Implementing Service Location ProtocolDirected Study: Networking at the Application LayerPresented by: Lucas StephensonTo: Richard Yu, Anthony WhiteheadFor: SYSC 5906

Tuesday, September-04-12

Overview

1. Purpose2. SLP OSS Options3. OpenSLP Provisions4. OpenSLP Test • Setup• Setup Issues• Tests• Results• Results Screenshot

5. Conclusion

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• Implement and verify that SLP can• Find suitable TCP/IP network endpoints

• Unknown/Unfamiliar networks• Any network service (novel, non-standard, uncommon, not

supported by DHCP)• Provide rudimentary query support

• Ensure solutions are low cost• Simple over the counter hardware• Low development time

Purpose

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SLP OSS Options• LiveTribe (http://livetribe.codehaus.org/LiveTribe-SLP)• A network service management console, contains an SLP module• Java based• Implemented into a broader software project

• jSLP (http://jslp.sourceforge.net/)• Java implementation of SLP• OSGi version available• 1 year since project activity/discussion

• OpenSLP (http://www.openslp.org/)• C cross platform implementation• Low activity, but some discussions• Java version available, but at least 10 years old 4

OpenSLP Provisions• Code libraries supporting all SLP messages• A host service application (daemon)• Enables SA and DA functionality• Required for DA and scope discovery• Not required for basic UA usage (without scopes)

• A tool that allows interaction with the local daemon to send network messages

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OpenSLP Test Setup• Setup• Consumer grade 802.11 a/b/g/n wireless router and 802.3 wired

router• Two Windows clients

• Client machine A:• Windows XP, wired network connection only

• Client machine B:• Windows 7, wired (802.11n) and wireless• OpenSLP daemon started, default configuration (SA)

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OpenSLP Test Setup Issues• Initially used version 1 (latest officially stable release) • Required compilation, requiring some minimal modifications• Had issues, (no responses from server, despite registered services)

• Tried version 2, windows binaries pre-compiled• Issues remained• Seemed services weren’t being registered• Created a simple C console implementation to register services

• The application worked!• Discovered it stopped working once application window was

closed• Local PID monitoring!• If a local application registers a service, the service is deregistered

if the application closes• Makes local registration using the command line useless!

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OpenSLP Tests• SLP allows services to be found using service types and service

types with query-able attributes.• Tests of each both types of request were performed• The following services were registered on machine “A”• service:io:diop://hostname.t1.com:1337 (-xChannels=5),(-xMuteable=true)

• service:io:diop://hostname.t2.com:1338 (-xChannels=7),(-xMuteable=false)

• Queries were performed using both the OpenSLP slptool and a C application using the OpenSLP Library, using the FindSrvs method.

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OpenSLP Results• The services were correctly found from machine “B” as well as

from machine “A” by querying for the abstract type or abstract and concrete types:• “service:io” or “service:io:diop”

• Varying LDAP queries on the 2 specified attributes also functioned, (see next slide)

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Finding Services

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Conclusion• SLP protocol can locate service endpoints on an TCP/IP

network.• Single requirement: agents representing services must be

accessible via multicast or broadcast.• Additional platforms: due to time and unavailability of up to

date code were not able to be verified. • Query functionality provides a powerful means to locate and

filter specific endpoints for compatible capabilities.• However: No interaction with the endpoints are inherent and

the endpoint doesn’t necessarily exist.

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Thanks 12