Browse Prior Art Database

Adding Session ID between UPnP Control Point and Media Server

IP.com Disclosure Number: IPCOM000172776D
Original Publication Date: 2008-Jul-14
Included in the Prior Art Database: 2008-Jul-14
Document File: 4 page(s) / 345K

Publishing Venue

Motorola

Related People

Wei Jiang: INVENTOR [+2]

Abstract

UPnP standard is widely used in home alliance devices. It enables access resource on other device by simply issuing a XML request based on HTTP connection. The request is wrapped in XML which provides extensional space for special usage. This document sets forth a method to add "Session ID" in XML message between UPnP Control Point and Media Server thus to improve the UPnP capability.

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Adding Session ID between UPnP Control Point and Media Server

By Wei Jiang, Grace Zhang

Motorola, Inc.

Mobile Device Business

 

ABSTRACT

UPnP standard is widely used in home alliance devices. It enables access resource on other device by simply issuing a XML request based on HTTP connection. The request is wrapped in XML which provides extensional space for special usage. This document sets forth a method to add “Session ID” in XML message between UPnP Control Point and Media Server thus to improve the UPnP capability.   

PROBLEM

In UPnP standard, the action request and response messages between Control Point and Media Server are wrapped in XML format. The XML document is formatted in schema defined by UPnP standards. Normally the action request message includes IN arguments as the actions request parameters, and the action response message includes OUT arguments as the action result. In the action request, the IN arguments include the ObjectID which identifies the current object that this action is working on. While the response message gives the result in the OUT arguments without ObjectID information. This kind of rule works well if the same action for one object is serially happened as listed in Figure 1 – Control Point wants to search Object 1 on Media Server with some search criteria, the request 1 sends out and the response 1 of request 1 returns. Then Control Point searches Object 2 on Media Server with another set of search criteria, the request 2 sends out and the response 2 of request 2 returns.

However when the same action happens several times concurrently for different objects on same Media Server, since the response message has no ObjectID parameter embedded, the Control Point cannot match the correct response to the right request. For example, as shown in Figure 2, Control Point sends out two browse actions (request 1 and request 2) to two folders of same Media Server simultaneously. Due to the Media Server processing or network condition, response 2 to request 2 returns to Control Point first while the response 1 to request 1 returns next. Since there is no item to differentiate which response should match to which request, the Control Point cannot process the browse result correctly.

Figure 1 UPnP Action Request/Response in Sequence

Figure 2 UPnP Action Request/Response Not In Sequence

Due to this constrain of the UPnP standard, many UPnP Control Point action requests can only be handled serially - the UPnP Control Point application  sends out the message, then blocks to wait for the response, and no concurrent UPnP actions are allowed before the completeness of this request/response session thus to guarantee the ATOM of this action.

Obviously the usage of UPnP is limited. It is possible that when viewing an UPnP Media Server, after browsing one remote Media Server folder but the brow...