WSReliability Demonstration

1
WS-Reliability Demonstration

• Showing that it works
• December 9, 2003

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Rationale for WS-Reliability

• Web Services increasing being utilized for
  operations that require transactional integrity.
• Unpredictable delay and multiple paths create
  havoc in complex applications with needs for
  coherent transmission of multiple messages.
• Thus, a normative mechanism that supports mission
  critical Web Services applications

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WS-Reliability Primary Features

• Guaranteed Delivery
• Messages are persisted at sender until
  responsibility for message has been transferred
  to receiver.
• Duplicate Elimination
• Duplicates caused by re-tries (or lost
  acknowledgements) are eliminated
• Message Ordering and Grouping
• Association of multiple messages into an ordered
  sequence. Guaranteed application receipt in
  correct order

4
The Standards Challenge

• Spec reads well, but
• does it work?
• Is it vague?
• How difficult to implement?
• What is unspecified that should be?
• My code works fine on localhost, but what about
  inter-operating with others?

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Interoperability Demo Purpose

• Test interoperability in a mixed-vendor
  environment.
• Gain implementation experience.
• Feedback that experience to the technical
  committee.
• Promote the standard and demonstrate usefulness

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Sender States
Prepare Request
AckTimeout
Prep Request Resent
Wait For Reply
DupofHeldMsgFault
ResendRequest
MsgExpiryFault
DupofDlvdMsgFault
SendTimeout
ReceiveAck
Delete Sent Msg
Prep Failure Notify
FailureReported
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Receiver States
AckOnlyRequest
Receive from Transport
Checking Expiry Time
Prior dlvy notified
DupElimRequest
Held waiting for Prior
nonDupNoOrder
Prior not dlvd
Prior dlvd
Expired
Checking Order
Deliver Msg
Checking for Duplicate
Non Dup Ordered
Prepare Expiry Fault
Dup of Dlvd Msg
Dup of held Msg
Prepare Ack
Prepare Dup of Held Fault
Prepare Dup of Delivered Fault
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Demo Configuration
Sender Test App
Receiver Test App
RMP2
RMP1
(WS-R node)

• Network
• trouble maker
• Message loss
• Message duplicates
• Message dis-ordering
• Ack loss

(WS-R node)
9
First Reliable Bank

• Bank requires that no account is permitted to
  have a negative balance at any time.
• Transfers are a withdrawal from one account
  followed by a deposit to another.

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Demo Scenarios
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Guaranteed Delivery

• Troublemaker sent to block all traffic
• Sender sends and continues to re-try
• Troublemaker allows message to pass
• Sender receives acknowledgement and deletes
  message

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Duplicate Elimination
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Demo Results

• Demonstrable interoperability after 36 hours of
  test