Have you seen the Splunk for InterMapper app?
http://splunk-base.splunk.com/apps/51549/splunk-app-for-network-monitoring-and-mapping-beta
It provides the ability to map your network devices (switches, routers, servers etc) on a rack image, world map or even a blank background and then pull it into Splunk. By pulling it into Splunk you can then drilldown on individual devices to see layer 2 and 3 information including any related log data.
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