Buffalo TeraStation III TS-IXL User Manual page 62

Gateway
Device, computer or software which connects
networks together. Packets pass through gateways
to travel between networks.
Subnet mask
Subnet masks divide networks into groups of
computers that have common, designated IP
address routing prefixes.
Degraded Mode
When errors occur in a RAID 1, RAID 5, or RAID 10
array because of a failing drive, the array enters
degraded mode to limit data loss. Performance will
be lowered, and though the array will try to maintain
data integrity if possible, data may be lost anyway.
For best results, replace the failing drive as soon as
possible.
Firewall
A firewall is a network device that is designed
to block unauthorized access while permitting
authorized communications. It may be hardware,
or software, or both. It will permit, deny, or proxy
traffic between domains based on rules and other
criteria.
Port Trunking
Port trunking (link aggregation) uses multiple
network connections in parallel to increase link
speed and redundancy.
Hot Spare
A hot spare is an extra hard drive that is connected
as a failover backup to increase reliability. When
another drive fails, the hot spare takes over its
functionality immediately.
Hot Swap
Hot swap components may be replaced without
shutting down or significantly interrupting the
system.
TeraStation IS Setup Guide 61