of different state variables, which are not fully elaborated here for simplicity). 6.1 State machine for soft state refreshes This subsection presents the single state for a given "established state" and transitions to itself under refresh conditions. By default, "refresh the established state" action is performed for all these transitions. ------------------- State: State_Estab (any established MA/RS state) ------------------- Condition Action State ------------------------+-------------------------+------------ (tg_SendMsg) && (Cmode) |tx_Msg_Cmode_up |State_Estab && (Upstream) | | | | (tg_SendMsg) && (Cmode) |tx_Msg_Cmode_down |State_Estab && (Downstream) | | | | (tg_SendMsg) && (Dmode) |tx_Msg_Dmode_up |State_Estab && (Upstream) | | | | (tg_SendMsg) && (Dmode) |tx_Msg_Dmode_down |State_Estab && (Downstream) | | | | rx_Response_Dmode | Refresh RS |State_Estab (Refresh) | | ------------------------+-------------------------+------------ 6.2 State machine for soft state teardowns This subsection presents the state machine for transitions for any established MA state and RS state under their timer teardown Tsenov, et al. Expires May 11, 2005 [Page 10] Internet-Draft GIMPS State Machine November 2004 conditions. ---------------------------------- STATE: RS_Established in DIRECTION (DIRECTION = {up, down}) ---------------------------------- Condition Action State ------------------------+-------------------------+------------ (TIMEOUT_RSstate)|| |Clear RS, |IDLE in (tg_SetStateLifetime(0))| tg_Network Notification |DIRECTION | |(Note 1) ------------------------+-------------------------+------------ ---------------------------------- STATE: MA_Established in DIRECTION (DIRECTION = {up, down}) ---------------------------------- Condition Action State ------------------------+-------------------------+------------ (TIMEOUT_MAstate)|| |(Clear MS)|| |IDLE in (tg_SetStateLifetime(0))|(Stop_using_existing MA) |DIRECTION |tg_Network Notification |(Note 1) ------------------------+-------------------------+------------ Note 1: If both downstream and upstream states are established, then this transition goes to RS/MA Established state only for the other DIRECTION. Tsenov, et al. Expires May 11, 2005 [Page 11] Internet-Draft GIMPS State Machine November 2004 7. State machine for the first GIMPS node in the flow path ----------- State: INIT ----------- Condition Action State ------------------------+-------------------------+------------ UCT | initialize variables |IDLE ------------------------+-------------------------+------------ ----------- State: IDLE ----------- Condition Action State ------------------------+-------------------------+------------- (tg_SendMsg) && (Dmode) |tx_Query_Dmode(NSLPinfo) |WAITRESP2 | | (tg_SendMsg) && (Cmode) |tx_Query_Dmode(MArequest)|WAITRESP1 | Queue NSLP msg info | ------------------------+-------------------------+------------- ---------------- State: WAITRESP1 ---------------- Condition Action State ------------------------+-------------------------+------------ (TIMEOUT_Refresh) && |tx_Query_Dmode(MArequest)|WAITRESP1 (!MaxRetry) | | | | (TIMEOUT_Refresh) && |tg_MessageDeliveryError |IDLE (MaxRetry) | | | | (rx_RESPONSE_Dmode |tx_Confirm_Cmode, |DownMA_Estab (MAinfo)) || | tx_queued_Msg_cmode, | (rx_RESPONSE_Cmode | (Establish MA) || | (MAinfo)) | (Re-use existing MA) | ------------------------+-------------------------+------------ Tsenov, et al. Expires May 11, 2005 [Page 12] Internet-Draft GIMPS State Machine November 2004 ------------------- State: DownMA_Estab (Downstream MA Established) ------------------- Condition Action State ------------------------+-------------------------+------------ rx_Msg_Cmode |tg_RecvMsg to Application|DownMA_Estab | | (tg_SendMsg) && (Cmode) |tx_Msg_Cmode |DownMA_Estab ------------------------+-------------------------+------------ ---------------- State: WAITRESP2 ---------------- Condition Action State ------------------------+-------------------------+------------ (TIMEOUT_Refresh) && |tx_Query_Dmode(NSLPinfo) |WAITRESP2 (!MaxRetry) | | | | (TIMEOUT_Refresh) && |tg_MessageDeliveryError |IDLE (MaxRetry) | | | | rx_Response_Dmode |(establish downstream RS)|DownRS_Estab ------------------------+-------------------------+------------ ------------------- State: DownRS_Estab (Downstream RS Established) ------------------- Condition Action State ------------------------+-------------------------+------------ TIMEOUT_Refresh |tx_Query_Dmode(Refresh) |DownRS_Estab | | rx_Response_Dmode |Refresh RS |DownRS_Estab (Refresh) | | | | (tg_SendMsg) && (Dmode) |tx_Msg_Dmode |DownRS_Estab ------------------------+-------------------------+------------ Tsenov, et al. Expires May 11, 2005 [Page 13] Internet-Draft GIMPS State