NSIS T. Tsenov
Internet-Draft H. Tschofenig
Intended status: Informational Nokia Siemens Networks
Expires: May 06, 2009 X. Fu
Univ. Goettingen
C. Aoun
E. Davies
Folly Consulting
November 02, 2008
GIST State Machine
draft-ietf-nsis-ntlp-statemachine-06.txt
Status of this Memo
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 becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
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 06, 2009.
Abstract
This document describes the state machines for the General Internet
Signaling Transport (GIST). The states of GIST nodes for a given flow
and their transitions are presented in order to illustrate how GIST
may be implemented.
Tsenov, et al. Expires May 06, 2009 [Page 1]
Internet-Draft GIST State Machine November 2008
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 . . . . . . . . . . . . . . . . . . . . . . . . 6
5.1 Common Procedures . . . . . . . . . . . . . . . . . . . . 7
5.2 Common Variables . . . . . . . . . . . . . . . . . . . . . 9
6. State machines . . . . . . . . . . . . . . . . . . . . . . . 10
6.1 Diagram notations . . . . . . . . . . . . . . . . . . . . 10
6.2 State machine for GIST querying node . . . . . . . . . . . 11
6.3 State machine for GIST responding node . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . 13
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1 Normative References . . . . . . . . . . . . . . . . . . 14
10.2 Informative References . . . . . . . . . . . . . . . . . 14
Appendix A. ASCII versions of the state diagrams . . . . . . . . 15
A.1 State machine for GIST querying node (Figure 2) . . . . 15
A.2 State Machine for GIST responding node (Figure 3) . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 21
Intellectual Property and Copyright Statements . . . . . . . 22
Tsenov, et al. Expires May 06, 2009 [Page 2]
Internet-Draft GIST State Machine November 2008
1. Introduction
The state machines described in this document are illustrative of how
the GIST protocol defined in [1] may be implemented for the GIST
nodes in different locations of a flow path. Where there are
differences - [1] is authoritative. The state machines are
informative only. Implementations may achieve the same results using
different methods.
There are two types of possible entities for GIST signaling:
- GIST querying node - GIST node that initiates the discovery of the
next peer;
- GIST responding node - GIST node that is the discovered next peer;
We describe a set of state machines for these entities to illustrate
how GIST may be implemented.
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,
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
Tsenov, et al. Expires May 06, 2009 [Page 3]
Internet-Draft GIST State Machine November 2008
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
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
Tsenov, et al. Expires May 06, 2009 [Page 4]
Internet-Draft GIST State Machine November 2008
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 }
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.
Tsenov, et al. Expires May 06, 2009 [Page 5]
Internet-Draft GIST State Machine November 2008
>
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.
5. Common Rules
Throughout the document we use terms defined in the [1], such as
Query, Response, Confirm.
State machine represents handling of GIST messages that match a
Message Routing State's MRI, NSLPID and SID and with no protocol
errors. Separate parallel instances of the state machines should
handle messages for different Message Routing States.
The state machine states represent the upstream/downstream peers
states of the Message Routing State.
For simplification not all objects included in a message are shown.
Only those that are significant for the case are shown. State
machines do not present handling of messages that are not significant
for management of the states.
Presented in this document state machines do not cover all functions
of a GIST node. Functionality of message forwarding, transmission of
NSLP data without MRS establishment and providing of the received
messages to the appropriate MRS, we refer as "Lower level pre-
processing" step. Pre-processing provides to the appropriate MRS FSM
only the messages which are matched against waiting Query/Response
cookies, or established MRS MRI+NSLPID+SID primary key. This is
presented by "rx_*" events in the state machines.
Management of a MA is considered in the document (e.g.,
tg_Establish_MA, tg_MA_established events), but its FSM is not
Tsenov, et al. Expires May 06, 2009 [Page 6]
Internet-Draft GIST State Machine November 2008
explicitly presented.
5.1 Common Procedures
Tg_SendMsg:
NSLP/GIST API message that request transmission of a NSLP message.
