Magnum 4K220 Switches Installation and User Guide (10/04)
6
www GarrettCom com
.
.
applications telcos, ISPs, broadcast equipment, medical, brokerage firm and financial
facilities.
2.2.3
Up-link port #39 for Cascading
The 4K220CR unit has an Up-link switch, located next to the port#
(39). The thumb-operated slide switch enables the port’s RJ-45 cable to either connect
to a user station or to be cascaded to another hub, when in the cross-over position. (See
Section 4.4 for more details about Up-link). Like all 4K220C ports, Port # 39 is a dual-
speed switched port which will sense the speed of the connected device. Use port # 39
in x-position on one 4K220CR and port 1 (or any port) on the second, i.e., use only one
crossover port for a cascaded connection.
When the Up-link port is used to cascade two 4K220C together, the auto-
sensing feature will cause the connecting up-link to operate at 100Mb FDX speed.
2.2.4
4K220C, 10/100 F/H dual-speed switched ports, RJ-45 (copper
only)
The Magnum 4K220CR has 40 switched RJ-45 ports that are dual speed
10/100Mbps and Auto-negotiating. The 10/100Mb switched ports are independently N-
way auto-negotiating for operation at 10 or 100Mb speed in full- or half-duplex mode
(as a default setting). They independently move to half-duplex mode at 10 Mb or at
100Mb speed if the device at the other end of the twisted pair cable is half-duplex or is
not an auto-negotiating device.
There are three LED’s for each port. The LK/Act (Link/Activity) steady ON
indicates Link with no traffic, and blinking indicates the port is receiving and
transmitting. The Speed LED indicates operation at 100Mb speed when ON and at 10
Mb speed when OFF (when auto-negotiation is enabled). The Fdx/Col LED is ON to
indicate full-duplex operation and OFF to indicate half-duplex mode and collisions. A
twisted pair cable must be connected into each RJ-45 10/100Mb port and a proper Link
(LK lit) must be made with the device at the other end of the cable in order for the
LEDs to provide valid indications of operating conditions.
2.2.5
Frame Buffering and Latency
The Magnum 4K220CR is a store-and-forward switch. Each frame (or
packet) is loaded into the Switch’s memory and inspected before forwarding can occur.
This technique ensures that all forwarded frames are of a valid length and have the
correct CRC, i.e., are good packets. This eliminates the propagation of bad packets,
