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A Method to Filter Useless SLP Service Information

IP.com Disclosure Number: IPCOM000202007D
Publication Date: 2010-Dec-01
Document File: 9 page(s) / 196K

Publishing Venue

The IP.com Prior Art Database


SLP (service location protocol) user agent always find useless service when there are SLP services running on multiple sub networks environment. This creates a big trouble for application which uses SLP to locate services. This disclosure provides a smart method to filter out garbage service and return only accessible ones. A pre-check for accessibility on each new service location registration is introduced, in which a policy is defined to check whether a new service location is routable to certain ethernet port, and only routable ones is retrieved. With this method, SLP will always provide ONLY accessible service location, and thus avoid garbage information and reduce useless network traffic.

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CN820090457 Xiu Lan Yu/China/IBM Yi SH Yang, Yao SH Ma

A Method to Filter Useless SLP Service Information

1. Background:

When running SLP service on a multiple sub networks environment, a general problem is that there are too many useless SLP services information that cannot be used by other hosts at all. Think about the gateway server that hosts SA/DA (Service Agent / Directory Agent) are running over multiple sub networks, and one of the sub network is internal-used only. If the UAs (User Agent) inside the internal-used sub network, including the UA running on the gateway server itself, are registering a lot of service information whose IP address are also from this internal-used sub network, all these service information registered on that gateway server's SA will be garbage information for the UA from other sub networks of the gateway. Because even UAs from other sub networks of the gateway server can see these services' information from SLP, they can never actually access these service. This often leads to a waste of time for specific SLP-invovled task. And also, end users can be very frustrated because SLP always find so many services but only few of they are accessible.

A live example is the problem for typical system management software application (normally running on a system software platform center, or call it SSPC) to find service. Typically these applications allows users to locate service (instead of input service IP/port) via SLP. Consider the case that some of the SA/DA are running over multiple sub networks, the application will spend huge time in checking these service information from SLP and pick the valid ones. The diagram 2 shows what happens in such situation:


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Diagram 1. The Network Topology of Common SLP Service Case

2. Summary of Invention:

To solve the problem raised above, a method to do service information categorizing in SLP service that hosted in gateway server in proposed in this disclosure. Generally speaking, when SLP client is retrieving information from SLP service that hosted in gateway server, the SLP service will only return the service information, whose location can be accessible from the sub-network of SLP client, to the client.

The solution is depicted in the following diagram. Assume that SLP service is hosted on the gateway server over multiple sub networks such as


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network 1, ...,

each Sub-

                                                              -i can access the location, this piece of service information will be categorized as eth-i-routable (eth is the ethernet interface connected that sub network), otherwise, it will be categorized as eth-i-none-routable. Later on, if the SLP client from Sub-


Network-i is requesting service information on this SLP service, only the

service information categorized as eth-i-routable will be returned. This solution is illustrated in...