IETF-50 UPnP Update

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IETF-50 UPnP Update

• Prakash Iyer
• Intel Corporation
• prakash.iyer_at_intel.com

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UPnP Forum Background

• Created in June 1999
• Open to everyone!
• No forum membership fees
• Membership agreement required
• Certification and logo program being put in place
• Over 300 forum members
• 4 Organizational Components
• 20-member Steering Committee oversees all Forum
  activities
• Marketing Committee oversees all marketing / PR
  activities
• Technical Committee resolves common technical
  issues
• Working Committees define Device Control
  Protocols (DCP)
• 5 WCs and 19 core devices

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UPnP Functional Components

• Control Point
• Initiates discovery and control of devices
• E.g. Remote control, PC
• Controlled Device
• A device that has a Device Control Protocol (DCP)
  defined for it
• DCP is essentially XML templates that describe
  device behavior and enable control and eventing
  on a device
• E.g. Internet Gateway, printer, HVAC
• Bridge
• A device that can essentially proxy a legacy or
  non-UPnP device by offering a DCP service for
  that device

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UPnP Addressing Discovery

• Addressing
• Supports Auto IPv4 address configuration, DHCP,
  link-local IPv4 addresses
• IPv6 in future
• Discovery
• Simple Service Discovery Protocol (SSDP)
  HTTP-MU
• Uses reserved local administrative scoped mcast
  address 239.255.255.250 port 1900
• Unsolicited advertisements HTTP/NOTIFY with
  ssdpalive
• Device unavailable HTTP/NOTIDY with ssdpbyebye
• Device solicitation HTTP/M-SEARCH with
  ssdpdiscover
• UPnP limits TTL to 4 to minimize network
  congestion

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UPnP Description Presentation

• Description
• XML templates defined by device-specific working
  groups a.k.a Device Control Protocols (DCP)
• Covers operational and configuration aspects of a
  device
• DCP hierarchy Devices (containers) and services
• Notion of ROOT device
• Generically offers GET and SET actions and
  specifies eventing
• Retrieved using HTTP GET
• Presentation (Optional)
• Web pages / text based UI

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UPnP Control Eventing

• Control
• XML-based actions, results and errors encoded in
  SOAP over HTTP over TCP
• Uses HTTP/POST or HTTP/M-POST with MAN header for
  soap envelope
• Responses within 30 seconds with HTTP/OK
• Eventing
• Based on Generic Event Notification Architecture
  (GENA)
• HTTP/SUBSCRIBE with callback URL
• HTTP/UNSUBSCRIBE
• HTTP/NOTIFY to deliver an event
• Events can be moderated
• UPnP restricts GENA to HTTP/TCP

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Usage Models

• Focus for v1.0 is on residential networks
• Discovery and control across the Internet likely
  for v2.0
• Needs more work in areas such as security
  authorization, scaling discovery, persistent
  device naming and possibly IPv6
• Interim solutions possible
• Outside-in to a residential gateway that also
  acts as a control point / bridge for other UPnP
  devices
• Outside-in to a gateway that relays requests to a
  device
• Requires NAT and firewall configuration on
  gateway
• Vendor proprietary end-to-end security

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Related Architecture Drafts

• draft_cai_ssdp_v1_03.txt
• draft-box-http-soap-01.txt
• Also a W3C technical report
• draft-cohen-gena-client-01.txt
• None of the above are active IETF drafts
• Plus
• Drafts in zeroconf working group
• Other related standards in W3C
• Forum Website is upnp.org
• Several documents restricted to members only