Hi there Tech-xperts,
I have a 2800 router and 3750 switch that will not operate at Gigabit speed. I've tried various combinations of fixed/auto speed and duplex settings, but they only seem to talk to each other when set to 100Mb.
Any fixes or suggestion greatly appreciated.
2821 router 12.4(20)T1
3750 switch Version 12.2(25)FZ
(3750 is actually a WS-C3750G-24WS-S25)
These are directly connected via a UTP cable.
The router interface config:
no ip address
encapsulation dot1Q 500 native
ip address 10.10.150.1 255.255.255.0
encapsulation dot1Q 520
ip address 10.10.120.1 255.255.255.0
encapsulation dot1Q 521
ip address 10.10.121.1 255.255.255.0
The switch interface config:
description rtr INMRTR01 via Riverbed
power inline never
switchport trunk encapsulation dot1q
switchport trunk native vlan 500
switchport mode trunk
I would say you have a faulty patch cable if it won't negotiate gig speed with both sides as auto. Gigabit uses all 8 wires to achieve gig whereas it uses 1,2,3,6 for any lower speeds . So if you don't have 8 good wires in your patch cable or connection between these 2 devices you won't get gig speed.