Network Glossary Q

quartet A set of four hex digits listed in an IPv6 address. Each quartet is separated by a colon.

querier election When multiple routers are connected to a subnet, only one should be sending IGMP queries. It is called a querier. IGMPv1 does not have any rules for electing a querier. In IGMPv2 and IGMPv3, a router with the lowest interface IP address on the subnet is elected as a querier.

Query (EIGRP) An EIGRP message that is used to ask neighboring routers to verify their route to a particular subnet. Query messages require an Ack.

query scope (EIGRP) The characterization of how far EIGRP Query messages flow away from the router that first notices a failed route and goes active for a particular subnet.

queue starvation A possible side effect of a scheduler that performs strict-priority scheduling of a queue, which can result in lower-priority queues getting little or no service.

QV See quantum value.

QoS pre-classification A process used in routers that are encrypting traffic to permit egress QoS actions to be taken on traffic that is being encrypted on that router. QoS pre-classification keeps a copy of each packet to be encrypted in memory long enough to take the appropriate egress QoS actions on that traffic as it leaves that router, because the encrypted traffic cannot be inspected for QoS actions.

quantum value The number of bytes in a queue that are removed per cycle in MDRR. Similar to byte count in the custom queuing (CQ) scheduler.