4.0 OPERATION
4.1 Dual-Speed Functionality, and Switching
The PXES6P Series 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
PXES6Ps 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. PXES6P 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.
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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 PXES6P Series 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 PXES6P 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
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removed or moved from one segment to another, the PXES6P 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 PXES6P 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 PXES6P will still work. The
auto-cross function cannot be disabled.
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