3Com plans a three-phase rollout of XRN technology.3Com\u00a0plans a three-phase rollout of XRN technology. Phase 1 products are shipping now. These support interconnection of two switches at a distance of up to 16 feet using a proprietary cable.We tested XRN support on 3Com's SuperStack models 4050 and 4060. XRN support also is available on the vendor's SuperStack 3 models, 4900, 4900SX, 4924 and 4950.For IP routing, Phase 1 switches support Routing Information Protocol. 3Com says it will support\u00a0Open Shortest Path First\u00a0within three to six months.In Phase 2, scheduled for release by year-end, up to four switches can be interconnected using fiber Gigabit Ethernet connections. The only distance limits are those for the fiber links, currently defined as 1.24 miles. In Phase 3, expected sometime in 2004, up to eight switches will make up an XRN stack, again with the only distance limitation being that of the Gigabit Ethernet interconnect. Back to main review: "XRN Interconnect architecture"