Magnum 6KL Managed Edge Switch Installation and User Guide
11/09
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4.2
Auto-Cross(MDIX) and Auto-negotiation, for RJ-45 ports
The RJ-45 ports independently support auto-cross (MDI or MDIX) in auto-
negotiation mode and will work properly with all the other connected devices with
RJ-45 ports whether they support Auto-negotiation (e.g 10Mb Hub, media converter)
or fixed mode at 10Mb or 100Mb Half/Full Duplex(managed switch) or not. No
cross-over cable is required while using the 6KL’s copper port to other devices.
Operation is according to the IEEE 802.3u standard.
The Managed 6KL’s Fast Ethernet copper ports can be set for either fixed 100Mb speed
or for 10/100 F/H N-way auto-negotiation per the IEEE802.3u standard. The selection is
made via MNS software. The factory default setting is for auto-negotiation. At 10Mb or
100Mb-fixed speed, the user may select half- or full-duplex mode by MNS Software for
each RJ-45 port separately. For detail information
See Section 2.3 of this manual for
information to access the “6K-MNS Software user guide”
One frequently-used application for the Managed Magnum 6KL Switch copper
ports is to connect one of them using a fiber media converter to another Switch in the
network backbone, or to some other remote 100Mb device. In this case, it is desirable to
operate the fiber link at 100Mb speed, and at either half- or full duplex mode depending
on the capabilities of the remote device. Standard commercially available Fast Ethernet
media converters mostly do not support auto-negotiation properly, and require that the
switched port to which they are connected be at the 100Mb fixed speed. Attachments to
a 10/100 auto-negotiation port typically will not work properly. The 6KL Switch’s RJ-
45 ports handle this situation by configuring the ports as per desired through MNS
software port settings and can check the port status of each port after the change.
When Magnum 6KL RJ-45 copper ports are set for auto-negotiation and are
connected to another auto-negotiating device, there are 4 different speed and F/H modes
possible depending on what the other device supports. These are: (1) 100Mb full-duplex,
(2) 100Mb half-duplex, (3) 10 Mb full-duplex and (4) 10 Mb half-duplex.
The auto-negotiation logic will attempt to operate in descending order and will normally
arrive at the highest order mode that both devices can support at that time. (Since auto-
negotiation is potentially an externally controlled process, the original “highest order
mode” result can change at any time depending on network changes that may occur). If
the device at the other end is not an auto-negotiating device, the 6KL’s RJ-45 ports will
try to detect its idle signal to determine 10 or 100 speed, and will default to half-duplex
at that speed per the IEEE standard.
General information -
Auto-negotiation per-port for 802.3u-compliant switches occurs when:
-- the devices at both ends of the cable are capable of operation at either
10Mb or 100Mb speed and/or in full- or half-duplex mode, and can
send/receive auto-negotiation pulses, and . . .
-- the second of the two connected devices is powered up*, i.e., when
