UPnP Device Architecture Generic 20000710

7/31/2019 UPnP Device Architecture Generic 20000710

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UPnP Device Architecture


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Networking is easy, exceptAd hoc networks don't have

resources just for the sake of thenetwork

E.g., DHCP, DNS, directory,

Network is unreliableNodes added / removed unpredictably

Programs need to talk to programs

But software is heterogeneousOne size doesn't fit all

Must upgrade system piece at a time


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UPnP Strategy1. Just send data over the network

(No executables) Minimize version issues

Minimize security issues

2. Keep implementation private

Be agnostic re: programming language, OS Update implementation w/o affecting interop

Improve performance

Reduce footprint

Improve capabilities3. Agree on meaning / format of data

Choose substrate of proven protocols

Define device (service) specific protocols in a

Forum


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UPnP TacticsStart simple

Build in only universal things thateverybody needs (and can live with)

Add as needed

Minimize requirementsBasic IP network connectivity

Common HTTP protocol stack

Leverage existing standardsHTTP, XML


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GoalsDescribe the protocols for

communication betweenControl points

Controller, usually client

DeviceControlled,

usually server

An actual device

might containboth functions

Device

Service

Control Point

Control Point

Device

Service


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Steps to UPnP Networking

0 Control point and device get addresses

1 Control point finds interesting device

2 Control point learns about device capabilities

3 Control point invokes actions on device

4 Control point listens to state changes of device

5 Control point controls device and/or views devicestatus using HTML UI

0 Addressing

1 Discovery

2 Description

5 Presentation

4 Eventing

3 Control


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Vendor-specific API above

Vendor-specific OS below

UPnP Protocol Stack

Vendor-

specific

physicalnet


UDP

IP

HTTPU/MU GENA SSDP SOAP

HTTP

HTTP GENA

TCP

UPnP Forum

UPnP vendor


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0* Control point and device get addresses






0* Addressing

1 Discovery

2 Description

5 Presentation4 Eventing3 Control


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1 Discovery Control point

finds interestingdevice

0 get address

1 discover device

Advertise / findtyped devices(services)

Guarantee ofminimalcapabilities

Simple

Devices

Advertise whenadded

Refreshadvertisements(cf. lease)

Canceladvertisementswhen removed

Control pointssearch as needed

Devices respond

Control pointsfilter


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1 Discovery: Protocol Stack

UPnP vendor

UPnP Forum


UDP

IP

HTTPMU

(multicast)GENA SSDP HTTPU

(unicast)SSDP


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1 Discovery: SSDP SidebarWhat is SSDP?

IETF Draft Simple Service DiscoveryProtocol

Key design principles

Administratively-scoped multicastUnicast responses

UDP

Very simple advertisements

Very simple search


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1 Discovery: AdvertisingWho? Device multicasts

When? Added or refresh (cf. lease)What?

1 time / service type with NT == service type

1 time / device type with NT == device type

1 time / device with NT == device UUID

1 time with NT == upnp:rootdevice

NOTIFY* HTTP/1.1HOST:239.255.255.250:1900

CACHE-CONTROL: max-age =seconds until advertisement expiresLOCATION:URL for UPnP description for root deviceNT:search targetNTS:ssdp:aliveUSN:advertisement UUID


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1 Discovery: SearchingWho? Control point multicasts

When? Looking for device or serviceWhat?

ST one of

Service type Device type

Device UUID

upnp:rootdevice

ssdp:all

M-SEARCH * HTTP/1.1

HOST:239.255.255.250:1900

MAN:"ssdp:discover"

MX:seconds to delay responseST:search target


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1 Discovery: RespondingWho? Device unicasts

When? If ST matches an NTWhat?

