1722.1 F2F April 7, 2010 1

1722.1 Enumeration & Connection Management

presented by Chris Pane

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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.

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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.

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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.

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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.

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AVB Network startup flow

Zero Configuration(IP Address/Svc

Discovery)

Control LinkHandshake

EnumerateStream

ConnectionMgmt

SRP

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Control Link

TCP Client Server Model Talkers/Listeners - Servers Controllers - Clients

Once established, AMP enumeration and stream connection management commands can flow.

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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

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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

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Proposed property Tree

/- - AudioInputs

VideoInputs+

System Vendor IDProduct IDRole Name

Analog+ AudioFormatsSampleRates

Digital- SPDIF_Left

SPDIF_Right

-

TalkerStreams+

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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

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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.

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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.

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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

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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

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Open Items

Multiple controller configurations Locate Functionality ? Redundant Streams ? Protocol Design Document