Tg_SetStateLifetime(time_period):
NSLP/GIST 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_MessageStatus:
NSLP/GIST API message informing NSLP application of unsuccessful
delivery of a message
Tg_RecvMsg:
NSLP/GIST API message that provides received message to the NSLP
Tg_NetworkNotification:
NSLP/GIST API message that informs NSLP for change in MRS
Tx_Query:
Transmit of Query message
Tx_Response:
Transmit of Response message
Tx_Confirm:
Transmit of Confirm message
Rx_Query:
Receive of Query message
Rx_Response:
Receive of Response message
Rx_Confirm:
Receive of Confirm message
Tx_Error:
Transmit of Error message
Rx_Error:
Receive of Error message
Queue NSLP info:
Save NLSP messages in a queue until a required MA association is
Tsenov, et al. Expires May 06, 2009 [Page 7]
Internet-Draft GIST State Machine November 2008
established
Tx_Data:
Transmit of Data message
Rx_Data:
Receive of Data message
T_Inactive_QNode:
Message Routing State lifetime timer in Querying Node
T_Expired_RNode:
Message Routing State lifetime timer in Responding Node
T_Refresh_QNode:
Message Routing State refresh timer in Querying Node
T_No_Response:
Timer for the waiting period for Response message in Querying Node
T_No_Confirm:
Timer for the waiting period for Confirm message in Responding
Node
Install downstream/upstream MRS:
Install new Message Routing State and save the corespoding peer
state info (IP address and UDP port or pointer to the used MA) for
the current Message Routing State or update the coresponding peer
state info.
DELETE MRS:
Delete installed downstream/upstream peer's info for the current
Message Routing State and delete the Message Routing State if
required.
Established MA:
A Message Association (MA) is established between the current node
and its upstream peer. The initiator for the establishment is the
upstream peer.
Re-use existing MA:
An existing MA between the current node and its peer is re-used.
DELETE MA:
Delete/disconnect used MA.
Stop using shared MA:
Stop using shared MA. If the shared MA is no more used by any
Tsenov, et al. Expires May 06, 2009 [Page 8]
Internet-Draft GIST State Machine November 2008
other MRSs, it depends on the local policy whether it is deleted
or kept.
REFRESH MRS:
Refreshes installed MRS.
Tg_MA_Error:
Error event with used MA.
Tg_InvalidRoutingState:
Notification from NSLP application for path change
Tg_Establish_MA:
Trigers establishment of MA.
Tg_MA_Established:
MA has been successfully established.
Tg_ERROR:
General Error event / system level error.
No_MRS_Installed:
Error response, send by the Responding node indicating lost
Confirm message.
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 GIST policy)is
provided. This is represented by the common variables Dmode, Cmode,
MAinfo, MApresent and Refresh.
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]
Dmode:
The message MUST be transmitted in Dmode. This is specified by
local policy rules and in case that the "Message transfer
attributes" are not set to any of the following values:
Tsenov, et al. Expires May 06, 2009 [Page 9]
Internet-Draft GIST State Machine November 2008
"Reliability" is set to TRUE.
"Security" is set to values that request special security handling
of a message.
"Local processing" is set to values that require services offered
by Cmode [1]
MAinfo:
GIST message parameters describing the required MA or proposed MA
e.g. "Stack-proposal" and "Stack-Configuration-Data".
NSLPdata:
NSLP application data.
RespCookie:
Responder Cookie that is being sent by the Responding node with
the Response message in case that its local policy requires a
confirmation from the querying node.
ConfirmRequired:
Confirm message is required by the local policy rule for
installation of the new MRS.
NewPeer:
Response message is received from new responding peer.
MAexist:
Existing MA will be reused.
CheckPeerInfo:
The sender of the received data message is matched against the
installed peer info in the MRS.
UpstreamPeerInstalled:
Upstream peer info is installed in the MRS.
6. State machines
The following section presents the state machine diagrams of GIST
peers.
