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Troubleshooting Ethernet Problems

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175 collisions/1165 output packets = 15.02% collisions

443 collisions/2858 output packets = 15.5% collisions

889 collisions/5590 output packets = 15.9% collisions

1020 collisions/6000 output packets = 17.0% collisions

All of these values are well in excess of 5 to 8 percent. It looks like a key

observation has been made, and now the problem statement can be written.
The collision percentage on Ethernet 0/1 exceeds healthy values and can be
blamed for causing slow network throughput.

Propose Solutions

The hard part is to determine what is causing the collisions. In this scenario, solu-
tions will be tried from Layer 1 up to Layer 2. Following are possible solutions:

Replace a faulty cable

Replace a faulty transceiver

Replace a faulty interface by changing the router

The proposed solutions are to test the cable--if the cable passes, then

change the transceiver. If that doesn't help, assume that the interface on the
router has gone bad. If the latter is the problem, the problem may be solved
by moving the connection to another interface on the same router or to a dif-
ferent interface on a different router.

Figure 5.6 depicts the physical hardware involved in this scenario. The

cable connects to the hub and to a transceiver that is connected to the
router's AUI interface.

F I G U R E 5 . 6

Ethernet physical hardware

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