1 time for each NT that matches

Very simple matching

HTTP/1.1 200 OK

CACHE-CONTROL: max-age =seconds until advertisement expires

LOCATION:URL for UPnP description for root device

ST: search targetUSN: advertisement UUID


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2* Control point learns about device capabilities




0 Addressing

1 Discovery

2* Description

5 Presentation4 Eventing3 Control


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2 Description Control point

learns about

device capabilities 0 get address

1 discover device

get URL for

description 2 retrieve descr

get URL forservicedescription

Declarecapabilities

Protocol stack

UPnP vendor

UPnP Forum


IP

HTTP

TCP


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2 Description Device description

Type

Physical container

Logical container

For each service

Type

URL fordescription

URL for control

URL foreventing

UI Icons

URL forpresentation

Services

Functional unitswithin devices

Servicedescription

ActionsState variables

Actual (vs.designed)implementation

Expressed in XML


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2 Description: XML Sidebar What is XML?

W3C Recommendation Extensible Markup Language

"Universal format for structured documents and data onthe Web."

Field names in

Field values between names

Defines 24 data typesui1, ui2, ui4, i1, i2, i4, int

r4, r8, number, fixed.14.4, float

char, string

date, dateTime, dateTime.tz, time, time.tz

boolean

bin.base64, bin.hex

uri

uuid


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2 Description: Device (phys)

base URL forall relative URLs

short user-friendly titlemanufacturer nameURL to manufacturer sitelong user-friendly titlemodel name

model numberURL to model sitemanufacturer's serial numberuuid:UUID

Universal Product Codeurn:schemas-upnp-org :device:deviceType

urn:schemas-upnp-org:service :serviceType:v

urn:upnp-org:serviceId :serviceIDURL to service descriptionURL forcontrolURL foreventing

Declarationsforotherservices (if any)go here

Descriptionof embeddeddevices (if any)go here

image/formathorizontal pixelsvertical pixelscolordepthURL to icon

XML to declare othericons, if any, go here

URL forpresentation

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2 Description: Device (logical)

base URL for all relative URLs

short user-friendly titlemanufacturernameURL to manufacturersitelong user-friendlytitl emodel namemodel numberURL to modelsitemanufacturer's serial numberuuid:UUIDUniversalProduct Code

urn:schemas-upnp-org:device:deviceType:v

urn:schemas-upnp-org:service:serviceType:vurn:upnp-org:serviceId:serviceIDURL to service descriptionURL for control

URL for eventingDeclarations for other services (if any) go here

Description of embedded devices (if any) go here

image/formathorizontal pixelsvertical pixelscolordepthURL to icon

XML to declare othericons, if any, go here

URL forpresentation

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2 Description: Device (other)

base URL forall relative URLs

short user-friendly titlemanufacturernameURL to manufacturersitelong user-friendlytitl emodel namemodel numberURL to modelsitemanufacturer's serial numberuuid:UUIDUniversalProduct Codeurn:schemas-upnp-org :device:deviceType

urn:schemas-upnp-org:service :serviceType:v

urn:upnp-org:serviceId :serviceIDURL to service descriptionURL forcontrolURL foreventing

Declarationsforotherservices (if any)go here

Descriptionof embeddeddevices (if any)go here

image/formathorizontal pixelsvertical pixelscolor depthURL to icon

XML to declare other icons, if any, go here

URL for presentation

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D i i S i ( )


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2 Description: Service (actns)

actionName

formalParameterName

inxoroutstateVariableName

Declarations for other arguments (if any) go here

Declarations for other actions (if any) go here

variableNamevariable datatypedefault valueminimum valuemaximum valueincrement value

variableNamevariable data typedefault valuesome valuesome value

Declarations forother state variables(if any)go here

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2 D i i S i ( )


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2 Description: Service (vars)

actionName

formalParameterNameinxoroutstateVariableName

Declarationsforother arguments(if any)go here

Declarations forotheractions (if any)go here

variableNamevariable datatypedefault value

minimum value

maximum valueincrement value

variableNamevariable data typedefault valuesome valuesome value

Declarations forother state variables(if any)go here

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2 D i i S i ( )


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2 Description: Service (vars)

actionName

formalParameterNameinxoroutstateVariableName

Declarationsforother arguments(if any)go here

Declarations forotheractions (if any)go here

variableNamevariable datatypedefault valueminimum valuemaximum valueincrement value

variableNamevariable data typedefault value

some valuesome value

Declarations for other state variables (if any) go here

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3 C t l


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3 Control Control point

invokes actions ondevice 0 get address

1 discover device

2 retrieve descrget URL for

control

3 send actions todevice

Protocol stack

UPnP vendor

UPnP Forum


IP

SOAP

HTTP

TCP

3 C t l SOAP Sid b


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3 Control: SOAP SidebarWhat is SOAP?

