Why 100Mbps and not 1Gps on the interface?

Question

Computer networks

There are computers with network cards: Intel(R) 82579LM Gigabit Network Adapter.
And there are switches: Cisco Catalyst 4500 Series Switches
And everything is connected by a twisted pair cable of category 5e.
Why does Windows show a speed of 100Mbps?
On tsiska: show int gi3/28 issues: Full-duplex, 100Mb/s; BW 100000 Kbps.
How to make gigabit?

Answer 1

Depending on how crimped, maybe you have 4 wires in total involved.

Answer 2

Show the output from the switch:
Show network card settings (duplex, speed, mdi/mdi-x).

Why does Windows show a speed of 100Mbps?

Possible causes: incorrect settings, problematic patch cord, problematic transceivers (unlikely, but possible).

How to make gigabit?

Determine and eliminate the cause of such a mode of operation of the equipment.

Answer 3

The length of the twisted pair is a comp-switch, the quality of the twisted pair (copper, copper-plated), the quality of the line (twisting, sockets), the correctness of the crimp.
Most likely the cable is long, or two pairs are crimped.
Try a normal patch cord from the store, connect a couple of meters to the switch and see the reaction.

Answer 4

If the patch is correct and short (that is, interference and interference are excluded), then we forcibly turn on 1G on both sides and check.