Networking hardware and software and data center topologies leveraging same

A system, comprising:

• one or more clusters, each cluster comprising a plurality of servers arranged in X unit racks with each rack including Y servers, wherein X is at least 2, wherein Y is at least 2, wherein each server of the Y servers is external to, and is directly connected to, a network interface card (NIC), wherein each server of the rack is optically connected via each server's NIC to all other servers in the rack, wherein each server of the rack is optically connected via each server's NIC to Z servers of other racks, wherein Z is at least 1, wherein any server in the cluster is configured to optically communicate with any other server of the cluster, wherein the NIC comprises a programmable switching ASIC (application-specific integrated circuit), wherein the NIC comprises a central processing unit (CPU) directly coupled to the switching ASIC,
• wherein the Y servers comprise a first server,
• wherein the first server's NIC is a first NIC that operates a first software engine configured to run on the first server,
• wherein the first software engine is configured to install rules that route a Synchronize (SYN) packet from a source virtual machine (VM) through the first software engine,
• wherein the first software engine is configured to append, to the SYN packet, a signed cookie,
• wherein the first NIC is configured to route the SYN packet to a destination VM,
• wherein after the SYN packet has been examined in hardware of the destination VM, the first NIC is configured to return the SYN packet to the first software engine,
• wherein the first software engine is configured to verify that the cookie of the SYN packet returned from the destination VM matches a policy of the destination VM, and
• wherein the first software engine is configured to return the SYN packet to the source VM which establishes a connection between the source VM and the destination VM.