I have an end-to-end Layer 3 routed access layer network using OSPF point-to-point connections. The design is Cisco 3750s for Access, 6500s Distribution and 7600s Core. There is a likely possibility that some servers will need clustering at the access layer, but reside on different access switches, hence different subnets. The servers aren't traffic intensive and I've been looking at a few options where I can span a VLAN over several access switches for the cluster to work. Cross-site clustering may also be an option and to date i've looked at VPLS, IRB.. If anyone has some options to consider it will be appreciated.