CLI Reference Guide-R07

Glossary
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IEEE 802.1D Specifies a general method for the operation of MAC bridges, including the Spanning Tree
Protocol.
IEEE 802.1Q VLAN Tagging—Defines Ethernet frame tags which carry VLAN information. It allows
switches to assign endstations to different virtual LANs, and defines a standard way for
VLANs to communicate across switched networks.
IEEE 802.1p An IEEE standard for providing quality of service (QoS) in Ethernet networks. The standard
uses packet tags that define up to eight traffic classes and allows switches to transmit
packets based on the tagged priority value.
IEEE 802.1s An IEEE standard for the Multiple Spanning Tree Protocol (MSTP) which provides
independent spanning trees for VLAN groups.
IEEE 802.1w An IEEE standard for the Rapid Spanning Tree Protocol (RSTP) which reduces the
convergence time for network topology changes to about 10% of that required by the older
IEEE 802.1D STP standard. (Now incorporated in IEEE 802.1D-2004)
IEEE 802.1X Port Authentication controls access to the switch ports by requiring users to first enter a
user ID and password for authentication.
IEEE 802.3ac Defines frame extensions for VLAN tagging.
IEEE 802.3x Defines Ethernet frame start/stop requests and timers used for flow control on full-duplex
links. (Now incorporated in IEEE 802.3-2002)
IGMP Internet Group Management Protocol. A protocol through which hosts can register with
their local router for multicast services. If there is more than one multicast switch/router on
a given subnetwork, one of the devices is made the “querier” and assumes responsibility for
keeping track of group membership.
IGMP Proxy Proxies multicast group membership information onto the upstream interface based on
IGMP messages monitored on downstream interfaces, and forwards multicast traffic based
on that information. There is no need for multicast routing protocols in an simple tree that
uses IGMP Proxy.
IGMP Query On each subnetwork, one IGMP-capable device will act as the querier — that is, the device
that asks all hosts to report on the IP multicast groups they wish to join or to which they
already belong. The elected querier will be the device with the lowest IP address in the
subnetwork.