Update README

README.md

@@ -2,6 +2,16 @@ FabricMon
 =========
 
 FabricMon is an InfiniBand fabric monitoring daemon written in Go. It uses cgo
-to call low-level functions in libibmad, libibumad, and libibnetdisc.
+to call low-level functions in libibmad, libibumad, and libibnetdiscover.
+
+InfiniBand switch modules for blade chassis are often unmanaged, with no simple
+way to query their port counters. FabricMon solves this by querying the subnet
+manager (SM), using management datagrams (MAD). The topology of the fabric is
+mapped using libibnetdiscover and the counters of any active switch ports
+are queried.
+
+The fabric topology is also offered as a .JSON file, which is parsed by
+FabricMon's web interface, based on the d3.js graph library, and displayed as
+an SVG force graph.
 
 This project is a work in progress, in the early stages of development.