Dante DFG48044X Руководство по установке и эксплуатации - Страница 15
Просмотреть онлайн или скачать pdf Руководство по установке и эксплуатации для Переключатель Dante DFG48044X. Dante DFG48044X 18 страниц. Digital fiber optic ethernet edge switch 10/100mbps standalone unit
Печатать страницу4.0 OPERATION
4.1 Dual-Speed Functionality and Switching
The DFG48044X Series Edge Switches provide SIX switched ports with combination of fiber and copper or copper
only. The architecture supports a dual speed switching environment, with standard auto-negotiation capability.
The switched RJ-45 ports are full- or half-duplex auto-sensing for mode and speed, and auto-cross for plug
polarity (See Section 4.2). When the connected device is 10 Mbps, the DFG48044X obeys all the rules of 10 Mbps
Ethernet configurations. The 10 Mbps users can "communicate" with 100Mbps users as well as other 10 Mbps users
through the switch. Similarly, the 100Mbps traffic obeys the rules of 100Mbps Ethernet, and can communicate with
10 Mb and 100Mb users. DFG48044X Series units are plug-and-play devices. There is no software configuring to be
done at installation or for maintenance, even for the LLL ports. The internal functions of both are described below.
Switching, Filtering and Forwarding
Each time a packet arrives on one of the switched ports, the decision is taken to either filter or to forward the
packet. Packets whose source and destination addresses lie on the same port segment will be filtered, constraining
them to one port and relieving the rest of the network from processing them. A packet whose destination address
is on another port segment will be forwarded to the appropriate port, and will not be sent to the other ports where
it is not needed. Packets needed for maintaining the operation of the network (such as occasional multi-cast
packets) are forwarded to all ports. The DFG48044XSeries Edge Switches operate in the store-and-forward
switching mode, which eliminates bad packets and enables peak performance to be achieved when there is heavy
traffic on the network.
Switching, Address Learning
The DFG48044X Series units have address table capacity of 2K node addresses, and are suitable for use
in large networks. They are self-learning, so that as nodes are added or removed or moved from one segment
to another, the DFG48044X Series switch automatically keeps up with node locations.
An address-aging algorithm causes least-used addresses to fall out in favor of new frequently-used
addresses. To reset the address buffer, cycle power down-and-up.
4.2 Auto-cross (MDIX), Auto-negotiation and Speed-sensing
The RJ-45 ports support auto-cross (MDI or MDIX) in the auto-negotiation mode according to the IEEE
802.3u standard. No crossover cables are needed on RJ-45 port, when connecting the DFG48044X to other
unmanaged switches, legacy hubs, managed switches, media-converter etc. Please note that there can be
conditions with managed switches where the switch manager fixes the port settings via software, and the result
of the auto-negotiation is changed in the managed switch by the manager commands. In such cases, the
10/100 speed or the F/H mode may be affected, but auto-cross in the DFG48044X will still work. The auto-cross
function cannot be disabled. When an RJ-45 cable connection is made, and each time LINK is enabled, auto-
negotiation takes place (except for legacy products, which do not have auto-negotiation and which go to the
default state accordingly). The DFG48044X Switch advertises its capability for 10 or 100 Mbps speed and F/H
duplex mode, and the device at the other end of the cable should similarly advertise / respond. Both sides will
agree to the speed and mode to be used per the 802.3u standard. Depending upon the devices connected, this
will result in agreement to operate at either 10 Mbps or 100Mbps speed and full or half-duplex mode.