6.1 Diagram notations
(see the .pdf version for missing diagram or
refer to Appendix A if reading the .txt version)
Tsenov, et al. Expires May 06, 2009 [Page 10]
Internet-Draft GIST State Machine November 2008
Figure 1: Diagram notations
6.2 State machine for GIST querying node
The following is a diagram of the GIST querying node state machine.
Also included is clarification of notation.
(see the .pdf version for missing diagram or
refer to Appendix A.1 if reading the .txt version)
Figure 1: GIST Querying Node State Machine
*) Response and Comfirm messages might be send either in Dmode or
Cmode, before or after MA establishment depending on node s local
3-way handshake policy and the availability of MAs to be reused.
See draft for details.
**) Depending on the local policy NSLPdata might be send as payload
of Query and Confirm messages. (piggybacking)
1) Initial request from NSLP is received, which triggers Query
messages requesting either D_mode or C_mode. Depending on node s
local policy NSLP data might be piggybacked in the Query
requesting D_mode. Query may carry Mainfo if C_mode transport is
needed.
2) Response message is received. If C_mode connection must be
established and there is no available MA to be reused, MA
establishment is initiated and waited to be completed.
3) Response message is received. If D_mode connection is requested or
available MA can be reused for requested C_mode, the MRS is
established.
4) No_Response timer expires. Query is resent.
5) No_Response timer expires and maximum number of retries has been
reached. NSLP application is notified for the GIST peer discovery
failure.
6) NSLP data is queued, because downstream peer is not discovered or
required MA is still not established.
7) Data message is received. It is checked if its sender matches the
installed downstream peer info in the MRS and then processed. In
WaitResponse state, this event might happen in the process of MA
upgrade, when the downstream peer is still not aware of
establishment of the new MA.
8) Provided NSLP data is sent via Data message towards downstream
GIST peer.
9) Refresh_QNode timer expires. Query message is sent.
10) Response message from the downstream GIST peer is received. The
peer is not changed. MRS is refreshed (Refresh_QNode timer is
restarted).
11) Path change detected. Response message from a new downstream GIST
peer is received. D_mode is requested or existing MA can be reused
Tsenov, et al. Expires May 06, 2009 [Page 11]
Internet-Draft GIST State Machine November 2008
for requested C_mode.
12) Path change detected. Response message from a new downstream GIST
peer is received. A new MA must be established for requested
C_mode.
13) Requested by NSLP application transport parameters requires
upgrade of established MRS from D_mode/C_mode to C_mode. NSLP
application notifies GIST for path change. Downstream GIST peer
discovery is initiated.
14) Sent Confirm message has not been received by downstream GIST
peer. Confirm message is resent.
15) MRS lifetime expires. Notification by NSLP application that MRS
is no longer needed.
16) MA is established.
17) MA establishment failure.
6.3 State machine for GIST responding node
The following is a diagram of the GIST responding node state machine.
Also included is clarification of notation.
(see the .pdf version for missing diagram or
refer to Appendix A.2 if reading the .txt version)
Figure 3: GIST Responding Node State Machine
1) A Query message is received. Explicit Confirm message is required
for MRS installation, based on the local policy. Query message
might carry piggybacked NSLP data which is provided to the NSLP
application.
2) A Query message is received. MRS is installed immediately, based
on the local policy. Query message might carry piggybacked NSLP
data which is provided to the NSLP application.
3) Confirm message is received which causes installation of the
complete MRS or just installation of the used MA as a upstream
peer info.
4) Sent Response message has not been received by upstream GIST peer.
Response message is resent.
5) In case of lost Confirm message, data messages might be received
from the upstream GIST node (it is unaware of the lost Confirm
message). Response indicating the loss of the Confirm is sent back
to the upstream GIST node.
6) No_Confirm timer expires. Note that all cases of lost handshake
GIST messages are handled only by GIST querying node via resend of
Query message.
7) NSLP data is sent if discovery process is successfully
accomplished or is queued if Confirm message is still expected to
confirm establishment of MA.
