Catalyst 2970 Port Speed

Unanswered Question
Jan 31st, 2007

I have Catalyst 2970 Switch running on defualt configurations, NO VLAN, NO IP Addressing, FULL DUPLEX, AUTO SPEED.

When i connect 1000Mbps System with this switch, few port shows connectivity at 1000 Mbps and few port shows connectivity at 100 Mbps.

I am unable to rectify this problem, can any one help me in this regard


I have this problem too.
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mheusinger Wed, 01/31/2007 - 04:30


unfortunately speed and duplex negotiation will not always give you the desired results. The recommendation in this case is to set speed and duplex to the desired values and not to use autonegotiation.

If you are sure both ports interconnected do support GigE then set the speed to 1000 and duplex to full.

Regards, Martin

sharafat1978 Thu, 02/01/2007 - 00:45

Thanks for ur support but all ports were working fine and all were showing 1000Mbps, then how they get auto change their status.

What could be the cause,.,. bcz i want to send back these switches to supplier.

ohassairi Thu, 02/01/2007 - 01:56

it could be a quality degradation in cables

try direct connection using short and new cables cat6.

sharafat1978 Thu, 02/01/2007 - 04:51

i have already tried this, i am using standard TYCO cat 6 patch cables.

cmccormick Fri, 02/02/2007 - 21:25

Try asking the switch what it sees...

test cable-diagnostics tdr int gi0/1

then after a few seconds:

show cable-diagnostics tdr interface gigabitEthernet 0/1

glen.grant Sat, 02/03/2007 - 07:07

I would look at the nic settings on these systems to see what they are set as , switch settings don't matter if the nic settings are set as something else . The switch can always sense speed ok but if the nic is set as something else then it will set the speed to the nic speed . Also you must verify the patch cables even if new , the cables must have 4 good pairs end to end as gigabit speeds take all 8 conductors , if you have 1 bad wire anywhere in that connection path it will default to 100 meg .

sharafat1978 Sat, 02/03/2007 - 07:58

Thanks for ur precious effort but i have checked all the ports of the switch with same nic and same cable,


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