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1722.1 Enumeration & Connection Management presented by Chris Pane. Intent. Present a straw man vision of how an AVB stream enumeration and connection protocol could work for 1722.1. Present vision from a top down, end to end point of view. Details will follow. Definitions. - PowerPoint PPT Presentation
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1722.1 F2F April 7, 2010 1
1722.1 Enumeration & Connection Management
presented by Chris Pane
1722.1 F2F April 7, 2010 2
Intent
Present a straw man vision of how an AVB stream enumeration and connection protocol could work for 1722.1.
Present vision from a top down, end to end point of view. Details will follow.
1722.1 F2F April 7, 2010 3
Definitions
Controller – An entity on the network that provides runtime stream allocation and connection requests.
AMP – AVB Management Protocol Channel - Media Content Node – Element in the property tree that
represents a hierarchical level. Property – A settable entity on a channel.
1722.1 F2F April 7, 2010 4
Requirements
• Atomic creation/removal of streams.• Configuration of streams (channels, settings)• Runtime channel status updates (Renamed input)• Error handling back to controller.• Must support the ability to learn about already
configured streams (i.e. Multiple Controllers). • Listeners and Talkers must be able to restore state
without the controller present on network.
1722.1 F2F April 7, 2010 5
Assumptions
• An AVB network can be comprised of Talkers/Listeners and Controllers.
• The IP address of Talkers and Listeners have already been provided and decided upon (via 1722.1 Discovery).
• Talkers and Listeners have already allocated their stream address ranges via MAAP.
• The scope is limited to stream creation, connection and teardown only.
1722.1 F2F April 7, 2010 6
AVB Network startup flow
Zero Configuration(IP Address/Svc
Discovery)
Control LinkHandshake
EnumerateStream
ConnectionMgmt
SRP
1722.1 F2F April 7, 2010 7
Control Link
TCP Client Server Model Talkers/Listeners - Servers Controllers - Clients
Once established, AMP enumeration and stream connection management commands can flow.
1722.1 F2F April 7, 2010 8
Example 1: Network Device Configuration
SPDIF_Right
Video Out 1
Controller
SPDIF_Left
Video In 1/- - AudioInputs
VideoInputs+
System Vendor IDProduct IDRole Name
Analog+ AudioFormatsSampleRates
Digital- SPDIF_Left
-
TalkerStreams+
AMP
TCP/IP Connection
1722.1 F2F April 7, 2010 9
Property Tree
Properties are presented to clients in a tree fashion (similar to a hierarchical filesystem).
A minimal subset of properties are defined and must exist in all implementations.
Wild card queries are supported Client can request that a place in the
properties tree is maintained by the server during life of control link
1722.1 F2F April 7, 2010 10
Proposed property Tree
/- - AudioInputs
VideoInputs+
System Vendor IDProduct IDRole Name
Analog+ AudioFormatsSampleRates
Digital- SPDIF_Left
SPDIF_Right
-
TalkerStreams+
1722.1 F2F April 7, 2010 11
System Node (/System)
All devices must provide the /System Node It will contain system information such as
Current Streams Device specific settings (Vendor ID, Manufacture
Id, …) ….others
1722.1 F2F April 7, 2010 12
AMP Commands
Handshake – Used to establish protocol parameters for use on the control link.
ACK – Acknowledge response when no data is expected back from a command.
EnumerateNode– Used to request from a device that it list a set of nodes given a specified node path on the tree.
1722.1 F2F April 7, 2010 13
AMP Commands (Continued) EnumerateProps – Request that a device enumerate the
properties that may exist on a given node. GetProp – Request the possible property values for a given
property. SetAnchor – Request that the device remember the location
within the property tree that the user is currently at. Stays valid until control link is broken.
PublishStream – Request that a specified stream be created atomically given the channels and properties that are specified in the command invocation.
ListenStream – Request that a listener connect to a stream.
1722.1 F2F April 7, 2010 14
AMP Device Example
DeviceController
AMP Handshake
Enum Nodes“\”)AudioInputs,VideoInputs,System
Enum Nodes(“\AudioInputs”)Analog/Digital
Enum Nodes(“\AudioInputs\Digital”)Spdif_left, Spdif_right
SetAnchor(“\AudioInputs\Digital”)ACK
Enum Props(“Spdif_left”)Formats, OptoDetect,
GetProp(“Formats”)AM824,AAC,MP3
Publish(“Str1”,SpdifL,SpdifR,(enc,AM824),sr,48k))Success
1722.1 F2F April 7, 2010 15
AMP Device Example (Continued)
When a device is processing a Publish stream request, it will be taking care of the SRP Talker/Listener SRP logic
A stream publish can fail if: The caller has requested something that can’t be
handled by the device “Hard Fail” An SRP request fails, causing a “Soft Failure”
condition
1722.1 F2F April 7, 2010 16
Open Items
Multiple controller configurations Locate Functionality ? Redundant Streams ? Protocol Design Document