8) Data messages are accepted only if complete MRS is installed,
Tsenov, et al. Expires May 06, 2009 [Page 12]
Internet-Draft GIST State Machine November 2008
e.g., there is installed upstream peer info. If not, then Confirm
message is expected and data message won t be accepted. Response
indicating the loss of the Confirm is sent back to the upstream
GIST node.
9) Change of the upstream GIST node (e.g., path change). Local policy
does not need explicit Confirm message for MRS installation. MRS
data is updated.
10) Change of the upstream GIST node or request for change of the
used connection mode (from D_mode/C_mode to better C_mode). Local
policy requires explicit Confirm message for MRS installation.
11) Request for change of the used connection mode (from
D_mode/C_mode to better C_mode). Local policy does not need
explicit Confirm message for MRS installation. MRS data is
updated.
12) MRS lifetime expires. Notification by NSLP application that MRS
is no longer needed.
7. Security Considerations
This document does not raise new security considerations. Any
security concerns with GIST are likely reflected in security related
NSIS work already (such as [1] or [6]).
8. Contributors
Christian Dickmann contributed to refining of the state machine since
01 version.
9. Acknowledgments
The authors would like to thank Robert Hancock, Ingo Juchem, Andreas
Westermaier, Alexander Zrim, Julien Abeille Youssef Abidi and Bernd
Schloer for their insightful comments.
Tsenov, et al. Expires May 06, 2009 [Page 13]
Internet-Draft GIST State Machine November 2008
10. References
10.1. Normative References
[1] Schulzrinne, H., "GIST: General Internet Signaling
Transport", draft-ietf-nsis-ntlp-16 (work in progress),
July 2008.
[2] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
10.2. Informative References
[3] Vollbrecht, J., Eronen, P., Petroni, N., and Y. Ohba,
"State Machines for Extensible Authentication Protocol
(EAP) Peer and Authenticator", RFC4137, August 2005.
[4] Institute of Electrical and Electronics Engineers,
"Standard for Local and Metropolitan Area Networks: Port-
Based
Network Access Control", IEEE 802-1X-2004, December
2004.
[5] Fajardo, V., Ohba, Y. and R. Lopez, "State Machines for
Protocol for Carrying Authentication for Network Access
(PANA)",
draft-ietf-pana-statemachine-07 (work in progress),
April 2008.
[6] Tschofenig, H. and D. Kroeselberg, "Security Threats for
NSIS", RFC 4081, June 2005.
Tsenov, et al. Expires May 06, 2009 [Page 14]
Internet-Draft GIST State Machine November 2008
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.
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 machine for GIST querying node (Figure 2)
-----------
State: IDLE
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
tg_SendMsg |tx_Query |Wait |1)
|start T_No_Response |Response |**
|Queue NSLP data | |
| | |
Tg_ERROR |Delete MRS |IDLE |
|IF (MA is used) | |
| ((Delete MA)|| | |
| (Stop using shared MA))| |
|Tg_NetworkNotification | |
| | |
------------------------+-------------------------+-----------+---
-----------
State: WaitResponse
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
rx_Response(MAinfo)&& |tg_Establish_MA |Wait MA |*
(!MAexist) |(tx_Confirm) |Establish. |2)
| | |
| | |
rx_Response)|| |Install MRS |Established|3)
(rx_Response(MAinfo)&& |IF (RespCookie) |Downstream |