Machine November 2004 8. State machine for intermediate GIMPS nodes ----------- State: INIT ----------- Condition Action State ------------------------+-------------------------+------------ UCT | initialize variables |IDLE ------------------------+-------------------------+------------ ----------- State: IDLE ----------- Condition Action State ------------------------+-------------------------+------------- (rx_Query_Dmode_up |tg_RecvMsg to App., |UpRS_Estab (MArequest)) && | tx_Response_Dmode_up | (!MApresent) | (MAinfo), establish RS | | | rx_Query_Dmode_up |tg_RecvMsg(NSLPinfo) to |UpRS_Estab (NSLPinfo) | Application, | | tx_Response_Dmode_up, | | establish RS | | | (rx_Query_Dmode_up |tg_RecvMsg to Application|UpMA_Estab (MArequest)) && | , tx_Response_Cmode_up | (MApresent) | (MAinfo), re-use | (MApresent) | existing MA | ------------------------+-------------------------+------------- Tsenov, et al. Expires May 11, 2005 [Page 14] Internet-Draft GIMPS State Machine November 2004 ----------------- State: UpRS_Estab (UPstream RS Established) ----------------- Condition Action State ------------------------+-------------------------+------------- (tg_SendMsg) && (Dmode) |tx_Query_Dmode_down |UpRS_Estab + | (NSLPinfo) | WaitResp for | | DownRS | | (tg_SendMsg) && (Cmode) |tx_Query_Dmode_down |UpRS_Estab + | (MArequest), queue NSLP| WaitResp for | msg info | DownRS | | rx_Confirm_Cmode_up |Estabsh MA |UpMA_Estab ------------------------+-------------------------+------------- --------------------------------------- State: UpRS_Estab + WaitResp for DownRS --------------------------------------- Condition Action State ------------------------+-------------------------+------------- (rx_Response_Dmode_down |tx_Confirm_Cmode_down, |UpRS_Estab + (MAinfo)) || | tx_queued_Msg_Cmode_down| DownMA_Estab (rx_Response_Cmode_down| estblish MA | (MAinfo)) | | | | rx_Response_Dmode_down |Establish RS |UpRS_Estab + | | DownRS_Estab ------------------------+-------------------------+------------- -------------------------------- State: UpRS_Estab + DownRS_Estab -------------------------------- Condition Action State ------------------------+-------------------------+------------- rx_Confirm_Cmode_up |Establish MA |DownRS_Estab + | | UpMA_Estab ------------------------+-------------------------+------------- Tsenov, et al. Expires May 11, 2005 [Page 15] Internet-Draft GIMPS State Machine November 2004 -------------------------------- State: DownRS_Estab + UpMA_Estab -------------------------------- Condition Action State ------------------------+-------------------------+------------- TIMEOUT_Refresh_down |tx_Query_Dmode_down |DownRS_Estab + | (Refresh) | UpMA_Estab ------------------------+-------------------------+------------- -------------------------------- State: UpRS_Estab + DownMA_Estab -------------------------------- Condition Action State ------------------------+-------------------------+------------- rx_Confirm_Cmode_up |Establish MA, |DownMA_Estab + | rx_Confirm_Cmode_up | UpMA_Estab ------------------------+-------------------------+------------- -------------------------------- State: DownMA_Estab + UpMA_Estab -------------------------------- (Refer Section "State machine for soft state") ----------------- State: UpMA_Estab ----------------- Condition Action State ------------------------+-------------------------+------------- (tg_SendMsg) && (Dmode) |tx_Query_Dmode_down |UpMA_Estab + | (NSLPinfo) | WaitResp for | | DownRS | | (tg_SendMsg) && (Cmode) |tx_Query_Dmode_down |UpMA_Estab + | (MArequest), queue NSLP| WaitResp for | msg info | DownRS | | rx_Confirm_Cmode_up | |UpMA_Estab ------------------------+-------------------------+------------- Tsenov, et al. Expires May 11, 2005 [Page 16] Internet-Draft GIMPS State Machine November 2004 --------------------------------------- State: UpMA_Estab + WaitResp for DownRS --------------------------------------- Condition Action State ------------------------+-------------------------+------------- (rx_Response_Dmode_down |tx_Confirm_Cmode_down, |UpMA_Estab + (MAinfo)) || | tx_queued_Msg_Cmode_down| DownMA_Estab (rx_Response_Cmode_down| , estblish MA | (MAinfo)) | | | | rx_Response_Dmode_down |Establish RS |UpMA_Estab + | | DownRS_Estab ------------------------+-------------------------+------------- Tsenov, et al. Expires May 11, 2005 [Page 17] Internet-Draft GIMPS State Machine November 2004 9. State machine for the last GIMPS node in the flow path ----------- State: INIT ----------- Condition Action State ------------------------+-------------------------+------------ UCT | initialize variables |IDLE ------------------------+-------------------------+------------ ----------- State: IDLE ----------- Condition Action State ------------------------+-------------------------+------------- (rx_Query_Dmode_up |tg_RecvMsg to App., |UpRS_Estab (MArequest)) && | tx_Response_Dmode_up | (!MApresent) | (MAinfo), Establish RS | | | rx_Query_Dmode |tg_RecvMsg(NSLP info) to |UpRS_Estab (NSLPinfo) | Appl., tx_Response_Dmode| | establish RS | | | rx_Query_Dmode |tg_RecvMsg to Application|UpMA_Estab (MArequest) | , tx_Response_Dmode_up | | (MAinfo), Re-use | | existing MA | ------------------------+-------------------------+------------- ----------------- State: UpRS_Estab ----------------- Condition Action State ------------------------+-------------------------+------------ (TIMEOUT_RSstate) || |Clear RS, |IDLE (tg_SetStateLifeTime(0))| tg_NetworkNotification | | | rx_Query_Dmode(Refresh) |Refresh RS, |UpRS_Estab | tx_Response(Refresh) | | | rx_Confirm_Cmode |Establish MA |UpMA_Estab ------------------------+-------------------------+------------ Tsenov, et al. Expires May 11, 2005 [Page 18] Internet-Draft GIMPS State Machine November 2004 ----------------- State: UpMA_Estab (Upstream MA Established) ----------------- Condition Action State ------------------------+-------------------------+------------ rx_Confirm_Cmode |Refresh MA |UpMA_Estab ------------------------+-------------------------+------------ Tsenov, et al. Expires May 11, 2005 [Page 19] Internet-Draft GIMPS State Machine November 2004 10. Security Considerations This document does not raise new security considerations. Any security concerns with GIMPS are likely reflected in security related NSIS work already (such as [1] or [6]). For the time being, the state machines described in this document do not consider the security aspect of GMIPS protocol itself. A future versions of this document will add security relevant states and state transitions. Tsenov, et al. Expires May 11, 2005 [Page 20] Internet-Draft GIMPS State Machine November 2004 11. Open Issues At this stage, normal GIMPS messages that carry NSLP data are not presented for all states. A default rules for handling of such messages at any "ESTABLISHED STATE" is provided. Messages exchanged through NSLP/GIMPS API and Refresh state messages are not completely described, too. These issues needs further consideration in the future version of the document. Route change and local repair need further consideration. Refreshment of Messaging Association (MA) state is currently not elaborated in the document (according to current GIMPS spec, there can be an idle timer but tearing down a MA can depend on a node's local policy). State machine represents handling of GIMPS messages that match the node address and NSLPID for the given flow. Bypass handling is left for future version of the document. There are further unclear issues with processing rules and message definition, e.g., soft state handling for both RS and MA states (and their combinations), which will be described in more detail in a future version of this document. Tsenov, et al. Expires May 11, 2005 [Page 21] Internet-Draft GIMPS State Machine November 2004 12. Acknowledgments The authors would like to thank Andreas Westermaier and Alex Zrim for helpful discussions with them. Tsenov, et al. Expires May 11, 2005 [Page 22] Internet-Draft GIMPS State Machine November 2004 13. References 13.1 Normative References [1] Schulzrinne, H., "GIMPS: General Internet Messaging Protocol for Signaling", draft-ietf-nsis-ntlp-04 (work in progress), October 2004. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", 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", draft-ietf-eap-statemachine-05 (work in progress), September 2004. [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/D9, January 2004. [5] Ohba, Y., "State Machines for Protocol for Carrying Authentication for Network Access (PANA)", draft-ohba-pana-statemachine-00 (work in progress), July 2004. [6] Tschofenig, H. and D. Kroeselberg, "Security Threats for NSIS", draft-ietf-nsis-threats-06 (work in progress), October 2004. Authors' Addresses Tseno Tsenov Siemens Otto-Hahn-Ring 6 Munich, Bayern 81739 Germany EMail: tseno.tsenov@mytum.de Tsenov, et al. Expires May 11, 2005 [Page 23] Internet-Draft GIMPS State Machine November 2004 Hannes Tschofenig Siemens Otto-Hahn-Ring 6 Munich, Bayern 81739 Germany EMail: Hannes.Tschofenig@siemens.com Xiaoming Fu University of Goettingen Telematics Group Lotzestr. 16-18 Goettingen 37083 Germany EMail: fu@cs.uni-goettingen.de Ingo Juchem University of Goettingen Telematics Group Lotzestr. 16-18 Goettingen 37083 Germany EMail: ijuchem@cs.uni-goettingen.de Tsenov, et al. Expires May 11, 2005 [Page 24] Internet-Draft GIMPS State Machine November 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Tsenov, et al. Expires May 11, 2005 [Page 25]