Another 2950 /3560 Connection

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Sep 13th, 2007
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I mistakenly posted this as a reply to someone else's question, but was not sure if it woul dbe seen by th ewhole group or just the person who replied....


I am also trying to connect a 24 port 2950 to a 24 port 3560 switch using a crossover cable between port 24 on each. I have tried using the following commands via hyper terminal: 2950:

int FA0/24

speed 100

duplex full

no snmp trap link-status

no logging event link-status

switchport mode trunk

!


and 3560:

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport mode trunk

no logging event link-status

speed 100

duplex full

no snmp trap link-status

!


However, about 20-30 seconds after I connect the crossover cable, the used port LED's on the 3560 switch blink 4-5 times per sec, vs ~1 per second with the cable disconnected, as if it has far more traffic. This causes issues with our devices. Can anyone tell me if this is the correct way to do what I am trying to do, or is there a better way? I also have the network assistant, but am unclear where/how to make the proper changes. Any help would be appreciated.




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royalblues Thu, 09/13/2007 - 13:42
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What type of issue are you seeing when you conenct the switches?


Are you seeing any errors on the interfaces connecting between these switches


Narayan

tweety1969 Thu, 09/13/2007 - 13:55
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Hi,


I noticed that you have not specified dot 1q encapsulation switchport trunk encapsulation dot1q on the fa 0/24 port of the 2950. Doe the 2950 default to isl encapsulation? I hope you resolve this issue i will watch with interest, Regards.


Andrew.

ankbhasi Thu, 09/13/2007 - 22:43
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Hi Andrew,


2950 only support dot1q so that command will not work on this switch.


Jon


Coming to the original post can you confirm what type of traffic you are having in your network. Also do you see any issues in your network or you are concerned with blinking LEDs?


Regards,


Ankur

rossiter1 Fri, 09/14/2007 - 03:54
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I am working today to capture what kind of extra traffic is present when I connect the ports using Ethereal or something similar, however the issue we see is that some of the devices (cognex vision systems) on the network get slow or disconnect. The reason I mentioned the LED's is because I did not have the data to decribe the traffic. The LED's is a quick easy way to know more packets are being sent.

rossiter1 Fri, 09/14/2007 - 04:20
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I am working today to capture what kind of extra traffic is present when I connect the ports using Ethereal or something similar, however the issue we see is that some of the devices (cognex vision systems) on the network get slow or disconnect. The reason I mentioned the LED's is because I did not have the data to decribe the traffic. The LED's is a quick easy way to know more packets are being sent.

rossiter1 Fri, 09/14/2007 - 11:09
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Just an update... I used Ethereal to analyze the data on the two switches and found that most/if not all of the additional data was due to multi-casting from Rockwell Automation PLCs. I filtered out the multi-cast and the problem went away. On the ocnnetcing port it is still quite fast, but on all other ports it is fine.

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