(MAexist)) | tx_Confirm(RespCookie)|MRS |
|tx_Data(Queued NSLP data)| |
| | |
Tsenov, et al. Expires May 06, 2009 [Page 15]
Internet-Draft GIST State Machine November 2008
(timeout T_No_Response) |Tx_Query |Wait |4)
&&(!MaxRetry) |restart T_No_Response |Response |
| | |
(timeout T_No_Response) |tg_MessageStatus |IDLE |5)
&&(MaxRetry) | | |
| | |
tg_SendMsg |Queue NSLP data |Wait |6)
| |Response |
| | |
rx_Data |IF(CheckPeerInfo) |Wait |7)
| tg_RecvMsg to Appl.|Response |
| | |
Tg_ERROR |(Delete MRS) |IDLE |
|IF (MA is used) | |
| ((Delete MA)|| | |
| (Stop using shared MA))| |
|Tg_NetworkNotification | |
| | |
------------------------+-------------------------+-----------+---
-----------
State: Established Downstream MRS
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
tg_SendMsg |tx_Data |Established|8)
|restart T_Inactive_QNode |Downstream |
| |MRS |
| | |
timeout T_Refresh_QNode |tx_Query |Established|9)
| |Downstream |
| |MRS |
| | |
(rx_Response)&& |Refresh MRS |Established|10)
(!NewPeer) |restart T_Inactive_QNode |Downstream |
| |MRS |
| | |
(rx_Response)|| |IF (MA is used) |Established|11)
(rx_Response(Mainfo)&& | (Delete MA)|| |Downstream |
(MAexist)))&&(NewPeer) | (Stop using shared MA)|MRS |
|Install MRS | |
|restart T_Inactive_QNode | |
|IF (RespCookie) | |
Tsenov, et al. Expires May 06, 2009 [Page 16]
Internet-Draft GIST State Machine November 2008
| tx_Confirm(RespCookie)| |
| | |
(rx_Response(MAinfo)&& |((Delete MA)|| |Wait MA |12)
(NewPeer)&&(!MA_exist)) |(Stop using shared MA)) |Establish. |*
|tg_Establish_MA | |
|(tx_Confirm) | |
| | |
((tg_SendMsg)&&(Cmode)&&|tx_Query |Wait |13)
(!MAexist))|| |Queue NSLP data |Response |
(tg_MA_error)|| | | |
(tg_InvalidRoutingState)| | |
| | |
rx_Response(No_MRS_ |tx_Confirm(RespCookie) |Established|14)
installed)|tx_Data(Queued NSLP data)|Downstream |
| |MRS |
| | |
(timeout T_Inactive_ |Delete MRS |IDLE |15)
QNode)|||IF (MA is used) | |
(tg_SetStateLifetime(0))| (Delete MA)|| | |
| (Stop using shared MA)| |
|Tg_NetworkNotification | |
| | |
rx_Data |IF(CheckPeerInfo) |Established|7)
| tg_RecvMsg to Appl.|Downstream |
| |MRS |
| | |
Tg_ERROR |(Delete MRS) |IDLE |
|IF (MA is used) | |
| ((Delete MA)|| | |
| (Stop using shared MA))| |
|Tg_NetworkNotification | |
| | |
------------------------+-------------------------+-----------+---
-----------
State: Wait MA Establishment
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
tg_MA_Established |Install MRS |Established|16)
|(tx_Confirm) |Downstream |*
|tx_Data(Queued NSLP data)|MRS |
| | |
tg_MA_error |Delete MRS |IDLE |17)
|tg_MessageStatus | |
Tsenov, et al. Expires May 06, 2009 [Page 17]
Internet-Draft GIST State Machine November 2008
| | |
tg_SendMsg |Queue NSLP data |Wait MA |6)
| |Establish. |
| | |
Tg_ERROR |Delete MRS |IDLE |
|IF (MA is used) | |
| ((Delete MA)|| | |
| (Stop using shared MA))| |
|Tg_NetworkNotification | |
| | |
------------------------+-------------------------+-----------+---
Figure 4
A.2. State Machine for GIST responding node (Figure 3)
-----------
State: IDLE
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
rx_Query&& |tx_Response |Wait |1)
(ConfirmRequired) |start T_No_Confirm |Confirm |
|IF(NSLPdata) | |
| tg_RecvMsg(NSLPdata)| |
| to Appl.| |
| | |
rx_Query&& |tx_Response |Established|2)
(!ConfirmRequired) |Install MRS |Upstream |
