HAVi Fast Track Application Development Seminar

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HAVi Fast TrackApplication Development Seminar
Home Audio Video interoperability
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Communication Media Manager, Messaging
System and Registry
Amal Prabhu Sony Electronics amal_at_arch.sel.sony.co
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Communication Media Manager

• System service that provides 1394 network
  services
• Implemented as a software element in every IAV
  and FAV device
• Services Provided
• Presents GUID representation of devices to HAVi
  modules
• Provides Async request and indication services
• Using Event Manager services, posts events that
  reflect bus resets and device plugging and
  unplugging

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Messaging System Introduction

• System service that provides the basic message
  transfer service
• Implemented as a software element in every IAV
  and FAV device
• Two Components
• Message Handling Layer
• Transport Adaptation Module (TAM)

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MS Services Allocation of SEID

• Every software element (SE) registers with MS a
  callback function and obtains a unique address
• These addresses are called Software Element
  IDentifier (SEID)
• SEID Composes of 64 bit Global Unique ID (GUID)
  of the device and 16 bit unique handle
• MS uses SEIDs to deliver HAVi messages to the
  software elements

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MS Services Message Transfer - I

• Delivers HAVi messages to SE in the network. The
  message is delivered in the callback function of
  the SE
• Supports two modes of data transfer
• simple mode
• reliable mode
• Simple mode No control performed
• Reliable mode MS uses acknowledgements for
  ensuring the delivery of messages

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MS Services Message Transfer - III
Simple Mode
IAV 1
IAV 2
MsgSendSimple()
Simple message
Invoke callback
Call returns
SE A
MS 1
MS 2
SE B
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MS Services Message Transfer - IV
Reliable Mode
IAV 1
IAV 2
MsgSendReliable()
Reliable message
Invoke callback
Callback returns
Ack/nak message
Call returns
SE A
MS 1
MS 2
SE B
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MS Services Message Transfer - V
Request Response Protocol
IAV 1
IAV 2
SEID B
MsgSendRequest()
Reliable message
Invoke callback
Callback returns
Ack message
Call returns
API called
MsgSendResponse()
Reliable/Simple message
Invoke callback
Ack/Noak message
Call returns
SE A
MS 1
MS 2
SE B
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MS Services Supervision

• With the aid of Event Manager services, MS
  provides Watches/Supervision services
• A SE can monitor the existence of any other SE
  using this service
• Example If a SE A monitors watches SE B, and SE
  B ceases to exist, SE A is notified in its
  callback about the disappearance of SE B

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MS Services Notification

• Using Event Manager services MS provides certain
  notification services in HAVi
• MS posts following events
• SystemReady() - Indicates that HAVi stack is
  initialized and operational
• MsgLeave() - Indicates that a SE has unregistered
  from HAVi
• MsgTimeOut() - Indicates that a certain message
  did not get acknowledged within 30 s (HAVi
  specified time out)

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Transport Adaptation Module (TAM)

• Provides 1394 services to the message handling
  layer
• Uses FCP command register to send and receive
  HAVi messages/fragments of messages
• Implements the fragmentation and reassembly of
  larger HAVi messages

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Registry Introduction - I

• System service that provides directory service in
  a HAVi network
• Implemented as a software element in every IAV
  and FAV device
• Maintains a database of the local software
  elements that have registered with it

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Registry Introduction - II

• Each entry in the Registry consists of SEID and
  the attributes of the software element
• Clients can retrieve attributes of any SEID in
  the network or SEIDs that match certain attribute
  criteria using the Registry API
• Clients can register in the registry so that they
  can be visible in HAVi network
• If necessary the Registry uses Registry protocol
  to retrieve results from other Registry to
  satisfy a query

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Registry Attributes

• An Attribute consists of
• Class of the attribute
• Name if the attribute
• Value
• Two classes of attributes
• System
• Private
• System attributes are those that are defined by
  HAVi specification
• SE with private attribute should preferably have
  a system attribute associated with it

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Registry System Attributes
Following attributes are defined in HAVi
Specification

• SoftwareElemenType
• VendorId
• HUID
• TargetId
• InterfaceId
• DeviceClass
• GuiReq
• MediaFormatId
• DeviceManufacturer
• DeviceModel
• SoftwareElementManufacturer
• SoftwareElementVersion
• AvLanguage
• UserPreferredName

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Registry Services Registration

• Clients are register or unregister from the HAVi
  registry using this service
• Following API provides this service
• RegisterElement()
• UnregisterElement()

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Registry Services Query

• Clients can query the registry to obtain a list
  of SE that satisfy certain attributes
• Clients can query the registry to obtain the
  attributes of a certain SE
• Following API provides this service
• RetrieveElement()
• GetElement()
• MultipleGetElement()

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Registry Services Notification

• Using Event Manager services Registry provides
  certain notification services in HAVi
• Registry posts following events
• NewSoftwareElement() - Indicates that a new SE
  has registered with HAVi Registry
• GoneSoftwareElement() - Indicates that an SE has
  unregistered from HAVi Registry

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Registry Protocol
IAV 1
IAV 2
MsgSendRequest( GetElement(Query))
MsgSendRequest()
Reliable message
Invoke callback
API called
MsgSendResponse(Query Result)
Simple message
Invoke callback
MsgSendResponse(Query Result)
SE A
REG 1
MS 1
MS 2
REG 2
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Home Audio-Video interoperability