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Link between Cisco C4506-E & C2950 is down when speed & duplex is NOT Auto

Hi All


I have C2950 running with 12.1(22)EA13 having uplinks connected to C4506-E (1) & C4506-E (2) 15.0(2)SG.

STP.JPG

Speed and duplex are default settings [Speed is auto & duplex is full]. Link between C4506E(1) Gi2/35 <<-->> C2950 Gi 0/1 is negotiated to Speed 1000 & Duplex full. Whereas other link C4506E(2) Gi 2/35 <<-->> C2950 Gi 0/2 is negotiated to Speed 100 & Duplex full.

I tried to configure link C4506E(2) Gi 2/35 <<-->> C2950 Gi 0/2 manual negotiation with speed 1000 & duplex full on both the end interfaces and found link is down.

Why one uplink negotiation happened to be 100 when other is negotiated to 1000 ?

Is there any bug identified with the current running IOS.?
Need help is fixing the problem.


Thanks in advance.

Everyone's tags (2)
6 REPLIES
Hall of Fame Super Gold

Link between Cisco C4506-E & C2950 is down when speed & duplex i

What happens if you set the link to 100 Mbps only?

Re: Link between Cisco C4506-E & C2950 is down when speed & dupl

I have configured MST with two instances and planned that C4506E(1) should be root for MST 10 and C4506E(2) is root for MST 11.

Due to this problem, i see that  STP for C2950 Gi 0/2 is in blocking state

XXXX-XXXX#sh spanning-tree root

                                        Root Hello Max Fwd

MST Instance           Root ID          Cost  Time Age Dly  Root Port

---------------- -------------------- ------ ----- --- ---  ----------------

MST00            24576 8843.e1bd.6a00      0    2   20  15  Gi0/1               

MST10            24586 8843.e1bd.6a00  20000    2   20  15  Gi0/1               

MST11            24587 8843.e1bd.6940  22000    2   20  15  Gi0/1

Reason:

XXXX-XXXX#sh int gi 0/1 | i dupl

  Full-duplex, 1000Mb/s, media type is RJ45

XXXX-XXXX#sh int gi 0/2 | i dupl

  Full-duplex, 100Mb/s, media type is RJ45

Actual my requirement is -


XXXX-XXXX#sh spanning-tree root

                                        Root Hello Max Fwd

MST Instance           Root ID          Cost  Time Age Dly  Root Port

---------------- -------------------- ------ ----- --- ---  ----------------

MST00            24576 8843.e1bd.6a00      0    2   20  15  Gi0/1               

MST10            24586 8843.e1bd.6a00  20000    2   20  15  Gi0/1               

MST11            24587 8843.e1bd.6940  22000    2   20  15  Gi0/2

Re: Link between Cisco C4506-E & C2950 is down when speed & dupl

Link goes down if i set it to 100 Manually.

Hall of Fame Super Gold

Link between Cisco C4506-E & C2950 is down when speed & duplex i

Wait a second ... What is the exact model of your 2950 switch?

Link between Cisco C4506-E & C2950 is down when speed & duplex i

Model : WS-C2950T-48-SI

Hall of Fame Super Gold

Link between Cisco C4506-E & C2950 is down when speed & duplex i

On the 2950, can you post the output to the command "sh interface g0/1 capa"?

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