|IF(NSLPdata) |MRS |
| tg_RecvMsg(NSLPdata)| |
| to Appl.| |
| | |
------------------------+-------------------------+-----------+---
-----------
State: WAIT CONFIRM
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
rx_Confirm |Install Upstream MRS |Established|3)
| |Upstream |
| |MRS |
| | |
Tsenov, et al. Expires May 06, 2009 [Page 18]
Internet-Draft GIST State Machine November 2008
rx_Query&& |tx_Response |Wait |4)
(ConfirmRequired) |start T_No_Confirm |Confirm |
|IF(NSLPdata) | |
| tg_RecvMsg(NSLPdata)| |
| to Appl.| |
| | |
rx_Data |tx_Error(No_MRS_ |Wait |5)
| installed)|Confirm |
| | |
timeout T_No_Confirm | |IDLE |6)
| | |
------------------------+-------------------------+-----------+---
-----------
State: Established Upstream MRS
-----------
Condition Action State Note
------------------------+-------------------------+-----------+---
tg_SendMsg |IF(!UpstreamPeerInfo) |Established|7)
| Queue NSLP data |Upstream |
|ELSE tx_Data |MRS |
| | |
rx_Data |IF(UpstreamPeerInfo) |Established|8)
| (tg_RecvMsg to Appl.)|Upstream |
| &&(restart_T_Expire_ |MRS |
| RNode)| |
|ELSE | |
| tx_Error(No_MRS_ | |
| installed)| |
| | |
rx_Query |IF (NewPeer) |Established|9)
| Update UpstreamPeerInfo|Upstream |
|tx_Response |MRS |
|restart T_Expire_RNode | |
| | |
(rx_Query)&& |Delete MRS |Wait |
(ConfirmRequired) |tx_Response |Confirm |
|start T_No_Confirm | |
|IF(MA is used) | |
| (Delete MA)|| | |
| (Stop using shared MA)| |
|IF(NSLPdata) | |
| tg_RecvMsg(NSLPdata) | |
| to Appl.| |
| | |
Tsenov, et al. Expires May 06, 2009 [Page 19]
Internet-Draft GIST State Machine November 2008
rx_Query(MAinfo)&& |Delete UpstreamPeerInfo |Established|11)
(!ConfirmRequired) |restart T_Expire_RNode |Upstream |
|tx_Response(MAinfo) |MRS |
| | |
(timeout T_Expire_RNode)|Delete MRS |IDLE |12)
|| |tg_NetworkNotification | |
(tg_SetStateLifetime(0))|IF(MA is used) | |
| (Delete MA)|| | |
| (Stop using shared MA)| |
| | |
rx_Confirm |Install UpstreamPeerInfo |Established|3)
|tx_Data(queued_NSLP_data)|Upstream |
| |MRS |
| | |
Tg_ERROR |(Delete MRS) |IDLE |
|IF (MA is used) | |
| ((Delete MA)|| | |
| (Stop using shared MA))| |
|Tg_NetworkNotification | |
| | |
------------------------+-------------------------+-----------+---
Figure 5
Tsenov, et al. Expires May 06, 2009 [Page 20]
Internet-Draft GIST State Machine November 2008
Authors' Addresses
Tseno Tsenov
Sofia,
Bulgaria
Email: tseno.tsenov@mytum.de
Hannes Tschofenig
Nokia Siemens Networks
Linnoitustie 6
Espoo 02600
Finland
Email: Hannes.Tschofenig@nsn.com
Xiaoming Fu
University of Goettingen
Computer Networks Group
Goldschmidtstr. 7
Goettingen 37077
Germany
Email: fu@cs.uni-goettingen.de
Cedric Aoun
Paris
France
Email: cedric@caoun.net
Elwyn B. Davies
Folly Consulting
Soham, Cambs
UK
Phone: +44 7889 488 335
Email: elwynd@dial.pipex.com
Tsenov, et al. Expires May 06, 2009 [Page 21]
Internet-Draft GIST State Machine November 2008
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
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.
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, THE IETF TRUST 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.
Intellectual Property
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. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Tsenov, et al. Expires May 06, 2009 [Page 22]
