MS-RDPEDYC Server Test Design Specification

Contents

• Technical Document Analysis
  • Technical Document Overview
  • Relationship to Other Protocols
  • Protocol Operations/Messages
  • Protocol Properties
• Test Method
  • Assumptions, Scope and Constraints
  • Test Approach
  • Test Scenarios
    • S1_EDYCBasicTest
• Test Suite Design
  • Test Suite Architecture
    • System under Test (SUT)
    • Test Suite Architecture
  • Technical Dependencies/Considerations
    • Dependencies
    • Technical Difficulties
    • Encryption Consideration
  • Adapter Design
    • Adapter Overview
    • Technical Feasibility of Adapter Approach
    • Adapter Abstract Level
• Test Cases Design
  • Traditional Test Case Design
  • Test Cases Description
    • S1_MultitransportConnectionInitiation
• Appendix
  • Glossary
  • Reference

Technical Document Analysis

Technical Document Overview

The Remote Desktop Protocol: Dynamic Channel Virtual Channel Extension, which supports features such as classes of priority (that may be used to implement bandwidth allocation) and individually connected endpoints using dynamic virtual channel (DVC) listeners.

Relationship to Other Protocols

The Remote Desktop Protocol: Multitransport Extension operates over the RDP-UDP protocol, as defined in [MS-RDPEUDP] section 1, 2, and 3. Protocol traffic is secured by using Transport Layer Security (TLS) ([RFC2246], [RFC4346] and [RFC5246]) for reliable RDP-UDP streams and Datagram Transport Layer Security (DTLS) ([RFC4347]) for unreliable (lossy) RDP-UDP streams. The TLS or DTLS handshake, as well as the encrypted payload, are embedded in the RDPUDP_SOURCE_PAYLOAD_HEADER as defined in [MS-RDPEUDP]. A multitransport connection is initiated by an RDP server sending the Initiate Multitransport Request PDU ([MS-RDPBCGR] section 2.2.1.15.1) to an RDP client over the main RDP connection.

Protocol Operations/Messages

There are 14 protocol data units (PDUs) described by [MS-RDPEDYC] protocol, and they can be classified into the following message flows:

| -------------| ------------- | | Message Flows | Number of PDUs| | DVC Capabilities Exchange| 4| | Open DVC| 2| | Send and receive DVC data| 4| | Close DVC| 1| | Soft-sync| 3|

The following sequence diagram presents an overview of these messages and protocols.

The open dvc, send and receive data, close dvc message flows are defined in [MS-RDPEDYC]. The Connection Sequence is described in following figure (Figure 1-2, 1-3, 1-4 and 1-5). All message exchanges in this diagram are strictly sequential, except where noted in the text that follows.

Figure 1-1: MS-RDPEDYC open DVC message Sequence

Figure 1-2: MS-RDPEDYC open DVC message Sequence

Figure 1-3: MS-RDPEDYC send and receive data message Sequence

Figure 1-4: MS-RDPEDYC close DVC message Sequence

Protocol Properties

• Remote Desktop Protocol: Dynamic Virtual Channel Extension messages are passed between a DVC manager on a server and a DVC manager on a client, and are transmitted over one of the following underlying transport mechanisms:
• A static virtual channel ([MS-RDPBCGR] sections 1.3.3 and 2.2.6), where the name of the channel is the ANSI character string "DRDYNVC" and bulk compression is enabled.
• A lossy or reliable UDP multitransport connection ([MS-RDPEMT] sections 1.3 and 2.2.2.3).
• The Remote Desktop Protocol: Dynamic Virtual Channel Extension does not establish any transport connections.

Test Method

Assumptions, Scope and Constraints

Assumptions:

• The RDP server machine should be configurable; in order to test some specific features or requirements, the test suite will try to trigger the server to act with specific configuration settings, such as capability set support.

Scope:

• The protocol server endpoint (RDP server) playing the server role will be tested. For Windows, the Remote Desktop Service (TermService) is the server endpoint.
• The protocol client endpoint (RDP client) playing the client role is out of scope.
• For Windows, the System Under Test (SUT) will be both Server SKUs and Client SKUs.
• External protocols are out of scope.

Constraint: There is no constraint for this Test Suite.

Test Approach

Traditional testing is chosen as the test approach in MS-RDPEDYC.

Reasons for choosing Traditional Testing

• The protocol is not completely stateful.

• The logic of this protocol is simple.

• For [MS-RDPBCGR], only 14 out of 50 PDUs in the connection/disconnection sequences are sent sequentially.

• For this protocol, all PDUs in the connection/disconnection sequences are sent sequentially.

• The combinations of parameters are not complex. Capability sets are the exception, which will be addressed through the use of configuration files.

Test Scenarios

Scenario	Priority	Test Approach	Description
S1_EDYCBasicTest	0	Traditional	This scenario is used to Verify MS-RDPEDYC open channel, send and receive data, close channel and soft-sync PDUs

Table 1 Test Suite Scenarios

S1_EDYCBasicTest

Preconditions:

MS-RDPBCGR connection is setup.

RDPServer supports EDYC.