IETF Draft Simple Object AccessProtocol

"Lightweight, XML-based protocol forexchange of information in a

decentralized, distributed environment."Envelope: defines a framework for

describing what is in a message andhow to process it.

Convention: represent remoteprocedure calls and responses.

3 C t l I k A ti


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3 Control: Invoke Action Who? Control point

When? To invoke action on device

What?

POSTpath of control URLHTTP/1.1HOST:host of control URL:port of control URLCONTENT-TYPE: text/xml; charset="utf-8"

SOAPACTION: "urn:schemas-upnp-org:service:serviceType:v#actionName"

in arg valueother in argsand their values (if any) go here

3 C t l A ti R lt


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3 Control: Action Result Who? Device

When? Action completes

What?

HTTP/1.1 200 OK

CONTENT-TYPE: text/xml; charset="utf-8"

out arg valueother out argsand their values (if any) go here

St t UP P N t ki


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4* Control point listens to state changes of device


0 Addressing

1 Discovery

2 Description

5 Presentation4* Eventing3 Control

4 E ti


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4 Eventing Control point

listens to statechanges of device 0 get address

1 discover device

2 retrieve descrget URL for

eventing

4 subscribe toevents from device

Basic push model

Simple

Protocol stack

UPnP vendor

UPnP Forum


IP

HTTP GENA

TCP

4 E ti GENA Sid b


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4 Eventing: GENA SidebarWhat is GENA?

IETF Draft General Event NotificationArchitecture

"Send and receive notifications usingHTTP over TCP/IP and administratively-

scoped multicast UDP."SUBSCRIBE to notifications

UNSUBSCRIBE

NOTIFYOf device availability

Of state variable changes

4 E ti S b ibi


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4 Eventing: SubscribingWho? Control point

When? Before receiving any eventsWhat?

SUBSCRIBEpublisher pathHTTP/1.1

HOST:publisher host:publisher portCALLBACK: NT:upnp:eventTIMEOUT: Second-requested subscription duration

4 E enting S bscription


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4 Eventing: SubscriptionWho? Device

When? Accepts subscriptionWhat?

Device immediately sends a special,initial event to control point with thevalue of all evented variables

HTTP/1.1 200 OK

SID: uuid:subscription-UUIDTIMEOUT: Second-actual subscription duration

4 Eventing Notify


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4 Eventing: NotifyWho? Device

When? A state variable changesWhat?

NOTIFYdelivery pathHTTP/1.1HOST:delivery host:delivery port

CONTENT-TYPE: text/xmlNT:upnp:eventNTS:upnp:propchangeSID: uuid:subscription-UUIDSEQ: event key

new valueOther variable names and values (if any) go here



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5* Control point controls device and/or views devicestatus using HTML UI

0 Addressing

1 Discovery

2 Description

5* Presentation4 Eventing3 Control

5 Presentation


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5 Presentation Control point

controls device

and/or viewsdevice statususing HTML UI 0 get address

1 discover device 2 retrieve descr

get URL forpresentation

5 load presentation

page

(Don't constrainimplementation)

Protocol stack

UPnP vendor


IP

HTTP

TCP

Summary


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Summary UPnP says

1. Just send data

2. Keep implementation private

3. Agree on content / format of data

UPnP is

Web-based protocols

Tailored by a Forum for device (service) types That are API, OS, physical network neutral

For discovery, description, control, eventing

(And simple HTML UI too)

For more information Resources: http://www.upnp.org

Questions? mailto:[email protected]
http://www.upnp.org/mailto:[email protected]:[email protected]://www.upnp.org/

Documents

UPnP Device Architecture Generic 20000710