Push Proxy Gateway
Encyclopedia
A Push Proxy Gateway is a component of WAP
Wireless Application Protocol
Wireless Application Protocol is a technical standard for accessing information over a mobile wireless network.A WAP browser is a web browser for mobile devices such as mobile phones that uses the protocol.Before the introduction of WAP, mobile service providers had limited opportunities to offer...

 Gateways that pushes URL notifications to mobile handsets. Notifications typically include MMS
Multimedia Messaging Service
Multimedia Messaging Service, or MMS, is a standard way to send messages that include multimedia content to and from mobile phones. It extends the core SMS capability that allowed exchange of text messages only up to 160 characters in length.The most popular use is to send photographs from...

, email, IM, ringtone downloads, and new device firmware notifications. Most notifications will have an audible alert to the user on the device. The notification will typically be a text string with a URL link. Note that only a notification is pushed to the device; the device must do something with the notification in order to download or view the content associated with it.

PUSH to PPG

A push message is sent as an HTTP POST to the Push Proxy Gateway. The POST will be a multipart XML document, with the first part being the PAP (Push Access Protocol) Section and the second part being either a Service Indication or a Service Loading.

+---------------------------------------------+
| HTTP POST | \
+---------------------------------------------+ | WAP
| PAP XML | | PUSH
+---------------------------------------------+ | Flow
| Service Indication or Service Loading XML | /
+---------------------------------------------+

POST

The POST contains at a minimum the URL being posted to (this is not standard across different PPG vendors), and the content type.

An example of a PPG POST:
POST /somelocation HTTP/1.1
Host: ppg.somecarrier.com
Content-Type: multipart/related; boundary=someboundarymesg; type="application/xml"

PAP

The PAP XML contains at the minimum, a element, a element, and an
element.

An example of a PAP XML:
--someboundarymesg
Content-Type: application/xml









The important parts of this PAP message are the address value and type. The value is typically a MSISDN and type indicates whether to send to an MSISDN (typical case) or to an IP Address. The TYPE is almost always MSISDN as the Push Initiator (PI) will not typically have the Mobile Station's IP address - which is generally dynamic. In the case of IP Address:
TYPE=USER@a.b.c.d

Additional capability of PAP can be found in the PAP
Push Access Protocol
Push Access Protocol is a protocol defined in WAP-164 of the Wireless Application Protocol suite from the Open Mobile Alliance...

 article.

Service Indication

A PUSH Service Indication (SI) contains at a minimum an element and a element.

An example of a Service Indication:
--someboundarymesg
Content-Type: text/vnd.wap.si





A new MMS has been received, download?


PPG delivery to mobile station

Once a push message is received from the Push Initiator, the PPG has two avenues for delivery. If the IP address of the Mobile Station is known to the PPG, the PPG can deliver directly to the mobile station over an IP bearer. This is known as "Connection Oriented Push". If the IP address of the mobile station is not known to the PPG, the PPG will deliver over an SMS
Short message service
Short Message Service is a text messaging service component of phone, web, or mobile communication systems, using standardized communications protocols that allow the exchange of short text messages between fixed line or mobile phone devices...

 bearer. Delivery over an SMS bearer is known as "Connectionless Push".

Connectionless Push

In Connectionless Push, an SMSC
Short message service center
A short message service center is a network element in the mobile telephone network which delivers SMS messages.-Operation:When a user sends a text message to another user, the message gets stored in the SMSC which delivers it to the destination user when they are available...

 BIND is required for the PPG to deliver its push message to the mobile station. Typically, a PPG will have a local SMS queuing mechanism running locally that it BINDs to, and which in turn BINDs to the carrier's SMSC. This mechanism should allow for queuing in the event of an SMS infrastructure outage, and also provide for message throttling.

Since a WAP Push message can be larger than a single SMS message can contain, the push message may be broken up into multiple SMS messages, as a multipart SMS.

Connection Oriented Push

In Connection Oriented pushes (where the device supports it), an SMSC
Short message service center
A short message service center is a network element in the mobile telephone network which delivers SMS messages.-Operation:When a user sends a text message to another user, the message gets stored in the SMSC which delivers it to the destination user when they are available...

 BIND is not required if the gateway is aware of the handsets IP Address. If the gateway is unable to determine the IP Address of the handset, or is unable to connect to the device, the push notification will be encoded and sent as an SMS
Short message service
Short Message Service is a text messaging service component of phone, web, or mobile communication systems, using standardized communications protocols that allow the exchange of short text messages between fixed line or mobile phone devices...

.

Connection Oriented Push is used less frequently than Connectionless Push for several reasons including:
  • Devices while registered to the network, may not have a data session (PDP Context in the GSM world) established.
  • A separate IP->MSISDN table has to be maintained in Connection Oriented Push.
  • Typically, the PPG or another part of the gateway has to receive RADIUS
    RADIUS
    Remote Authentication Dial In User Service is a networking protocol that provides centralized Authentication, Authorization, and Accounting management for computers to connect and use a network service...

     or other accounting packets in order to support Connection Oriented Push.

Other PUSH Attributes

  • Push notifications can be confirmed or unconfirmed. Most carriers use unconfirmed pushes due to the high volume and resource constraints related to confirmed push. This is controlled by setting confirmed in the quality-of-service tag element.
  • Push notifications can be set to expire if not delivered before a certain time. This is controlled by setting deliver-before-timestamp in the pushmessage element.


Many other attributes exist and are detailed in the specifications at the Open Mobile Alliance
Open Mobile Alliance
The Open Mobile Alliance is a standards body which develops open standards for the mobile phone industry.- Principles :Mission: To provide interoperable service enablers working across countries, operators and mobile terminals....

 and other sites.

PPG Vendors

PPG vendors include Nokia Siemens Networks
Nokia Siemens Networks
Nokia Siemens Networks is a global data networking and telecommunications equipment company headquartered in Espoo, Finland. It is a joint venture between Nokia of Finland and Siemens of Germany...

, Ericsson
Ericsson
Ericsson , one of Sweden's largest companies, is a provider of telecommunication and data communication systems, and related services, covering a range of technologies, including especially mobile networks...

, Bytemobile, Gemini Mobile Technologies
Gemini Mobile Technologies
Gemini Mobile Technologies, Inc. develops wireless software infrastructure solutions for mobile companies, including 3D community applications that send messaging and multimedia content to wireless devices...

, Openwave
Openwave
Openwave is a software company. Based in Redwood City, California, USA, Openwave is historically significant in its introduction of the Mobile Internet and its expansion into a large successful mobile software supplier in the mobile telecom sector...

, Acision
Acision
Acision is a privately held mobile communications network infrastructure company specialising in messaging and charging systems that enable popular services such as Short message service , Multimedia Messaging Service , mobile internet browsing, Mobile Broadband and voicemail.-History:Acision's...

, Huawei
Huawei
Huawei is a Chinese multinational networking and telecommunications equipment and services company headquartered in Shenzhen, Guangdong, China...

, Azetti, Alcatel,WIT Software ,ZTE ,and open source Kannel
Kannel (telecommunications)
In computing, Kannel is an open source WAP gateway. It provides the essential part of the WAP infrastructure as open source software to everyone so that the market potential for WAP services, both from wireless operators and specialized service providers, will be realized as efficiently as...

.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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