NEC ElectraElite IPK, Руководство по программированию

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Electra Elite IPK Document Revision 4
Programming Manual 3 - 55
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Flow Control for Full Duplex Selection (Memory Block 1-16-16)
Use this Memory Block to specify whether or not Full duplex IEEE802.3x Flow
Control is enabled for each HUB(8)-U( ) ETU port.
Back Pressure for Half Duplex (Memory Block 1-16-17)
Use this Memory Block to specify whether or not half-duplex Back Pressure
Flow Control is enabled for each HUB(8)-U( ) ETU port.
4.3 Quality of Service Configuration with VLANs
Quality of Service (QoS) is a means of giving priority to time-sensitive network
voice or video traffic. Diffserv and another router-based queuing method
(layer 3 of the OSI model) do not solve the problem of network congestion on
the LAN. Networks for voice and video should use switching hubs instead of
dumb hubs. The HUB(8) ETU is a layer 2 switch that supports the IEEE
802.1p standard for QoS for IEEE 802.1q standard VLANs.
VLANs may be implemented for reasons other than QoS such as reducing
broadcast traffic on the network, security, or managing multiple paths to a
destination. Using Voice over IP (VoIP), QoS is yet another reason to
implement VLANs. Congestion may occur on the LAN typically on the trunk
connecting the Ethernet switches, between switches and routers, or on the
backplane of a switch-supporting network-intensive application (e.g., imaging
or video).
Figure 3-2 Quality of Service Configuration