Typical Sequence:

The typical scenario sequence is as follows:

• The client and server build an RDPBCGR connection to the server.

• The server sends DVC Capability exchange request and gets client response.

• The server sends create DVC channel request and gets client response.

• The client sends DVC data (compressed/uncompressed) to server and gets response.

• The server sends DVC close channel request and close the channel.

Test Suite Design

Test Suite Architecture

System under Test (SUT)

• From the third party point of view, the SUT is a component that implements MS-RDPEDYC Server.
• From the Windows implementation point of view, the SUT is the Remote Desktop Service (TermService).

Test Suite Architecture

Figure 1 illustrates the architecture of the MS-RDPEDYC test suite for server endpoint testing.

Figure 1 RDP Server Test Suite Architecture

Technical Dependencies/Considerations

Dependencies

There are no dependencies.

Technical Difficulties

There are no technical difficulties.

Encryption Consideration

• When using the RDP standard security mechanism, MS-RDPBCGR messages are encrypted; however, you can turn off server-side encryption by setting the encryption level to low.

• When using external security protocols, such as TLS and CredSSP, the MS-RDPBCGR transport is encrypted; this encryption cannot be turned off.

• The MS-RDPEDYC messages are encrypted by selected underlying transport protocol TLS or DTLS.

Adapter Design

Adapter Overview

The MS-RDPEDYC Server Test Suite implements a protocol adapter. The protocol adapter is used to receive messages from the SUT and to send messages to the SUT. The protocol adapter is built upon the protocol test suite library, which is implemented with managed code.

Technical Feasibility of Adapter Approach

The protocol adapter uses the protocol SDK library to generate protocol messages, which are sent to SUT. The protocol adapter uses the protocol test suite library to consume protocol messages which are received from the SUT. The MS-RDPBCGR and MS-RDPEDYC SDK libraries will parse and decode the received messages and send them to protocol adapter.

Adapter Abstract Level

Protocol Adapter

Protocol adapter defined tens of interfaces. These interfaces can be summarized as following:

• Send Message interfaces
  • Send interface for each client-to-server message.
• Receive Message events
  • Receive event for each server-to-client message.
• Other interfaces
  • StartMultitransportConnect: Establish the underlying multitransport connection with SUT
  • Disconnect: Disconnect all underlying multitransport connection with SUT.

Test Cases Design

Traditional Test Case Design

The Traditional test approach is used to design all test cases. The following table shows the number of test cases for each scenario.

Scenario	Test cases	BVT	P0	P1
S1_EDYCBasicTest	3	1	1	2

Test Cases Description

The test suite is a synthetic RDP client. In the following descriptions, all instances of the term “Test Suite” can be understood as the RDP client.

Common prerequisites for all test cases:

• The RDP service is started and listening the service port which serves as the RDP server.

• The test suite knows the IP address and port number on which RDP server is listening.

• The RDP server supports the dynamic virtual channel.

Common cleanup requirements:

• The test suite disconnects all RDP connections if any.

• The SUT deletes all data caches from previous RDP connections.

The common prerequisites and cleanup requirements are not listed in any of the test cases. Only prerequisites and cleanup requirements unique to the test case are listed in the corresponding test case descriptions.

S1_EDYC_CreateAndCloseChannel

S1_EDYCBasicTest
Test ID	S1_EDYC_CreateAndCloseChannel
Priority	P0
Description	This test case is used to verify SUT can create and close DVC channel.
Prerequisites	RDPBCGR connection is setup
Test Execution Steps	Initiate and complete an RDP connection to RDP Server (SUT).
	RDP Server sends Capability exchange pdu
	RDP Server requests to create DVC channel
	RDP Server requests to close DVC channel
Cleanup	N/A

S1_EDYC_SendCompressedDataSequence

S1_EDYCBasicTest
Test ID	S1_EDYC_SendCompressedDataSequence
Priority	P0
Description	This test case is used to verify SUT can create and close DVC channel.
Prerequisites	RDPBCGR connection is setup
Test Execution Steps	Initiate and complete an RDP connection to RDP Server (SUT).
	RDP Server sends Capability exchange pdu
	RDP Server requests to create DVC channel
	RDP Client sends data to server and expect response
	RDP Server requests to close DVC channel
Cleanup	N/A

S1_EDYC_SendUncompressedData

S1_EDYCBasicTest
Test ID	S1_EDYC_SendUncompressedData
Priority	P1
Description	This test case is used to verify SUT can process DYNVC_DATA data.
Prerequisites	RDPBCGR connection is setup
Test Execution Steps	Initiate and complete an RDP connection to RDP Server (SUT).
	RDP Server sends Capability exchange pdu
	RDP Server requests to create DVC channel
	RDP Client sends uncompressed DYNVC_Data PDU to server
	RDP Server requests to close DVC channel
Cleanup	N/A

Appendix

Glossary

SUT: System under Test. In this spec, it’ indicates the MS-RDPEDYC server implementation. Test Suite: The synthetic RDP client which is used to test against SUT.

Reference

• Technical Document: [MS-RDPEDYC].pdf