Cisco NSS2000 - Gigabit Storage System Chassis Administration Manual page 173

Glossary of Storage-Related Terms & Acronyms
Cisco Small Business NSS2000 Series Administration Guide
G
Gigabit: Also Gbit or Gb. A unit of information or data storage equivalent to
1,000,000,000 (1 billion) bits.
Gigabtye (GB): A unit of information or data storage equivalent to 1,000,000,000 (1
billion) bytes.
H
High Availability: A term applied to a class of electronic devices where a system
design protocol has been applied and implemented to ensure a higher/improved
degree of operational continuity during a given measurement period.
Hotplug: The ability to add or remove hardware without first powering down the
system.
I
IEEE 802. 1 ad: Protocols that provide separate instances of MAC services to
multiple independent users on a bridged LAN (local area network) in a way that
does not require cooperation among the users, but does require a minimum of
cooperation between users and the MAC service provider.
IEEE 802. 1 p: An IEEE standard that provides quality of service (QoS) in 802-based
networks at the MAC level. 802. 1 p uses three bits (defined in 802. 1 q) to allow
switches to reorder packets based on priority level (traffic class expediting and
dynamic multicast filtering). It also defines the Generic Attributes Registration
Protocol (GARP) and the GARP VLAN Registration Protocol (GVRP). GARP lets
client stations request membership in a multicast domain, and GVRP lets them
register into a VLAN. Eight different classes of service are available, expressed
through three extra bits on the Ethernet Frame. The way traffic is treated when
assigned to any particular class is undefined and left to the implementation. The
IEEE however has made some broad recommendations. 802. 1 p is used within the
IEEE 802. 1 D and IEEE 802. 1 Q standards.
IEEE 802. 1 Q: An Ethernet, Layer 2 standard for providing VLAN identification and
QoS (Quality of Service) levels for devices on a network. This is achieved by
adding four bytes to the Ethernet frame header of a data packet (three bits of
which assign up to eight priority or QoS levels and 12 bits identify up to 4096
VLANs).
B
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