Regarding Bandwidth Congestion on Trunks

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Dec 11th, 2009
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Greetings… I’ve been facing bandwidth congestion problem between two switches (Cisco 3550 and Cisco 3524XL).  At times I see high transmit and receive load on the trunk connecting these two switches. I tried configuring net flow on these two switches but I guess net flow is not supported in this entire series (Cisco 3500 Series). Even no output is seen in “show ip accounting”. Can somebody advice me how exactly can I spot the high bandwidth consumers on these two switches.

Is there any device or software that can help me out with this problem (to spot the top talkers) or any other methodology (irrespective of IOS) to achieve the same?


Mayank Nauni

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Ganesh Hariharan Fri, 12/11/2009 - 10:15
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For sniffing the traffic configure  a span port on trunk and using tools like sinffer pro you can see which host is consuming how much amount of bandwidth and what type of traffic.



Giuseppe Larosa Fri, 12/11/2009 - 10:19
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Hello Mayank,

before trying to capture traffic on the trunk link.

How many vlans are permitted on the trunk link?

if you don't use switchport trunk allowed vlan or VTP pruning you can have unnecessary broadcast traffic moving on the trunk link.

first method is to be preferred because it helps also in minimizing the number of STP instances running on each switch.

Hope to help



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