.Which type of network connection requires a straight-through cable?
A. host to host
B. switch to router
C. switch to switch
D. host to router’s Ethernet port
Correct Answer: B
A switch to router connection requires a straight-through cable. Straight-through cables are also used for host to switch communication.
A crossover cable is used to connect “like” devices, and a straight through cable is used when connecting “unlike” devices. The one exception to this rule is when connecting a
computer NIC to an Ethernet port on a router, a crossover cable is used. In summary, the following list describes when to use crossover and straight through cables:
Host to host Crossover
Host NIC to router Crossover
Host to switch Straight through
Switch to Switch Crossover
Switch to router Straight through
The difference between straight-through and crossover lies in the location of the wire termination on the two ends of an RJ-45 cable. If the unshielded twisted-pair (UTP) cable wire
connects Pin 1 of one side to Pin 1 of other side and Pin 2 to 2 through all eight Pins of the RJ-45 connector, the cable is said to be straight-through.
On the other hand, if the Pin 1 of one side RJ-45 cable connected to Pin 3 of other end and Pin 2 connects to Pin 6 of other side, it is called as crossover cable. The cable type to be
used depends upon circuit connection on the hardware. Some devices have ports that are capable of identifying the cable type and automatically adjusting the port setting to be a
standard or uplink port.
Host-to-host, switch-to-switch, and host-to-Ethernet-port would all use a crossover cable to connect in the network. The following figure shows the pin layout for a crossover cable:
Select the appropriate cabling type based on implementation requirements
Cisco > Product Support > End-of-Sale and End-of-Life Products > Cisco 7000 Series Routers > Troubleshooting Technotes > Cabling Guide for Console and AUX Ports > Document