Network Administrator Nightmare "Network Looping"

What hardware do you have for switches and routers?

Do you have Border Gateway Protocol (BGP) and/or Spanning Tree Protocol (STP) available?

We just have 2 switch in same LAN

The only way I know of to make a loop with just 2 switches is to have 2 or more ethernet cables connecting between those 2 switches. Have you eliminated that possiblity?

Yes

How do you know it is looping, are you experiencing any problems? You could use wireshark which many people use and it inspects packets on the network, you can see where they are coming from and going. http://www.wireshark.org/

let us know what the problem is and perhaps we can help out.

Can you guide me what is the step to detect or analysis using wireshark ,i already install i ca. See many component they..don't knowhow to start

wireshark takes some time to learn, you'll have to just go with the directions and just play with it until you see how it works. Look into Solarwinds as well, they have good free tools.

Are you having a specific problem or just interested in monitoring the network?

The net of it is that you need to answer the questions the experts are asking in detail, one by one.  They asked about the configuration of your network.  They gave specific information regarding how networks may loop.  They asked about how you noticed the loop, what messages you have received, etc.  You should respond to each of these questions in kind and in detail so that they can best assist you.  Wireshark is a complex tool and may be needed to resolve this problem, but that cannot be known until you provide the details being requested...RG

Actually i just want to learn how to detect the looping to prepare this happen on future ,because i have facing few time in my different client site ,usually we will check the switch indicator can know already but i still need to learn how to analysis the packet.thank you