How do High Priority Transmits Affect VG Performance?
Allowing high priority transmits on a VG network changes the deterministic nature of VG drastically. The allocation of network bandwidth between all high priority transmissions and all normal priority transmissions becomes probabilistic (just like CSMA/CD Ethernet). This does not mean that VG loses its deterministic nature: it means the network bandwidth available for normal priority transmissions is dependent on how much high priority traffic there is. Even when there are high priority transmits on VG network, VG still guarantees fair access to the network for all nodes on the network. In other words, network bandwidth is first distributed evenly to all nodes that have high priority transmit requests pending, and what is left over gets divided evenly between all nodes that have normal transmit requests pending. Only the amount of bandwidth allocated for normal priority transmits becomes probabilistic. Normal transmit requests will still get serviced even if all the network bandwidth i