Loop prevention issue in network switch

In layer 2 network environment especially in big network that running in spanning tree protocol, loop will always occurred.  When loop happen network will become congest and every user will be affected. Unless the network run in layer 3 environment than loop will only affect that switch only.

The issue is looping always happen in 3rd party unmanaged mini-switch. Refer to diagram below for a better understand.

How to connect Extremenetworks Summitx150 to a 3Com 5500G series

Today I learn a lesson that if you want to connect a Extremenetworks switch(SummitX150) to 3com 5500G series via layer 2 please remove pvid vlan management. Let say if your extremenetworks switch contain 2 vlan example vlan 2 is for pc and vlan 3 is for network management i.e. for remote access via telnet or ssh. What you need to do is to remove the pivd vlan in the interface that directly connect to extremenetworks switch.

3COM 5500G
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