for another of the opposite type. This provides a quick check of the cable, and sub-
stituting a straight-through cable for a cross-over cable may lead to evidence of
equipment that is mislabeled or misconfigured. Note that Ethernet uses wires 1, 2,
3, and 6. While T1 circuits on RJ-45 use wires 1, 2, 4, and 5. Swapping different
cross-over cables will also lead to problems--for example, if a T1 cross-over is
used for an Ethernet connection.
routing and trunking. Routing and trunking within the Catalyst system may
include an RSM, or route switch module, which is a 400Mbit 7500 series
router on a card that operates within the Catalyst chassis. Trunking may
incorporate one of many protocols, including ISL, 802.10, 802.1q, and
ATM LANE. The effect of trunking is the same, however. A single physical
medium may be used to connect multiple VLANs (or ELANs) between
switches and routers.
switched networks is the port isolation inherent in switches. Such isolation
prevents the use of a protocol analyzer in a switched environment, without
connecting directly to the wire between the switch and workstation, and
such a connection cannot be full-duplex, as a general rule.
switch is commanded to copy all packets that would be sent to the worksta-
tion interface to another port as well. This port is not assigned a VLAN--it
takes on the identity of the original port.
[rx|tx|both]