The ancients, struck with this irreducibleness of the elements of human life to calculation, exalted Chance into a divinity; but that is to stay too long at the spark, which glitters truly at one point, but the universe is warm with the latency of the same fire.
A visitor location register (VLR) is a server in a cellular network that supports roaming functions for users outside the coverage area of their own HLR.
A virtual LAN (VLAN) abstracts the idea of the LAN; A VLAN might comprise a subset of the ports on a single switch or subsets of ports on multiple switches. By default, systems on one VLAN don't see the traffic associated with systems on other VLANs on the same network.