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New Member

VLAN Traffic Monitoring

Hi all

I have a 2900XL core switches which in turn connected to several 2950 switches. All are connected to VLAN 1.

I have a few questions:

When people say broadcast traffic should not be more than 20% of the VLAN traffic.

1. Does it mean the broadcast of a single port in the 2950 switch or the core switch ?

2. How do i know the VLAN traffic ?

Any tools etc and how is the setup?

Hope comeone can help. :)

Thanks in Advance.

Alan

12 REPLIES
Silver

Re: VLAN Traffic Monitoring

If there is VLAN, the broadcast mean within the VLAN because it will not travel outside the VLAN. If there is no VLAN then the broadcast will be in the whole network.

In normal case, the switch will not block the port if there is broadcast storm. You have to configure it. Please check below :

http://www.cisco.com/en/US/products/hw/switches/ps637/products_configuration_guide_chapter09186a008007e838.html

Could you explain more about the second question ?

New Member

Re: VLAN Traffic Monitoring

Hi Jack

Thanks for your help. With regard to the second question, what I mean is

How do I monitor the VLAN and broadcat traffic respectively. What tool do i need.

I am using a 2900XL as my core switch and 2950 as my other switches.

Thanks in advance.

Blue

Re: VLAN Traffic Monitoring

an excellent tool for monitoring traffic would be a sniffer. (aka protocol analyzer)

http://ethereal.com has the best freeWare sniffer. with this tool, you can view each and every broadcast packet or just graph the percentage of broadcasts vs other types of traffic.....(many more features)

New Member

Re: VLAN Traffic Monitoring

THanks, a question, if using a ethereal , how do I use it to monitor traffic on a particular VLAN

Thanks in Advance

Re: VLAN Traffic Monitoring

Hi

Connect a PC/laptop with the sniffer software and connect it to a port on the core switch 2900XL and span the VLAN. Your VLAN will your source traffic and the PC would be your destination.

Say if you want to capture vlan 2 statistics and you connect your PC to port 10, configure the following commands and start ethereal.

Monitor session 1 source vlan 2

monitor session 1 destination interface fa 0/10

HTH

Narayan

New Member

Re: VLAN Traffic Monitoring

Thanks for the reply. Do I have to setup anything on the Ethereal. Any parameter to configure?

Someone please help. Thanks

Re: VLAN Traffic Monitoring

Just plug the laptop and start the application

It will start the capture.

Capture for about 5 minutes and analyse

HTH

Please rate useful posts

Narayan

Re: VLAN Traffic Monitoring

Hi Narayanan,

This is Guru Prasad.R from Saksoft Ltd. I am working as Network Engineer for past 1 year here. Also i had worked as part-time technical assistace in Networking Environment for 3 years too.

Since, i am new guy to this networking world i may require your guidance, support for making my career the best one.

I had finished my CCNA & 2-MCP exams one for Server 03 & another for Exchange Server 03. Also currently i doing with CCNP-Switching[BCMSN] exam.

Kindly help me to make my career the best one. Expeting your kindness on the same.

I had noted down ur contact number in Cisco profile. Below given my contact details:

Guru Prasad.R

Mobile: +91-9840822258

Mail id: itguruprasad@yahoo.com

Expecting your reply mail for the same.

Thanks & Regards,

Guru Prasad .R

Re: VLAN Traffic Monitoring

Hi Guru,

This is not the right forum to post these questions.

Narayan

New Member

Re: VLAN Traffic Monitoring

Hi, thanks for your reply. From the packet capture, how do i know which one is my vlan traffic. I have only vlan 1.

THnaks in advance for your advice as i am not very good in traffic analysing.

Regards

Alan

Re: VLAN Traffic Monitoring

Hi Alan,

If you have only one vlan, this is your VLAN traffic.

HTH

Narayan

New Member

Re: VLAN Traffic Monitoring

Hi Narayan

Thanks for all your kind and patience help. I will try and past again if I have any problem. Thanks again.

Regards

Alan

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